To see the other types of publications on this topic, follow the link: Bypass.
Journal articles on the topic 'Bypass'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Bypass.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Abla, Adib A., Cameron M. McDougall, Jonathan D. Breshears, and Michael T. Lawton. "Intracranial-to-intracranial bypass for posterior inferior cerebellar artery aneurysms: options, technical challenges, and results in 35 patients." Journal of Neurosurgery 124, no. 5 (May 2016): 1275–86. http://dx.doi.org/10.3171/2015.5.jns15368.
Full textAbstract:
OBJECT Intracranial-to-intracranial (IC-IC) bypasses are alternatives to traditional extracranial-to-intracranial (EC-IC) bypasses to reanastomose parent arteries, reimplant efferent branches, revascularize branches with in situ donor arteries, and reconstruct bifurcations with interposition grafts that are entirely intracranial. These bypasses represent an evolution in bypass surgery from using scalp arteries and remote donor sites toward a more local and reconstructive approach. IC-IC bypass can be utilized preferentially when revascularization is needed in the management of complex aneurysms. Experiences using IC-IC bypass, as applied to posterior inferior cerebellar artery (PICA) aneurysms in 35 patients, were reviewed. METHODS Patients with PICA aneurysms and vertebral artery (VA) aneurysms involving the PICA’s origin were identified from a prospectively maintained database of the Vascular Neurosurgery Service, and patients who underwent bypass procedures for PICA revascularization were included. RESULTS During a 17-year period in which 129 PICA aneurysms in 125 patients were treated microsurgically, 35 IC-IC bypasses were performed as part of PICA aneurysm management, including in situ p3-p3 PICA-PICA bypass in 11 patients (31%), PICA reimplantation in 9 patients (26%), reanastomosis in 14 patients (40%), and 1 V3 VA-to-PICA bypass with an interposition graft (3%). All aneurysms were completely or nearly completely obliterated, 94% of bypasses were patent, 77% of patients were improved or unchanged after treatment, and good outcomes (modified Rankin Scale ≤ 2) were observed in 76% of patients. Two patients died expectantly. Ischemic complications were limited to 2 patients in whom the bypasses occluded, and permanent lower cranial nerve morbidity was limited to 3 patients and did not compromise independent function in any of the patients. CONCLUSIONS PICA aneurysms receive the application of IC-IC bypass better than any other aneurysm, with nearly one-quarter of all PICA aneurysms treated microsurgically at our center requiring bypass without a single EC-IC bypass. The selection of PICA bypass is almost algorithmic: trapped aneurysms at the PICA origin or p1 segment are revascularized with a PICA-PICA bypass, with PICA reimplantation as an alternative; trapped p2 segment aneurysms are reanastomosed, bypassed in situ, or reimplanted; distal p3 segment aneurysms are reanastomosed or revascularized with a PICA-PICA bypass; and aneurysms of the p4 segment that are too distal for PICA-PICA bypass are reanastomosed. Interposition grafts are reserved for when these 3 primary options are unsuitable. A constructive approach that preserves the PICA with direct clipping or replaces flow with a bypass when sacrificed should remain an alternative to deconstructive PICA occlusion and endovascular coiling when complete aneurysm occlusion is unlikely.
2
Finlay, Erik, Sam Palmer, Benjamin Abes, Benjamin Abo, and Jennifer Fishe. "Clinical, Operational, and Socioeconomic Analysis of EMS Bypass of the Closest Facility for Pediatric Asthma Patients." Western Journal of Emergency Medicine 22, no. 4 (July 15, 2021): 972–78. http://dx.doi.org/10.5811/westjem.2021.4.50382.
Full textAbstract:
Introduction: Pediatric hospital care is becoming increasingly regionalized, with fewer facilities providing inpatient care for common conditions such as asthma. That trend has major implications for emergency medical services (EMS) medical care and operations because EMS historically transports patients to the closest facility. This study describes EMS transport patterns of pediatric asthma patients in greater depth, including an analysis of facility bypass rates and the association of bypass with demographics and clinical outcomes. Methods: This was a retrospective study of pediatric asthma patients ages 2-18 years transported by Lee County, FL EMS between March 1, 2018 – December 31, 2019. A priori, we defined bypass as greater than five minutes extra transport time. We performed geospatial analysis and mapping of EMS pediatric asthma encounters. We used the Pediatric Destination Tree (PDTree) project’s tiered approach to characterize receiving hospital facility pediatric capability. We analyzed incidence and characteristics of bypass, and bypass and non-bypass patient characteristics including demographics, emergency department (ED) clinical outcomes, and socioeconomic disadvantage (SED). Results: From the study period, there were a total of 262 encounters meeting inclusion criteria, 254 (96.9%) of which could be geocoded to EMS incident and destination locations. Most encounters (72.8%) bypassed at least one facility, and the average number of facilities bypassed per encounter was 1.52. For all 185 bypass encounters, there was a median additional travel time of 13.5 minutes (interquartile range 7.5 – 17.5). Using the PDTree’s classification of pediatric capability of destination facilities, 172 of the 185 bypasses (93%) went to a Level I facility. Bypass incidence varied significantly by age, but not by minority status, asthma severity, or by the area deprivation index of the patient’s home address. Overall, the highest concentrations of EMS incidents tended to occur in areas of greater SED. With regard to ED outcomes, ED length of stay did not vary between bypass and non-bypass patients (P = 0.54), and neither did hospitalization (P = 0.80). Conclusion: We found high rates of bypass for pediatric EMS encounters for asthma exacerbations, and that bypass frequency was significantly higher in younger age groups. With national trends pointing toward increasing pediatric healthcare regionalization, bypass has significant implications for EMS operations.
3
Tayebi Meybodi, Ali, Wendy Huang, Arnau Benet, Olivia Kola, and Michael T. Lawton. "Bypass surgery for complex middle cerebral artery aneurysms: an algorithmic approach to revascularization." Journal of Neurosurgery 127, no. 3 (September 2017): 463–79. http://dx.doi.org/10.3171/2016.7.jns16772.
Full textAbstract:
OBJECTManagement of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options.METHODSAneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm.RESULTSBetween 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery–MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up.CONCLUSIONSThe bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.
4
Sanai, Nader, Zsolt Zador, and Michael T. Lawton. "BYPASS SURGERY FOR COMPLEX BRAIN ANEURYSMS." Neurosurgery 65, no. 4 (October 1, 2009): 670–83. http://dx.doi.org/10.1227/01.neu.0000348557.11968.f1.
Full textAbstract:
Abstract OBJECTIVE Bypass surgery for brain aneurysms is evolving from extracranial-intracranial (EC-IC) to intracranial-intracranial (IC-IC) bypasses that reanastomose parent arteries, revascularize efferent branches with in situ donor arteries or reimplantation, and reconstruct bifurcated anatomy with grafts that are entirely intracranial. We compared results with these newer IC-IC bypasses to conventional EC-IC bypasses. METHODS During a 10-year period, 82 patients underwent bypass surgery as part of their aneurysm management. A quarter of the patients presented with ruptured aneurysms and two-thirds presented with compressive symptoms from unruptured aneurysms. Most aneurysms (82%) had non-saccular morphology and 56% were giant sized. Common locations included the cavernous internal carotid artery (23%), middle cerebral artery (20%), and posteroinferior cerebellar artery (12%). RESULTS Forty-seven patients (57%) received EC-IC bypasses and 35 patients (43%) received IC-IC bypasses, including 9 in situ bypasses, 6 reimplantations, 11 reanastomoses, and 9 intracranial grafts. Aneurysm obliteration rates were comparable in EC-IC and IC-IC bypass groups (97.9% and 97.1%, respectively), as were bypass patency rates (94% and 89%, respectively). Three patients died (surgical mortality, 3.7%), and 4 patients were permanently worse as a result of bypass occlusions (neurological morbidity, 4.9%). At late follow-up (mean duration, 41 months), good outcomes (Glasgow Outcome Scale score 5 or 4) were measured in 68 patients (90%) overall, and were similar in EC-IC and IC-IC bypass groups (91% and 89%, respectively). Changes in Glasgow Outcome Scale score were slightly more favorable with IC-IC bypass (6% worse or dead after IC-IC bypass versus 14% with EC-IC bypass). CONCLUSION IC-IC bypasses compare favorably to EC-IC bypasses in terms of aneurysm obliteration rates, bypass patency rates, and neurological outcomes. IC-IC bypasses can be more technically challenging to perform, but they do not require harvest of extracranial donor arteries, spare patients a neck incision, shorten interposition grafts, are protected inside the cranium, use caliber-matched donor and recipient arteries, and are not associated with ischemic complications during temporary arterial occlusions. IC-IC bypass can replace conventional EC-IC bypass with more anatomic reconstructions for selected aneurysms involving the middle cerebral artery, posteroinferior cerebellar artery, anterior cerebral artery, and basilar apex.
5
Bremmer, Jochem P., Bon H. Verweij, Catharina J. M. Klijn, Albert van der Zwan, L. Jaap Kappelle, and Cornelis A. F. Tulleken. "Predictors of patency of excimer laser–assisted nonocclusive extracranial-to-intracranial bypasses." Journal of Neurosurgery 110, no. 5 (May 2009): 887–95. http://dx.doi.org/10.3171/2008.9.jns08646.
Full textAbstract:
Object Excimer laser–assisted nonocclusive anastomosis (ELANA) is a technique that can be used for extracranial-to-intracranial (EC-IC) bypasses, without the necessity of temporary occlusion of the donor or recipient artery. Information on predictors of patency of EC-IC bypasses in general and the ELANA bypass in particular is sparse. The authors studied 159 ELANA EC-IC bypasses to find predictors of patency. Methods From a prospective database of patients who underwent EC-IC bypass surgery, 143 consecutive patients who underwent a total of 159 ELANA bypasses were studied. The associations of patient characteristics, surgical aspects, and technical aspects specific to the ELANA technique with intraoperative and postoperative bypass patency were studied using logistic regression analysis. Results At the end of the operation, 146 (92%) of the 159 bypasses were patent. A first attempt to create a bypass was almost 8 times more likely (OR 7.6, 95% CI 2.1–27.5; p = 0.02) to result in a patent bypass than a second attempt. Administration of a small amount of heparin during the operation was also associated with bypass patency (OR 5.2, 95% CI 1.1–24.9; p = 0.04). One hundred twenty-three (77%) of the 159 bypasses were functional at patency assessments during the 1st month after the operation. Older age (OR 1.043 for every year of increase in age, 95% CI 1.010–1.076; p = 0.01), male sex (OR 2.9, 95% CI 1.3–6.5; p = 0.01), and high intraoperative bypass flow (OR 1.017 for every milliliter per minute increase in flow, 95% CI 1.004–1.030; p = 0.01) were associated with postoperative bypass patency. Conclusions Attempts to create a second EC-IC ELANA bypass after the first one are more likely to fail, whereas administration of heparin to the patient during the procedure increases the intraoperative bypass patency rate. Postoperative patency results are better in male and in older patients. Intraoperative bypass flow measurements are essential because high bypass flow is an important determinant of postoperative patency.
6
Stapleton, Christopher J., Gursant S. Atwal, Ahmed E. Hussein, Sepideh Amin-Hanjani, and Fady T. Charbel. "The cut flow index revisited: utility of intraoperative blood flow measurements in extracranial-intracranial bypass surgery for ischemic cerebrovascular disease." Journal of Neurosurgery 133, no. 5 (November 2020): 1396–400. http://dx.doi.org/10.3171/2019.5.jns19641.
