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Irsale, Swagat Appasaheb Adanur Sabit. "Polymeric textile stents prototyping and modeling /." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Summer/doctoral/IRSALE_SWAGAT_42.pdf.
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Qing, Kaixiong, and 庆开雄. "Thoracic endovascular stent graft repair (TEVAR) for treating type B aortic dissections (TBAD) : a hemodynamic and morphologic perspective." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/197128.
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TEVAR has been used extensively to treat TBAD. The principle of treatment involve placement of a stent graft in the true lumen to cover the primary tear, thereby excluding the false lumen. Success depends on a combination of factors: reduction of false lumen pressure and perfusion, thrombosis of the false lumen, and remodeling of the aorta leading to eventual healing. The long-term goals are to prevent continuous growth of the false lumen, reinterventions, and aneurysm rupture. The success of TEVAR depends on a combination of factors, including the blood flow and pressure in the two aortic lumens, and remodeling is a dynamic process. Much controversy exists regarding the ideal timing of TEVAR, its efficacy in effecting complete false lumen exclusion, the long-term durability of the repair, and the fate of the aortic size. The objective of this thesis is to examine the morphological and hemodynamic changes within the aortic lumens after TEVAR, using a combination of ex-vivo animal models and computational tomography analysis. The residual pressure of the true and false lumens in TBAD models was studied. Volumetric analyses of CT scan of patients were compared. The ultimate goals are to determine if it is beneficial to treat type B dissections early, and to determine long-term morphological results.
In ex-vivo hemodynamic study, 28 fresh porcine aortas models were created to simulate three different pathological scenarios of TBAD: model A represented pre-treated TBAD; model B represented post-treated TBAD with patent false lumen; and model C represented chronic stage of post-treated TBAD with false lumen thrombosis. True lumen and false lumen pressure differences were compared between the three models. Pressure effect was successfully reduced by 30% in model C in comparison with the other two models. No hemodynamic parameters were significantly different between model A and model B.
Aortic remodeling parameters were volumetrically analyzed and compared between two groups of patients who underwent endo-grafting for uncomplicated TBAD (group A) and dissecting aneurysms (group B). Modern DIOCM processing workstations and software were used to reconstruct thoracic aorta with serial CT scans. The true lumen, false lumen, thrombus and aortic size were measured volumetrically. Stent graft migration and area of inlet and outlet were also quantified. There were progressive migration and continuous expansion of the stent graft on patients in both groups. Favorable aortic remodeling was observed in most. One fourth of all patients demonstrated aortic volume increase at 36 months. However, there was no difference between group A and group B in terms of stent graft re-shaping and aortic remodeling.
In conclusion, Aortic remodeling after TEVAR in treating TBAD is a continuous process. There were no significant differences between chronic dissections and dissecting aneurysms in all morphological parameters. Treating chronic dissections before aneurysm formation does not seem to have a morphologic advantage. Sealing of primary entry tear with introducing thrombosis could significantly reduce false lumen pressure. However, the remaining pressure accumulations should be considered to reduce by further excluding distal reentry tears in those patients who undergo progressive false lumen expansion after TEVER.published_or_final_version
Surgery
Doctoral
Doctor of Philosophy
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Leung, Kar-ming, and 梁嘉銘. "Stent assisted coiling for wide-neck cerebral aneurysms." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4290528X.
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Leung, Kar-ming. "Stent assisted coiling for wide-neck cerebral aneurysms." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B4290528X.
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Hessian, Renee. "Drug eluting stents versus bare metal stents for the treatment of coronary artery disease: A review of the benefits and harms." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28149.
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Drug eluting stents (DES) have been found to reduce restenosis and the rate of repeat angiographic procedures related to restenosis. However, an increase in harms with their use has been suspected. Therefore, there may be an important trade-off of efficacy for harms with the use of DES, especially over the long term.
We conducted asystematic review and meta-analysis of RCT, examining the efficacy of DES versus bare metal stents (BMS). A separate review was then conducted which included non randomized studies, as well as RCT to evaluate long term harms of DES when compared to BMS. Analysis demonstrated that there was significant efficacy noted for DES over BMS, especially for the sirolimus coated stents. The long-term data demonstrated preserved efficacy of DES with no significant increase in the harms of death, myocardial infarction, stent thrombosis or revascularization for a follow-up extending out to four years.
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Dolla, William Jacob Spenner Becker Bryan R. "Drug diffusion and structural design criteria for conventional and auxetic drug-eluting stents." Diss., UMK access, 2006.
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Thesis (Ph. D.)--School of Computing and Engineering and Dept. of Chemistry. University of Missouri--Kansas City, 2006."A dissertation in engineering and chemistry." Advisor: Bryan R. Becker. Typescript. Vita. Description based on contents viewed Jan. 26, 2007; title from "catalog record" of the print edition. Includes bibliographical references (leaves 127-130). Online version of the print edition.
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Appanaboyina, Sunil. "Computational hemodynamic study of endovascular stenting in patient-specific cerebral aneurysms." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3233.
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Thesis (Ph.D.)--George Mason University, 2008.Vita: p. 83. Thesis director: Juan R. Cebral. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Title from PDF t.p. (viewed Aug. 27, 2008). Includes bibliographical references (p. 78-82). Also issued in print.
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Mut, Fernando. "Extensions to the computational hemodynamics modeling of cerebral aneurysms." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3284.
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Thesis (Ph.D.)--George Mason University, 2008.Title from PDF t.p. (viewed Oct. 14, 2008). Thesis director: Juan R. Cebral. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computational Sciences and Informatics. Vita: p. 98. Includes bibliographical references (p. 90-97). Also available in print.
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Irsale, Swagat Appasaheb Adanur Sabit. "Textile prosthesis for vascular applications." Auburn, Ala., 2004. http://hdl.handle.net/10415/953.
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Lam, Shang-king. "Computational fluid dynamic analyses of the endovascular stent-graft at the thoracic aorta with different biomechanical factors." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41758031.
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Waterhouse, Anna. "Bioengineering a coronary stent with covalently immobilised tropoelastin." Thesis, The University of Sydney, 2011. https://hdl.handle.net/2123/28916.
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This thesis describes the characterisation and development of covalently immobilised recombinant human tropoelastin (TE) on a plasma-activated coating (PAC) as a potential stent coating for the treatment of coronary artery disease. A biomimetic approach was used to create a biocompatible coating with an immobilised human protein to enhance biointegration of an implanted stent. A coating that enhanced endothelialisation while displaying low tbrombogenicity was developed and characterised in vitro and in vivo.
Covalent binding of TE to PAC was verified using ELISA and radiolabelled TE. Modulating the gas composition of the PAC, and therefore its mechanical and biological properties, resulted in varying amounts of covalently bound TE. The nitrogen containing PA Cs covalently bound up to 89± 1 % of physisorbed TE. The N2/Ar PAC covalently bound a monolayer of TE and was chosen for further characterisation. The covalent binding capacity of PAC extended for at least a year, retaining 65±1 % of its covalent TE binding capacity. Restoration of the full covalent binding capacity was achieved upon heat treatment of the PAC.
TE was shown to support the attachment and proliferation of endothelial cells (ECs) when physisorbed to tissue culture plastic (TCP). This was comparable to other adhesive extracellular matrix proteins, fibronectin and collagen. The morphology and distribution of ECs cultured on 316L SS, PAC and PAC+TE was investigated using reflective, fluorescence and scanning electron microscopy. PAC+TE supported increased endothelial attachment and proliferation compared to uncoated 3 l 6L SS and PAC. An EC phenotype was confirmed on 316L SS, PAC and PAC+TE by immunofluorescent labelling of endothelial cell specific markers, CD3 I and vWF.
As the thrombogenicity of blood contacting medical devices is crucial, methodology was developed to test the haemocompatibility of metallic surfaces in vitro. In static adhesion assays using whole heparinised blood, PAC was found to confer low thrombogenicity compared to 3 l 6L SS, and nitrogen again modulated this property. PAC and PAC+TE showed lower thrombogenicity than 316L SS after 60 min incubation. A modified Chandler loop was developed to test the tbrombogenicity of metallic surfaces in the presence of flowing blood. PAC and PAC+TE were again found to display low thrombogenicity, resulting in a 3-fold increase in the time to thrombus formation compared to 3 I 6L SS. This effect correlated with a 65±1 % increase in soluble P-selectin, a platelet activation marker on 3 l 6L SS. No significant platelet activation occurred on PAC or PAC+TE. The low thrombogenicity of PAC was retained for between 3 and 7 months. Furthermore, TE coated 3 I 6L SS displayed lower thrombogenicity than uncoated 316L SS, or fibronectin-or collagen-coated 316L SS.
The PAC was translated to a 316L SS laser cut stent for evaluation and in vivo testing. The PAC deposition was altered to coat all surfaces and resisted delamination. In vitro crimping and expansion of the PAC stent showed only the formation of nanocracks, compared to the large scale delamination observed on a commercially available Taxus Liberte stent. The covalent TE binding capacity and non-thrombogenicity of the PAC were maintained on the stent PAC.
