Journal articles on the topic 'Stenosis'
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Al-Azawy, Mohammed Ghalib, Zahraa Ahmed Hamza, and Alaa Ahmed Alkinani. "Non-invasive evaluation of blood flow through a healthy and stenosed coronary artery." Wasit Journal of Engineering Sciences 10, no. 3 (February 21, 2023): 58–74. http://dx.doi.org/10.31185/ejuow.vol10.iss3.369.
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The current numerical analysis was utilised to compare the hemodynamic effects caused by flow disruptions in coronary arteries with and without stenosis in order to evaluate the hemodynamic importance of patient-specific coronary stenosis using Computational Fluid Dynamics (CFD) to provide information to the public, particularly surgeons, and assist them in reducing the risk of stenosis. Assuming the flow is turbulent and non-Newtonian viscosity, the Carreau model is incorporated by utilizing STAR-CCM+ 2021.2.1. The test model is a patient-specific coronary stenosis with area stenosis (60%). The velocity, shear stress, and strain rate were evaluated and revealed that the stenosed artery experiences more hemodynamic impacts as the flow rate increases compared to the normal artery. The turbulent kinetic energy and turbulent viscosity ratio findings showed that the TKE and TVR are almost the same downstream of the stenoses, with the TKE and TVR being somewhat higher with the stenosed artery model than the unstenosed artery model, and it increases as the flow increases. Moreover, to determine the stenosis severity, the coefficient of pressure drop (CDP) and lesion flow coefficient (LFC) were used and showed that the CDP value be higher in stenosed artery (107pa) compared to a normal artery (5.2pa) but it was less when the flow increased (84.4pa), (2.5pa) respectively. whereas the LFC value in the stenoses artery is higher (0.61) and rises as flow increases (0.69).
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BANERJEE, MOLOY K., DEBABRATA NAG, RANJAN GANGULY, and AMITAVA DATTA. "HEMODYNAMICS IN STENOSED ARTERIES — EFFECTS OF STENOSIS SHAPES." International Journal of Computational Methods 07, no. 03 (September 2010): 397–419. http://dx.doi.org/10.1142/s021987621000226x.
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A numerical analysis has been carried out to investigate the hemodynamic flow through stenosed arteries having mild (S = 25%) to severe (S = 65%) occlusions and under different regimes of flow Reynolds numbers ( Re ) ranging from 50 to 400. Influence of different stenosis shapes (rectangular, trapezoidal, cosine, and Gaussian) on key hemodynamic parameters e.g., recirculation length, wall shear stress (WSS), pressure drop, and irreversible pressure loss coefficient (C I ) are studied. It has been observed that for S = 25%, no flow separation takes place with cosine and Gaussian shaped stenoses for all the Re values considered, while for rectangular or trapezoidal shapes the flow begins to separate at Re = 400. At higher degrees of stenosis, post-stenotic recirculation is noticed for all the shapes considered — the largest recirculation length being observed with the rectangular shape. The peak centerline velocity in the stenosed region is more sensitive to a change in the degree of occlusion for rectangular stenosis than the other shapes. From the study, it is also revealed that the irreversible pressure loss coefficient (C I ) is the maximum for rectangular shaped stenosis, while it is the least for Gaussian shape. It is observed that at high Re regime, C I becomes insensitive to Re values and can be approximated to be a function of the degree of stenosis (S) and the stenosis shape only.
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Liu, H., X. Wu, Y. Xing, K. Liu, and H. Zhang. "Neurology (Stroke)." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 42, S1 (May 2015): S36. http://dx.doi.org/10.1017/cjn.2015.165.
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Background: Cerebral artery stenosis is an important risk factor for ischemic strokes. This study aims to explore intracranial and extracranial artery stenosis in a large northeast Chinese cohort. Methods: We recruited 14793 outpatients and hospitalized patients to identify cerebral artery stenosis. Artery stenosis screening was done with transcranial Doppler (TCD) for intracranial arteries and carotid duplex sonography for extracranial arteries. Results: More intracranial than extracranial artery stenoses were identified (4255 versus 2809, i.e. 28.8% versus 19.0%, P<0.05). Similarly, mere intracranial stenosis was significantly more common than extracranial artery stenosis in this population (2632 versus 1186, i.e. 17.8% versus 8%, P<0.05). Among all identified intracranial arteries stenoses, the proportion of middle cerebral artery (MCA) stenosis was the highest. More intracranial than extracranial artery stenoses was seen within each age group, and rates of both increased with age. Intracranial and extracranial artery stenosis was more frequently identified in males than females. Conclusions: Incidence of cerebral artery stenosis in the population increases with age. Intracranial artery stenosis is more common than extracranial artery stenosis and the MCA stenosis accounted for the highest proportion, within each age group. More males suffer from intracranial or extracranial artery stenosis than females.
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Tong, Y., P. G. Matthews, and J. P. Royle. "Outcome of Endovascular Intervention for Infrainguinal Vein Graft Stenosis." Cardiovascular Surgery 10, no. 6 (December 2002): 545–50. http://dx.doi.org/10.1177/096721090201000605.
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Assisted graft patency rate following revision of a graft stenosis is far better than that following thrombectomy of an occluded graft. Graft revision by endovascular means has been proposed as a suitable alternative to more invasive surgery. This study reports our experience with endovascular treatment of vein graft stenosis. Between December 1992 and September 2000, percutaneous transluminal balloon angioplasty (PTA) was performed on 90 vein graft stenoses in 87 infrainguinal vein bypass grafts identified by routine graft duplex scan (peak systolic velocity, PSV > 300 cm/sec). All 90 stenoses treated by PTA were retrospectively analysed for stenosis-free patency rate (life-table analysis). Re-stenosis was defined by PSV exceeding 300 cm/sec at the same site of the vein graft where a stenosis was dilated. Ninety vein graft stenoses (72 primary stenoses and 18 recurrent stenoses) in 33 femoropopliteal (above knee), 30 femoropopliteal (below knee) and 24 femorotibial vein bypass grafts were treated by PTA. The timing of PTA ranged from one to 252 months (mean. 23.9 months) from the initial surgery. Cumulative stenosis-free patency rate after PTA was 55.8% at 6 months, 54.0% at one year and 45.0% at three years. Stenosis-free patency rate at six months was significantly lower for revision of recurrent stenosis (25.9%) than for primary stenosis (61.6%) ( P = 0.01). The revision of duplex scan detected vein graft stenosis with endovascular intervention was associated with an acceptable stenosis-free patency rate. However, recurrent stenosis treated by PTA had a significantly inferior outcome. Direct surgical revision would be more appropriate for recurrent lesions.
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Liu, Biyue, and Dalin Tang. "Influence of Distal Stenosis on Blood Flow Through Coronary Serial Stenoses: A Numerical Study." International Journal of Computational Methods 16, no. 03 (March 17, 2019): 1842003. http://dx.doi.org/10.1142/s0219876218420033.
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Computer simulations of the blood flow through right coronary arteries with two stenoses in the same arterial segment are carried out to investigate the interactions of serial stenoses, especially the effect of the distal stenosis. Various mathematical models are developed by varying the location of the distal stenosis. The numerical results show that the variation of the distal stenosis has significant impact on coronary hemodynamics, such as the pressure drop, flow shifting, wall shear stress and flow separation. Our simulations demonstrate that the distal stenosis has insignificant effect on the disturbed flow pattern in the regions of upstream and across the proximal stenosis. In a curved artery segment with two moderate stenoses of the same size, the distal stenosis causes a larger pressure drop and a more disturbed flow field in the poststenotic region than the proximal stenosis does. A distal stenosis located at a further downstream position causes a larger pressure drop and a stronger reverse flow.
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Lougheed, Nick, Jeff Jaskolka, Rob Beecroft, and Ravi Menezes. "Determination of the Best Parameter for Defining the Hemodynamic Significance of an Iliac Artery Stenosis Detected on Computed Tomography Angiography." Canadian Association of Radiologists Journal 67, no. 3 (August 2016): 298–303. http://dx.doi.org/10.1016/j.carj.2015.09.005.
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Purpose The purpose of this study was to determine the best parameter, derived from computed tomography angiography (CTA) for accurate prediction of a hemodynamically significant stenosis of the common or external iliac artery. Methods A retrospective keyword search was performed on the Radiology Information System at our tertiary academic medical centre. Reports from January 2008 to September 2013 were searched using the keywords iliac, stenosis, and pressure. Patients who had both and CTA and a pelvic angiogram with pressure measurements obtained across a potential stenosis were selected. Using 3D postprocessing software (TeraRecon, Foster City, CA), the CTAs were analysed for the following parameters of each lesion: minimum diameter of stenosis, minimum cross-sectional area of stenosis, percent narrowing of vessel diameter, and percent reduction in vessel area. The percent stenosis was calculated in reference to the outer diameter at the point of maximal narrowing and also in reference to a normal segment of vessel more distal to the stenosis. These parameters were then compared with the measured pressure gradient using receiver-operating characteristic analysis and the Mann-Whitney U test to determine which best predicted a significant stenosis, defined as a greater than 10% drop in systolic pressure across a lesion. Results One hundred and two stenoses in 83 patients (26 women, 57 men; 47-88 years old) were identified. Mean diameter of the stenosis was 2.8 mm for significant stenosis compared to 3.8 mm in nonsignificant stenoses ( P = .005). Mean minimum area for significant stenoses was 11.8 mm2 compared to 17.22 mm2 for nonsignificant stenoses ( P = .032) No other variables showed a significant difference between significant and nonsignificant stenoses. A minimum diameter of ≤4.0 mm at the level of a stenosis is 92% sensitive and 48% specific for predicting a hemodynamically significant iliac artery stenosis, with a positive predictive value of 88%. Conclusions A simple measurement of the minimum diameter of an iliac artery at the level of stenosis is the best predictor of the hemodynamic significance of a stenosis in the common or external iliac artery.