Full textAbstract:
OBJECTIVEIn extracranial-intracranial (EC-IC) bypass surgery, the cut flow index (CFI) is the ratio of bypass flow (ml/min) to donor vessel cut flow (ml/min), and a CFI ≥ 0.5 has been shown to correlate with bypass patency. The authors sought to validate this observation in a large cohort of EC-IC bypasses for ischemic cerebrovascular disease with long-term angiographic follow-up.METHODSAll intracranial bypass procedures performed at a single institution between 2003 and 2018 were reviewed. Demographic, clinical, angiographic, and operative data were recorded and analyzed according to bypass patency with univariate and multivariate statistical analyses.RESULTSA total of 278 consecutive intracranial bypasses were performed during the study period, of which 157 (56.5%) were EC-IC bypasses for ischemic cerebrovascular disease. Intraoperative blood flow measurements were available in 146 patients, and angiographic follow-up was available at a mean of 2.1 ± 2.6 years after bypass. The mean CFI was significantly higher in patients with patent bypasses (0.92 vs 0.64, p = 0.003). The bypass patency rate was 83.1% in cases with a CFI ≥ 0.5 compared with 46.4% in cases with a CFI < 0.5 (p < 0.0001). Adjusting for age, sex, diagnosis, and single versus double anastomosis, the CFI remained a significant predictor of bypass patency (p = 0.001; OR 5.8, 95% CI 2.0–19.0). A low CFI was also associated with early versus late bypass nonpatency (p = 0.008).CONCLUSIONSA favorable CFI portends long-term EC-IC bypass patency, while a poor CFI predicts eventual bypass nonpatency and can alert surgeons to potential problems with the donor vessel, anastomosis, or recipient bed during surgery.
7
Klopries, Elena-Maria, Zhiqun Daniel Deng, Theresa U. Lachmann, Holger Schüttrumpf, and Bradly A. Trumbo. "Surface bypass as a means of protecting downstream-migrating fish: lack of standardised evaluation criteria complicates evaluation of efficacy." Marine and Freshwater Research 69, no. 12 (2018): 1882. http://dx.doi.org/10.1071/mf18097.
Full textAbstract:
Surface bypasses are downstream migration structures that can help reduce hydropower-induced damage to migrating fish. However, no comprehensive design concept that facilitates good surface bypass performance for a wide range of sites and species is available. This is why fish-passage efficiencies at recently built bypass structures vary widely between 0% and up to 97%. We reviewed 50 surface bypass performance studies and existing guidelines for salmonids, eels and potamodromous species to identify crucial design criteria for surface bypasses employed in North America, Europe and Australia. Two-tailed Pearson correlation of bypass efficiency and bypass design criteria shows that bypass entrance area (r=0.3300, P=0.0036) and proportion of inflow to the bypass (r=0.3741, P=0.0032) are the most influential parameters on bypass efficiency. However, other parameters such as guiding structures (P=0.2181, ordinary Student’s t-test) and trash-rack spacing (r=–0.1483, P=0.3951, Spearman correlation), although not statistically significant, have been shown to have an effect on efficiency in some studies. The use of different performance criteria and efficiency definitions for bypass evaluation hampers direct comparison of studies and, therefore, deduction of design criteria. To enable meta-analyses and improve bypass design considerations, we suggest a list of standardised performance parameters for bypasses that should be considered in future bypass-performance studies.
8
Gayá, J., A. Del Río Prego, J. Guilleuma, P. Vela, A. Arribas, J. J. López Parra, and V. Paredero Del Bosque. "Coronary Steal Syndrome." Cardiovascular Surgery 1, no. 2 (April 1993): 186–89. http://dx.doi.org/10.1177/096721099300100221.
Full textAbstract:
A patient who suffered recurrent myocardial ischaemia and cerebrovascular symptoms 56 months after a quadruple coronary bypass is reported. Three coronary arteries had been bypassed using reversed saphenous vein and the other using the left internal mammary artery (IMA). Coronary angiography demonstrated patency of all bypasses but the presence of an obstruction of the left subclavian artery proximal to the origin of the left IMA, with angiographic criteria of the steal syndrome. The patient's symptoms were relieved by bypass from the left common carotid artery to the distal left subclavian artery. The pathophysiology, diagnosis, prevention and treatment of coronary steal syndrome are discussed.
9
Andrawes, Peter A., Masood A. Shariff, John P. Nabagiez, Richard Steward, Basem Azab, Natasha Povar, Mirala Sarza, et al. "Evolution of Minimally Invasive Coronary Artery Bypass Grafting." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 13, no. 2 (March 2018): 81–90. http://dx.doi.org/10.1097/imi.0000000000000483.
Full textAbstract:
Objective Minimally invasive coronary surgery approach for coronary artery bypass grafting is a safe and reproducible procedure for multivessel revascularization. This study reviewed a single surgeon's experience with minimally invasive coronary surgery coronary artery bypass grafting, including operative time, number of bypasses, and conversion to sternotomy. Methods A prospective database of consecutive minimally invasive coronary surgery coronary artery bypass grafting procedures from 2005 to 2013 was reviewed. A small anterolateral left thoracotomy allowed left internal mammary artery harvest, proximal anastomoses on the ascending aorta, and distal coronary anastomoses. Early cases were compared with the later cases, focusing on grafting strategies that led to a standardized approach with Propensity Score Matching analysis. Results Seven hundred consecutive cases were divided into early (1–200) and late (201–700) groups. In the late group, the number of triple-vessel disease patients trended higher (50% vs. 57%, P = 0.0674) and the number of bypasses increased (2.3 ± 0.8 vs. 2.7 ± 1.0, P < 0.0001). Conversion to sternotomy significantly decreased between the groups (6% vs. 0.6%, P < 0.0001). There was no difference in rate of postoperative complications between the groups except for prolonged intubation (10% vs. 5%, P = 0.0236) and shortened length of stay (5.9 ± 6.7 vs. 5.5 ± 6.0, P = 0.0268). Propensity score matching analysis (n = 177) was significant for total bypass performed and time per bypass ( P < 0.05). The late group was further divided into subgroups of one hundred each (subgroup 1 through 5). Operative times differed significantly (subgroup 1: 249 ± 71.2, subgroup 2: 259 ± 85.8, subgroup 3: 244 ± 71.0, subgroup 4: 270 ± 58.4, and subgroup 5: 246 ± 47.9, P < 0.005). Conclusions As experience with minimally invasive coronary surgery coronary artery bypass grafting increased, the ideal sequence of steps to optimize surgical outcome was defined. The number of bypassed vessels increased and the operative time and conversion to sternotomy decreased.
10
Solaković, Emir, Dragan Totić, and Sid Solaković. "Femoro-Popliteal Bypass Above Knee with Saphenous Vein vs Synthetic Graft." Bosnian Journal of Basic Medical Sciences 8, no. 4 (November 20, 2008): 367–72. http://dx.doi.org/10.17305/bjbms.2008.2899.
Full textAbstract:
There is still debate whether sintethic graft (polytetrafluoroethylene or Dacron) is equivalent to vein as bypass graft material for the above-knee femoropopliteal bypass. Therefore, we performed prospective randomized trial to compare vein with polytetrafluoroethylene/dacron for femoropopliteal bypasses with the distal anastomosis above the knee. Between January 2000 and June 2003, 121 femoropopliteal bypasses were performed. The indications for operation were severe claudication in 96 cases, rest pain in 16 cases, and ulceration in 9 cases. After randomization, 60 reversed saphenous venous bypasses and 61 polytetrafluoroethylene/ dacron bypasses were performed. No perioperative mortality was seen, and 5% of the patients had minor infections of the wound, not resulting in loss of the bypass, the limb, or life. After 5 years, 37% of the patients had died and 7% were lost to follow-up. Only once saphenous vein was necessary for coronary artery bypass grafting. Primary patency rates after 5 years were 76,6% for venous bypass grafts and 59,1% for polytetrafluoroethylene/dacron grafts (p=0,035). Secondary patency rates were 83,3% for vein and 69,2% for polytetrafluoroethylene/dacron bypasses (p = 0,036). In the venous group, 10 bypasses failed, leading to four new bypasses. In the polytetrafluoroethylene group, 22 bypasses failed, leading to 12 reinterventions. After 5 years of follow-up, we conclude that a bypass with saphenous vein has better patency rates at all intervals and needs fewer reoperations. Saphenous vein should be the graft material of choice for above-knee femoropopliteal bypasses and should not be preserved for reinterventions. Polytetrafluoroethylene/dacron is an acceptable alternative if the saphenous vein is not available.
11
Yoon, Seungwon, Jan-Karl Burkhardt, and Michael T. Lawton. "Long-term patency in cerebral revascularization surgery: an analysis of a consecutive series of 430 bypasses." Journal of Neurosurgery 131, no. 1 (July 2019): 80–87. http://dx.doi.org/10.3171/2018.3.jns172158.
Full textAbstract:
OBJECTIVELarge cohort analysis concerning intracerebral bypass patency in patients with long-term follow-up (FU) results is rarely reported in the literature. The authors analyzed the long-term patency of extracranial-to-intracranial (EC-IC) and intracranial-to-intracranial (IC-IC) bypass procedures.METHODSAll intracranial bypass procedures performed between 1997 and 2017 by a single surgeon were screened. Patients with postoperative imaging (CT angiography, MR angiography, or catheter angiography) were included and grouped into immediate (< 7 days), short-term (7 days–1 year), and long-term (> 1 year) FU groups. Data on patient demographics, bypass type, interposition graft type, bypass indication, and radiological patency were collected and analyzed with univariate and multivariate (adjusted multiple regression) models.RESULTSIn total, 430 consecutive bypass procedures were performed during the study period (FU time [mean ± SD] 0.9 ± 2.2 years, range 0–17 years). Twelve cases were occluded at FU imaging, resulting in an overall cumulative patency rate of 97%. All bypass occlusions occurred within a week of revascularization. All patients in the short-term FU group (n = 76, mean FU time 0.3 ± 0.3 years) and long-term FU group (n = 89, mean FU time 4.1 ± 3.5 years) had patent bypasses at last FU. Patients who presented with aneurysms had a lower rate of patency than those with moyamoya disease or chronic vessel occlusion (p = 0.029). Low-flow bypasses had a significantly higher patency rate than high-flow bypasses (p = 0.033). In addition, bypasses with one anastomosis site compared to two anastomosis sites showed a significantly higher bypass patency (p = 0.005). No differences were seen in the patency rate among different grafts, single versus bilateral, or between EC-IC and IC-IC bypasses.CONCLUSIONSThe overall bypass patency of 97% indicates a high likelihood of success with microsurgical revascularization. Surgical indication (ischemia), low-flow bypass, and number of anastomosis (one site) were associated with higher patency rates. EC-IC and IC-IC bypasses have comparable patency rates, supporting the use of intracranial reconstructive techniques. Bypasses that remain patent 1 week postoperatively and have the opportunity to mature have a high likelihood of remaining patent in the long term. In experienced hands, cerebral revascularization is a durable treatment option with high patency rates.