The endothelialisation of PAC and PAC+TE stents was evaluated in vivo. This study marks the first comparator analysis of bare metal stents (BMS), PAC and PAC+ TE stents in a well-characterised model of rabbit bilateral iliac stenting. PAC and PAC+ TE stents were well tolerated and showed no gross inflammatory response. Cell coverage of stent struts occurred by 7 days post-implantation with endotheJialisation occurring both between the struts and over the struts in all samples. PAC and PAC+ TE showed no difference in the rate of endothelialisation compared to BMS, the standard corrunerciaJly available stents.
In further work, covalently immobilised TE was found to be susceptible to proteolytic cleavage by the common blood plasma proteases kallikrein and thrombin, which predominantly cleave TE at its arginine 515 residue. A mutant form of TE, R5 I 5A was shown to resist proteolytic cleavage at the 515 residue and thus retained the C-terminus of the protein which is required for cell attachment. This mutant form of TE retained the equivalent level of covalent binding to PAC and would therefore be a suitable candidate for application to a PAC stent for in vivo evaluation.
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Da, Silveira Eduardo. "Cost-effectiveness decision analyses comparing covered to uncovered self-expandable metal stents to elective or on-demand polyethylene stent changes in patients with distal malignant biliary obstruction." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84091.
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Introduction. Endoscopic placement of stents is the preferred treatment for palliation of obstructive symptoms in non-operative candidates but significant differences in procedure and stent-related costs, patency of stents survival of patients exist. Aim. To determine the cost-effectiveness of two strategies using Polyethylene (PE) stents (PE with replacement on demand; PE with routine exchange every 3 months), as well as uncovered (U-SEMS) and covered self-expandable metal stent (C-SEMS) in the management of distal malignant biliary obstruction. Methods. A Markov model comparing four different initial approaches was designed: (1) PE stent with replacement on demand (PE-D); (2) PE stent changed every 3 months (PE-Q3); (3) U-SEMS or (4) C-SEMS. Probabilities and parameters for distribution were abstracted from randomized controlled trials and imputed to a 12-month time horizon. Effectiveness was calculated as number of occlusion-free months. Procedural and complication-related costs were obtained from the Canadian Institute for Health Information and a Provincial perspective was adopted. A probabilistic cost-effectiveness analysis using Monte Carlo simulations was utilized to obtain a posterior joint distribution for costs and effectiveness. Average and incremental net health benefits, probabilities of cost-effectiveness and value of information were determined across a range of willingness to pay (Rc) values. Results. PE-D has the lowest CE ratio, followed by C-SEMS at an incremental cost-effectiveness ratio (ICER) of $146.64$/month of stent patency. C-SEMS has the lowest CE ratio under the following scenarios: probability of survival at 12 months greater than 83%, ERCP costs higher than $1,282.90, cost C-SEMS less than $1,485.60 and cost ratio between ERCP and C-SEMS greater than 0.4. In the probabilistic analysis, PE-D is the strategy with the highest probability of cost-effectiveness for willingness to pay values lower than $150.60. HowConclusion. Conditional to the willingness to pay and current Canadian costs, PE-D and C-SEMS are the strategies with the highest probabilities of cost-effectiveness. However, a significant level of uncertainly remains and wrong decisions will occur given the existent information. Acquisition of further knowledge to decrease the uncertainty level may be indicated if it costs less than the opportunity losses.
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Lam, Shang-king, and 林省京. "Computational fluid dynamic analyses of the endovascular stent-graft at the thoracic aorta with different biomechanical factors." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41758031.
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Morrison, Douglass A. "The epidemiology of high-risk coronary artery disease and the choice between stents and surgery." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280632.
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For coronary artery disease (CAD) patients, who cannot be managed with risk factor modification and pharmacologic medical therapy, coronary artery bypass graft surgery (CABG) and percutaneous coronary intervention (PCI), are the primary means of treatment. CABG has been considered the standard for patients who are 'high-risk,' because of anatomic or functional characteristics, but stents and modern pharmacologic adjuncts have made PCI much more competitive. Additionally, as the population ages and becomes more comorbid, some of the features of CABG that allowed 'control' of functionally high-risk patients (such as general anesthesia and heart lung bypass) become disadvantages, especially for hemodynamically unstable patients. This dissertation summarizes the only prospective, multicenter, randomized clinical trial (RCT), and prospective registry of CABG versus PCI, specific to high-risk patients: AWESOME. Previously unpublished 5-year survival data is analyzed in the context of the published AWESOME randomized trial, registry and pre-specified subset 3-year results. Qualitative summaries of all published RCTs comparing medical therapy with CABG or PCI and comparing PCI (with or without stents) with CABG are included (Appendix B). Taken together, these data allow the conclusion that PCI is not simply an alternative for high-risk patients, but that for specific patient groups, such as ST-elevation myocardial infarction (STEMI), hemodynamically compromised unstable angina/non-STEMI, and patients with major comorbidity, PCI is the preferred initial revascularization strategy in 2004.
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Martinez, Adam W. "Design and development of an elastin mimetic stent with therapeutic delivery potential." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45926.
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Stenting remains a common treatment option for atherosclerotic arteries. The main drawback of early stent platforms was restenosis, which has been combated by drug eluting stents; however, these stents have suffered from a higher incidence of late stage thrombosis. To address current stenting limitations, the major research focuses have been the development of the next generation of drug eluting stents and first generation bioabsorbable stents. The main objective of this dissertation was the design and development of a new class of bioabsorbable stent composed of elastin mimetic protein polymers. The first phase explored different stent design schemes and fabrication strategies. Successfully fabricated stents were then mechanically tested to ensure they possessed sufficient mechanical strength. Additionally, described herein is the potential to modulate the properties of the elastin mimetics through different crosslinking strategies. We have demonstrated that chemical crosslinking allows for the tailoring of the physical, mechanical, drug delivery, and endothelialization properties of these materials. The potential for drug delivery from this elastin mimetic stent was benchmarked as was the potential to endothelialize these stents. Furthermore, we developed the necessary delivery systems to allow for deployment in the rat aorta model.
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Halwani, Dina. "Metal-tissue interactions in early stage biocorrosion of metallic stents." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2007m/halwani.pdf.
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Thesis (M.S.)--University of Alabama at Birmingham, 2007.Additional advisors: Peter G. Anderson, Brigitta C. Brott, Jack E. Lemons. Description based on contents viewed Feb. 4, 2008; title from title screen. Includes bibliographical references (p. 69-70).
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Yang, Hua. "Study of Mechanical Performance of Stent Implants Using Theoretical and Numerical Approach." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804879/.
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The coronary heart disease kills more than 350,000 persons/year and it costs $108.9 billion for the United States each year, in spite of significant advancements in clinical care and education for public, cardiovascular diseases (CVD) are leading cause of death and disability to the nation. A cardiovascular disease involves mainly heart or blood vessels (arteries, veins and capillaries) or both, and then mainly occurs in selected regions and affects heart, brain, kidney and peripheral arteries. As a surgical interventions, stent implantation is deployed to cure or ameliorate the disease. However, the high failure rate of stents used in patients with peripheral artery diseases has lead researchers to give special attention towards analyzing stent structure and characteristics. In this research, the mechanical properties of a stent based on the rhombus structure were analyzed and verified by means of analytical and numerical approaches. Theoretical model based on the beam theory were developed and numerical models were used to analyze the response of these structures under various and complex loading conditions. Moreover, the analysis of the stent inflation involves a model with large deformations and large strains, nonlinear material properties need to be considered to accurately capture the deformation process. The maximum stress values were found to occur in localized regions of the stent. These regions were generally found along the inner radii of each of the connected links connecting each of the longitudinal struts. Stress values throughout the whole stent were typically much lower. The peak engineering stress values were found to be less than the material ultimate strength (limit stress 515Mpa), indicating a safe stent design throughout expansion range. Lastly, the rheological behavior of blood can be quantified by non-Newtonian viscosity. Carreau model is introduced and simulates the situation in the artery, then the available shear stress in the model would help to the future analysis in the contact analysis of stent and the artery.
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Huang, Henry Yen-Chin Graduate School of Biomedical Engineering Faculty of Engineering UNSW. "Theoretical and experimental modelling of stress within the neck of endoluminal grafted artery." Awarded by:University of New South Wales. Graduate School of Biomedical Engineering, 2006. http://handle.unsw.edu.au/1959.4/29146.
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The success of endoluminal stent-graft treatment for abdominal aortic aneurysm relies on maintenance of an effective seal when the stent expands into the healthy artery. Clinical observation of aortic neck dilation following endoluminal grafting has led to the hypothesis that excessive stent expansion forces may cause remodelling and dilation of the artery to accommodate the strong forces. This may lead to failure of the seal, hence so-called endoleak. In this research, we analysed the force field generated by aortic stent-grafts and investigated in vitro approaches for studying the effects of these forces on cells within the vascular wall. The pressure-deformation behaviour of ovine arteries was examined experimentally and was found to vary with artery type. A finite element model of abdominal aorta (AA) characterised by Mooney-Rivlin hyperelastic material properties was validated. The property inputs were derived from the polynomial form of the strain energy density function proposed by Patel and Vaishnav. Stent-artery contact simulations revealed stresses 1.2-19 times higher than within a normal vessel at 120 mmHg when contacted by a zig-zag, square cross-section stent that expanded the AA by 3-16%. Streses 1.3-23 times normal were predicted for circular cross-section stents at the same range of expansions. The stress distribution was determined to be concentrated at the contacting surface and within the inner region of the aortic wall. These results confirmed that the forces within the vessel wall are likely to place unnatural physiological demands on the cells within. We then developed an in vitro system for studying the impact of this mechanical stress on cells within a three dimensional (3D) structure. A 20 wt% poly(vinyl alcohol) (PVA) - 5 wt% collagen tubular construct was developed to support cells, and was shown to sustain physiological blood pressures. Two cell-seeding techniques were examined, direct cell encapsulation and surface cell-seeding. Both demonstrated the capability of entrapping viable cells within the construct that remained viable for up to 4 days. In conclusion, stent contact does create abnormal stress concentrations within the vessel wall with a magnitude severely higher than physiological levels. A feasible tubular construct and an in vitro system were developed, enabling further assessments on the effects of these abnormality on the cells.