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Varnava, A. M., and M. J. Davies. "Relation between coronary artery remodelling (compensatory dilatation) and stenosis in human native coronary arteries." Heart 86, no. 2 (August 1, 2001): 207–11. http://dx.doi.org/10.1136/hrt.86.2.207.
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OBJECTIVESTo investigate the contribution of plaque size and vessel remodelling to coronary artery stenosis and to assess the role of vessel shrinkage (negative remodelling) across a wide range of lesions.DESIGNPostmortem study of coronary remodelling in perfusion fixed hearts.SUBJECTS24 men and 24 women who died suddenly with coronary artery disease.MAIN OUTCOME MEASURESPercentage stenosis, percentage plaque burden, percentage remodelling, and arc of normal vessel were measured and related to age, sex, smoking status, and history of hypertension.RESULTSThere was a positive relation between percentage stenosis and percentage plaque burden (r = 0.6, p < 0.0001) and an inverse relation between percentage stenosis and percentage remodelling (r = –0.4, p < 0.0001). Multilinear regression modelling showed that luminal stenosis = 1.0 (plaque burden) − 0.4 (vessel remodelling). Remodelling was greater in lesions that would not have been significant at angiography (⩽ 25% stenosis) than in the remaining lesions (25.9 (26)% v10.0 (21.1)%, p < 0.0001, respectively) and was reduced in segments with circumferential plaques (12.7 (24.5)% v20.7 (24.3)% in eccentric plaques, p = 0.001). Remodelling did not correlate with age, sex, or smoking. Negative remodelling was present in 62 lesions with a stenosis > 25% versus 10 lesions with ⩽ 25% stenosis (p < 0.0001). Lesions with negative remodelling had greater plaque burden and luminal stenosis and a reduced arc of normal segment.CONCLUSIONOutward arterial remodelling negates the stenosing effect of increasing plaque size. Significant coronary stenoses arise from a failure of this outward remodelling in the face of a large plaque burden. Coronary arterial remodelling is unrelated to sex or smoking and is plaque specific.
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Loree, H. M., R. D. Kamm, C. M. Atkinson, and R. T. Lee. "Turbulent pressure fluctuations on surface of model vascular stenoses." American Journal of Physiology-Heart and Circulatory Physiology 261, no. 3 (September 1, 1991): H644—H650. http://dx.doi.org/10.1152/ajpheart.1991.261.3.h644.
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Turbulence frequently develops when blood passes through a stenosis. To study the hypothesis that turbulence near a plaque surface can cause pressure fluctuations that may promote plaque rupture, models of intravascular stenoses were studied. Experimental conditions simulated peak flow in the coronary and carotid arteries through a stenosis of 80 or 90% diameter reduction and into a region where the plaque had widened distally to a 50-75% stenosis. For symmetric stenoses at carotid artery flow rates, peak pressure fluctuations were observed 1-1.5 upstream diameters distal to the stenosis, but there were no significant turbulent pressure fluctuations at coronary artery flow rates. Stenosis asymmetry strongly increased the intensity of turbulent pressure fluctuations at flows simulating carotid flow and resulted in significant pressure fluctuations for coronary flow conditions. Increasing stenosis severity from 80 to 90% increased the root mean square pressure fluctuations 3.6-fold. These studies predict peak to peak pressure fluctuations of 15 mmHg in a 90% asymmetric coronary stenosis; it is possible that turbulence may play a role in acute damage of atherosclerotic plaques, particularly in asymmetric stenoses.
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Tirinescu, Dacian Călin, Cosmina Ioana Bondor, Dan Ştefan Vlăduțiu, Ioan Mihai Pațiu, Diana Moldovan, Remus Orășan, and Ina Maria Kacsó. "Ultrasonographic diagnosis of stenosis of native arteriovenous fistulas in haemodialysis patients." Medical Ultrasonography 18, no. 3 (September 18, 2016): 332. http://dx.doi.org/10.11152/mu.2013.2066.183.fis.
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Aims: Ultrasound (US) examination is an important tool in the diagnosis of arteriovenous (AVF) stenoses; different US measures are available for assessing the severity of stenoses. The aim of our study was to analyse risk factors and consequences of AVF stenosis and its severity and to compare the usefulness of different US measures of stenoses’ severity. Material and methods: Ninety-seven prevalent patients from a single dialysis centre with patent AVF were included. We recorded history of disease, clinical and laboratory data. US was used to diagnosis the stenosis and to measure blood flow in the brachial artery, resistivity index (RI), and the diameter of the vessels (arteries, anastomosis, venous outflow). Results: Stenosis was present in 54.64% of the patients (59.6% juxtaanastomotic). Stenosis patients had higher age, lower diameter of the brachial artery, lower anastomosis diameter, and lower diastolic blood pressure (DBP). Atherosclerosis, delayed maturation of AVF, and statin treatment were more prominent in the stenosis group. Logistic regression disclosed delayed maturation, cholesterol, atherosclerosis, and DBP as significant predictors of stenosis. When severe stenosis was measured by the diameter reduction, stenosis patients had higher age, lower HDL cholesterol, and poorer dialysis efficacy. Flow in the brachial artery and RI were less useful for identifying risk factors or differences in outcome. Conclusions: Prevalence of stenosis was high in our cohort, more than half of the patients having some degree of stenosis. Risk factors for stenosis were related to atherosclerosis, low DBP, and delayed maturation of AVF. Diameter of stenosis is the most useful marker of severity.
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He, Fan, Lu Hua, and Tingting Guo. "Fluid–structure interaction analysis of hemodynamics in different degrees of stenoses considering microcirculation function." Advances in Mechanical Engineering 13, no. 1 (January 2021): 168781402198901. http://dx.doi.org/10.1177/1687814021989012.
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In developed countries, stenosis is the main cause of death. To investigate hemodynamics within different degrees of stenoses, a stenosis model incorporating fluid–structure interaction and microcirculation function is used in this paper. Microcirculation is treated as a seepage outlet boundary condition. Compliant arterial wall is considered. Numerical simulation based on fluid–structure interaction is performed using finite element method. Our results indicate that (i) the increasing degree of stenosis makes the pressure drop increase, and (ii) the wall shear stress and the velocity in the artery zone may be more sensitive than the pressure with the increase of percentage stenosis, and (iii) there are higher wall shear stress and flow velocity in the post-stenosis region of severer stenosis. This work contributes to understand hemodynamics for different degrees of stenoses and it provides detailed information for stenosis and microcirculation function.
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Schwartz, J. S., and R. J. Bache. "Effect of arteriolar dilation on coronary artery diameter distal to coronary stenoses." American Journal of Physiology-Heart and Circulatory Physiology 249, no. 5 (November 1, 1985): H981—H988. http://dx.doi.org/10.1152/ajpheart.1985.249.5.h981.
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Previous studies have suggested that worsening hemodynamic severity of coronary stenoses in response to distal arteriolar dilation may be related to dilation of the normal epicardial artery adjacent to the stenosis resulting in increasing percent stenosis. To test this hypothesis we used sonomicrometry to continuously measure external circumflex coronary artery diameter distal to snare stenoses of varying severity in 19 open-chest dogs and 5 awake, chronically instrumented dogs. Arteriolar dilation produced by release of a transient coronary occlusion or by intracoronary injection of adenosine caused a decrease in circumflex coronary diameter distal to the stenosis. Regression analysis showed that circumflex diameter and pressure distal to the stenosis were directly related (mean r: transient occlusion, 0.86 +/- 0.04; adenosine, 0.97 +/- 0.01). The close relationship between pressure and diameter suggests that the decrease in diameter in response to arteriolar dilation was a passive effect. Passive coronary narrowing distal to a stenosis suggests that a similar effect may occur within a compliant stenosis, thus partly explaining the increase in severity of compliant stenoses in response to arteriolar dilation.
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Su, C. M., D. Lee, R. Tran-Son-Tay, and W. Shyy. "Fluid Flow Structure in Arterial Bypass Anastomosis." Journal of Biomechanical Engineering 127, no. 4 (February 15, 2005): 611–18. http://dx.doi.org/10.1115/1.1934056.
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The fluid flow through a stenosed artery and its bypass graft in an anastomosis can substantially influence the outcome of bypass surgery. To help improve our understanding of this and related issues, the steady Navier-Stokes flows are computed in an idealized arterial bypass system with partially occluded host artery. Both the residual flow issued from the stenosis—which is potentially important at an earlier stage after grafting—and the complex flow structure induced by the bypass graft are investigated. Seven geometric models, including symmetric and asymmetric stenoses in the host artery, and two major aspects of the bypass system, namely, the effects of area reduction and stenosis asymmetry, are considered. By analyzing the flow characteristics in these configurations, it is found that (1) substantial area reduction leads to flow recirculation in both upstream and downstream of the stenosis and in the host artery near the toe, while diminishes the recirculation zone in the bypass graft near the bifurcation junction, (2) the asymmetry and position of the stenosis can affect the location and size of these recirculation zones, and (3) the curvature of the bypass graft can modify the fluid flow structure in the entire bypass system.
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Intan Diyana Munir, Nurul Aini Jaafar, and Sharidan Shafie. "Solute Dispersion in an Unsteady Herschel-Bulkley Flow through an Inclined Stenosed Arter." Journal of Advanced Research in Numerical Heat Transfer 14, no. 1 (October 11, 2023): 29–38. http://dx.doi.org/10.37934/arnht.14.1.2938.
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Motivated by the concept of blood flow in a stenosed artery, this present research investigates the influence of stenosis shape in terms of height and arterial inclination on the blood flow and solute dispersion behaviour through an inclined stenosed artery. The blood rheology is depicted using the Herschel-Bulkley model in a laminar, axisymmetric and incompressible unsteady flow through the stenosed artery. The effect of stenosis is focused on the stenosis height for both sine and cosine stenosis. Parameters of arterial inclination are also investigated to observe the effect of inclination on the blood velocity and dispersion function. Perturbation method is adopted in solving for the blood flow velocity under the effect of stenosis height and arterial inclination. The dispersion function of solute dispersion is solved using the obtained blood velocity by adopting the Generalized Dispersion Model (GDM) in obtaining steady dispersion functions. This present study shows that the increase in stenosis height decreases both blood velocity and dispersion function. Meanwhile, the increase in arterial inclination increases the blood velocity and dispersion function. The effect of stenosis height also affects blood velocity and dispersion function for the sine stenosis more than the cosine stenosis.