12
Mohit, Alex A., Laligam N. Sekhar, Sabareesh K. Natarajan, Gavin W. Britz, and Basavaraj Ghodke. "High-flow Bypass Grafts in the Management of Complex Intracranial Aneurysms." Operative Neurosurgery 60, suppl_2 (February 1, 2007): ONS—105—ONS—123. http://dx.doi.org/10.1227/01.neu.0000249243.25429.ee.
Full textAbstract:
Abstract THE MAJORITY OF intracranial aneurysms can be treated by either endovascular coiling or microsurgical clipping. A small group of aneurysms may require vascular bypass or reconstruction for their management. A variety of vascular reconstruction techniques are available, including direct suture, patch grafting, local reimplantations, side to side anastomosis, and bypass grafts. Bypass grafts may include low-flow (superficial temporal to middle cerebral) and high-flow bypass grafts using either the radial artery or saphenous vein. In this article, the indications and techniques of high-flow bypasses and concurrent aneurysm management are discussed. Troubleshooting of these bypasses is also illustrated. Seven intraoperative videos have been provided to demonstrate the various techniques of radial artery graft harvesting, cervical exposure of carotid vessels, bypasses, and concurrent aneurysm management.
13
Quiñones-Hinojosa, Alfredo, and Michael T. Lawton. "In Situ Bypass in the Management of Complex Intracranial Aneurysms: Technique Application in 13 Patients." Operative Neurosurgery 57, suppl_1 (July 1, 2005): 140–45. http://dx.doi.org/10.1227/01.neu.0000163599.78896.f4.
Full textAbstract:
Abstract OBJECTIVE: Cerebral revascularization is an important part of the treatment of complex intracranial aneurysms that require deliberate occlusion of a parent artery. In situ bypass brings together intracranial donor and recipient arteries that lie parallel and in close proximity to one another rather than using an extracranial donor artery. An experience with in situ bypasses was retrospectively reviewed. METHODS: Thirteen aneurysms were treated with in situ bypasses between 1997 and 2004. During this time, 1071 aneurysms were treated microsurgically and 46 bypasses were performed as part of the aneurysm treatment. RESULTS: Treated aneurysms were located at the middle cerebral artery (MCA) in five patients, posteroinferior cerebellar artery (PICA) in three patients, vertebral artery in three patients, and anterior communicating artery in two patients. Seven aneurysms were fusiform or dolichoectatic, and six aneurysms were saccular. Microsurgical revascularization techniques included side-to-side anastomosis of intracranial arteries in eight patients and aneurysm excision with end-to-end reanastomosis of the parent artery in five patients. In situ bypasses included A3–A3 anterior cerebral artery bypass in two patients, anterior temporal artery-MCA bypass in one patient, MCA–MCA bypass in one patient, and PICA–PICA bypass in four patients. Aneurysm excision with arterial reanastomosis included three MCA aneurysms and two PICA aneurysms. On angiography, all aneurysms were completely obliterated and 12 bypasses were patent. CONCLUSION: In situ bypass is a safe and effective alternative to extracranial-intracranial bypasses and high-flow bypasses using saphenous vein or radial artery grafts. Although in situ bypasses are more demanding technically, they do not require harvesting a donor artery, can be accomplished with one anastomosis, and are less vulnerable to injury or occlusion.
14
Baranoski, Jacob F., Colin J. Przybylowski, Justin R. Mascitelli, Michael J. Lang, and Michael T. Lawton. "Anterior Inferior Cerebellar Artery Bypasses: The 7-Bypass Framework Applied to Ischemia and Aneurysms in the Cerebellopontine Angle." Operative Neurosurgery 19, no. 2 (November 26, 2019): 165–74. http://dx.doi.org/10.1093/ons/opz347.
Full textAbstract:
Abstract BACKGROUND Aneurysms of the anterior inferior cerebellar artery (AICA) are rare. Primary clip reconstruction of these lesions is a challenge because of the limited surgical exposure and frequent nonsaccular aneurysm morphology. Endovascular treatment options exist, but outcomes are equivalent to those for open surgery. Historically, AICA aneurysms not amenable to clipping or primary coiling have been treated with parent vessel sacrifice. OBJECTIVE To determine whether an AICA revascularization strategy would afford for the safe treatment of AICA aneurysms and other posterior circulation pathologies without compromising perfusion of the AICA territories. METHODS We describe a series of AICA bypasses to treat 4 AICA aneurysms and 3 vertebral artery/AICA occlusions. RESULTS We used 7 types of bypasses to revascularize the AICA territory. Bypass types included extracranial-to-intracranial (EC-IC) bypass without an interpositional graft, EC-IC with an interpositional graft, in situ bypass, reanastomosis, reimplantation, intracranial-to-intracranial bypass with interpositional graft, and combination bypasses. In particular, we performed the following 7 bypasses: OA-a3 AICA, OA-RAG-a3 AICA, p3 PICA-a3 AICA, a2 AICA reanastomosis, V4 VA-a3 AICA, V3 VA-SVG-a3 AICA, and a combined OA-a3 AICA bypass and p3 PICA reanastomosis. AICA revascularization allows for the safe treatment of AICA aneurysms and other posterior circulation pathologies without compromising perfusion of the AICA territories. CONCLUSION All 7 AICA bypasses are feasible for application to AICA aneurysms and ischemic disease. Our experience with the 7-bypass framework demonstrates the utility of the framework as a decision-making tool and the breadth of bypass innovation possible in this anatomically challenging region.
15
Arnone, Gregory D., Ziad A. Hage, and Fady T. Charbel. "Single Vessel Double Anastomosis for Flow Augmentation – A Novel Technique for Direct Extracranial to Intracranial Bypass Surgery." Operative Neurosurgery 17, no. 4 (January 23, 2019): 365–75. http://dx.doi.org/10.1093/ons/opy396.
Full textAbstract:
AbstractBACKGROUNDA double anastomosis using a single superficial temporal artery (STA) donor branch for both a proximal side-to-side (S2S) and a distal end-to-side anastomosis is a novel direct bypass technique for use in selected patients necessitating flow augmentation.OBJECTIVETo describe the single-vessel double anastomosis (SVDA) technique, including its indications, advantages, and limitations, in addition to reporting our cases series of patients who underwent a SVDA bypass surgery.METHODSPatients undergoing a SVDA bypass at a single institution between January 2010 and February 2016 were retrospectively reviewed. Intraoperative flow data was collected, including STA cut-flow, bypass flows, and cut flow index (CFI). Bypass patency was assessed by cerebral angiography and quantitative magnetic resonance angiography with noninvasive optimal vessel analysis. Adverse events occurring during the hospital stay and clinical status at last follow up was recorded.RESULTSSeven patients underwent SVDA bypass. Mean follow-up was 14.5 mo. Initial CFI for the S2S bypasses averaged 0.56 ± 0.25 and CFI after the SVDA averaged 1.15 ± 0.24. There was a statistically significant average difference in CFI before and after the SVDA bypass (p < .013). Thirteen bypasses (93%) were patent postoperatively, and remained patent at last follow up. Four patients experienced various postoperative complications. None of the patients had a new stroke since hospital discharge.CONCLUSIONSVDA is a novel technique that can be advantageous for selected cases of extracranial-to-intracranial bypass. Expertise in bypass procedures is a necessary prerequisite. Graft patency rates and complications appear comparable to other bypass techniques.
16
Burkhardt, Jan-Karl, Sonia Yousef, Halima Tabani, Arnau Benet, Roberto Rodriguez Rubio, and Michael T. Lawton. "Combination Superficial Temporal Artery-Middle Cerebral Artery Bypass and M2–M2 Reanastomosis With Trapping of a Stented Distal Middle Cerebral Artery Aneurysm: 3-Dimensional Operative Video." Operative Neurosurgery 15, no. 5 (May 12, 2018): E67—E68. http://dx.doi.org/10.1093/ons/opy097.
Full textAbstract:
Abstract Distal middle cerebral artery (MCA) aneurysms often have non-saccular morphology and cannot be clipped, requiring revascularization and trapping instead. Combination bypasses are needed when 2 arteries exit the aneurysm, and extracranial–intracranial and intracranial–intracranial bypasses can be used. This video demonstrates a combination bypass used to treat a previously stented distal MCA aneurysm with both a superficial temporal artery (STA)-to-MCA bypass and an M2-to-M2 reanastomosis. This 56-yr-old man presented with distal left-sided MCA aneurysm 2 years earlier and attempted stent-assisted coiling was aborted after the aneurysm was perforated with stenting alone. Follow-up angiography demonstrated progressive aneurysm enlargement, and he was referred for surgery. The patient consented for the procedure and a pterional craniotomy extended posteriorly exposed the distal Sylvian fissure and efferent M4-cortical arteries. After splitting the Sylvian fissure, the “flash fluorescence” technique with indocyanine green (ICG) videoangiography identified an M4 recipient artery from the deeper of 2 exiting branches for STA–MCA bypass.1 The aneurysm was then trapped, and inflow and the more superficial outflow arteries were anastomosed end to end (M2–M2 in-situ bypass). A platelet plug that developed at the reanastomosis site was broken apart with mechanical manipulation, and ICG videoangiography demonstrated patency of both bypasses. The patient recovered without any neurological deficits, and postoperative computed tomography angiography confirmed bypass patency. Combination bypasses are needed when unclippable bifurcation aneurysms require revascularization. Careful intraoperative evaluation of patency of the bypass is imperative and helps identifying and addressing any potential early bypass occlusion.
17
Abla, Adib A., and Michael T. Lawton. "Anterior cerebral artery bypass for complex aneurysms: an experience with intracranial-intracranial reconstruction and review of bypass options." Journal of Neurosurgery 120, no. 6 (June 2014): 1364–77. http://dx.doi.org/10.3171/2014.3.jns132219.
Full textAbstract:
Object The authors describe their experience with intracranial-to-intracranial (IC-IC) bypasses for complex anterior cerebral artery (ACA) aneurysms with giant size, dolichoectatic morphology, or intraluminal thrombus; they determine how others have addressed the limitations of ACA bypass; and they discuss clinical indications and microsurgical technique. Methods A consecutive, single-surgeon experience with ACA aneurysms and bypasses over a 16-year period was retrospectively reviewed. Bypasses for ACA aneurysms reported in the literature were also reviewed. Results Ten patients had aneurysms that were treated with ACA bypass as part of their surgical intervention. Four patients presented with subarachnoid hemorrhage and 3 patients with mass effect symptoms from giant aneurysms; 1 patient with bacterial endocarditis had a mycotic aneurysm, and 1 patient's meningioma resection was complicated by an iatrogenic pseudoaneurysm. One patient had his aneurysm discovered incidentally. There were 2 precommunicating aneurysms (A1 segment of the ACA), 5 communicating aneurysms (ACoA), and 3 postcommunicating (A2–A3 segments of the ACA). In situ bypasses were used in 4 patients (A3-A3 bypass), interposition bypasses in 4 patients, reimplantation in 1 patient (pericallosal artery-to-callosomarginal artery), and reanastomosis in 1 patient (pericallosal artery). Complete aneurysm obliteration was demonstrated in 8 patients, and bypass patency was demonstrated in 8 patients. One bypass thrombosed, but 4 years later. There were no operative deaths, and permanent neurological morbidity was observed in 2 patients. At last follow-up, 8 patients (80%) were improved or unchanged. In a review of the 29 relevant reports, the A3-A3 in situ bypass was used most commonly, extracranial (EC)–IC interpositional bypasses were the second most common, and reanastomosis and reimplantation were used the least. Conclusions Anterior cerebral artery aneurysms requiring bypass are rare and can be revascularized in a variety of ways. Anterior cerebral artery aneurysms, more than any other aneurysms, require a thorough survey of patient-specific anatomy and microsurgical options before deciding on an individualized management strategy. The authors' experience demonstrates a preference for IC-IC reconstruction, but EC-IC bypasses are reported frequently in the literature. The authors conclude that ACA bypass with indirect aneurysm occlusion is a good alternative to direct clip reconstruction for complex ACA aneurysms.