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Canena, Jorge Manuel Tavares. "Próteses no tubo digestivo: evolução e aplicações no século XXI." Doctoral thesis, Faculdade de Ciências Médicas. Universidade Nova de Lisboa, 2012. http://hdl.handle.net/10362/7874.
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RESUMO: A utilização das próteses metálicas auto-expansíveis é um tratamento paliativo e definitivo muito eficaz em doentes com obstrução maligna coló-retal e gastroduodenal. Este tratamento está associado a taxas de morbilidade e de intervenção adicional aceitáveis. O recurso a próteses expansíveis em doenças benignas pode constituir uma opção terapêutica válida. As próteses biodegradáveis e as próteses metálicas totalmente cobertas podem ser utilizadas, com eficácia aceitável, num grupo de doentes com estenóses refractárias do esófago e para os quais não estão disponíveis grandes opções de tratamento. As próteses metálicas totalmente cobertas podem ser um tratamento de excepção em situações benignas biliares onde anteriormente a cirurgia era a única opção disponível. As próteses metálicas são a opção de escolha no tratamento paliativo do colangiocarcinoma hilar, independentemente do tipo de lesão. Em doentes com estenoses do tipo II de Bismuth a colocação bilateral de próteses metálicas, sempre que tecnicamente possíveis, deve ser recomendada pois está associada a uma maior patência das próteses e a uma menor taxa de reintervenção.
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Shin, Minchul. "MRI evaluation of a stented abdominal aorta of a rabbit /." Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/shin.pdf.
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Thesis (M.S.)--University of Alabama at Birmingham, 2007.Title from PDF of title page (viewed October 13, 2009). Additional advisors: Brigitta C. Brott, Jack E. Lemons, Steven G. Lloyd. Includes bibliographical references (p. 28-31).
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Yugueros, Castellnou Xavier. "Estudio experimental in vitro de la técnica del stent paralelo en la reparación endovascular de los aneurismas de la aorta abdominal." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/669918.
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El stent paralelo es una técnica utilizada en la reparación endovascular de los aneurismas complejos de la aorta abdominal con muy buenos resultados aunque todavía no totalmente estandarizada.
El objetivo de este estudio ha sido evaluar mediante modelos in vitro, parámetros técnicos fundamentales (grado de sobredimensión, la mejor manera de medirlo y la mejor combinación de materiales) en dos configuraciones distintas de stent paralelo: en 2 y 3 chimeneas (chEVAR) para la reparación de los aneurismas sin cuello infrarrenal; y en configuración tipo sándwich para preservar la arteria hipogástrica.
Para ello se recrearon modelos sintéticos de una aorta visceral y de una extensión iliaca siguiendo los diámetros y las características anatómicas habituales en la práctica clínica. En ellos se introdujeron distintos dispositivos con distinto grado de sobredimensión, reproduciendo el mismo procedimiento y simulando las mismas condiciones fisiológicas in vivo.
El análisis de cada reconstrucción se realizó mediante tomografía computarizada (TC) y un programa de procesamiento de imagen evaluando el área de gutters (zonas no cubiertas ni por el stent paralelo ni por la endoprótesis principal), el grado de compresión de los stents y la presencia o ausencia de malposicionamiento o infolding (replegado de la endoprótesis principal generando nuevos gutters).
Respecto a la configuración en 2-3 chimeneas viscerales, los resultados obtenidos fueron a favor de una mejor adaptación de los componentes a sobredimensiones crecientes (15%, 30% o 40%), con una tendencia no significativa a una menor área de gutters. A mayor sobredimensión se evidenció también una tendencia a una mayor compresión del stent paralelo y sobre todo a un mayor riesgo infolding, especialmente en aquellos modelos con 3 stents paralelos, sobredimensiones extremas (> 30%) y combinaciones de materiales de baja fuerza radial. Por todo ello, se consideró que la sobredimensión entorno al 30% es la idónea al reducir al mínimo el área de gutters sin generar compresión significativa de la rama visceral ni tampoco infolding.
Analizando las distintas combinaciones de materiales, nuestros resultados mostraron que tanto para 2 como para 3 chimeneas, los stents balón expandibles y las endoprótesis de alta fuerza radial, se comprimen menos que las combinaciones de baja fuerza radial aunque a expensas de una significativa mayor área de gutters. A raíz de dichos resultados no se pudo extrapolar una recomendación clínica especifica al respecto.
Respecto al configuración en sándwich para preservar el flujo hipogástrico, los resultados mostraron un comportamiento parecido con una reducción progresiva del área de gutters a mayor sobredimensión de diámetro (<30%, 30-55%, 55-75% y > 75%), aunque a expensas de una mayor compresión del stent paralelo y de un mayor infolding. Se consideró por tanto una sobredimensión de diámetros entre el 30 y el 55% como la idónea, al reducir al mínimo el área de gutters sin generar compresión significativa de la rama visceral ni tampoco infolding
Respecto las distintas formas de medición de la sobredimensión, se obtuvo una correlación prácticamente perfecta entre la sobredimensión de áreas clásicamente descrita con la sobredimensión de perímetros y la de diámetros, recomendando el uso de esta última al simplificar de manera importante la planificación del procedimiento.
Respecto a los distintos dispositivos analizados, no se obtuvieron diferencias en las variables evaluadas salvo una tendencia no significativa a un menor infolding con la utilización de stents autoexpandibles como dispositivo para la arteria iliaca interna.Parallel stenting is a surgical procedure used in endovascular repair of complex abdominal aortic aneurysms. The objective of this study has been to evaluate, using in vitro models, some critical technical aspects (oversizing degree, the best way to measure as well as best device combination) in two parallel stent different configurations: 2 and 3 visceral chimneys (chEVAR) and in a sandwich configuration to preserve the hypogastric artery. Synthetic models of a visceral aorta and an iliac extension were constructed following the usual anatomical diameters and characteristics. In them, different devices with different oversizing degree were introduced, reproducing the same procedure and simulating the same physiological conditions as in vivo. The analysis of each reconstruction was performed using computed tomography (CT) and image processing software. Main variables were gutter area (area not covered by either the parallel stent or the main endograft), stent compression and malpositioning or infolding (internal folding of the main endograft generating new gutters). Regarding 2-3 visceral chimney configuration, 30% was the best oversizing degree, reducing gutter area to the minimum without significant branch compression or infolding. Analyzing best device combination, balloon expandable stents and high radial force endografts, were associated with less compression than low radial force materials but at the expense of a significantly larger gutter area. Regarding sandwich configuration to preserve hypogastric flow, our results showed that 30 - 55% diameter oversizing was the best, being associated with less gutter area without significant visceral branch compression or infolding. Analyzing oversizing measuring methods, a practically perfect correlation was obtained between all of them, (areas, perimeters and diameters) recommending the use of the latter as significantly simplifying procedure planning. Regarding device combinations, no clear differences were obtained excepting a non-significant tendency to lower infolding with self-expanding stents for the internal iliac artery.
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Dimble, Dipesh S. "Geometry modeling for patterned and repetitive configurations." Birmingham, Ala. : University of Alabama at Birmingham, 2006. http://www.mhsl.uab.edu/dt/2007m/dimble.pdf.
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Roy, Alexander M. "Prediction of low and high cycle multiaxial fatigue of superelastic nitinol stents via uniaxial fatigue based equations." Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527412.
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Esterhuyse, Anton. "Structural design of a stent for a percutaneous aortic heart valve." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2706.
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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.Elderly patients suffering from aortic valvular dysfunction are often denied aortic valve replacement due to the fact that they are classified as too old and fragile to handle the physical stress of open-heart surgery and cardio-pulmonary bypass. There exists a need for an alternative solution which places less physical stress on the body. The development of a percutaneous aortic heart valve (PAHV), which may be implanted through a minimally invasive procedure, will provide a solution to old and fragile patients who otherwise have a very limited life expectancy. The development of such a device entails a costly and time-consuming process which involves a number of phases, including a prototype development phase, an in-vitro testing phase, an animal trial phase and a human trial phase. This thesis focuses on the design and analysis of the stent component for a PAHV, suitable for implantation in sheep (animal trial phase). The process of developing a first prototype, involved an analysis of the stent design requirements. This analysis was followed by a concept generation phase as well as comprehensive finite element (FE) analyses of the most promising concepts. The objective of the FE analyses was to determine the effects of a variation in strut width on the performance characteristics of the concepts. Based on the results of the FE analyses, final geometries were selected for each of the two most promising concepts. Subsequent to the selection of the final geometries, a number of prototypes were manufactured. The prototypes were subjected to an electro-polishing process. An experimental analysis was also conducted on the prototypes to evaluate the accuracy of the (FE) simulations as well as the actual performance of the stent prototypes. The results of the FE analyses and experimental analyses indicated that strut width had a substantial influence on the parameters that were defined to characterise stent performance. The results of the analyses also highlighted the advantages and disadvantages of each concept and aided in identifying the concept that would be most suitable for the required application. Limitations of the study were identified and recommendations were made to assist the continued research and development of the device.