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Tang, D., J. Yang, C. Yang, and D. N. Ku. "A Nonlinear Axisymmetric Model With Fluid–Wall Interactions for Steady Viscous Flow in Stenotic Elastic Tubes." Journal of Biomechanical Engineering 121, no. 5 (October 1, 1999): 494–501. http://dx.doi.org/10.1115/1.2835078.
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Arteries with high-grade stenoses may compress under physiologic conditions due to negative transmural pressure caused by high-velocity flow passing through the stenoses. To quantify the compressive conditions near the stenosis, a nonlinear axisymmetric model with fluid–wall interactions is introduced to simulate the viscous flow in a compliant stenotic tube. The nonlinear elastic properties of the tube (tube law) are measured experimentally and used in the model. The model is solved using ADINA (Automatic Dynamic Incremental Nonlinear Analysis), which is a finite element package capable of solving problems with fluid–structure interactions. Our results indicate that severe stenoses cause critical flow conditions such as negative pressure and high and low shear stresses, which may be related to artery compression, plaque cap rupture, platelet activation, and thrombus formation. The pressure field near a stenosis has a complex pattern not seen in one-dimensional models. Negative transmural pressure as low as −24 mmHg for a 78 percent stenosis by diameter is observed at the throat of the stenosis for a downstream pressure of 30 mmHg. Maximum shear stress as high as 1860 dyn/cm2 occurs at the throat of the stenoses, while low shear stress with reversed direction is observed right distal to the stenosis. Compressive stresses are observed inside the tube wall. The maximal principal stress and hoop stress in the 78 percent stenosis are 80 percent higher than that from the 50 percent stenosis used in our simulation. Flow rates under different pressure drop conditions are calculated and compared with experimental measurements and reasonable agreement is found for the prebuckling stage.
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Spaetgens, Renée L., Walter J. Duncan, and Glenn P. Taylor. "Supravalvar aortic stenosis with supravalvar pulmonary stenosis and peripheral vascular stenoses." Cardiology in the Young 12, no. 3 (May 2002): 290–93. http://dx.doi.org/10.1017/s104795110200063x.
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A non-dysmorphic 10 month old female was discovered at surgery to have severe vasculopathy of both the systemic and pulmonary arteries. These findings were confirmed by pathologic examination. Followup angiography has confirmed multiple sites of vascular obstruction which appear to be worsening. Angioplasty has only partially relieved these obstructions. The pathology and possible etiology are reviewed.
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Morisaki, Yudai, Ichiro Nakagawa, Koji Omoto, Takeshi Wada, Kimihiko Kichikawa, and Hiroyuki Nakase. "Endovascular treatment of idiopathic intracranial hypertension caused by multiple venous sinus stenoses." Surgical Neurology International 10 (March 26, 2019): 47. http://dx.doi.org/10.25259/sni-94-2019.
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Background: Idiopathic intracranial hypertension (IIH) shows symptoms by elevating intracranial pressure. Although sinus stenosis has been detected in many patients with IIH, the role of sinus stenosis in IIH remains obscure. Endovascular treatment for IIH due to transverse sinus stenosis has been frequently documented; however, IIH due to multiple sinus stenoses including the superior sagittal sinus (SSS) is rare. Here, we report a case of IIH due to multiple sinus stenoses treated by sinus stenting. Case Presentation: A 47-year-old woman suffered from intractable headache with IIH presented with stenosis of the right transverse and SSS. Stent placement was carried out since intracranial hypertension and trans-stenotic cerebral venous pressure gradient (CVPG) were presented, and her intractable headache disappeared. Conclusion: IIH can be caused by venous sinus stenoses and stent placement could be an appropriate treatment in patients who demonstrated a CVPG.
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Graziotti, P. P., A. Piccinelli, L. Faggiano, M. Scanzi, and A. Calabrò. "Urethral Stenosis following Transurethral Resection." Urologia Journal 59, no. 1 (February 1992): 50–52. http://dx.doi.org/10.1177/039156039205900111.
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The authors report the results of a multicentric prospective study on risk factors related to post-TURP stenosis. 47 different parameters were considered and 21 urethral stenoses (9% of 234 patients) are reported. Meatal stenoses are included, but were not considered for statistical correlation with other sites. Final data, statistically examined, show that electrotomes (Martin/Danieli), urethral lubricant and rubber catheters, singly or jointly, are possibly related to post-TURP urethral stenosis.
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Durst, Christopher R., David A. Ornan, Michael A. Reardon, Prachi Mehndiratta, Sugoto Mukherjee, Robert M. Starke, Max Wintermark, et al. "Prevalence of dural venous sinus stenosis and hypoplasia in a generalized population." Journal of NeuroInterventional Surgery 8, no. 11 (January 8, 2016): 1173–77. http://dx.doi.org/10.1136/neurintsurg-2015-012147.
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Background and purposeWhile recent literature has described the prevalence of transverse sinus stenosis in patients with idiopathic intracranial hypertension, tinnitus, and refractory headaches, it is unclear what the prevalence is in the general population. This study evaluates the prevalence of venous sinus stenosis and hypoplasia in the general patient population.Materials and methods355 of 600 consecutive patients who underwent CT angiography of the head met the inclusion criteria. The diameters of the dural venous sinuses were recorded. Each study was evaluated by a neuroradiologist for the presence of stenoses. Univariate and multivariate statistical analyses were performed by a statistician.ResultsThe prevalence of unilateral transverse sinus stenosis or hypoplasia in a sample of patients representing the general population was 33%, the prevalence of bilateral transverse sinus stenosis was 5%, and the prevalence of unilateral stenosis with contralateral hypoplasia was 1%. A multivariate analysis identified arachnoid granulations as a predictor of stenosis (p<0.001). Gender trended toward significance (p=0.094). Race was not a significant predictor of stenosis (p=0.745).ConclusionsThe prevalence of bilateral transverse sinus stenosis in the general population is not trivial. These data may be used as a reference for understanding the mechanistic role of stenoses in idiopathic intracranial hypertension, tinnitus, and refractory headaches.
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Czaja, Judith M., and Thomas V. McCaffrey. "Acoustic Measurement of Subglottic Stenosis." Annals of Otology, Rhinology & Laryngology 105, no. 7 (July 1996): 504–9. http://dx.doi.org/10.1177/000348949610500702.
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A device that determines cross-sectional area (CSA) of the airway by acoustic ref lections (Hood, Inc) was used to measure subglottic area. Airway models were made from Plexiglas rings with known internal dimensions similar to clinically encountered stenoses of various lengths and diameters. Acoustic measurements of airway area were made and compared to actual CSA. There is a strong correlation between CSA measured acoustically and the actual area of simulated stenoses. However, when the CSA of the stenosis was <0.64 cm2, the signal was impaired, resulting in overestimation of the stenotic CSA. In simulated stenoses with a CSA of <0.38 cm2, acoustic measurement of the CSA beyond the stenotic segment was unreliable. Determination of the origin of stenosis was accurate with this method. The CSA of cadaver airways was also measured acoustically. The CSA 2.0 cm below the glottis of normal airways in males ranged from 1.28 to 2.74 cm2 and in females 0.87 to 1.43 cm2, with means of 2.16 and 1.09 cm2. It appears that acoustic measurement of CSA of subglottic stenosis is a feasible clinical technique that yields dimensions of the airway in situations in which direct measurements are impossible. It was suggested that this technique be used for assessment of subglottic stenosis and evaluation of the efficacy of treatment of subglottic stenosis.
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Razumnikova, O. M., I. V. Tarasova, O. A. Trubnikova, and O. L. Barbarash. "The changes in the structure of cognitive functions and anxiety in cardiac surgery patients depending on the severity of carotid arteries." Complex Issues of Cardiovascular Diseases 11, no. 1 (March 25, 2022): 36–48. http://dx.doi.org/10.17802/2306-1278-2022-11-1-36-48.
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Highlights. The article revealed that severe (more than 50%) carotid artery (CA) stenosis was associated with significant slowdown of the information selection processes, and these patients were characterized by older age and tendency to an increase in trait anxiety compared to the patients without CA stenosis.It was found that the reduced attention and memory was a typical feature of the cognitive status in patients with severe CA stenosis in the early postoperative period of cardiac surgery in comparison with the patients without CA stenosis. At the same time the speed characteristics indicators of the information selection processes in these patients are positively related to state anxiety.Aim. The cardiac surgery patients were studied in order to analyze the postoperative changes in the efficiency of selection information and memory processes depending on the degree of carotid artery (CA) stenosis (including more than 50%) and the age and the role of the trait anxiety indicator assessed before surgery.Methods. The prospective study included 229 patients undergoing elected coronary artery bypass grafting (CABG) or CABG and carotid endarterectomy (CEE). Each study participant underwent clinical, instrumental and extended psychometric examination before cardiac surgery and at 7-10 days after surgery. The evaluation of the extracranial vessels state was carried out before surgery using color duplex scanning. Based on the results of assessing the extracranial vessels state, all patients were divided into three groups: no stenosis (n = 124), CA stenosis less than 50% (n = 69) and more than 50% (n = 36).Results. It was found out that the patients with CA stenoses more than 50% are characterized by a slower reaction under different conditions of visual stimuli selection and by an older age as compared with patients with no stenoses as well as patients with stenoses less than 50%. In the postoperative period of cardiac surgery in comparison with testing before surgery there was an improvement in the information selection stability (an increase in the number of processed symbols per 4 minute of the Bourdon's test (p<0.00006)) and short-term memory (p = 0.03) only in the group of patients without stenoses. The patients with stenoses of less than 50% had an increase the of the information selection stability but the short-term memory decrease (p<0.05) whereas the group with stenoses more than 50% had a decrease in both the stability of information selection and short-term memory (p<0,05). Additional factors of cognitive deficit in CA stenosis patients were trait anxiety associated with memory impairment and a history of stroke that related to a decrease in the effectiveness of a complex visual-motor reaction.Conclusion. The comprehensive analysis of the cognitive status of cardiac surgery patients with different severity of CA stenosis showed that an increase in the age and stenosis degree is the factor of the reaction time slowdown under different conditions of information selection. To differentiate groups of patients depending on the severity of stenosis in the postoperative period the testing short-term memory and stability of attention is informative. These indicators improve in the group without stenosis but decrease in the group with pronounced stenosis. The trait anxiety and the history of stroke were the additional factors of memory impairment due to CA stenosis.