18
Gadzhiagaev, V. S., An N. Konovalov, O. D. Shekhtman, and Sh Sh Eliava. "Revascularization techniques in surgical treatment of large and giant anterior cerebral artery aneurysms: literature review." Vestnik nevrologii, psihiatrii i nejrohirurgii (Bulletin of Neurology, Psychiatry and Neurosurgery), no. 7 (June 16, 2022): 486–96. http://dx.doi.org/10.33920/med-01-2207-03.
Full textAbstract:
Despite common use of revascularization for aneurysms of other locations, the role of bypass has been ignored for long time. In this study we describe actual status of revascularization in surgical treatment of ACA aneurysms based on an analysis of current literature. Search of literature was performed in data bases PubMed and Web of Science. Treatment of 80 patients in 24 articles was evaluated. In situ A3‑A3 bypass and extra — intracranial bypass with the superficial temporal artery are the most used techniques. The contralateral superficial temporal artery is the most convenient interposition graft for bypasses performed in patients with ACA aneurysms. There are no significant differences between extra-intracranial and intra-intracranial bypasses in terms of bypass patency and ischemic complications. The choice between different bypass techniques is based on an individual patient anatomy and surgeon preference.
19
Romiti, Marcello, Fausto Miranda, Francisco Cardoso Brochado-Neto, Marise Kikuchi, and Maximiano Albers. "Importance Of The Arteriographic Anatomy Of The Descending Genicular Artery And Sural Arteries In Patients With Atherosclerotic Occlusion Of The Popliteal Artery." Vascular 14, no. 4 (July 2006): 201–5. http://dx.doi.org/10.2310/6670.2006.00043.
Full textAbstract:
Bypasses to the descending genicular artery (DGA) or the medial sural artery (MSA) have been performed with acceptable rates of midterm success. The arteriographic appearance of the DGA, the MSA, and the lateral sural artery (LSA) was described and the applicability of bypass to these vessels was investigated. The arteriograms of 45 patients who had occlusion of the below-knee popliteal artery were analyzed to determine the presence, dominance, and extension of collaterals for each perigeniculate branch, which were used to assess the applicability of a perigeniculate bypass. A dominant perigeniculate artery was found in 26 arteriograms and corresponded to 13 DGAs, 9 MSAs, and 4 LSAs. Of 14 applicable perigeniculate bypasses, 2 would be an obligatory bypass and 12 would be an alternative to a conventional infrapopliteal bypass. Although rarely an obligatory solution, a bypass to a perigeniculate branch artery represents a valuable alternative.
20
Stewart, Luke, Benjamin J. Pearce, Adam W. Beck, and Emily L. Spangler. "Examination of race and infrainguinal bypass conduit use in the Society for Vascular Surgery Vascular Quality Initiative." Vascular 28, no. 6 (May 25, 2020): 739–46. http://dx.doi.org/10.1177/1708538120927704.
Full textAbstract:
Background Vein conduit is known to have better patency than prosthetic for infrainguinal bypass. Here we explore if racial disparities exist in infrainguinal bypass vein conduit use amid preoperative patient and systemic factors. Methods Retrospective Society for Vascular Surgery Vascular Quality Initiative data for 23,959 infrainguinal bypasses between 2003 and 2017 for occlusive disease were analyzed. For homogeneity, only infrainguinal bypasses originating from the common femoral artery were included. Demographics of patients receiving vein vs prosthetic were compared and logistic regression analyses were performed with race and preoperative factors to evaluate for predictors of vein conduit use. Results Adjusted regression models demonstrated black patients were 76% as likely ( p < .001) and Hispanic patients 79% as likely ( p = .003) to have vein conduit compared to white patients. Factors positively correlating with vein use included vein mapping, more distal bypass target, tissue loss or acute ischemia bypass indications, commercial insurance, and weight. Factors against vein use included advanced age, female gender, ASA class 4, urgent procedure, preoperative mobility limitation, prior CABG or leg bypass, prior smoking, preoperative anticoagulation, and a bypass performed in the Southern US or before 2012. While black and Hispanic patients were less likely to receive vein, they were vein mapped at similar or higher rates than other groups. Conclusion Racial disparities exist in conduit use for infrainguinal bypass, with black and Hispanic patients less likely to receive vein bypasses. However, the contribution of race to conduit selection is small in adjusted and unadjusted models. Overall, pre-operative variables in the Vascular Quality Initiative poorly predicted vein conduit use for infrainguinal bypass.
21
Sasajima, T., Y. Kubo, M. Kokubo, Y. Izumi, and M. Inaba. "Comparison of Reversed and in Situ Saphenous Vein Grafts for Infragenicular Bypass: Experience of Two Surgeons." Cardiovascular Surgery 1, no. 1 (February 1993): 38–43. http://dx.doi.org/10.1177/096721099300100111.
Full textAbstract:
A series of 241 consecutive autogenous vein bypasses for chronic lower-limb ischaemia performed by two surgeons since 1980 was reviewed. After 1985, in situ vein bypass was employed preferentially and was compared with reversed vein bypass. The two groups of patients had similar risk factors, indications and outflow. Of the 241 bypasses, 157 were to the below-knee popliteal artery and 84 to infrapopliteal arteries. The utilization rates of a single ipsilateral saphenous vein were 57.5% for reversed and 71.9% for in situ vein bypass. However, in situ vein bypass was impossible in 43 procedures and these were changed to the reversed operation with contralateral vein. The primary 5-year patency rates of reversed and in situ vein bypass grafts to the popliteal artery were 82.5 versus 74.5%, and the primary 4-year patency rates for infrapopliteal bypass 68.5 versus 80.0%. The respective secondary patency rates were 94.2 versus 92.1% and 85.7 versus 91.1%. The main cause of graft failure was vein graft stenosis (reversed vein bypass, 13.0%; in situ, 11.1%), which usually occurred in the first 2 years after surgery. Of 23 grafts revised for stenosis. 21 were salvaged and restenosis rarely occurred. Both reversed and in situ vein bypass grafts were equally effective, but careful surveillance for 2 years and aggressive revision were extremely important after either type of reconstruction.
22
Abla, Adib A., Gurpreet Gandhoke, Justin C. Clark, Mark E. Oppenlander, Gregory J. Velat, Joseph M. Zabramski, Felipe C. Albuquerque, Peter Nakaji, Robert F. Spetzler, and John E. Wanebo. "Surgical Outcomes for Moyamoya Angiopathy at Barrow Neurological Institute With Comparison of Adult Indirect Encephaloduroarteriosynangiosis Bypass, Adult Direct Superficial Temporal Artery–to–Middle Cerebral Artery Bypass, and Pediatric Bypass." Neurosurgery 73, no. 3 (June 14, 2013): 430–39. http://dx.doi.org/10.1227/neu.0000000000000017.
Full textAbstract:
Abstract BACKGROUND: Untreated, moyamoya angiopathy is a progressive vaso-occlusive process that can lead to ischemic or hemorrhagic stroke. OBJECTIVE: To review 1 institution's surgical experience with both direct and indirect bypass (encephaloduroarteriosynangiosis) in adult and pediatric groups. METHODS: A retrospective review was conducted of a consecutive series of patients treated for moyamoya angiopathy between 1995 and 2009. RESULTS: Thirty-nine adult patients underwent indirect bypass as their initial therapy; 29 adult patients underwent direct bypass. Twenty-four pediatric patients included 20 indirect bypasses and 4 direct bypasses. Overall, 140 hemispheres were treated; 48 patients received revascularization of both hemispheres. There were 14 additional revascularization procedures (10% per hemisphere) performed over a site of continued hypoperfusion postoperatively. Fourteen postoperative ischemic strokes occurred during the entire follow-up (10% per hemisphere), and the Kaplan-Meier analysis was not significantly different between groups (P = .59). Four grafts (9.09%) had failed at radiographic follow-up of the 44 direct bypasses performed. Before the initial surgery, the modified Rankin Scale score was 1.58 ± 0.93, 1.48 ± 0.74, and 1.8 ± 1.1 in the pediatric, adult direct, and adult indirect groups (P = .39). At last follow-up, it was 1.29 ± 1.31, 1.09 ± 0.90, and 1.94 ± 1.51 (P = .04) in the pediatric, adult direct, and adult indirect groups. CONCLUSION: This series demonstrates that both direct and indirect bypasses can be equally effective in preventing stroke. However, in adult patients, direct bypass patients had significantly greater improvement in symptoms, as seen in modified Rankin Scale scores. Pediatric patients, despite undergoing predominantly indirect bypasses, fared roughly the same as the adults in the direct bypass group.
23
Uchino, Haruto, Jae-Hoon Kim, Noriyuki Fujima, Ken Kazumata, Masaki Ito, Naoki Nakayama, Satoshi Kuroda, and Kiyohiro Houkin. "Synergistic Interactions Between Direct and Indirect Bypasses in Combined Procedures: The Significance of Indirect Bypasses in Moyamoya Disease." Neurosurgery 80, no. 2 (January 19, 2017): 201–9. http://dx.doi.org/10.1227/neu.0000000000001201.
Full textAbstract:
Abstract BACKGROUND: Whether additional indirect bypasses effectively contribute to revascularization in combined procedures remains unclear in patients with moyamoya disease. OBJECTIVE: To evaluate the longitudinal changes associated with combined procedures while following up pediatric and adult patients long term and to assess whether any other clinical factors or hemodynamic parameters affected these changes to determine an optimal surgical strategy. METHODS: We studied 58 hemispheres in 43 adults and 39 hemispheres in 26 children who underwent combined revascularization for moyamoya disease. To evaluate bypass development, we assessed the sizes of the superficial temporal artery and middle meningeal artery using magnetic resonance angiography. Multivariate analysis determined the effects of multiple variables on bypass development. RESULTS: Indirect bypass (middle meningeal artery) development occurred in 95% and 78% of the pediatric and adult hemispheres, respectively. Of these, dual development of direct and indirect bypasses occurred in 54% of the pediatric hemispheres and in 47% of the adult hemispheres. Reciprocal superficial temporal artery regression occurred in 28% of the hemispheres during the transition from the postoperative acute phase to the chronic phase during indirect bypass development. Good indirect bypass development was associated with adult hemispheres at Suzuki stage 4 or greater (odds ratio, 7.4; 95% confidence interval, 1.4-39.4; P = .02). Disease onset type and preoperative hemodynamic parameters were not considered predictors for the development of surgical revascularization. CONCLUSION: Simultaneous direct and indirect bypass development was most frequently observed, regardless of patient age and hemodynamic status. Applying indirect bypass as an adjunct to direct bypass could maximize revascularization in adults and children.