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Khaddam, Sinan M. D. "Difference in outcomes between central airway lesions requiring stents and lesions that donot in patients with NSCLC." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553513958608363.
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Rossbach, Cornelius. "Randomisierter Vergleich von Medikamenten freisetzenden Stents mit minimal-invasiver Bypasschirurgie für isolierte proximale LAD-Stenosen – Ein 7-Jahres-Follow-Up." Doctoral thesis, Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-221662.
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OBJECTIVES The aim of this analysis was to assess the 7-year long-term safety and effectiveness of a randomized comparison of percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SES) versus minimally invasive direct coronary artery bypass (MIDCAB) surgery for the treatment of isolated proximal left anterior descending lesions.
BACKGROUND Long-term follow-up data comparing PCI by SES and MIDCAB surgery for isolated proximal left anterior descending lesions are sparse.
METHODS Patients were randomized either to PCI with SES (n ¼ 65) or MIDCAB (n ¼ 65). Follow-up data were obtained after 7 years with respect to the primary composite endpoint of death, myocardial infarction, and target vessel revas-
cularization. Angina was assessed by the Canadian Cardiovascular Society classification and quality of life with Short Form 36 and MacNew quality of life questionnaires.
RESULTS Follow-up was conducted in 129 patients at a median time of 7.3 years (interquartile range: 5.7, 8.3). There were no significant differences in the incidence of the primary composite endpoint between groups (22% PCI vs. 12%
MIDCAB; p ¼ 0.17) or the endpoints death (14% vs. 17%; p ¼ 0.81) and myocardial infarction (6% vs. 9%, p ¼ 0.74). However, the target vessel revascularization rate was higher in the PCI group (20% vs. 1.5%; p < 0.001). Clinical symptoms and quality of life improved significantly from baseline with both interventions and were similar in magnitude between groups.
CONCLUSIONS At 7-year follow-up, PCI by SES and MIDCAB in isolated proximal left anterior descending lesions yielded similar long-term outcomes regarding the primary composite clinical endpoint and quality of life. Target vessel revascularization was more frequent in the PCI group. (Randomied Comparison of Minimally Invasive Direct Coronary Artery Bypass Grafting and Percutaneous Coronary Intervention With Drug-Eluting Stents in Patients With Proximal Stenosis of the Left Anterior Descending Coronary Artery; NCT00299429) (J Am Coll Cardiol Intv 2014;-:-–-) © 2014 by the American College of Cardiology Foundation.
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Alagarsamy, Karthik. "Application of High Entropy Alloys in Stent Implants." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984159/.
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High entropy alloys (HEAs) are alloys with five or more principal elements. Due to these distinct concept of alloying, the HEA exhibits unique and superior properties. The outstanding properties of HEA includes higher strength/hardness, superior wear resistance, high temperature stability, higher fatigue life, good corrosion and oxidation resistance. Such characteristics of HEA has been significant interest leading to researches on these emerging field. Even though many works are done to understand the characteristic of these HEAs, very few works are made on how the HEAs can be applied for commercial uses. This work discusses the application of High entropy alloys in biomedical applications. The coronary heart disease, the leading cause of death in the United States kills more than 350,000 persons/year and it costs $108.9 billion for the nation each year in spite of significant advancements in medical care and public awareness. A cardiovascular disease affects heart or blood vessels (arteries, veins and capillaries) or both by blocking the blood flow. As a surgical interventions, stent implants are deployed to cure or ameliorate the disease. However, the high failure rate of stents has lead researchers to give special attention towards analyzing stent structure, materials and characteristics. Many works related to alternate material and/or design are carried out in recent time. This paper discusses the feasibility of CoCrFeNiMn and Al0.1CoCrFeNi HEAs in stent implant application. This work is based on the speculation that CoCrFeNiMn and Al0.1CoCrFeNi HEAs are biocompatible material. These HEAs are characterized to determine the microstructure and mechanical properties. Computational modeling and analysis were carried out on stent implant by applying CoCrFeNiMn and Al0.1CoCrFeNi HEAs as material to understand the structural behavior.
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Arauz, Garofalo Gianluca. "Prospects of microwave spectrometry for vascular stent monitoring. Towards a non-invasive and non-ionizing follow-up alternative." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/404376.
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Throughout this thesis we have assessed the prospects of microwave spectrometry (MWS) as a non-ionizing non-invasive monitoring alternative for stented patients in a very early proof-of-concept stage.
In Chapter 1 we have provided a generalist retrospective medical background along with a state-of-the-art summary of existing microwave-based stent monitoring approaches. First, we have introduced cardiovascular diseases in general, and ischemic heart disease in particular. Next we have reviewed how percutaneous coronary interventions addressed the medical problem represented by atherosclerosis, giving a special emphasis to balloon angioplasty, bare-metal stenting and drug-eluting stenting. We have further exposed how the outcomes of such revolutionary strategies were compromised by the high rates of post-procedural complications, making unavoidable the invasive and ionizing follow-up of stented patients. Finally, we have summarized existing non-invasive and non-ionizing stent monitoring alternatives based in microwave techniques.
In Chapter 2 we have introduced the working principle of our MWS setup. We have first presented how this arrangement can obtain the absorbance of a stent as a function of the frequency and the incidence angle of the microwave fields. We have also shown how these data are combined in a single two-dimensional chart, and how we recognize therein the characteristic resonance frequencies of stents at a glance. As an example, we have presented a typical absorbance diagram to illustrate the general features of such resonances. In particular we have highlighted that these resonances are discrete and have multi-lobed angular patterns.
In Chapter 3 we have characterized many stents having a wide variety of nominal sizes to better understand their characteristic resonances in terms of microwave scattering. First, we have found that the resonance frequency obeys a reciprocal dependence on the stent length. This has allowed us to obtain an empirical expression for such relationship just by adjusting two fitting parameters. However, we have not been able to find an analogous expression for the dependence on the stent diameter. In any case, while investigating the latter, we have unexpectedly uncovered how the particular stent architecture influences the corresponding resonance frequencies. By gathering all these individual results we have finally suggested a straightforward half-theoretical half-empirical model linking the resonance frequencies of stents with their structural integrity (through their length), with their particular architecture (through the scaling factor), as well as with their surrounding medium (through the dielectric permittivity and the magnetic permeability). We have also theoretically estimated the resonance frequencies of implanted stents from their corresponding values in free space conditions, showing that in vivo resonance frequencies should be around one order of magnitude smaller than their free space counterparts.
Finally, in Chapters 4 and 5 we have explored the potential diagnostic capabilities of MWS in two possible scenarios: stent fracture (SF) and in-stent neoatherosclerosis (ISNA). We have started both chapters reviewing the incidence, the medical implications, and the mechanism of these two stent-related complications. SF has been evaluated in Chapter 4 by means of two “fracture tests” consisting in a successive series of strut cuts. We have shown that MWS provides qualitative indicators for single and multiple strut fractures (downshift of the fundamental resonance frequency), and also quantitative indicators for single or multiple complete transverse linear SFs (split and upshift of that frequency). ISNA has been evaluated in Chapter 6 by means of four ``cholesterol tests'' consisting in a gradual process of increasing cholesterol deposition. We have shown that MWS provides an indicator for a growing presence of cholesterol around a stent (downshift of the fundamental resonance frequency). We have concluded this chapter calculating the theoretical evolution of the resonance frequencies along a cholesterol deposition process, estimating the upper limit for the resonance frequency displacement. Taking together the results we have reported in Chapters 5 and 6, we have shown that MWS could potentially warn about SF and ISNA.
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Rose, Stacey Loren. "In Vitro Model of Vascular Healing in the Presence of Biomaterials." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13955.
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Coronary artery stent placement has been a significant advance in the percutaneous treatment of atherosclerotic disease, and tissue engineered vascular grafts may provide a viable alternative to autologous segments for small diameter vessels. However, in-stent restenosis remains an important limitation, and tissue engineered grafts have poor patency and high risk of thrombus formation due to their inability to maintain a confluent, adherent, and quiescent endothelium. While animal models provide insight into the pathophysiology of these situations, elucidation of the relative importance of stent or graft components, hemodynamic factors, and molecular factors is difficult. Very little research has focused on bridging gaps in knowledge concerning blood/biomaterial interactions, blood/endothelial cell interactions, and endothelial cell/smooth muscle cell cross-talk. The work presented within this thesis will do just that. The objective of this thesis research was to elucidate the influence of biomaterial-induced activation of leukocytes on endothelial cell or smooth muscle cell phenotype, as well as endothelial cell/smooth muscle cell cross-talk in co-culture systems. Towards this goal, two complimentary in vitro endothelial cell/smooth muscle cell co-culture models with divergent smooth muscle cell phenotype were developed and characterized. Using these systems, it was found that the presence of more secretory smooth muscle cells (as would be seen in wound healing or disease) in general enhanced endothelial cell activation in response to biomaterial-pretreated monocytes, while the presence of less secretory smooth muscle cells (to model more quiescent smooth muscle cells found in uninjured healthy vessels) suppressed endothelial cell activation in response to biomaterial-pretreated monocytes (and neutrophils to a small degree). Additionally, biomaterial-pretreated monocytes and neutrophils amplified a smooth muscle cell phenotypic shift away from a more quiescent state. It is likely that the compounding effect of secretory smooth muscle cells and biomaterial-activated leukocytes are responsible for altered vascular wound healing upon implantation of stents or vascular grafts. Understanding the specific signals causing these effects, or signals delivered by contractile smooth muscle cells that limit these effects help to provide design criteria for development of devices or grafts capable of long term patency.