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Haas, Leandro José, Bernardo Przysiezny, Thaize Regina Scramocin, Natalia Tozzi Marques, Leticia Saori Tutida, Marina Piquet Sarmento, Omar Ahmad Omar, et al. "Using the Casper Stent in Carotid Angioplasty: A Single Center Experience." Arquivos Brasileiros de Neurocirurgia: Brazilian Neurosurgery 41, no. 01 (January 4, 2022): e1-e6. http://dx.doi.org/10.1055/s-0041-1740405.
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Abstract Objectives To establish the success rate in endovascular internal carotid artery (ICA) stenosis recanalization using the double-layer stent Casper-RX (Microvention, Inc 35 Enterprise, Aliso Viejo, California, United States of America) and to identify the main comorbidities in individuals with ICA stenosis, morphological characteristics of the stenosis, diagnostic methods, intraoperative complications, as well as morbidity and mortality within 30 days of the surgical procedure. Materials and Methods Retrospective analysis of 116 patients undergoing ICA angioplasty with a degree of stenosis ≥ 70% using Casper-RX stenting who underwent this procedure from April 2015 to December 2019. Results Technical success was achieved in 99.1% of the patients. Three of them had postprocedural complications: one transient ischemic attack (TIA) and two puncture site hematomas. A cerebral protection filter was not used in only two procedures, as these consisted of dissection of the carotid. There was satisfactory recanalization and adequate accommodation of the stents in the previously stenosed arteries, with no restenosis in 99.4% of the cases. Conclusion The endovascular treatment of extracranial carotid stenoses using the Casper-RX stent showed good applicability and efficacy. Although only two cases of thromboembolic complications occurred during the procedure, further investigation and studies on the effectiveness of this new device are needed.
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Strony, J., A. Beaudoin, D. Brands, and B. Adelman. "Analysis of shear stress and hemodynamic factors in a model of coronary artery stenosis and thrombosis." American Journal of Physiology-Heart and Circulatory Physiology 265, no. 5 (November 1, 1993): H1787—H1796. http://dx.doi.org/10.1152/ajpheart.1993.265.5.h1787.
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Shear stress and alterations in blood flow within a stenosed artery promote platelet-dependent thrombosis. Using the Folts model of coronary thrombosis, we evaluated morphology, histology, and the hemodynamic properties of the stenosed vessel in 18 animals. The average stenosis created was 58 +/- 8%, with stenosed vessel diameters ranging from 0.084 to 0.159 cm. Histological examination of the stenosed vessel demonstrated that thrombi were composed primarily of platelets and formation occurred 1.0 mm downstream from the apex of the constriction, propagating distally. Peak shear stress occurred just upstream from the apex of the stenosis and varied from 520 to 3,349 dyn/cm2. Only small differences in shear forces were noted when blood viscosity was calculated using Newtonian and non-Newtonian properties. In contrast, shear stress computed for Poiseuille flow with use of the stenosis diameter underestimated the apical shear stress. Blood flow remained laminar within the stenosis with a Reynolds number range of 292-534. Our data indicate that the geometry of the stenosis inflow region must be considered in the evaluation of platelet activation and thrombus formation within a stenosed artery.
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de Waard, Guus A., Christopher J. Broyd, Christopher M. Cook, Nina W. van der Hoeven, Ricardo Petraco, Sukhjinder S. Nijjer, Tim P. van de Hoef, et al. "Diastolic-systolic velocity ratio to detect coronary stenoses under physiological resting conditions: a mechanistic study." Open Heart 6, no. 1 (March 2019): e000968. http://dx.doi.org/10.1136/openhrt-2018-000968.
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ObjectiveDiastolic-systolic velocity ratio (DSVR) is a resting index to assess stenoses in the left anterior descending artery (LAD). DSVR can be measured by echocardiographic or intracoronary Doppler flow velocity. The objective of this cohort study was to elucidate the fundamental rationale underlying the decreased DSVR in coronary stenoses.MethodsIn cohort 1, simultaneous measurements of intracoronary Doppler flow velocity and pressure were acquired in the LAD of 228 stable patients. Phasic stenosis resistance, microvascular resistance and total vascular resistance (defined as stenosis and microvascular resistance combined) were studied during physiological resting conditions. Stenoses were classified according to severity by strata of 0.10 fractional flow reserve (FFR) units.ResultsDSVR was decreased in stenoses with lower FFR. Stenosis resistance was equal in systole and diastole for every FFR stratum. Microvascular resistance was consistently higher during systole than diastole. In lower FFR strata, stenosis resistance as a percentage of the total vascular resistance increases both during systole and diastole. The difference between the stenosis resistance as a percentage of total vascular resistance during systole and diastole increases for lower FFR strata, with an accompanying rise in diastolic-systolic resistance ratio. A significant inverse correlation was observed between DSVR and the diastolic-systolic resistance ratio (r=0.91, p<0.001). In cohort 2 (n=23), DSVR was measured both invasively and non-invasively by transthoracic echocardiography, yielding a good correlation (r=0.82, p<0.001).ConclusionsThe rationale by which DSVR is decreased distal to coronary stenoses is dependent on a comparatively higher influence of the increased stenosis resistance on total vascular resistance during diastole than systole.
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Koennecke. "Carotid stenosis - When is revascularization appropriate?" Vasa 38, no. 3 (August 1, 2009): 203–11. http://dx.doi.org/10.1024/0301-1526.38.3.203.
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Approximately 15% of ischemic strokes are caused by extracranial carotid stenoses. Revascularization of a symptomatic stenosis is very efficacious in carefully selected patients. This review outlines criteria which help to identify those who will benefit most from carotid endarterectomy (CEA) for symptomatic stenosis. Asymptomatic carotid stenosis is a common condition in the general population over 50 years, but nonetheless associated with a low risk of ischemic stroke. Consequently, the therapeutic yield of CEA is much lower in asymptomatic stenosis and women seem not to benefit at all. In the future, specific morphological MRI features may help to identify stenoses prone to become symptomatic. In addition to their significance for stroke, it has been demonstrated that atherosclerotic lesions can be regarded as an indicator of cardiovascular morbidity which may help to identify high-risk patients for cardiovascular events.
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Duncavage, James A., Robert H. Ossoff, and Robert J. Toohill. "Carbon Dioxide Laser Management of Laryngeal Stenosis." Annals of Otology, Rhinology & Laryngology 94, no. 6 (November 1985): 565–69. http://dx.doi.org/10.1177/000348948509400608.
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A retrospective review of 20 cases of laryngeal stenosis treated with the carbon dioxide laser was conducted at the Medical College of Wisconsin and Northwestern University. The stenoses were grouped into four categories: supraglottic, glottic, subglottic, and combined glottic-subglottic. Twenty patients had 21 lesions excised by 40 laser procedures. Eleven of 21 stenoses were successfully managed by carbon dioxide laser endoscopy: 3 of 3 supraglottic, 6 of 10 glottic, 2 of 4 subglottic, and 0 of 4 combined laryngeal/tracheal stenoses. Eleven of the 20 patients had significant airway improvement or decannulation. Soft tissue stenoses of the supraglottic area respond favorably to carbon dioxide laser excision. In other regions of the larynx, the use of supplemental stents, steroid injections, dilatations, and the microtrapdoor surgical flap technique in scar stenosis may increase the rate of success. The lower success rate in the posterior commissure, subglottic, and combined laryngotracheal stenoses is due to the circumferential, thick stenosis with a vertical depth of more than 1 cm and the fibrotic fixation of the arytenoid cartilages. Small cicatrices appear to respond better to laser vaporization than the large ones which frequently recur.
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Schirmer, Clemens M., and Adel M. Malek. "WALL SHEAR STRESS GRADIENT ANALYSIS WITHIN AN IDEALIZED STENOSIS USING NON-NEWTONIAN FLOW." Neurosurgery 61, no. 4 (October 1, 2007): 853–64. http://dx.doi.org/10.1227/01.neu.0000298915.32248.95.
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Abstract OBJECTIVE The endothelium is functionally regulated by the magnitude and spatiotemporal gradients of wall shear stress (WSS). Although flow separation and reversal occur beyond high-grade stenoses, little is known of the WSS pattern within clinically relevant mild to moderate stenoses. METHODS An axisymmetric geometry with 25, 50, and 75% stenosis criteria (quantified in accordance with the North American Symptomatic Carotid Endarterectomy Trial) was used to generate a high-resolution, hybrid, tetrahedral-hexahedral computational mesh with boundary-layer enrichment to improve near-wall shear stress gradient (WSSG) computation. Time-dependent computational fluid dynamic analysis was performed using a non-Newtonian Carreau-Yasuda model of blood to yield the shear-dependent viscosity. RESULTS Transition to secondary flow patterns was demonstrated in stenoses of 25, 50, and 75%. A focal region with near-wall flow reversal and retrograde WSS was identified within the stenosis itself and was found to migrate cyclically during the cardiac pulse. A zone of zero WSS and divergent WSSG that shifts in toward the throat with increasing stenotic severity was identified. Focal zones of high WSSG with converging and/or diverging direction were uncovered within the stenosis itself, as were expected changes in the distal poststenotic region. These zones of divergent WSSG shift over a substantial length of the stenosis during the course of the cardiac cycle. CONCLUSION Luminal WSS demonstrates dynamic direction reversal and high spatial gradients within the distal stenosis throat of even clinically moderate lesions. These findings shed light on the complex vessel wall hemodynamics within clinical stenoses and reveal a mechanical microenvironment that is conducive to perpetual endothelial functional dysregulation and stenosis progression.