24
Williams, Brian A., Michael L. Kentor, John P. Williams, Molly T. Vogt, Stacey V. DaPos, Christopher D. Harner, and Freddie H. Fu. "PACU Bypass after Outpatient Knee Surgery Is Associated with Fewer Unplanned Hospital Admissions but More Phase II Nursing Interventions." Anesthesiology 97, no. 4 (October 1, 2002): 981–88. http://dx.doi.org/10.1097/00000542-200210000-00034.
Full textAbstract:
Background The authors recently proposed a recovery scoring system for outpatients receiving regional anesthesia (RA) or general anesthesia (GA). This scoring system was designed to allow qualifying patients to be directly routed to the phase II (step-down) recovery unit instead of the traditional postanesthesia care unit (PACU). We report PACU bypass rates using these criteria, and the extent to which PACU bypass was associated with (1) required nursing interventions in the step-down recovery unit, and (2) successful same-day discharge. Methods Day-of-surgery outcomes were studied for 894 outpatients undergoing outpatient sports medicine surgery on the lower extremity. We determined PACU-bypass rates, nursing interventions in the step-down recovery unit for common symptoms, and unplanned hospital admissions. Using logistic regression, we analyzed step-down nursing interventions based on PACU requirement versus PACU bypass, and anesthesia techniques used (GA vs. not, peripheral nerve blocks vs. not). Results Eighty-seven percent (778/894) of all patients bypassed PACU. Of PACU-bypass patients, 241/778 (31%) required step-down nursing interventions. Of patients requiring PACU, only 19/116 (16%) required additional interventions in step-down (P < 0.001). PACU-bypass patients were almost three times more likely (odds ratio 2.9,P < 0.001) to require at least one nursing intervention in the step-down unit, when compared with patients requiring PACU. Fewer unplanned admissions were required by patients who bypassed PACU (odds ratio = 0.3,P = 0.007). Conclusions For outpatient lower extremity surgery, applying our PACU-bypass criteria led to an 87% PACU bypass rate with no reportable adverse events.
25
Pathi, Vivek L., Paul S. Ramphal, Geoffrey A. Berg, and Kenneth J. D. MacArthur. "Emergency Bypass Without Bypass!" Annals of Thoracic Surgery 62, no. 3 (August 1996): 877–78. http://dx.doi.org/10.1016/s0003-4975(96)00285-8.
Full text
26
van Doormaal, Tristan P. C., Albert van der Zwan, Bon H. Verweij, Luca Regli, and Cornelis A. F. Tulleken. "Giant Aneurysm Clipping Under Protection of an Excimer Laser–Assisted Non-occlusive Anastomosis Bypass." Neurosurgery 66, no. 3 (March 1, 2010): 439–47. http://dx.doi.org/10.1227/01.neu.0000364998.95710.73.
Full textAbstract:
Abstract OBJECTIVE To define the safety and clinical value of giant aneurysm clipping under protection of an excimer laser–assisted non-occlusive anastomosis (ELANA) bypass. METHODS We report 32 patients with an uncoilable intracerebral giant aneurysm, operated on with the aid of an ELANA protective bypass between January 1, 1994, and January 1, 2008. We retrospectively collected data from patient records. Follow-up data were updated by telephone interview. We defined a favorable outcome as a successfully treated aneurysm and a better or equal postoperative modified Rankin scale (mRS) score compared with the preoperative mRS. RESULTS In total 33 bypasses were constructed, of which 31 (94%) were patent during the rest of the procedure. The first failed bypass was salvaged during a second procedure. Of the second failed bypass, the ELANA anastomosis could be reused during second bypass surgery. All 32 aneurysms could be treated. The bypasses served as protection during temporary parent vessel occlusion (n = 24, 75%), control during aneurysm rupture (n = 3, 9%), and in all patients as an indicator for recipient artery narrowing during clip placement. Four bypasses (12%) eventually had to partially (n = 3) or fully (n = 1) replace recipient artery flow at the end of surgery. Postoperatively, 3 patients (9%) had a hemorrhagic complication and 2 patients (6%) had an ischemic complication. At long-term follow-up (mean, 6.1 ± 3.4 y), 28 patients (88%) had a favorable functional outcome. CONCLUSION The ELANA protective bypass is a safe and useful instrument for the treatment of these difficult aneurysms.
27
Knott, Mueller, Pander, and Geist. "Fish Passage and Injury Risk at a Surface Bypass of a Small-Scale Hydropower Plant." Sustainability 11, no. 21 (October 30, 2019): 6037. http://dx.doi.org/10.3390/su11216037.
Full textAbstract:
In contrast to the efforts made to develop functioning fishways for upstream migrants, the need for effective downstream migration facilities has long been underestimated. The challenge of developing well-performing bypasses for downstream migrants involves attracting the fish to the entrance and transporting them quickly and unharmed into the tailrace. In this study, the acceptance of different opening sizes of a surface bypass as well as the injuries which fish experience during the passage were examined. Overall bypass acceptance was low compared to the turbine passage. There was no significant difference in the number of downstream moving fish between the small and the large bypass openings. Across all fish species, no immediate mortality was detected. Severe injuries such as amputations or bruises were only rarely detected and at low intensity. Scale losses, tears and hemorrhages in the fins and dermal lesions at the body were the most common injuries, and significant species-specific differences were detected. To increase bypass efficiency, it would likely be useful to offer an alternative bottom bypass in addition to the existing surface bypass. The bypass injury potential could be further reduced by structural improvements at the bypass, such as covering protruding components.
28
Muralidhar, R., and Suraj Muralidhar. "Extra anatomical bypass grafting for limb salvage: a case report." International Surgery Journal 4, no. 9 (August 24, 2017): 3146. http://dx.doi.org/10.18203/2349-2902.isj20173693.
Full textAbstract:
Extra-anatomical bypass grafting is a recognised method of lower limb re-vascularisation in high-risk patients who cannot tolerate aortic cross clamping, or in those with a hostile abdomen1. Extra-anatomic bypasses are surgical arterial bypass procedures that circumvent the “normal” anatomical pathways. While such procedures can be performed in any vascular bed, the term most frequently is used to describe those bypasses that reroute blood to the lower extremities, avoiding intracavitary procedures3. Initially introduced as alternative revascularization methods in the treatment of peripheral arterial occlusive disease and as techniques for bringing blood back to the lower extremities. Here, we present you a case of Peripheral Arterial Occlusive Disease where an Axillo-Femoral bypass was done.
29
Amin-Hanjani, Sepideh, John H. Shin, Meide Zhao, Xinjian Du, and Fady T. Charbel. "Evaluation of extracranial–intracranial bypass using quantitative magnetic resonance angiography." Journal of Neurosurgery 106, no. 2 (February 2007): 291–98. http://dx.doi.org/10.3171/jns.2007.106.2.291.
Full textAbstract:
Object To date, angiography has been the primary modality for assessing graft patency following extracranial–intracranial bypass. The utility of a noninvasive and quantitative method of assessing bypass function postoperatively was evaluated using quantitative magnetic resonance (MR) angiography. Methods One hundred one cases of bypass surgery performed over a 5.5-year period at a single institution were reviewed. In 62 cases, both angiographic and quantitative MR angiographic data were available. Intraoperative flow measurements were available in 13 cases in which quantitative MR angiography was performed during the early postoperative period (within 48 hours after surgery). There was excellent correlation between quantitative MR angiographic flow and angiographic findings over the mean 10 months of imaging follow up. Occluded bypasses were consistently absent on quantitative MR angiograms (four cases). The flow rates were significantly lower in those bypasses that became stenotic or reduced in diameter as demonstrated by follow-up angiography (nine cases) than in those bypasses that remained fully patent (mean ± standard error of the mean, 37 ± 13 ml/minute compared with 105 ± 7 ml/minute, p = 0.001). Flows were appreciably lower in poorly functioning bypasses for both vein and in situ arterial grafts. All angiographically poor bypasses (nine cases) were identifiable by absolute flows of less than 20 ml/minute or a reduction in flow greater than 30% within 3 months. Good correlation was seen between intraoperative flow measurements and early postoperative quantitative MR angiographic flow measurements (13 cases, Pearson correlation coefficient = 0.70, p = 0.02). Conclusions Bypass grafts can be assessed in a noninvasive fashion by using quantitative MR angiography. This imaging modality provides not only information regarding patency as shown by conventional angiography, but also a quantitative assessment of bypass function. In this study, a low or rapidly decreasing flow was indicative of a shrunken or stenotic graft. Quantitative MR angiography may provide an alternative to standard angiography for serial follow up of bypass grafts.
30
Ferraz, Álvaro Antônio Bandeira, Cristiano Souza Leão, Josemberg Marins Campos, Antônio Roberto Barros Coelho, Bruno Zilbestein, and Edmundo Machado Ferraz. "An experimental study of the electrical activity of the bypassed stomach in the Roux-en-Y gastric bypass." Arquivos de Gastroenterologia 44, no. 2 (June 2007): 162–67. http://dx.doi.org/10.1590/s0004-28032007000200015.
Full textAbstract:
BACKGROUND: Surgical options for morbid obesity are diverse, and the Roux-en-Y gastric bypass, initially described by Fobi has gained popularity. Knowledge about the physiology of the bypassed stomach is limited because this newly produced segment of the stomach is inaccessible to endoscopic or contrast radiological studies. AIM: To evaluate the myoelectric activity of the bypassed stomach and its reply to the feeding. METHODS: An experimental protocol was conducted to evaluate postoperative gastric bypassed motility in dogs submitted to the Roux-en-Y gastric bypass procedure. Two groups of five animals were studied on postoperative fasting and after a standard meal, recording electrical response and control activity. Both control and Roux-en-Y gastric bypass operated study group had a pair of electrodes placed on three points of the remaining stomach: fundus, body and antrum. Data registration was performed after complete ileus resolution, and analysed with DATA Q Inst. series 200. RESULTS: The results achieved on the conditions of this study suggest that: 1. the remaining stomach maintain the same pattern of motility; 2. there is a reduced fasting electromyography activity following the Roux-en-Y gastric bypass procedure; 3. significantly reduced fasting electric control activity when compared both groups, and a markedly reduced fasting response electric activity and; 4. the electric response to the feeding kept the same standard of the stomach, however in a statistically reduced way. CONCLUSION: The electrical activity of the bypassed stomach of Roux-en-Y gastric bypass procedure kept the same pattern but in a statistically reduced number of contraction.
31
Yamaguchi, Kohji, Akitsugu Kawashima, Takakazu Kawamata, Tomokatsu Hori, and Yoshikazu Okada. "Successful Superficial Temporal Artery-Anterior Cerebral Artery Direct Bypass Using a Long Graft for Moyamoya Disease: Technical Note." Operative Neurosurgery 67, no. 3 (September 1, 2010): ons145—ons149. http://dx.doi.org/10.1227/01.neu.0000382975.86267.40.