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Wang, Yan, and 王焱. "Atherosclerotic disease of the carotid, coronary and renal arteries: diagnosis, angioplasty and the effect ofstent surface on early thrombosis and restenosis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31246060.
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Khan, Muhammad Farhan. "Design optimisation for stent manufacture." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52353/.
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Intravascular stents of various designs are currently used to prop open diseased arteries and there is evidence that different stent geometries have different in-stent restenosis rates. The majority of commercially available stents are designed generically to fit all individuals. Recent advances in imaging and catheter technologies, however, allow measurement of lesion shape and stiffness. Incorporating patient specific data into the stent design process could enable the development of customised stents. Considering the variety of lesion types, it is envisaged that better outcomes will be achieved if a stent is custom designed in such a way that it has variable radial stiffness longitudinally to hold the varying pressure of plaque and healthy artery at the same time while maintaining an acceptable lumen diameter. This type of operation is suitable for topology optimisation potentially allowing for optimal material distribution of a stent. The primary aim of this research is to develop new stent designs for a set of plaque types and investigate the final radius of the lumen after stent implantation. Stent geometries were obtained by topology optimisation for minimised compliance under different stenosis levels and plaque materials. Three types of stenosis levels by area, i.e. 30%, 40% and 50% with each type having three different plaque material properties i.e. calcified, cellular and hypocellular were studied. The optimisation results were transformed to clear design concepts and their performance was evaluated by implanting them in their respective stenosed artery types using finite element analysis. The results were compared with a generic stent in similar arteries, which showed that the new designs showed less recoil. In the hardest (calcified) of plaques studied, topology optimised designs overall resulted in 2%, 2% and 6% residual area stenosis compared to 10%, 29% and 35% from the generic design in arteries with 30%, 40% and 50% stenosis respectively. It was shown that higher material distribution resulted in the central region of the stent in order to resist implantation recoil due to higher plaque compressive loads. Additive manufacturing (AM) was utilised to validate the computational approach used in this thesis. This work provides a proof of concept for stents tailored to specific lesions in order to minimise recoil and maintain a patent lumen in stenotic arteries.
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Warden, C. "Management of left-sided malignant colonic obstruction : an audit of a stent based protocol." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11006.
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Includes abstract.Includes bibliographical references.
Colonic self-expanding metallic stents (SEMS) are proven to be safe and effective in the management of selected cases of malignant colonic obstruction. Since 2005, we have used endoscopic decompression with SEMS as the primary treatment of all patients with left-sided obstructing colorectal cancer, in the absence of perforation. The purpose of the study was to assess the safety and efficacy of this management protocol.
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Chong, Chuh Khiun. "Endovascular stent-graft repair of abdominal aortic aneurysms : an in vitro modelling." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367821.
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Bertrand, Olivier F. "Prevention of coronary restenosis using a radioactive stent : radiobiological studies." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ64515.pdf.
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Jones, Steven. "A computational fluid dynamics analysis of the distraction forces experienced by stent-grafts following fenestrated Endovascular Aneurysm Repair." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/2052119/.
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Introduction One option for repair of abdominal aortic aneurysms with inadequate length of infrarenal neck is fenestrated Endovascular Aneurysm Repair. Significant complications may be caused by stent-graft migration and component distraction which are both resisted by fixation force and provoked by haemodynamic distraction force. The hypotheses tested in this thesis are that larger angulation of vessels is associated with greater distraction force and that greater distraction force is associated with higher incidence of migration and component distraction. Method Interobserver variation of a new method of angle measurement was compared with the standard method currently in use in our unit. Computer models of complete fenestrated stent-grafts and their individual components (proximal body, distal body and limb extensions) were then constructed based on the postoperative computed tomography scans of 54 patients. Computational Fluid Dynamic analysis in steady state was used to quantify the distraction force acting on each device. Blood pressure was kept constant at 160mmHg and the impact of morphological features upon distraction force was assessed. To test the second hypothesis, patient-specific blood pressures were used to obtain in situ distraction forces that were then related to the incidence of migration and component distraction. Results There were no significant differences between the old and new methods of angle measurement (p=.723, WSR). Inlet cross-sectional area (XSA) exhibited a strong, positive correlation with total RDF in complete stent-grafts, proximal body and distal body components. Outlet angulation ≥45° was significantly associated with greater total RDF in complete stent-grafts and limb extension components (Median total RDF in complete stent-grafts with angle < 45° = 2.6N vs 6.2N in those ≥45°, p < .001. Limb extensions: 1.4N vs 2.1N, p = .004, MWU). There was no significant difference between total RDF acting on the proximal or distal bodies that underwent migration or component distraction versus those that did not. Limb extensions that were observed to migrate were exposed to significantly greater total RDF compared to those that did not migrate (Median total RDF 2.9N, range 2.7-6.3N versus 1.6N, range 0.4-3.8N, p = .003, MWU). Conclusions For a given blood pressure XSA was the most important morphological determinant of total RDF. Outlet angulation of complete stent-grafts and limb extensions was associated with significantly greater total RDF. In limb extensions, greater distraction force was significantly associated with migration. The results suggest caution when planning distal seal in ectatic iliac vessels.
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Behravan, Bita [Verfasser], and Gisela [Akademischer Betreuer] Steins. "The hidden psycho-social dimensions of cosmetic surgery / Bita Behravan ; Betreuer: Gisela Steins." Duisburg, 2018. http://d-nb.info/1164376365/34.
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Fransson, Roland. "Mätning av gångförmåga efter operation av lumbal spinal stenos och korrelation mot subjektivt skattad gångförmåga i hälsofunktionsindex." Thesis, Linnéuniversitetet, Institutionen för idrottsvetenskap (ID), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-50817.
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Lumbal spinal stenos är ett av de vanligaste patologiska tillstånden i ryggen. Primärt mål för de flesta av interventionerna vid lumbal spinal stenos är en förbättring av gångförmågan. I det Svenska ryggregistret för uppföljning av kirurgi saknas utvärdering av objektivt uppmätt gångförmåga. Syfte: Att undersöka hur objektivt uppmätt gångförmåga påverkas efter en operation av lumbal spinal stenos samt hur den korrelerar mot subjektivt skattad gångförmåga och mot skattad rygghälsa samt livskvalitet. Metod: Etthundrasjuttiotre patienter i ålder 50-81 år utförde pre och 24 månader postoperativt ett standardiserat six minutes walk test (6 MWT) samt besvarade enkäter om självskattad gångförmåga, livskvalitet (EQ5D) och rygghälsa (ODI). Signifikans på förändring av medelvärdet av gångförmågan beräknades med ett parat t-test och 95 % konfidensintervall. Korrelation mellan uppmätt gångförmåga och självskattad gångförmåga samt mot EQ5D och ODI beräknades med Spearmans rangkorrelation. Resultat: Gångförmågan mätt med 6MWT förbättrades från 314 meter preoperativt till 396 meter 24 månader postoperativt. Korrelationen mellan uppmätt gångförmåga och självskattad gångförmåga var 0,68 postoperativt. Korrelationen mellan 6 MWT och EQ5D var 0,60 och mot ODI 0,65, 2 år postoperativt. Konklusion: Resultatet i denna studie visade på en signifikant förbättring av objektivt uppmätt gångförmåga två år efter en operation av lumbal spinal stenos. Korrelationen mellan självskattad gångförmåga och 6 MWT var moderat. Korrelationen mellan 6 MWT och EQ5D var moderat och moderat till stark mot ODI.Lumbar spinal stenosis is one of the most common pathological conditions in the lower back. A primary goal for most of the interventions for lumbar spinal stenosis is an improvement of walking ability. In the Swedish back registry for follow-up surgery objectively measured gait is missing. Objective: To examine how objectively measured walking capacity is affected by an operation of lumbar spinal stenosis and how it correlates with subjective estimated walking capacity, back health (ODI) and quality of life (EQ5D). Method: Onehundredseventythree patients in age 50-81 years performed pre and 24 months postoperatively a standardized six minutes walk test (6 MWT) and responded to questionnaires about self-rated gait, EQ5D and ODI. Significance of the change in mean walking ability was calculated by using a paired t-test and 95% confidence intervals. Correlation between the measured gait and self-rated gait as well as against EQ5D and ODI were calculated with Spearman rank correlation. Result: Walking capacity measured by the 6MWT improved from 314 to 396 meters, 24 months postoperatively. The correlation between the measured and self-rated gait were 0,68 postoperatively. Correlation between 6MWT and EQ5D were 0,60 and against ODI 0.65, 2 years postoperatively. Conclusion: The results of this study showed a significant improvement in objectively measured walking capacity, two years after an operation of lumbar spinal stenosis. Correlation between self-rated gait and 6 MWT were moderate. Correlation between 6MWT and EQ5D were moderate and against ODI moderately strong.