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Nordmeyer, Hannes, René Chapot, and Patrick Haage. "Endovascular Treatment of Intracranial Atherosclerotic Stenosis." RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren 191, no. 07 (April 4, 2019): 643–52. http://dx.doi.org/10.1055/a-0855-4298.
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Background Intracranial atherosclerotic stenosis (ICAS) causes 5 – 10 % of all ischemic strokes in the European population. Indication for endovascular treatment is a special challenge and the selection of material as well as interventional techniques essentially differs from the treatment of extracranial stenoses. According to recent studies patient selection became evidence based; however the method should not be abandoned. New technical approaches can contribute to avoid complications. Method We performed a review of the literature with regard to conservative as well as endovascular treatment of ICAS. Different technical approaches are discussed and strategies to avoid complications are stressed. Based on the treatment indication, the positions of the authorities and the professional societies are taken into account. Results and Conclusion A single self-expanding stent is approved for the treatment of ICAS. Balloon mounted and other self-expanding Stents are available for off-label use. Anatomical conditions and features of the stenosis determine the choice of material. Distal wire perforations causing intracranial bleedings may occur during exchange manoeuvres and constitute one of the technical complications in the treatment of ICAS. In contrast, there is hardly any efficient way to eliminate the risk of ischemia in the territory of perforating arteries arising from the intracranial posterior circulation and the middle cerebral artery. The results of the randomized prospective trials strengthen the conservative treatment of ICAS. Endovascular treatment should not be withheld from patients with either hemodynamic stenosis, recurrent ischemic events under best medical treatment in the territory of the stenosed vessel or acute occlusions of a stenosis. Key Points: Citation Format
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Bexell, Daniel, Randolph M. Setser, Paul Schoenhagen, Michael L. Lieber, Sorin J. Brener, Thomas B. Ivanc, Eva M. Balazs, et al. "Influence of Coronary Artery Stenosis Severity and Coronary Collateralization on Extent of Chronic Myocardial Scar: Insights from Quantitative Coronary Angiography and Delayed-Enhancement MRI." Open Cardiovascular Medicine Journal 2, no. 1 (September 10, 2008): 79–86. http://dx.doi.org/10.2174/1874192400802010079.
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Objectives:In patients with chronic ischemic heart disease, the relationship between coronary artery lesion severity and myocardial scarring is unknown.The purpose of this study was to examine the relationship between proximal coronary artery stenosis severity, the amount of coronary collateralization, and myocardial scar extent in the distal distribution of the affected coronary artery based on both quantitative coronary angiography (QCA) and delayed-enhancement magnetic resonance imaging (DE–MRI).Methods:Thirty-four patients (26 males, 8 females; age range: 35-86 years) with a coronary artery containing a single, proximal stenosis ≥30% by quantitative coronary angiography (QCA) underwent DE-MRI. The relationship between stenosis severity, collateralization, and myocardial scar morphology (area, transmurality and patchiness) was examined using linear mixed-model ANCOVA.Results:There was a statistically significant correlation between stenosis severity and scar extent (r=0.53, p<0.01). Patients with hemodynamically significant stenoses (≥70%) exhibited significantly greater collateralization (p<0.05) and scar extent (p<0.01) than patients with <70% stenosis. However, scarring was often found in patients with stenoses <70%. Also, greater stenosis severity (93±14%) and mean scar extent (41±35%) were found in patients with collaterals than in patients without collaterals (diameter stenosis 48±10%, p<0.01) (scar extent 19±29%, p=0.01).Conclusions:Using QCA and DE-MRI, we demonstrate a significant relationship between coronary artery stenosis severity and myocardial scar extent, in the absence of a documented history of acute infarction. The relationship likely reflects increasing ischemia leading to scar formation in the range of angiographically significant stenosis. However, in the absence of collateralization, scar was observed without significant stenosis, especially in females.
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Miklusica, J., I. Dedinska, B. Palkoci, J. Fialova, D. Osinova, M. Vojtko, and L. Laca. "Ureteral Stenosis of Transplanted Kidney." Acta Medica Martiniana 17, no. 2 (August 28, 2017): 32–40. http://dx.doi.org/10.1515/acm-2017-0010.
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AbstractIntroduction: Ureteral stenosis is one of the most commonly reported urological complications after kidney transplantation. Material and methods: This is a retrospective analysis of the risk factors for ureteral stenosis (type of donor, age of donor, presence of interior polar arteria, unilateral dual transplantation, diabetes mellitus of the recipient and the donor, BK positivity, child recipient, cold ischaemia time, and delayed graft function), as well as the causes and types of treating ureteral stenoses. Results: In the group of 278 patients, the occurrence was 7.2 %. The medial of occurrence of ureteral stenoses was 24.6 months. The independent risk factor for ureteral stenosis in our group was the age of the donor ≥ 70 years [HR 6.5833; 95 % CI 2.2448-19,3070 (P = 0.0006)], BK positivity [HR 13.6667; 95 % CI 6.9127-27.0196 (P<0.0001)], cold ischaemia time > 1080 min [HR 4.0368; 95 % CI 1.7250-9,4465 (P = 0.0013)], and diabetes mellitus in the donor’s history [HR 16.2667; 95 % CI 7.8629-33.6525 (P <0.0001)]. The most frequent type of treating the ureteral stenosis in our group was retroureteroneocystostomy. After surgical treatment, we recorded no recurrence of stenosis. Conclusion: In our analysis, the confirmed independent risk factor was diabetes mellitus of the donor. However, further monitoring and analyses of large groups of patients are necessary. Surgical treatment of ureteral stenosis is safe. However, the most important momentum in surgical treatment of ureteral stenosis still remains the surgeon´s experience in the given type of treatment.
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Erkenova, A. M., N. M. Danilov, Yu G. Matchin, V. V. Kushnir, S. A. Gaman, and I. E. Chazova. "Оценка чувствительности методов диагностики в выявлении гемодинамически значимых односторонних стенозов почечных артерий." Eurasian heart journal, no. 2 (May 27, 2024): 78–85. http://dx.doi.org/10.38109/2225-1685-2024-2-78-85.
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Objective. Assessment of renal artery stenosis significance in patients with resistant arterial hypertension using non-invasive diagnostic methods and to compare them with the results of selective angiography and methods of physiological assessment of renal artery stenoses.Materials and methods. Prospectively, 156 patients with drug-resistant arterial hypertension and signs of renal artery stenosis detected by doppler ultrasonography of renal arteries were included in the study. Subsequently, 25 patients were excluded from the study due to multiple variant renal blood supply and bilateral renal artery stenosis. The remaining patients (n=131) underwent selective angiography of renal arteries, and 66 of them additionally underwent CTA of renal arteries with intravenous contrast. If the artery narrowing was 90% or more (n=27) in diameter, the stenosis was considered hemodynamically significant and further stenting of the affected artery was performed, and in case of 60-90% stenosis (n=52) additional assessment of functional significance of the stenosis was performed by measuring translesional pressure gradient, fractional blood flow reserve, instantaneous blood flow reserve (iFR) and Pd/ Pa ratio. Results. Among all patients (n=131), in whom the doppler ultrasonography of renal arteries showed signs of unilateral renal artery stenosis, after angiography combined with additional methods of functional significance assessment, hemodynamically significant renal artery stenosis was confirmed in 41% of cases (n=54). Thus, the sensitivity of doppler ultrasonography of renal arteries in detection of hemodynamically significant stenoses was 74%, prognostic value of positive 78% and negative result 64% (p<0,001). According to CTA (n=66) renal artery stenosis was confirmed in 56 patients. The results of CTA of renal arteries in 88% of cases coincided with the results of selective angiography, and using additional functional methods hemodynamically significant stenosis was confirmed in 32 (48%) patients. The sensitivity of CTA in detection of hemodynamically significant stenoses of renal arteries was 69%, specificity 91%, prognostic value of positive and negative results was 91 and 68% respectively. According to selective angiography, out of 131 patients, 24 patients had no renal artery stenosis, 28 patients had stenosis <60%, 27 patients had renal artery stenosis >90% and 52 patients had stenosis 60-90%. Patients with stenosis <60% were not considered candidates for renal artery stenting.
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Bulger, Christopher M., Weihua Gao, Chad Jacobs, and Walter J. McCarthy. "Beyond the Categories: A Formula-Driven Prediction of Carotid Stenosis." Journal for Vascular Ultrasound 29, no. 1 (March 2005): 15–20. http://dx.doi.org/10.1177/154431670502900102.
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Purpose Current methods to predict carotid stenosis from ultrasound duplex criteria involve assigning a category of stenosis on the basis of an individual laboratory-defined combination of peak systolic velocity (PSV), end diastolic velocity (EDV), and ratio of internal carotid artery velocity to common carotid artery velocity. This study will define a formula by use of regression analysis of the duplex ultrasound criteria compared with the angiographic results. This study will then compare the formula predictions of stenosis with the current means of combining categories to determine whether there is an increase in accuracy and correlation with angiographic findings. Methods A retrospective review of the duplex scans and NASCET-defined angiogram results from 209 patent carotid arteries in 114 patients over the course of 4 yr at a single institution was performed. Regression analysis comparing each of the PSV, EDV, and internal carotid artery/common carotid artery ratios (RATIO) with angiographic stenosis was performed. Simple and multiple linear regression equations were obtained. The equation was tested for validity. The data were then reanalyzed by use of the formulas, and predicted stenoses from the formulas were obtained. The formula-predicted stenoses (F1 and F2), category-based stenoses (READAS), and angiographic stenoses were compared. A determination was then made of their statistically significant difference by use of the Wilcoxon signed rank test and receiver operator curve (ROC) analysis. Results An r2 value of 0.7231, 0.6341, and 0.7262 was obtained, respectively, for the equations comparing PSV, EDV, and ICA/CCA ratio with angiographic stenosis. Limiting the data to stenosis >30% resulted in correlation coefficients between the regression formula predicted data and the angiographic data of 0.71. A statistically significant difference was demonstrated between the category results and angiography ( p < 0.0001). No statistically significant difference was demonstrated between the formula-predicted data and the angiographic data. ROC analysis and Area (AZ) test demonstrated a statistically significant difference and better prediction of a >60% stenosis by the regression equation than by the current category method ( p < 0.05). Conclusion Regression analysis of duplex data versus NASCET-defined angiographic findings allows formation of a model to predict carotid stenosis. This can be done with greater accuracy than the commonly accepted means of categorizing the duplex results.