Full textAbstract:
Abstract BACKGROUND: Although some patients with moyamoya disease need revascularization in the anterior cerebral artery (ACA) territory, there are few reports on direct bypass in the ACA territory because of the difficult surgical technique. OBJECTIVE: To report our technical strategy for superficial temporal artery (STA)-ACA bypass. METHODS: We performed simultaneous STA-ACA and STA-middle cerebral artery direct bypasses in 7 patients with moyamoya disease using the following strategies: creating 2 separate craniotomies for the 2 bypasses, dissecting a long STA graft and securing a recipient ACA around the bregma for the STA-ACA bypass, and using loose stitches at the anastomoses. One branch of the STA was dissected for a length of approximately 10 cm. The graft coursed on the brain surface under the bone bridge and was directly anastomosed to the cortical branch of the ACA. At the anastomoses, the stitches were widely spaced and loose to facilitate expansion of the orifice. RESULTS: This method prevented kinking of the graft. Postoperative angiograms revealed good patency of the STA-ACA bypass in all patients. After the bypasses, 5 patients no longer had transient ischemic attacks or stroke, 1 patient was almost completely free of transient ischemic attacks, and 1 patient had only residual contralateral symptoms. In all 7 patients, patency of the bypass was satisfactory during follow-up periods ranging from 9 to 23 months (mean 16.4 months). CONCLUSION: This method of STA-ACA bypass provides successful and reliable direct revascularization of the ACA territory in patients with moyamoya disease. Further investigation of the possible merit of this surgery in improving cognitive function is warranted.
32
Davidovic, Lazar, Ilija Kuzmanovic, Dusan Kostic, Ilijas Cinara, Slobodan Cvetkovic, Miljko Ristic, Dusan Velimirovic, and Dragica Jadranin. "Obturator or "lateral" bypass in the management of infected vascular prostheses at the groin." Srpski arhiv za celokupno lekarstvo 130, no. 1-2 (2002): 27–32. http://dx.doi.org/10.2298/sarh0202027d.
Full textAbstract:
The infection of the previously implanted vascular graft at the groin, is associated with great mortality and morbidity rate [1]. The authors present a retrospective study in which they analyzed management of infected vascular prostheses at the groin, using obturator bypass in 26 cases, and "lateral" bypass in 15 cases. The indications for obturator bypass reconstructions included: 20 infections of aorto-femoral grafts, two infected pse udoaneurysms in the groin after RTA of the superficial femoral artery, and 4 infections of iliac-femoral grafts. The indications for lateral bypass reconstructions were: infections after aorto-femoral reconstructions - 8 cases; infection after femora-popliteal reconstructions - 4 cases; infection after iliac-femoral reconstruction - 2 patients, and one infected pseudoaneurysm in the groin after RTA of the superficial femoral artery. In 3 subjects obturator bypass was performed using extraperitoneal approach while in other 23 patients transperitoneal approach was done by donor's artery. The obturator bypass was performed using a PTFE graft in 3 cases and Dacron graft in 23. The donor's artery used for obturator bypass was a noninfected proximal part of aortofemoral graft in 20 cases, and iliac artery in 6 patients. The superfical femoral artery was recipient artery for obturator bypass in 3 cases, deep femoral artery in one case, and above the knee popliteal artery in 22 cases (Figure 1). In two patients transperitoenal approach to donors artery for "lateral" bypass has been used, and in 13 cases extraperitoneal. The proximal noninfected part of aorto femoral graft was used as a donor's artery for lateral bypass in 8 patients, while common iliac artery in 7 subjects. In 5 cases recon structions were performed using PTFE grafts, in 3 using autologous saphenous vein grafts, and in 7 using Dacron grafts. The recipient artery for "lateral" bypass was deep femoral in 8 cases, superficial femoral in three patients and above the knee popliteal artery in 4 subjects. After both types of reconstruction, extirpation of infected grafts from the groin was performed (Figure 2). The control examination was performed using physical and Doppler ultrasonographic examinations, one, 3, 6, 12 months, and then every year after the operation. In cases with suspected graft infection or thrombosis, control angography was also performed. One intraoperative perforation of the urinary bladder has been done accidentally during obturator bypass reconstruction. The mean follow-up period for patients with obturator bypasses was 2.3 years, while 2.1 years for patients with "lateral" bypasses. Comparing with "lateral" bypass, obturator bypass showed statistically significant lower (p < 0.05) 30- day mortality and early graft infection rate, as well as statistically significant better early and total limb salvage rate. There were no statistically significant differences (p > 0.05) between obturator and "lateral" bypass procedures having in mind, late graft infection rate, as well as early and late graft patency (Figures 3 and 4). In cases with infected vascular prostheses in the groin, the authors recommend obturator bypass comparing with "lateral" bypass.
33
Tracz, Marian, and Mariusz Kieć. "Operational problems of 2+1 bypass road sections." Archives of Transport 38, no. 2 (June 30, 2016): 79–89. http://dx.doi.org/10.5604/08669546.1218797.
Full textAbstract:
The paper presents several problems of designing trunk-road bypasses of towns, which can be very helpful in improving their traffic performance. Such roads perform supplementary functions to the operation of network of motorways and express-roads constructed in Poland over the last decade. These problems include: selection of the cross section, selection and design of intersections and interchanges on bypasses, safety and traffic operation problems. The authors highlight the advantages of bypasses and point out some errors, which can be seen in the operation stage, basing on research and observation of 8 bypasses. In the paper traffic operation and road safety analyses for Zyrardow bypass are presented. The final part of the paper gives conclusions and recommendations for 2+1 bypass use and design.
34
Cherian, Jacob, Visish Srinivasan, Peter Kan, and Edward AM Duckworth. "Double-Barrel Superficial Temporal Artery-Middle Cerebral Artery Bypass: Can It Be Considered “High-Flow?”." Operative Neurosurgery 14, no. 3 (August 18, 2017): 288–94. http://dx.doi.org/10.1093/ons/opx119.
Full textAbstract:
Abstract BACKGROUND Traditionally, superficial temporal artery-middle cerebral artery (STA-MCA) bypass uses one STA branch. Its augmentation of flow has classically been described as “low flow.” In a double-barrel STA-MCA bypass, however, both branches of the STA are utilized. Here we hypothesize that this should not be considered “low flow.” OBJECTIVE To review quantitative flow data from our cases and investigate the impact of double-barrel STA-MCA bypass on total flow augmentation, and to assess whether double-barrel STA-MCA bypass might be useful in situations that traditionally demand more complex bypass strategies. METHODS Intraoperative flow probe measurements from STA-MCA bypass cases were retrospectively tabulated and compared. Cut flow and bypass flow measurements were, respectively, taken before and after completion of anastomoses. The higher value was labeled best observed flow (BOF). RESULTS We identified 21 STA-MCA bypass cases with available intraoperative flow probe measurements, of which 17 utilized double-barrel technique. Only 1 STA branch was available in 4 cases. Significantly higher average BOF was seen when utilizing 2 STA branches (69 vs 39 cc/min, P < .001). A majority (9/17) of double-barrel bypasses provided BOF ≥ 65 cc/min (120 cc/min maximum). The single branch bypass maximum BOF was 40 cc/min. CONCLUSION Double-barrel bypass technique significantly enhances STA-MCA flow capacity and may be useful in situations in which a high-flow bypass is needed. The 2 efferent limbs allow flexibility in distributing flow across separate at-risk territories. The method compares favorably to other descriptions of high-flow bypass without the morbidity of graft harvest or an additional cervical incision.
35
Acerbi, Francesco, Elio Mazzapicchi, Jacopo Falco, Ignazio Gaspare Vetrano, Francesco Restelli, Giuseppe Faragò, Emanuele La Corte, et al. "The Role of Bypass Surgery for the Management of Complex Intracranial Aneurysms in the Anterior Circulation in the Flow-Diverter Era: A Single-Center Series." Brain Sciences 12, no. 10 (October 3, 2022): 1339. http://dx.doi.org/10.3390/brainsci12101339.
Full textAbstract:
Despite the increasing popularity of flow diverters (FDs) as an endovascular option for intracranial aneurysms, the treatment of complex aneurysms still represents a challenge. Combined strategies using a flow-preservation bypass could be considered in selected cases. In this study, we retrospectively reviewed our series of patients with complex intracranial aneurysms submitted to bypass. From January 2015 to May 2022, 23 patients were selected. We identified 11 cases (47.8%) of MCA, 6 cases (26.1%) of ACA and 6 cases (26.1%) of ICA aneurysms. The mean maximal diameter was 22.73 ± 12.16 mm, 8 were considered as giant, 9 were fusiform, 8 presented intraluminal thrombosis, 10 presented wall calcification, and 18 involved major branches or perforating arteries. Twenty-five bypass procedures were performed in 23 patients (two EC–IC bypasses with radial artery graft, seventeen single- or double-barrel STA–MCA bypasses and six IC–IC bypasses in anterior cerebral arteries). The long-term bypass patency rate was 94.5%, and the total aneurysm exclusion was 95.6%, with a mean follow-up of 28 months. Median KPS values at last follow-up was 90, and a favorable outcome (KPS ≥ 70 and mRS ≤ 2) was obtained in 87% of the cases. The use of bypass techniques represents, in selected cases, a valid therapeutic option in the management of complex anterior circulation aneurysms when a simpler direct approach, including the use of FD, is considered not feasible.
36
Sclafani, Robert A., Marianne Tecklenburg, and Angela Pierce. "The mcm5-bob1 Bypass of Cdc7p/Dbf4p in DNA Replication Depends on Both Cdk1-Independent and Cdk1-Dependent Steps in Saccharomyces cerevisiae." Genetics 161, no. 1 (May 1, 2002): 47–57. http://dx.doi.org/10.1093/genetics/161.1.47.
Full textAbstract:
Abstract The roles in DNA replication of two distinct protein kinases, Cdc7p/Dbf4p and Cdk1p/Clb (B-type cyclin), were studied. This was accomplished through a genetic and molecular analysis of the mechanism by which the mcm5-bob1 mutation bypasses the function of the Cdc7p/Dbf4p kinase. Genetic experiments revealed that loss of either Clb5p or Clb2p cyclins suppresses the mcm5-bob1 mutation and prevents bypass. These two cyclins have distinct roles in bypass and presumably in DNA replication as overexpression of one could not complement the loss of the other. Furthermore, the ectopic expression of CLB2 in G1 phase cannot substitute for CLB5 function in bypass of Cdc7p/Dbf4p by mcm5-bob1. Molecular experiments revealed that the mcm5-bob1 mutation allows for constitutive loading of Cdc45p at early origins in arrested G1 phase cells when both kinases are inactive. A model is proposed in which the Mcm5-bob1 protein assumes a unique molecular conformation without prior action by either kinase. This conformation allows for stable binding of Cdc45p to the origin. However, DNA replication still cannot occur without the combined action of Cdk1p/Clb5p and Cdk1p/Clb2p. Thus Cdc7p and Cdk1p kinases catalyze the initiation of DNA replication at several distinct steps, of which only a subset is bypassed by the mcm5-bob1 mutation.
37
Uzum, Mehmet, Isik Kutlu, and Mehmet Celkan. "Comparison of platelet activation in patients undergoing coronary bypass surgery with conventional and mini extracorporeal systems." Azerbaijan Journal of Cardiovascular Surgery 5, no. 1 (2024): 13. http://dx.doi.org/10.5455/azjcvs.2024.03.06.