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CLERICI, ALBERTO. "Development of a novel technology platform for thoracoscopic aortic valve replacement." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2745352.
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Sinigaglia, Riccardo. "Studio mediante gait analysis dei risultati a breve termine del trattamento della stenosi severa multilivello del canale vertebrale lombare mediante decompressione e distrazione interspinosa." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3423222.
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The clinical syndrome of neurogenic claudication due to lumbar spinal stenosis (LSS) is a frequent source of pain in the lower back and extremities, impaired walking, and other forms of disability in the elderly. Although the incidence and prevalence of symptomatic lumbar spinal stenosis have not been established, this condition is one of the most frequent indication for spinal surgery in patients older than 65 years of age.
The treatment strategy depends on the severity of clinical symptom. After nonoperative treatement failure, surgical decompression should be considered.
Aim of our prospective non-randomized clinical study was to analized short term results, efficancy, and complications after decompression and interspinous distraction surgery for severe multilevel LSS, and to analyzed difference in body and spine balance and movement using gait analysis,.
Between March 2009 and March 2010 12 patients were selected for our study. 4 (33.3%) were female, 8 (66.7%) were male. Mean age at surgery was 63.50±15.23 (range 39-82) years. A mean of 2.50±0.80 (range 1-4) sympthomatic levels were treated for patient. Mean operative time was 90.42±18.40 minutes. In all procedures there was just light intraoperative blood loss. Mean hospitalization was 3.08±1.08 days. There was a mean return to walk after 1.83±0.58 days.
Results of our short term prospective nonrandomized clinical study shown that decompressive recalibrage plus interspinous distraction is an effective and safe procedure for severe multilevel LSS. Patients had improvement both on sympthoms and on functionality and capacity.
All patients were satisfied for the procedure, with a personal satisfaction rate (0-10) of 8.33±1.53. After surgery there were significant statistical improvement in VAS pain (pv=0.000), in ODI lumbar function (pv=0.000), and in SF36 health status (pv=0.000).
Gait analysis showed an objective, and not just subjective, improvement in patient functionality and capacity. Trials proved a global improvement in spinal range of motion after surgery (pv=0.001 both on flexion-extension, and on lateral bending, and on axial rotation), with re-distribution of plantar anterior-posterior loading, and better plantar loading distribution on static trials, signs of improved balance. There were reduction of postures to prevent pain. There was a statistical improvement in walking capacity.
It will be important to continue follow-up of patients, implementing sample, in order to verify long-term follow-up, real focus on treatment choice.La stenosi del canale vertebrale lombare (LSS) è una patologia tipica dell’età avanzata che si manifesta classicamente con claudicatio neurogenica, o spinale, e disabilità progressiva nella deambulazione associata o meno a lombalgia- lombosciatalgia. Sebbene l’incidenza e la prevalenza delle forme sintomatiche di LSS non sia stata ancora bene stabilita, questa patologia degenerativa è la principale causa di chirurgia vertebrale nei pazienti oltre i 65 anni. Il trattamento dei pazienti con LSS si basa sulle sue manifestazioni cliniche. Dopo iniziale fallimento di terapie conservative, diversi autori consigliano il trattamento chirurgico. Scopo del nostro lavoro clinico prospettico non randomizzato è stato studiare risultati, efficacia, e complicanze a breve termine del trattamento della LSS mediante recalibraggio decompressivo associato ad artrorisi interspinosa, analizzando mediante la gait analysis il reale effetto su equilibrio e motilità della colonna segmentale lombare e globale. Tra Marzo 2009 e Marzo 2010 sono stati selezionati per il nostro studio 12 pazienti, 4 (33.3%) femmine, 8 (66.7%) maschi. L’età media era 63.50±15.23 (range 39-82) anni. Sono stati trattati in media 2.50±0.80 (range 1-4) livelli stenotici sintomatici per paziente. Il tempo operatorio medio è stato 90.42±18.40 minuti. Le perdite ematiche intraoperatorie sono state trascurabili. Il ritorno alla deambulazione autonoma è avvenuto dopo una media di 1.83±0.58 giorni dall’intervento. La durata media dell’ospedalizzazione è stata 3.08±1.08 giorni. I risultati del nostro studio clinico prospettico non randomizzato a breve termine dimostrano come l’intervento di recalibraggio associato a distrazione interspinosa Coflex sia procedura efficace e sicura nel trattamento della stenosi del canale vertebrale lombare severa multilivello. Questo intervento, oltre alla risoluzione dei sintomi, porta ad un miglioramento della funzionalità e delle capacità dei pazienti. Tutti i pazienti erano soggettivamente soddisfatti dell’intervento effettuato, con un indice di soddisfazione personale medio di 8.83±1.11 su una scala da 0 a 10. Dopo l’intervento si ha un miglioramento statisticamente significativo del dolore (pv=0.000), della funzionalita’ lombare (pv=0.000), e dello stato di salute (pv=0.000). La gait analysis ha dimostrato un miglioramento della funzionalità e delle capacità dei pazienti non solo legato a questionari clinici soggettivi, ma rilevato oggettivamente. Si ha un miglioramento della motilità della colonna su tutti i 3 piani dello spazio (pv=0.001 sia per la flesso-estensione, che per la deviazione laterale, che per la rotazione assiale), una ridistribuzione dei carichi sull'asse antero-posteriore ed una migliorata distribuzione delle pressioni plantari durante le prove statiche, segno di maggiore equilibrio, una riduzione degli atteggiamenti posturali attuati per prevenire il dolore, un miglioramento delle capacità deambulatorie. Sarà importante tenere seguito nel tempo questo gruppo di pazienti, implementando sia il campione che il follow-up, per verificare l’effettiva tenuta nel tempo dei risultati, nodo cruciale nella scelta del trattamento.diante gait
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Vanbiervliet, Geoffroy. "Validation clinique et métabolique de l'approche endoscopique par notes de la chirurgie bariatrique sur modèle porcin vivant." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM5073.
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Introduction – Le but de ce travail était de développer un modèle expérimental endoscopique de chirurgie bariatrique par technique NOTES, simple, reproductible et de le valider à la fois sur le plan clinique (faisabilité, tolérance) et sur le plan métabolique (physiopathologie et mode d’action). Matériels et méthodes - Les études furent menées au sein du CERC et de l’unité INSERM UMRS 1260. L’animal étudié fut le cochon domestique, âgé de 3 à 4 mois, sains et non obèse. Les endoscopies étaient réalisées à l’aide d’un gastroscope double canal opérateur et de matériel d’endoscopie couramment disponible. Plusieurs étapes de développement furent mises en place de la confection d’un modèle animal d’anastomose gastro-jéjunale par technique endoscopique NOTES exclusive à l’évaluation de l’impact métabolique d’un modèle de by-pass gastrique à visée bariatrique utilisant l’anastomose gastro-jéjunale par apposition prothétique luminale. Résultats – Le modèle d’anastomose gastro-jéjunale choisi pour sa faisabilité et son innocuité fut développé par apposition des lumières digestives gastriques et grêliques avec prothèse en technique NOTES trans digestive. L’évaluation métabolique expérimentale du by-pass gastrique utilisant ce mode opératoire permit de constater une amélioration significative de l’insulino-résistance non véhiculées par le GLP-1. Conclusion – Le concept d’anastomose digestive par NOTES exclusive et apposition luminale prothétique est établi et le modèle de by-pass endoscopique utilisant ce mode opératoire est faisable semblant présenter un impact métabolique significatifIntroduction - The aim of this study was to develop an endoscopic experimental model of NOTES bariatric surgery using a simple, reproducible technique and to validate it both clinically (feasibility, tolerance) and metabolically (pathophysiology and action plan). Materials and Methods - The studies were conducted within the CERC and INSERM UMRS 1260 unit. The animal was the pig, aged 3 to 4 months, healthy and not obese. Endoscopies were performed using a dual channel gastroscope operator and the endoscopy equipment currently available. Several development stages were set up from the development of an animal model of gastrointestinal anastomosis using an exclusive endoscopic NOTES procedure to the evaluation of the metabolic impact of gastric bypass bariatric model described using the gastrointestinal anastomosis by luminal apposing stent technique. Results - The gastro-jejunal anastomosis model chosen for its feasibility and safety was developed by luminal apposing gastric and small bowel digestive lumens with a specific metallic covered stent and NOTES technique. The experimental evaluation of the metabolic gastric bypass using this procedure allowed to observe a significant improvement in insulin resistance none mediated by GLP-1 and incretin effect. Conclusion - The concept of anastomosis with luminal apposing stent and exclusive NOTES technique is established and endoscopic bypass model using this procedure is feasible pretend to present a significant metabolic impact
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MAGALHÃES, NETO Galeno Egydio José de. "Remoção endoscópica de anel em pacientes submetidos á derivação gástrica em y de Roux utilizando prótese plástica autoexpansível." Universidade Federal de Pernambuco, 2014. https://repositorio.ufpe.br/handle/123456789/17974.