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Terada, T., H. Yokote, Y. Kinoshita, M. Tsuura, O. Masuo, K. Nakai, and T. Itakura. "Endovascular Treatment for Tandem Internal Carotid Stenosis." Interventional Neuroradiology 3, no. 2_suppl (November 1997): 208–11. http://dx.doi.org/10.1177/15910199970030s245.
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Three patients with tandem internal carotid stenoses were treated in one operation including carotid endarterectomy (CEA) for the proximal stenosis and percutaneous transluminal angioplasty (PTA) for the distal stenosis. We devised a Y-shaped shunt tube which we used for CEA, while a PTA balloon catheter was introduced via the tube to perform PTA guided by portable digital subtraction angiography (DSA). No cerebrovascular events occurred during follow-up. Our approach avoids the risk of a second procedure while effectively treating tandem stenoses.
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Ito, Hidemichi, Masashi Uchida, Taigen Sase, Yuichiro Kushiro, Tetsuya Ikeda, Hiroshi Takasuna, Ichiro Takumi, Kotaro Oshio, and Yuichiro Tanaka. "A case of tandem stenoses at the proximal common and internal carotid arteries treated with transbrachial stenting: a case report." Interventional Neuroradiology 25, no. 2 (November 4, 2018): 225–29. http://dx.doi.org/10.1177/1591019918806471.
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The transfemoral approach is a common technique for carotid artery stenting. However, it has the risk of distal embolism when stenting for a stenosis of the proximal common carotid artery because of poor stability of the guiding catheter resulting in difficulty in setting the embolic protection device prior to stenting. We present a novel therapeutic approach and technique for the treatment of tandem carotid stenoses including the proximal common carotid artery. A 63-year-old man presented with double stenoses at the common carotid artery and internal carotid artery. We used a transbrachial sheath guide that had a 6 Fr (2.24 mm, 0.088 inch) internal diameter and was 90 cm long, and was specifically designed for direct cannulation to the common carotid artery, like a modified Simmons catheter. Because the sheath guide positioned in the aortic arch made it possible to introduce safely the embolic protection device distal to the internal carotid artery stenosis without touching the plaque at the stenosis with no use of any coaxial catheters or guidewires, carotid artery stenting for tandem stenoses could be successfully carried out. The postoperative course was uneventful. In carotid artery stenting, especially for stenosis of the proximal common carotid artery, the sheath guide designed for transbrachial carotid cannulation was useful in stenting the tandem carotid stenoses.
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Depairon, Michèle, C. P. Ferrier, P. Tutta, E. Descombes, G. van Melle, and J. P. Wauters. "Stellenwert der Duplexsonographie der Brachialarterie zur Überwachung von vaskulären Zugängen bei Hämodialysepatienten." Vasa 30, no. 1 (February 1, 2001): 53–58. http://dx.doi.org/10.1024/0301-1526.30.1.53.
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Background: Vascular access (VA) stenosis with subsequent thrombosis remains one of the major causes of morbidity and hospitalization in haemodialysis patients. The present cross-sectional study was planned in order to analyze the usefulness of brachial artery duplex ultrasound for detection and prediction of vascular access stenoses. Methods: Color duplex ultrasound (Apogée Cx 200, sectorial probe 7.5 MHz) was used to obtain the anatomical pattern of the VA and flow velocity waveforms of the brachial artery in 77 non-selected VA (47 Ciminio-Brescia fistulae and 30 PTFE grafts). In each VA, the resistance index (RI), the mean blood flow rate (Q) and the blood flow ratio index (QI) (QI = VA flow rate/contralateral flow rate) were calculated at the level of the brachial artery. The sensitivity and specificity of these brachial Doppler parameters were calculated for the detection of VA stenosis. In normal VA, positive (PPV) and negative predictive (NPV) values were calculated for the development of clinical stenotic complications 3 months post ultrasound examination. Results: Thirteen of the 77 VA (17%) were identified as stenosed by duplex ultrasound and confirmed by fistulography and/or during surgical exploration. The best screening tests for VA stenosis detection were a QI threshold < 4.0 with a sensitivity and specificity of 69 and 69% and an RI > 0.55 with a sensitivity and specificity of 62 and 66%, respectively. In the VA considered as normal by ultrasound, the prediction of subsequent stenosis within three months post-ultrasound examination gave a PPV of only 18% and 19% for RI and QI, respectively. NPV for RI and QI were 90% and 88%. Conclusions: While Doppler ultrasound is a useful non-invasive test for the detection of prevalent VA stenosis, our results do not confirm that abnormal brachial Doppler flow parameters can predict short term development of VA stenosis.
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Ito, Hideki, Masato Mutsuga, Yoshiyuki Tokuda, and Akihiko Usui. "Modified sutureless repair using left atrial appendage flap for acquired left-sided pulmonary vein stenosis." European Journal of Cardio-Thoracic Surgery 58, no. 2 (February 8, 2020): 395–97. http://dx.doi.org/10.1093/ejcts/ezaa032.
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Abstract Pulmonary vein stenosis is a well-known complication after radiofrequency catheter ablation of atrial fibrillation. Although surgical repair is indicated for younger patients and patients with multiple stenoses, the appropriate procedure for acquired pulmonary vein stenosis has not been established. In this study, we report the successful outcome of our modified sutureless technique using a left atrial appendage flap for left-sided pulmonary vein stenosis after radiofrequency catheter ablation.
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Hofstra, L., D. C. Bergmans, K. M. Leunissen, A. P. Hoeks, P. J. Kitslaar, M. J. Daemen, and J. H. Tordoir. "Anastomotic intimal hyperplasia in prosthetic arteriovenous fistulas for hemodialysis is associated with initial high flow velocity and not with mismatch in elastic properties." Journal of the American Society of Nephrology 6, no. 6 (December 1995): 1625–33. http://dx.doi.org/10.1681/asn.v661625.
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Stenotic intimal thickening at the venous end of prosthetic arteriovenous (AV) fistulas for hemodialysis has been associated with perianastomotic mismatch in elastic properties, and low shear rates. In a prospective way, the role of these factors on the occurrence of intimal hyperplasia in prosthetic AV fistulas in hemodialysis patients was investigated. In 24 hemodialysis patients, the elastic properties were assessed in the distal graft segment and the outflow vein postoperatively with the use of Vessel Wall Doppler Tracking (VWDT), a noninvasive ultrasound technique. In addition, normalized peak systolic velocity (nPSV) was calculated from diameter (VWDT) and peak systolic velocity. The initial mismatch around the venous anastomoses and local nPSV were correlated with the occurrence of stenoses during follow-up (2 yr). The detection of a stenosis was performed with both Duplex ultrasound and angiography. In four cases, a stenosis developed in the venous anastomosis; in eight cases, a stenosis developed in the venous outflow segment; and in four cases, stenoses developed at both sites. A better initial match in elastic properties around the venous anastomosis was observed in the fistulas developing a stenosis at this site as compared with the nonstenotic fistulas (P < 0.05). The initial local nPSV values at the site of the later stenosis were higher in the fistulas developing a stenosis as compared with the nonstenotic fistulas (P < 0.05). It was concluded that the occurrence of stenoses in prosthetic AV fistulas for hemodialysis in or adjacent to the venous anastomoses is associated with a high initial flow velocity but not with a mismatch in elastic properties.
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Krajíčková, Dagmar, Antonín Krajina, Roman Herzig, Vendelín Chovanec, Miroslav Lojík, Jan Raupach, Ondřej Renc, Oldřich Vyšata, and Libor Šimůnek. "Percutaneous Transluminal Angioplasty for Atherosclerotic Stenosis of Vertebral Artery Origin." Journal of Clinical Medicine 13, no. 14 (July 9, 2024): 4010. http://dx.doi.org/10.3390/jcm13144010.
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Background: In patients with vertebral artery origin (VAO) stenosis and concomitant stenoses of other cerebral feeding arteries, data on the risk of percutaneous transluminal angioplasty (PTA) alone and with stent placement (PTAS) for VAO stenosis are limited. We aimed to determine how the presence of polystenotic lesions in other cerebral feeding arteries and concomitant carotid artery stenting (CAS) affect the periprocedural risk and long-term effect of PTA/S for atherosclerotic VAO stenosis. Methods: In a retrospective descriptive study, consecutive patients treated with PTA/S for ≥70% VAO stenosis were divided into groups with isolated VAO stenosis and multiple stenoses. We investigated the rate of periprocedural complications in the first 72 h and the risk of restenosis and ischemic stroke (IS)/transient ischemic attack (TIA) during the follow-up period. Results: In a set of 66 patients aged 66.1 ± 9.1 years, polystenotic lesions were present in 56 (84.8%) patients. 21 (31.8%) patients underwent endovascular treatment for stenosis of one or more other arteries in addition to VAO stenosis (15 underwent CAS). During the periprocedural period, no patient suffered from an IS or died, and, in the polystenotic group with concomitant CAS, there was one case of TIA (1.6%). During a mean follow-up period of 36 months, we identified 8 cases (16.3%) of ≥50% asymptomatic VA restenosis, and, in the polystenotic group, 4 (8.9%) cases of IS. Conclusion: The presence of severe polystenotic lesions or concomitant CAS had no adverse effect on the overall low periprocedural risk of PTA/S of VAO stenosis or the risk of restenosis during the follow-up period.