Full textAbstract:
Aim: The aim of this study was to compare platelet activation in patients undergoing coronary bypass surgery with conventional and mini extracorporeal systems. Material and Methods: Our study is a retrospective study and a total of 116 patient data were obtained. Patients were divided into two groups as conventional extracorporeal and mini extracorporeal system bypass patients. Equal numbers of patients (n=58) were included in both groups. The data of patients who underwent coronary bypass surgery with conventional and mini extracorporeal systems between January 2022 and December 2022 were included in the study. Results: In our study, no significant difference was found between patients bypassed with conventional and mini extracorporeal system in terms of pump time and cross-clamp time. Although the duration of intensive care unit stay and total hospitalization were found to be shorter in patients bypassed with the mini-extracorporeal (MECC) system than those bypassed with the conventional method, the difference between the groups was not significant. As a result of our study, it was observed that postoperative ejection fraction (EF) values significantly increased and hematocrite (HTC), hemoglobin (Hb), platelet (PLT) and procalcitonin (PCT) values significantly decreased in both groups of patients who underwent bypass with conventional and MECC system, and no significant difference was found between pre- and postoperative mean platelet volume (MPV) and platelet distribution width (PDW) values. As a result of our study, postoperative PLT and PCT values in the MECC group were found to be significantly higher than those in patients who underwent bypass with the conventional method. Conclusion: Considering the results obtained in our study, it is seen that the values in patients bypassed with the MECC system are more favorable than those bypassed with the standard method, but more studies on the subject are needed.
38
Kawashima, Masatou, Albert L. Rhoton, Necmettin Tanriover, Arthur J. Ulm, Alexandre Yasuda, and Kiyotaka Fujii. "Microsurgical anatomy of cerebral revascularization. Part I: Anterior circulation." Journal of Neurosurgery 102, no. 1 (January 2005): 116–31. http://dx.doi.org/10.3171/jns.2005.102.1.0116.
Full textAbstract:
Object. Revascularization is an important component of treatment for complex aneurysms that require parent vessel occlusion, skull base tumors that involve major vessels, and certain ischemic diseases. In this study, the authors examined the microsurgical anatomy of cerebral revascularization in the anterior circulation by demonstrating various procedures for bypass surgery. Methods. Twenty-five adult cadaveric specimens were studied, using 3 to 40 magnification, after the arteries and veins had been perfused with colored silicone. The microsurgical anatomy of cerebral revascularization in the anterior circulation was examined with the focus on the donor, recipient, and graft vessels. The techniques discussed in this paper include the superficial temporal artery (STA)—middle cerebral artery (MCA), middle meningeal artery (MMA)—MCA, and side-to-side anastomoses; short arterial and venous interposition grafting; and external carotid artery/internal carotid artery (ICA)—M2 and ICA—ICA bypasses. Bypass procedures for cerebral revascularization are divided into two categories depending on their flow volume: low-flow and high-flow bypasses. A low-flow bypass, such as the STA—MCA anastomosis, is used to cover a relatively small area, whereas a high-flow bypass, such as the ICA—ICA anastomosis, is used for larger areas. Cerebral revascularization techniques are also divided into two types depending on the graft materials: pedicled arterial grafts, such as STA and occipital artery grafts, and free venous or arterial grafts, which are usually saphenous vein and radial artery grafts. Pedicled arterial grafts are mainly used for low-flow bypasses, whereas venous or arterial grafts are used for high-flow bypasses. Conclusions. It is important to understand the methods of bypass procedures and to consider indications in which cerebral revascularization is needed.
39
Ciancio, Gaetano, and Mark Soloway. "The Use of Natural Veno-Venous Bypass during Surgical Treatment of Renal Cell Carcinoma with Inferior Vena Cava Thrombus." American Surgeon 68, no. 5 (May 2002): 488–90. http://dx.doi.org/10.1177/000313480206800519.
Full textAbstract:
Renal cell carcinoma associated with inferior vena cava thrombus complicates radical nephrectomy. Various approaches have been used to deal with this problem including veno-venous and cardiopulmonary bypass. Using natural veno-venous bypass may prevent the use of another type of bypass. A total of 16 patients underwent removal of renal cell carcinoma and an intracaval tumor thrombus without using veno-venous bypass. One of the natural veno-venous bypasses consisted in the mobilization of the liver off the retrohepatic inferior vena cava to allow enhanced access, vascular control, and hepatic venous drainage. The other natural bypass involved the preservation and use of collateral veins created by the longstanding obstruction of the inferior vena cava. In all 16 patients surgery was successful. Inferior vena cava clamping above and below the tumor thrombus did not result in systemic hypotension. There was no intraoperative mortality. There were no other complications. Mobilization of the liver off the retrohepatic inferior vena cava and preservation of collateral drainage (right testicular or ovarian veins and/or lumbar veins) were useful techniques in dealing with renal cell carcinoma with intracaval thrombus. These natural veno-venous bypasses allow vascular isolation of the inferior vena cava without disturbing the venous return to the heart and thereby help to prevent hemodynamic instability.
40
Phair, John, John Futchko, Eric B. Trestman, Matthew Carnevale, Patricia Friedmann, Harshal Shukla, Karan Garg, and Issam Koleilat. "Protamine sulfate use during tibial bypass does not appear to increase thrombotic events or affect short-term graft patency." Vascular 28, no. 6 (May 11, 2020): 708–14. http://dx.doi.org/10.1177/1708538120924149.
Full textAbstract:
Objectives While the use of protamine sulfate as a heparin reversal agent has been extensively reviewed in patients undergoing carotid endarterectomy and coronary artery bypass grafting, there is a lack of literature on protamine’s effects on lower extremity bypasses. The purpose of this study was to determine the risk of protamine sulfate dosing after tibial bypass on thrombotic or bleeding events, including early bypass failure. Methods We performed a retrospective review of our institutional database for patients undergoing primary distal peripheral bypass from January 2009 through December 2015 (contralateral bypass was considered to be a new primary bypass). Primary endpoints include composite thrombotic events (myocardial infarction, stroke, amputation at 30 days and patency less than 30 days) and composite bleeding events (bleeding or transfusion). Results A total of 152 tibial or peroneal bypasses in 136 patients with critical limb ischemia were identified. Of these, 78 (57.4%) patients received protamine sulfate intraoperatively and 58 (42.6%) did not. There were no differences in composite thrombotic or hemorrhagic outcomes. Protamine use had no effect on the rates of perioperative MI (9.0% versus 3.5%, p = 0.20), stroke (1.3% versus 1.7%, p = 0.83), or perioperative mortality (5.1% versus 3.5%, p = 0.64). There was no significant difference in composite post-operative bleeding events (20.7% versus 14.1%, p = 0.31) or composite thrombotic events (17.2% versus 18.0%, p = 0.91). Patients who received protamine undergoing bypass with non-autogenous conduit had significantly higher-recorded median operative blood loss (250 mL versus 150 mL, p = 0.0097) and median procedure lengths (265 min versus 201 min, p = 0.0229). No difference in 30-day amputation-free survival was noted (91.0% versus 91.4%, p = 0.94). Follow-up Kaplan–Meier estimation did not demonstrate a difference in 30-day patency (91.7% versus 88.5%, p = 0.52). Conclusions Heparin reversal with protamine sulfate after tibial or peroneal bypass grafting is not associated with higher cardiovascular morbidity, bypass thrombosis, amputation, or mortality. Additionally, there was no statistically significant difference in post-operative bleeding or thrombosis complications for patients who did not receive protamine, although the findings are suggestive of a potential difference in a more adequately powered study. Our results suggest that protamine sulfate is safe for intraoperative use without increased risk of thrombotic complications or early tibial bypass graft failure.
41
Bidstrup, B. P. "Coronary bypass without cardiopulmonary bypass." Asia Pacific Heart Journal 8, no. 1 (May 1999): 60–61. http://dx.doi.org/10.1016/s1328-0163(99)90026-x.
Full text
42
Schauer, Grant D., Lisanne M. Spenkelink, Jacob S. Lewis, Olga Yurieva, Stefan H. Mueller, Antoine M. van Oijen, and Michael E. O’Donnell. "Replisome bypass of a protein-based R-loop block by Pif1." Proceedings of the National Academy of Sciences 117, no. 48 (November 16, 2020): 30354–61. http://dx.doi.org/10.1073/pnas.2020189117.
Full textAbstract:
Efficient and faithful replication of the genome is essential to maintain genome stability. Replication is carried out by a multiprotein complex called the replisome, which encounters numerous obstacles to its progression. Failure to bypass these obstacles results in genome instability and may facilitate errors leading to disease. Cells use accessory helicases that help the replisome bypass difficult barriers. All eukaryotes contain the accessory helicase Pif1, which tracks in a 5′–3′ direction on single-stranded DNA and plays a role in genome maintenance processes. Here, we reveal a previously unknown role for Pif1 in replication barrier bypass. We use an in vitro reconstitutedSaccharomyces cerevisiaereplisome to demonstrate that Pif1 enables the replisome to bypass an inactive (i.e., dead) Cas9 (dCas9) R-loop barrier. Interestingly, dCas9 R-loops targeted to either strand are bypassed with similar efficiency. Furthermore, we employed a single-molecule fluorescence visualization technique to show that Pif1 facilitates this bypass by enabling the simultaneous removal of the dCas9 protein and the R-loop. We propose that Pif1 is a general displacement helicase for replication bypass of both R-loops and protein blocks.
43
Ramanathan, Dinesh, Nancy Temkin, Louis J. Kim, Basavaraj Ghodke, and Laligam N. Sekhar. "Cerebral Bypasses for Complex Aneurysms and Tumors." Neurosurgery 70, no. 6 (March 6, 2012): 1442–57. http://dx.doi.org/10.1227/neu.0b013e31824c046f.
Full textAbstract:
Abstract BACKGROUND: Various techniques of cerebral bypasses are used to treat aneurysms and tumors. OBJECTIVE: To study long-term clinical and radiological outcome of various bypass types and to analyze techniques used in the management of long-term graft problems. METHODS: A consecutive series of patients who underwent revascularization during a 5-year period were analyzed for indications, graft patency, and neurological outcomes. Potential risk factors for bypass problems and the management of bypass stenosis were studied. RESULTS: A total of 80 patients (69 with aneurysms and 11 with tumors) underwent 88 bypasses (59 extracranial-to-intracranial [EC-IC] bypasses [10 low flow, 49 high flow], 9 intracranial-to-intracranial [IC-IC] bypasses [3 long, 6 short], and 20 local bypasses), with mean radiological follow-up of 32 months (range, 1–53 months). At late follow-up, 5 of 9 (56%) IC-IC (5 short, 0 long grafts), 8 of 9 (90%) EC-IC low-flow, 44 of 48 (92%) EC-IC high-flow, and all local bypasses were patent. Four patients with EC-IC high-flow bypass occlusions were asymptomatic, but transient ischemic attacks were noted in 3 of 6 patients with graft stenosis. None of the risk factors evaluated were significantly predictive of EC-IC graft occlusions or stenosis. EC-IC HF graft stenoses were permanently corrected by microsurgery (n = 4) or endovascular surgery (n = 1). CONCLUSION: The EC-IC and local bypasses have higher long-term patency rates (91% and 100%) compared with IC-IC bypasses (66%, 0% long graft). Some EC-IC bypasses may occlude asymptomatically (9%) or develop graft stenosis (13%) over the long term. Microsurgical and endovascular surgical techniques have been developed to treat graft stenosis.