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O uso de anel na derivação gástrica em Y de Roux (DGYR) está associado à intolerância alimentar pós-operatória, cujo tratamento clássico tem sido a remoção cirúrgica. Um novo método utilizando prótese plástica autoexpansível (PPAE) induz erosão intragástrica do anel, o qual é removido por via endoscópica de forma minimamente invasiva. Objetiva-se analisar a eficácia e a segurança dessa técnica de remoção de anel após DGYR. Estudo prospectivo longitudinal de série de 41 pacientes com intolerância alimentar associada à presença de anel, que foram, tratados por via endoscópica, entre 2007 e 2013. O grupo apresentava média de idade igual a 44,1 anos, IMC médio de 27,0 Kg/m², e vômitos foram os sintomas mais frequentes (n=37), com ocorrência diária em 46,3%. O sucesso terapêutico foi definido como a melhora dos sintomas após a remoção do anel. O implante de PPAE foi realizado sob anestesia geral e guiado por radioscopia, sendo utilizado endoscópio padrão. Os pacientes receberam alta após 24 horas com dieta líquida e inibidor de bomba de prótons (IBP), que foi prescrito durante o tempo médio de permanência da PPAE, que foi de 15,3 dias. A prótese promoveu erosão completa de anel em 24 (58,5%) pacientes e no grupo restante, a remoção em segundo estágio após 7 dias com pinça de corpo estranho. Houve três casos de migração da prótese com eliminação espontânea por via retal. O efeito adverso mais comum foi vômito (n=7). Não houve complicações graves, nem necessidade de remoção precoce da prótese. Após seguimento médio de 6 meses, não houve mudança significativa no IMC e 78% dos pacientes foram capazes de ingerir carne vermelha. A remoção do anel com uso de prótese endoscópica demonstrou ser um procedimento seguro e eficaz, com100% dos anéis sendo removidos com sucesso e 29,3% de ocorrência de eventos adversos leves (vômitos). Esta técnica é uma alternativa adequada na remoção do anel, evitando a intervenção cirúrgica e reduzindo a possibilidade de reganho de peso.
Ring dysfunction after roux-en-y gastric bypass (RYGB) causing delayed gastric emptying on Fobi pouch is classically treated by surgical ring removal. In a novel way of using selfexpandable stents, intraluminal erosion of the ring is achieved, allowing its removal by endoscopy, with no need of surgery. No study has shown clinical applicability of this principle in RYGB banded with silastic ring. In this case series we analyze endoscopic removal of noneroded dysfunctional rings after RYGB using self-expandable plastic stents (SEPS). This is a prospective case series of 41 patients with delayed gastric emptying secondary to extrinsic compression of the ring after RYGB between 2007 and 2013. Successful ring removal, symptoms improvement, weight control and adverse events were evaluated. Mean age of subjects was 44.1 years, median BMI at treatment was 27.0 Kg/m2. Most common symptom was vomiting (n=37), with daily occurrence in 46.3%. Success was defined as symptoms improvement after stent and ring removal. SEPS placement was done under general anesthesia and fluoroscopic guidance. A standard gastroscope (Pentax Medical, Montvale, NJ), and a PolyflexTM stent (25x21x150mm) (Boston Scientific, Natick, MA) were used in all cases. All patients were discharged after a 2-hour observation period, with liquid diet and proton pump inhibitor. SEPS induced complete erosion in 24 patients, allowing for simultaneous stent and ring removal. The median time of stenting was 15 days. There was one case of stent migration, which was naturally expelled. Most common adverse event was vomiting (n=7). There was no early stent removal, and no serious complications. After a mean follow-up of 6 months, there was no significant change in mean BMI, and 78% of patients are able to ingest solid foods. Endoscopic stents led to ring intraluminal erosion in 100% of subjects, allowing for successful removal of dysfunctional rings. The procedure is technically feasible and safe, with a 29.3% occurrence of mild adverse events (vomiting), and no serious complications. It proved to be a reasonable alternative for ring removal in our casuistic, avoiding surgery, and decreasing the possibility of weight regain.
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von, Sachsen Sandra. "Einsatz numerischer Simulationen für einen Vergleich von Stentgrafts in der endovaskulären Gefäßmedizin." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-178083.
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Der Einsatz numerischer Simulationen zur Bearbeitung klinischer Fragestellungen ist eine innovative Vorgehensweise. Im Rahmen der vorliegenden Arbeit wurde eine Methode zur Auswertung von Ergebnissen einer Finite-Elemente-Analyse zum Stentgraftverhalten konzipiert, implementiert und im Rahmen einer deutschlandweiten Benutzerstudie getestet. Für einen Vergleich unterschiedlicher Stentgraftkonfigurationen im Kontext mit dem patientenspezifischen Gefäß wurden Stentgraftbewertungsgrößen eingeführt. Hierzu gehören die Fixierungskraft und der Kontaktstatus zwischen Stentringen und Blutgefäßbestandteilen. Für eine Bereitstellung der Ergebnisgrößen im gefäßmedizinischen Arbeitsumfeld wurde eine graphische Mensch-Maschine-Schnittstelle entwickelt. Diese ermöglicht eine quantitative und qualitative Auswertung von Stentgraftbewertungsgrößen. Hierfür wurden Module zur automatisierten Auswertung von Fixierungskräften sowie zur 2D- und 3D- Ergebnisvisualisierung implementiert. Im Rahmen der Benutzerstudie wurde die Anwendung der entwickelten Methode für die Ermittlung des Einsatzpotenzials numerischer Simulationen zur Unterstützung der Stentgraftauswahl demonstriert. Im Ergebnis wurde als wesentliches Einsatzpotenzial die Festlegung eines Mindestmaßes an Überdimensionierung, die Optimierung der Schenkellänge sowie der Ver- gleich unterschiedlicher Stentgraftdesigns ermittelt. Weiterhin konnten grundlegende Anforderungen an ein System zur Generierung und Bewertung von Stentgraftkonfigurationen im klinischen Alltag definiert werden. Zu den wesentlichen Funktionen, die der Implanteur für einen Vergleich von Stentgrafts benötigt, zählen eine Übersichtskarte zu farbkodiertem Migrationsrisiko pro Stentgraft und Landungszone, die Visualisierung des Abdichtungszustandes der Stentkomponenten sowie die Darstellung von Stentgraft- und Gefäßdeformationen im 3D-Modell.
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Harrypaul, Ashika. "The assessment of two year clinical outcomes after stent implantation for the treatment of coronary artery disease." Thesis, 2013. http://hdl.handle.net/10321/812.
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Submitted in fulfilment of the Master’s Degree in Clinical Technology,
Durban University of Technology, 2012.The sirolimus-eluting stent (Cypher) was the first approved drug- eluting stent by the Food and Drug Administration in April 2003. This is a stent that is based on a bare-metal stent and is coated with a layer of polymer incorporating sirolimus and releasing it by diffusion. Drug-eluting stents reduced risk of restenosis and repeat revascularization as compared with bare-metal stents. Clinical data has raised concerns that drug-eluting stents are associated with late untoward events. Objectives: The objective of this study was to test the hypothesis that stenting is safe and effective treatment for coronary artery disease. Methods and Results: Sirolimus-eluting stenting was performed in 30 patients with 34 coronary lesions. Detailed clinical follow-up data was collected by personal interview or telephone contact at 1, 6, 12 and 24 months. Patients were followed for 2 years for the occurrence of angina and cardiovascular events namely death, myocardial infarction, stent thrombosis and target lesion revascularization. The mean age of the cohort was 62.33±10.99 years; 83 percent were male, 6 percent were diabetic, 53 percent had hypertension. In spite of the overall patient and lesion complexity there were no incidences of major adverse cardiac events and all patients remained angina free out to two years. Dual antiplatelet therapy with aspirin and plavix varied from at least four weeks to one year. One patient had a bleeding event. Conclusions: Treatment of lesions with sirolimus-eluting stents is associated with a sustained clinical benefit two years after device implantation.
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Papariella, Kelly M. "Interfacial properties of oligo(ethylene glycol)-terminated self-assembled monolayers on stainless steel 316L." 2007. http://digital.library.duq.edu/u?/etd,126010.
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Kamenskiy, Alexey. "Coupled hemodynamics and mechanics of the repaired human carotid artery." 2009. http://proquest.umi.com/pqdweb?did=1934063431&sid=1&Fmt=2&clientId=14215&RQT=309&VName=PQD.
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Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009.Title from title screen (site viewed February 25, 2010). PDF text: 1 v. (ca. 280 p. : ill.). UMI publication number: AAT 3386755. Includes bibliographical references. Also available in microfilm and microfiche formats.
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Russ, Jonathan Brent. "Computational Design of Structures for Enhanced Failure Resistance." Thesis, 2021. https://doi.org/10.7916/d8-rfmz-6x23.
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The field of structural design optimization is one with great breadth and depth in many engineering applications. From the perspective of a designer, three distinct numerical methodologies may be employed. These include size, shape, and topology optimization, in which the ordering typically (but not always) corresponds to the order of increasing complexity and computational expense. This, of course, depends on the particular problem of interest and the selected numerical methods. The primary focus of this research employs density-based topology optimization with the goal of improving structural resistance to failure.