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Cao, Xiangyu, Jun Wang, Chenglin Tian, Zhihua Du, Hui Su, Xinfeng Liu, Bin Lv, Shengyuan Yu, Xing Chen, and Ferdinand Hui. "Solitaire AB stent-angioplasty for stenoses in perforator rich segments: A single-center experience." Interventional Neuroradiology 26, no. 5 (August 25, 2020): 608–14. http://dx.doi.org/10.1177/1591019920951651.
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Background Vascular angioplasty and stenting of middle cerebral artery (MCA) and basilar artery (BA) stenoses are associated with poor clinical outcomes and high mortality rates thought to be related to the abundance of perforating arteries in those segments. This study explores the use of Solitaire AB as an off-label vascular stent to treat stenoses in the MCA and BA. Methods Solitaire AB stents were placed during angioplasty and stenting of MCA and BA stenoses in patients at our department between January 2015 and May 2017 with 6-36 months follow-up. Operative results were assessed by follow-up angiography and transcranial doppler after the procedure. Neurologic status was evaluated before and after treatment according to the modified Ranking Scale (mRS). Results A total of 32 patients were included in the study. Seventeen (53.12%) patients presented with MCA stenosis and 15 (46.87%) with BA stenosis. The 30-day rate of procedure-related complications was 3.1% (1/32). Post-stenting residual stenosis degrees ranged from 0% to 40% (mean 13.44% ± 10.66%). Mean degree of residual stenosis in 26 patients followed up by DSA was 8.64% ± 9.67%. The mRS 0-2 was achieved in all (100%) patients at 6-12 months post-procedure. Conclusions Our study indicates the off-label use of Solitaire AB for stenting is effective and safe for MCA and BA stenoses with high technical success and low complications. We recommend that lesion-specific therapy with an anatomically fitted stent design enables optimal treatment for intracranial stenosis.
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SCHOENBERG, STEFAN O., MICHAEL BOCK, FRIEDRICH KALLINOWSKI, and ARMIN JUST. "Correlation of Hemodynamic Impact and Morphologic Degree of Renal Artery Stenosis in a Canine Model." Journal of the American Society of Nephrology 11, no. 12 (December 2000): 2190–98. http://dx.doi.org/10.1681/asn.v11122190.
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Abstract. In a noninvasive comprehensive magnetic resonance (MR) examination, the morphologic degree of renal artery stenosis was correlated to corresponding changes in renal artery flow dynamics. Different degrees of stenosis were created with the use of a chronically implanted inflatable arterial cuff in seven dogs. For each degree of stenosis, an ultrafast three-dimensional gadolinium MR angiography with high spatial resolution was performed, followed by cardiac-gated MR flow measurements with high temporal resolution for determination of pulsatile flow profiles and mean flow. Flow was also measured by a chronically implanted flow probe. In three of the dogs, trans-stenotic pressure gradients (ΔP) also were measured via implanted catheters. Five different degrees of stenosis could be differentiated in the MR angiograms (0%, 30%, 50%, 80%, >90%). The MR flow data agreed with the flow probe within ±20%. Stenoses between 30 and 80% gradually reduced the early systolic peak (Max1) of the flow profile but only minimally affected the midsystolic peak (Max2) or mean flow. Stenoses of more than 90% significantly depressed mean flow by more than 50%. The ratio between Max1 and Max2 (Rmax1/2) gradually fell with the degree of stenosis. The onset of significant mean flow reduction and ΔP was indicated by a drop of Rmax1/2 below 1 to 1.2. Thus, the analysis of high-resolution flow profiles allows detection of early hemodynamic changes even at degrees of stenoses not associated with a reduction of mean flow. Rmax1/2 allows differentiation of the grade of hemodynamic compromise for a given morphologic stenosis independent of mean flow in a single comprehensive MR examination.
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Hashimoto, M., O. Watanabe, and H. Hirano. "Extraforaminal Stenosis in the Lumbosacral Spine." Acta Radiologica 37, no. 3P2 (May 1996): 610–13. http://dx.doi.org/10.1177/02841851960373p238.
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Purpose: To review experience with MR images of extraforaminal (EF) stenosis in the lumbosacral spine. Material: MR images from 9 patients with 10 EF stenoses were reviewed. The diagnosis was confirmed in 6 patients at surgery, and in 4 on the basis of findings of nerve root injection combined with nerve block. Results and Conclusion: All patients had congenital lumbosacral anomalies with various degrees of fixation between the last formed level and the pelvis. In all cases, affected roots were compressed between the transverse process of the last lumbar segment and the sacral ala. MR using coronal plane imaging demonstrated the root impingement directly in the far lateral zone in all patients. However, sagittal and axial images were unable to define the EF stenoses in all patients. The results of this study show that a transitional vertebra is a cause of EF stenosis and that MR images using coronal plane are useful in the assessment of EF stenosis.
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McCAffrey, Thomas V. "Management of Laryngotracheal Stenosis on the Basis of Site and Severity." Otolaryngology–Head and Neck Surgery 109, no. 3 (September 1993): 468–73. http://dx.doi.org/10.1177/019459989310900313.
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Seventy-five cases of laryngotracheal stenosis treated between 1981 and 1991 were reviewed to determine the effectiveness of surgical treatment on the basis of site and severity of stenosis. Decannulation and absence of exertional dyspnea were the criteria of successful management. The treatment methods used were endoscopic laser incision and dilatation, expansion laryngotracheoplasty, and segmental resection. Endoscopic procedures were effective in treating thin (< 1 cm) stenoses in the subglottis and trachea. Laryngotracheoplasty was most effective in treating thick stenoses of the glottis and subglottis. Tracheal stenoses were most effectively treated by segmental resections. The probability for decannulation decreased with longer narrower stenoses and with increasing clinical stage. (OTOLARYNGOL HEAD NECK SURG 1993;109:468-73.)
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Li, Xiaoyun, Ling Wang, Chi Zhang, Shuyu Li, Fang Pu, Yubo Fan, and Deyu Li. "Why Is ABI Effective in Detecting Vascular Stenosis? Investigation Based on Multibranch Hemodynamic Model." Scientific World Journal 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/185691.
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The ankle-brachial index (ABI), defined as the ratio of systolic pressure in the ankle arteries and that in the brachial artery, was a useful noninvasive method to detect arterial stenoses. There had been a lot of researches about clinical regularities of ABI; however, mechanism studies were less addressed. For the purpose of a better understanding of the correlation between vascular stenoses and ABI, a computational model for simulating blood pressure and flow propagation in various arterial stenosis circumstances was developed with a detailed compartmental description of the heart and main arteries. Particular attention was paid to the analysis of effects of vascular stenoses in different large-sized arteries on ABI in theory. Moreover, the variation of ABI during the increase of the stenosis severity was also studied. Results showed that stenoses in lower limb arteries, as well as, brachial artery, caused different variations of blood pressure in ankle and brachial arteries, resulting in a significant change of ABI. Furthermore, the variation of ABI became faster when the severity of the stenosis increased, validating that ABI was more sensitive to severe stenoses than to mild/moderate ones. All these in findings revealed the reason why ABI was an effective index for detecting stenoses, especially in lower limb arteries.
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Siebes, Maria, Steven A. J. Chamuleau, Martijn Meuwissen, Jan J. Piek, and Jos A. E. Spaan. "Influence of hemodynamic conditions on fractional flow reserve: parametric analysis of underlying model." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 4 (October 1, 2002): H1462—H1470. http://dx.doi.org/10.1152/ajpheart.00165.2002.
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Pressure-based fractional flow reserve (FFR) is used clinically to evaluate the functional severity of a coronary stenosis, by predicting relative maximal coronary flow (Qs/Qn). It is considered to be independent of hemodynamic conditions, which seems unlikely because stenosis resistance is flow dependent. Using a resistive model of an epicardial stenosis (0–80% diameter reduction) in series with the coronary microcirculation at maximal vasodilation, we evaluated FFR for changes in coronary microvascular resistance ( R cor= 0.2–0.6 mmHg · ml−1 · min), aortic pressure (Pa = 70–130 mmHg), and coronary outflow pressure (Pb = 0–15 mmHg). For a given stenosis, FFR increased with decreasing Pa or increasing R cor. The sensitivity of FFR to these hemodynamic changes was highest for stenoses of intermediate severity. For Pb > 0, FFR progressively exceeded Qs/Qn with increasing stenosis severity unless Pb was included in the calculation of FFR. Although the Pb-corrected FFR equaled Qs/Qn for a given stenosis, both parameters remained equally dependent on hemodynamic conditions, through their direct relationship to both stenosis and coronary resistance.
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Santamore, W. P., and A. A. Bove. "A theoretical model of a compliant arterial stenosis." American Journal of Physiology-Heart and Circulatory Physiology 248, no. 2 (February 1, 1985): H274—H285. http://dx.doi.org/10.1152/ajpheart.1985.248.2.h274.
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Recent clinical and experimental evidence indicates that coronary artery stenoses may rapidly change their size and shape in response to alterations in vasomotor tone and intraluminal pressure. This theoretical study models a partially compliant arterial stenosis to examine the hemodynamic impact of these alterations. In rigid vessels, a 98% reduction in luminal area would predictably produce subendocardial ischemia in the resting state. In contrast, stenoses, with part of the arterial wall normal by the underlying plaque, responded to vasoconstriction and to changes in intraluminal pressure. With part of the arterial wall normal by the plaque, both vasoconstriction and decreases in intraluminal pressure could increase the hemodynamic severity of the stenosis. Further, the more eccentrically positioned the underlying plaque was, the greater the effects of vasoconstriction and intraluminal pressure on stenotic severity. Thus the morphological configuration of the plaque and the normal wall segment in the stenosis appear to be important determinants of the hemodynamic response of the stenosis to vasoconstriction and blood pressure changes. In turn, these changes in stenotic severity can greatly influence flow through the vessel.