44
Mota Prado, Mariana. "Bypasses Institucionais no Brasil." Revista da Faculdade de Direito da Universidade Federal de Uberlândia 49, no. 1 (September 7, 2021): 8–28. http://dx.doi.org/10.14393/rfadir-v49n1a2021-62774.
Full textAbstract:
Uma estratégia de reforma que pode ajudar os formuladores de políticas públicas a superar a resistência à mudança institucional é "um bypass institucional". Um bypass institucional não tenta modificar, alterar ou reformar as instituições existentes. Ao invés disso, cria um novo caminho que visa ser mais funcional do que a instituição preexistente. Depois de discutir o que caracteriza um bypass, o presente artigo apresenta dois exemplos do Brasil: uma reforma burocrática chamada Poupatempo, que consiste em um balcão único para diversos serviços burocráticos; e uma reforma policial chamada Unidade de Polícia Pacificadora (UPP). Partindo desses dois estudos de caso brasileiros, o trabalho discute como os bypasses podem ajudar a superar a resistência ex-ante às reformas. Por fim, analisa o que poderia caracterizar um bypass bem sucedido.
45
Patel, Nirav J., and Michael K. Morgan. "ICA aneurysm surgically treated utilizing a choroidal to PCOM bypass and vein bypass." Neurosurgical Focus 39, videosuppl1 (July 2015): V14. http://dx.doi.org/10.3171/2015.7.focusvid.14622.
Full textAbstract:
This video shows the surgical repair of a 2.3 cm ICA aneurysm found in a 58-year-old woman, who presented for right eye vision changes. The patient underwent a right modified orbitozygomatic craniotomy and saphenous vein bypass from the common carotid to the temporal M2. The aneurysm was then opened and repaired. However, since the anterior choroidal artery was not filling, a salvage bypass between the anterior choroidal and the PCOM was done. Both bypasses were patent and the patient has done well with a mRS of 1 for vision symptoms.The video can be found here: http://youtu.be/ciMyzfXgo8I.
46
Woitzik, Johannes, Peter Horn, Peter Vajkoczy, and Peter Schmiedek. "Intraoperative control of extracranial—intracranial bypass patency by near-infrared indocyanine green videoangiography." Journal of Neurosurgery 102, no. 4 (April 2005): 692–98. http://dx.doi.org/10.3171/jns.2005.102.4.0692.
Full textAbstract:
Object. Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial—intracranial bypass patency. Methods. Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moyamoya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)—middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA—posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter—equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography. In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA—MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG videoangiography could be positively validated during the postoperative course by performing DS or CT angiography. Conclusions. Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG videoangiography may help reduce the incidence of early bypass graft failure.
47
Nisson, Peyton L., Xinmin Ding, Ali Tayebi Meybodi, Ryan Palsma, Arnau Benet, and Michael T. Lawton. "Revascularization of the Posterior Inferior Cerebellar Artery Using the Occipital Artery: A Cadaveric Study Comparing the p3 and p1 Recipient Sites." Operative Neurosurgery 19, no. 2 (February 28, 2020): E122—E129. http://dx.doi.org/10.1093/ons/opaa023.
Full textAbstract:
Abstract BACKGROUND Revascularization of the posterior inferior cerebellar artery (PICA) is typically performed with the occipital artery (OA) as an extracranial donor. The p3 segment is the most accessible recipient site for OA-PICA bypass at its caudal loop inferior to the cerebellar tonsil, but this site may be absent or hidden due to a high-riding location. OBJECTIVE To test our hypothesis that freeing p1 PICA from its origin, transposing the recipient into a shallower position, and performing OA-p1 PICA bypass with an end-to-end anastomosis would facilitate this bypass. METHODS The OA was harvested, and a far lateral craniotomy was performed in 16 cadaveric specimens. PICA caliber and number of perforators were measured at p1 and p3 segments. OA-p3 PICA end-to-side and OA-p1 PICA end-to-end bypasses were compared. RESULTS OA-p1 PICA bypass with end-to-end anastomosis was performed in 16 specimens; whereas, OA-p3 PICA bypass with end-to-side anastomosis was performed in 11. Mean distance from OA at the occipital groove to the anastomosis site was shorter for p1 than p3 segments (30.2 vs 48.5 mm; P < .001). Median number of perforators on p1 was 1, and on p3, it was 4 (P < .001). CONCLUSION Although most OA-PICA bypasses can be performed using the p3 segment as the recipient site for an end-to-side anastomosis, a more feasible alternative to conventional OA-p3 PICA bypass in cases of high-riding caudal loops or aberrant anatomy is to free the p1 PICA, transpose it away from the lower cranial nerves, and perform an end-to-end OA-p1 PICA bypass instead.
48
Kram, Harry B., and Masashi Uriu. "Minimally Invasive Endoscopic Video-Assisted in Situ Bypass: First 15 Cases." American Surgeon 65, no. 11 (November 1999): 1003–8. http://dx.doi.org/10.1177/000313489906501101.
Full textAbstract:
The purpose of the present study was to determine the feasibility of endoscopic video-assisted (EVA) in situ bypass with greater saphenous vein (SV) for femorotibial revascularization. Fifteen consecutive patients who underwent EVA lower extremity revascularization were included in the present report. EVA in situ bypass was successfully accomplished in 12 of 15 (80%) patients. Two patients had major SV injuries (endoscopic scissors), and 6 patients had minor SV injuries (dissecting ring, clip applicator, valvulotome). Postoperatively, 2 patients developed subcutaneous abscesses in the thigh graft tunnel, and 5 patients developed minor calf wound necrosis. Eight of 12 (67%) EVA in situ bypasses were patent at 6- to 32-month follow-up (mean, 24 months), and 2 of 12 (17%) patients died with patent EVA in situ bypasses; one other patient experienced EVA in situ bypass thrombosis 6 months postoperatively without further surgical treatment. Ten of 12 (83%) patients who underwent EVA in situ bypass had successful surgical outcomes, and 11 of 12 (92%) avoided major amputation; 1 patient eventually required below-knee amputation because of nonhealing foot lesions despite a patent EVA in situ bypass. We conclude that EVA in situ bypass with SV is a practical technique for limiting the length and number of incisions necessary to completely eliminate SV tributaries. On the basis of experience gained from the present series, we recommend the following: 1) strategic placement of the initial small skin incisions to maximize exposure of the SV and inflow/outflow arteries; 2) beginning gas insufflation into the perivenous space during initial SV dissection, rather than after creation of the perivenous tunnel; 3) no transection of clipped SV tributaries with the endoscopic scissors; 4) minimal use of the dissecting ring to expose the SV and its tributaries, instead using continuous gas insufflation and the balloon dissector; and 5) completion angiography to inspect the bypass graft and runoff.
49
Januszewski, Jacob, Jeffrey S. Beecher, David J. Chalif, and Amir R. Dehdashti. "Flow-based evaluation of cerebral revascularization using near-infrared indocyanine green videoangiography." Neurosurgical Focus 36, no. 2 (February 2014): E14. http://dx.doi.org/10.3171/2013.12.focus13473.
Full textAbstract:
Object Indocyanine green (ICG) videoangiography has been established as a noninvasive technique to gauge the patency of a bypass graft; however, intraoperative graft patency may not always correlate with graft flow. Altered flow through the bypass graft may directly cause delayed graft occlusion. Here, the authors report on 3 types of flow that were observed through cerebral revascularization procedures. Methods Between February 2009 and September 2013, 48 bypass procedures were performed. Excluded from analysis were those cases in which ICG videoangiography was not performed during surgery (whether it was not available or there was a technical issue with the microscope or the quality of ICG angiography) and/or in which angiography or CT angiography was not done within 24–72 hours after surgery. After anastomosis, bypass patency was assessed first using a noninvasive technique and then with ICG videoangiography, and flow through the graft was characterized. Patients who received a vein or radial artery graft were also evaluated with intraoperative angiography. Results Thirty-three patients eligible for analysis were retrospectively analyzed. The patients had undergone extracranial-intracranial (EC-IC) or IC-IC bypass for ischemic stroke (13 patients), moyamoya disease (10 patients), and complex aneurysms (10 patients; 6 giant or large aneurysms, 2 carotid blister-like aneurysms, and 2 dissecting posterior inferior cerebellar artery [PICA] aneurysms). Thirty-six bypasses were performed including 26 superficial temporal artery (STA)–middle cerebral artery (MCA) bypasses (2 bilateral and 1 double-barrel), 6 EC-IC vein grafts, 1 EC-IC radial artery graft, 1 PICA-PICA bypass, 1 MCA–posterior cerebral artery bypass, and 1 occipital artery–PICA bypass. Robust anterograde flow (Type I) was noted in 31 grafts (86%). Delayed but patent graft enhancement and anterograde flow (Type II) was observed in 4 cases (11%); 1 of these cases with an EC-IC vein graft degraded gradually to very delayed flow with no continuity to the bypass site (Type III). Additionally, 1 STA-MCA bypass graft revealed no convincing flow (Type III). The 5 patients with Type II or III grafts were evaluated with a flow probe and reexploration of the bypass site, and in all cases the reason the graft became occluded was believed to be recipient-vessel competitive flow. In no case was there evidence of stenosis or a technical issue at the site of the anastomosis. Three patients with Type II and the 1 patient with Type III flow (11% of procedures) did not have a patent bypass on postoperative imaging. Conclusions Indocyanine green videoangiography is reliable for evaluating flow through the EC-IC or IC-IC bypass. The type of flow observed through the graft has a direct relationship with postoperative imaging findings. Despite the possibility of competitive flow, Type III and some Type II flows through the graft indicate the need for graft evaluation and anastomosis exploration.
50
Ekelund, K. M., and E. Ekblad. "Structural, neuronal, and functional adaptive changes in atrophic rat ileum." Gut 45, no. 2 (August 1, 1999): 236–45. http://dx.doi.org/10.1136/gut.45.2.236.
Full textAbstract:
BACKGROUNDInactivity of the gut leads to atrophic changes of which little is known.AIMSTo investigate structural, neuronal, and functional changes occurring in bypassed rat ileum.METHODSMorphometry was used to characterise the atrophic changes. The numbers of enteric neurones, their expression of neurotransmitters, and the presence of interstitial cells of Cajal were studied using immunocytochemistry and in situ hybridisation. Motor activity was studied in vitro.RESULTSAdaptive changes in bypassed ileum include atrophy and remodelling of the gut wall. The total numbers of submucous and myenteric neurones per unit length increased one and four weeks after bypass but were identical to sham operated intestine 10 weeks after bypass. Neurones expressing vasoactive intestinal peptide, neuropeptide Y, or pituitary adenylate cyclase activating peptide decreased gradually in number in bypassed ileum. Nitric oxide synthase expressing neurones were increased, particularly in the myenteric ganglia. No change in the frequency and distribution of interstitial cells of Cajal was noted. The contractile response elicited by electrical stimulation of sham operated ileum consisted of a fast cholinergic twitch followed by a slower non-adrenergic, non-cholinergic contraction. In the bypassed ileum an identical biphasic contraction was elicited; however, the entire response was non-adrenergic, non-cholinergic. The relaxatory response to electrical stimulation in sham operated ileum was nitric oxide mediated; after bypass it was non-nitrergic.CONCLUSIONSNotable atrophic changes were seen in the rat ileum after bypass. The enteric nervous system reacted with neuronal cell death and plasticity in terms of release and expression of neurotransmitters.