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Spacek, Miloslav, Jan Vacha, Milan Kaminek, Martin Hutyra, Radomir Nykl, Martin Sluka, and Milos Taborsky. "Comparison of angiographic estimation and invasive hemodynamic measurement of the significance of non-infarct-related residual stenoses in ST-elevation myocardial infarction patients." Archives of Medical Science – Atherosclerotic Diseases 8, no. 1 (January 3, 2024): 169–76. http://dx.doi.org/10.5114/amsad/172971.
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IntroductionUp to 50% of patients with ST elevation myocardial infarction (STEMI) have ≥ 50% stenosis in a major non-infarct-related artery. Several studies have evaluated the prognostic value of the completion of revascularization with overall inconclusive results. Selection of the stenoses was based on the angiographic evaluation, invasive hemodynamic measurement or the combined approach. It is unknown whether such a selection provides correlation of comparable patient groups.Material and methodsWe enrolled 51 patients (62.7 ±10.2 years) with acute STEMI and at least one residual (50–90%) stenosis in a non-infarct-related major coronary artery (excluding left main coronary artery). Overall 65 stenoses (67.9 ±10.7%) were evaluated angiographically following primary percutaneous coronary intervention and the hemodynamic significance was estimated with respect to the stenosis severity, caliber of the arterial segment, localization of the stenosis (proximity) as well as the estimated size of the supplied vascular territory. During subsequent hospitalization, invasive measurement of the hemodynamic significance using fractional flow reserve (FFR) was performed to guide the final revascularization strategy (FFR value of ≤ 0.80 considered significant).ResultsBased on angiographic evaluation, a total of 44 stenoses would be recommended for treatment, whereas only 31 stenoses were revascularized based on FFR measurement. Moreover, visual evaluation and hemodynamic measurement were discrepant in 27 of 65 (41.5%) stenoses.ConclusionsWe observed a weak correlation between visual angiographic evaluation and invasive hemodynamic measurement. More stents would be implanted based on angiographic evaluation compared to FFR measurement.
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Kalimanovska-Ostric, Dimitra, Branislava Ivanovic, Vladimir Ostric, Vesna Knezevic, Vesna Stojanov, and Dragan Simic. ""Flash" pulmonary oedema as a clinical manifestation of renovascular hypertension." Srpski arhiv za celokupno lekarstvo 131, no. 5-6 (2003): 208–10. http://dx.doi.org/10.2298/sarh0306208d.
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One of the clinical manifestations of renovascular hypertenzion (RVH) may be a recurrent pulmonary oedema both in the absence or in the presence of systolic left ventricular dysfunction. This type of pulmonary oedema characterized as "flash" pulmonary oedema is ascribed to elevated angiotensin II concentrations with consequent hypertension as well as to volume overload resulting from decreased pressure natriuresis when there are significant stenoses of both or one renal arteries. The investigation included 30 patients with RVH treated by percutaneous transluminal angioplasty of the stenosed renal artery (PTRA) and/or stent implantation (PTR-ST) and 30 patients with surgical resection of the abdominal aortic aneurysm (AAA). The first group was divided in two subgroups according to the etiology of renal artery stenosis (RAS). In the subgroup with fibromuscular dysplasia (FMD) the mean age was 37.5 years, in the subgroup with atherosclerotic renal artery stenosis (ARAS) 54.8 years and in the group with operated AAA 68.6 years. There were more females than males only in the FMD subgroup (10:3). Two patients of the first group experienced pulmonary oedema, both in the subgroup with atherosclerotic renal artery stenosis associated with atherosclerosis of other arteries. Normalization of the blood pressure following PTRA in both and an uncomplicated course after a surgical myocardial revascularization in one of them illustrates the importance of renal revascularization. Pulmonary oedema occurred preoperatively in four out of 30 patients with abdominal aortic aneurysm in whom significant renal artery stenoses coexisted. Two patients died despite surgery, one patient is clinically stable and the medicament treatment of heart failure is inevitable in the fourth with a left ventricular aneurysm following myocardial infarction. The occurrence or reoccurrence of pulmonary oedema in the absence of other explanation should suggest the possibilty of billateral or unilateral renal artery stenosis requiring renal revascularization for blood pressure regulation as well as for elimination of other manifestations/complications.
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Mehrabi, Mohsen, and Saeed Setayeshi. "Computational Fluid Dynamics Analysis of Pulsatile Blood Flow Behavior in Modelled Stenosed Vessels with Different Severities." Mathematical Problems in Engineering 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/804765.
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This study focuses on the behavior of blood flow in the stenosed vessels. Blood is modelled as an incompressible non-Newtonian fluid which is based on the power law viscosity model. A numerical technique based on the finite difference method is developed to simulate the blood flow taking into account the transient periodic behaviour of the blood flow in cardiac cycles. Also, pulsatile blood flow in the stenosed vessel is based on the Womersley model, and fluid flow in the lumen region is governed by the continuity equation and the Navier-Stokes equations. In this study, the stenosis shape is cosine by using Tu and Devil model. Comparing the results obtained from three stenosed vessels with 30%, 50%, and 75% area severity, we find that higher percent-area severity of stenosis leads to higher extrapressure jumps and higher blood speeds around the stenosis site. Also, we observe that the size of the stenosis in stenosed vessels does influence the blood flow. A little change on the cross-sectional value makes vast change on the blood flow rate. This simulation helps the people working in the field of physiological fluid dynamics as well as the medical practitioners.
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Davis, Thomas S., Monica S. Epelman, Peace C. Madueme, Karen S. Bender, and Gul H. Dadlani. "MRI detection of occult venous anomalies in a patient with Williams syndrome: a case report." Cardiology in the Young 30, no. 4 (February 27, 2020): 568–70. http://dx.doi.org/10.1017/s104795112000030x.
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AbstractWilliams syndrome is a multisystem, congenital disorder which is commonly associated with arterial stenoses: supravalvar aortic stenosis and peripheral pulmonary artery stenosis. Venous abnormalities have not been previously reported in children with Williams syndrome. We present a case of a 3-year-old girl with Williams syndrome and diffuse venous ectasia as detected by MRI.
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Ben Farhat, F., M. Sabbah, M. Ben Abid, N. Bibani, N. Bellil, K. Aoun, A. Bouratbine, and D. Gargouri. "P226 Does faecal Calprotectin help differentiate inflammatory from fibrous stenosis in Crohn’s disease?" Journal of Crohn's and Colitis 15, Supplement_1 (May 1, 2021): S277—S278. http://dx.doi.org/10.1093/ecco-jcc/jjab076.352.
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Abstract Background Digestive stenosis is the most common complication of Crohn’s disease. It can be either inflammatory or fibrous. The clinical, biological and especially morphological characteristics of the stenosis can help differentiate inflammatory stenosis from fibrous stenosis. The aim of our study was to evaluate the performance of fecal calprotectin (FC), a marker of intestinal inflammation, in identifying the type of stenosis. Methods A prospective study including all patients followed for Crohn’s disease in the Gastroenterology Department of Habib Thameur Hospital over a 6-month period from July 2020 to December 2020 was performed. Clinical, biological, endoscopic and radiological data were collected. The inflammatory nature of the stenosis was mainly retained according to radiological activity signs objectified by cross-sectional imaging. All patients were given a FC assay at the time of inclusion. FC was dosed by using the Bulhmann® FCAL ELISA technique. The statistical study was carried out using the SPSS software version 22.0 (p value significant if lower than 0.05). Results Fifty patients were included in our study (mean age 40.54 years [18–67] and sex ratio (M/F) = 1.77). The average evolution time of the disease was 8 years [6 months- 27 years]. The disease was ileal in 16 patients, colic in 4 patients and ileocolic in 30. Twenty patients (40%) had an intestinal stenosis whose location was: ileocaecal anastomosis (n=9), ileal (n=8) and colic (n=3). Multiple stenoses (colic and ileal) were noted in 3 patients. Fifteen patients were on medical treatment at the time of inclusion: 7 patients were on Infliximab, 5 were on azathioprine and 3 were on 5ASA. Digestive symptoms such as diarrhoea or subocclusive syndromes were noted in 7 patients. A biological inflammatory syndrome (CRP >10mg/L) was noted in 8 patients. Of the 20 stenoses included, 8 were of the inflammatory type (40%). In the presence of stenosis, the mean level of FC was 224.9 μg/g. A high level of FC was associated with the inflammatory type of stenosis (p<0.001). A cut-off of 135 µg/g had a sensitivity 100% and a specificity of 90%. CRP did not differentiate between inflammatory stenosis and fibrous stenosis (p=0.4). Conclusion According to our study, FC is a good marker of intestinal inflammation allowing to differentiate an inflammatory from a fibrous stenosis during Crohn’s disease better than the usual biological markers. These results should be confirmed by larger studies.
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Downing, J. M., and D. N. Ku. "Effects of Frictional Losses and Pulsatile Flow on the Collapse of Stenotic Arteries." Journal of Biomechanical Engineering 119, no. 3 (August 1, 1997): 317–24. http://dx.doi.org/10.1115/1.2796096.
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High-grade stenosis can produce conditions in which the artery may collapse. A one-dimensional numerical model of a compliant stenosis was developed from the collapsible tube theory of Shapiro. The model extends an earlier model by including the effects of frictional losses and unsteadiness. The model was used to investigate the relative importance of several physical parameters present in the in vivo environment. The results indicated that collapse can occur within the stenosis. Frictional loss was influential in reducing the magnitude of collapse. Large separation losses could prevent collapse outright even with low downstream resistances. However, the degree of stenosis was still the primary parameter governing the onset of collapse. Pulsatile solutions demonstrated conditions that produce cyclic collapse within the stenosis. This study predicts certain physiologic conditions in which collapse of arteries may occur for high-grade stenoses.