Beginning with brittle fracture, two topology optimization based formulations are proposed in which low weight designs are achieved with substantially increased fracture resistance. In contrast to the majority of the current relevant literature which favors stress constraints with linear elastic physics, we explicitly simulate brittle fracture using the phase field method during the topology optimization procedure. In the second formulation, a direct comparison is made against results obtained using conventional stress-constrained topology optimization and the improved performance is numerically demonstrated. Multiple enhancements are proposed including a numerical efficiency gain based on the Schur-complement during the analytical sensitivity analysis and a new function which provides additional path information to the optimizer, making the gradient-based optimization problem more tractable in the presence of brittle fracture physics.
Subsequently, design for ductile failure and buckling resistance is addressed and a numerically efficient topology optimization formulation is proposed which may provide significant design improvements when ductile materials are used and extreme loading situations are anticipated. The proposed scheme is examined regarding its impact on both the peak load carrying capacity of the structure and the amount of external work required to achieve this peak load, past which the structure may no longer be able to support any increase in the external force. The optimized structures are also subjected to a post-optimization verification step in which a large deformation phase field fracture model is used to numerically compare the performance of each design. Significant gains in structural strength and toughness are demonstrated using the proposed framework.
Additionally, the failure behavior of 3D-printed polymer composites is investigated, both numerically and experimentally. A large deformation phase field fracture model is derived under the assumption of plane-stress for numerical efficiency. Experimental results are compared to numerical simulations for a composite system consisting of three stiff circular inclusions embedded into a soft matrix. In particular, we examine how geometric parameters, such as the distances between inclusions and the length of initial notches affect the failure pattern in the soft composites. It is shown that the mechanical performance of the system (e.g. strength and toughness) can be tuned through selection of the inclusion positions which offers useful insight for material design.
Finally, a size optimization technique for a cardiovascular stent is proposed with application to a balloon expandable prosthetic heart valve intended for the pediatric population born with Congenital Heart Disease (CHD). Multiple open heart surgical procedures are typically required in order to replace the original diseased valve and subsequent prosthetic valves with those of larger diameter as the patient grows. Most expandable prosthetic heart valves currently in development to resolve this issue do not incorporate a corresponding expandable conduit that is typically required in a neonate without a sufficiently long Right Ventricular Outflow Tract (RVOT). Within the context of a particular design, a numerical methodology is proposed for designing a metallic stent incorporated into the conduit between layers of polymeric glue. A multiobjective optimization problem is solved, not only to resist the retractive forces of the glue layers, but also to ensure the durability of the stent both during expansion and while subject to the anticipated high cycle fatigue loading. It is demonstrated that the surrogate-based optimization strategy is effective for understanding the trade-offs between each performance metric and ultimately efficiently arriving at a single optimized design candidate. Finally, it is shown that the desired expandability of the device from 12mm to 16mm inner diameter is achievable, effectively eliminating at least one open heart surgical procedure for certain children born with CHD.
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Rossbach, Cornelius. "Randomisierter Vergleich von Medikamenten freisetzenden Stents mit minimal-invasiver Bypasschirurgie für isolierte proximale LAD-Stenosen – Ein 7-Jahres-Follow-Up." Doctoral thesis, 2015. https://ul.qucosa.de/id/qucosa%3A15479.
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OBJECTIVES The aim of this analysis was to assess the 7-year long-term safety and effectiveness of a randomized comparison of percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SES) versus minimally invasive direct coronary artery bypass (MIDCAB) surgery for the treatment of isolated proximal left anterior descending lesions.
BACKGROUND Long-term follow-up data comparing PCI by SES and MIDCAB surgery for isolated proximal left anterior descending lesions are sparse.
METHODS Patients were randomized either to PCI with SES (n ¼ 65) or MIDCAB (n ¼ 65). Follow-up data were obtained after 7 years with respect to the primary composite endpoint of death, myocardial infarction, and target vessel revas-
cularization. Angina was assessed by the Canadian Cardiovascular Society classification and quality of life with Short Form 36 and MacNew quality of life questionnaires.
RESULTS Follow-up was conducted in 129 patients at a median time of 7.3 years (interquartile range: 5.7, 8.3). There were no significant differences in the incidence of the primary composite endpoint between groups (22% PCI vs. 12%
MIDCAB; p ¼ 0.17) or the endpoints death (14% vs. 17%; p ¼ 0.81) and myocardial infarction (6% vs. 9%, p ¼ 0.74). However, the target vessel revascularization rate was higher in the PCI group (20% vs. 1.5%; p < 0.001). Clinical symptoms and quality of life improved significantly from baseline with both interventions and were similar in magnitude between groups.
CONCLUSIONS At 7-year follow-up, PCI by SES and MIDCAB in isolated proximal left anterior descending lesions yielded similar long-term outcomes regarding the primary composite clinical endpoint and quality of life. Target vessel revascularization was more frequent in the PCI group. (Randomied Comparison of Minimally Invasive Direct Coronary Artery Bypass Grafting and Percutaneous Coronary Intervention With Drug-Eluting Stents in Patients With Proximal Stenosis of the Left Anterior Descending Coronary Artery; NCT00299429) (J Am Coll Cardiol Intv 2014;-:-–-) © 2014 by the American College of Cardiology Foundation.
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Vediappan, Rajan Sundaresan. "Modifying Post-Surgical Wound Healing." Thesis, 2021. http://hdl.handle.net/2440/130740.
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“Surgery is a profession defined by its authority to cure by means of bodily invasion. The brutality and risks of opening a living person's body have long been apparent, the benefits only slowly and haltingly worked out”, says Atul Rawande on reviewing 200 yrs. of Surgery as a specialty in NEJM. My research focuses on working out these benefits, specifically looking at reduction of scar tissue formation in ENT, Abdominal & Spine surgery. Scar tissue formation is an outcome of healing process that can be excessive due to inflammation or infection and thereby has the ability to curtail the benefits or warrant revision surgery. Multiple strategies have been tested and employed thus far and none have given favourable results without causing additional harm or economic burden in health care costs. I propose to use a hydrogel synthesized by combining Chitosan and Dextran aldehyde -Chitin is an exoskeleton extracted polymer and Dextran Aldehyde a sugar, with added noveldrugs Deferiprone and Gallium Protoporphyrin providing additional anti scaring and antibiotic properties which could potentially augment the healing properties of the gel. I have conducted 3 types of studies. There are 2 animal studies and a Phase 1 Human clinical trial. The animal studies are an abdominal surgery rat model and a spine surgery sheep model. These studies show the safety and efficacy of this chitogel-drug combination at various dosages and illustrate the healing benefits of gel-drug combination.Thesis (Ph.D.) -- University of Adelaide, Adelaide Medical School, 2021
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Zhih-CherngChen and 陳志成. "The Factors Affect the Decision about Coronary Artery Bypass Surgery or Percutaneous Coronary Intervention with Drug-Eluting Stent in Patient with Complex Coronary Artery Disease." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/77213571362767733583.
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碩士國立成功大學
高階管理碩士在職專班(EMBA)
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According to the Ministry of Health and Welfare of the Republic of China, heart disease was ranked as the second highest leading cause of death in Taiwan (The Ministry of Health and Welfare, 2011). Most cardiovascular deaths are related to coronary artery heart diseases (CAD), heart failure caused by myocardial ischemia , arrhythmia, and poor quality of life. The study framework was based on The Theory of Planned Behavior (TPB) developed by Icek Ajzen (1985, 1991). Behavior analysis was carried out to investigate attitude towards behavior, subjective norm, perceived behavioral control and behavior intention of patients that chose drug-eluting stents. Socio-demographic was found to have significant influence on medical behavior.
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Engelbrecht, Karien. "Lifestyle adaptations of patients with coronary artery disease who underwent coronary artery bypass graph surgery, percutaneous transluminal coronary angioplasty or insertion of a coronary stent." Thesis, 2008. http://hdl.handle.net/10210/795.
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Coronary Artery Disease (CAD) is one of the most common cardiovascular disorder in adults. CAD often results in myocardial infarction or angina (Wilson, 2003:21). It is an accepted fact that the incidence of CAD has reached endemic proportions in South Africa (Venter, 1993:15). Coronary Artery Bypass Graft (CABG) surgery, Percutaneous Transluminal Coronary Angioplasty (PTCA) and insertion of a coronary stent are major therapeutic approaches to the treatment of CAD. However, these procedures do nothing to correct the underlying disease process (Hunt, Hendrata, Myles, 2000:389; Venter, 1993:15). Due to physiological changes patients suffering from CAD are expected to make lifestyle adaptations, in order to improve quality of life and prevent further damage to coronary arteries (Gotto, 1987:29). It is suspected that patients do not always adapt their lifestyle when they suffer from CAD, or if they do, do not maintain these adaptations. The following question emerges: • Do patients with coronary artery disease adapt their lifestyle and if they do, do they maintain these adaptations? The purpose of this study is to explore and describe the extent to which patients with CAD who underwent CABG, PTCA or insertion of a coronary stent adapt their lifestyles and to what extent they maintain these adaptations. Secondly, the purpose is to set guidelines to help with the improvement of lifestyle adaptations and contingency of adaptations. The objectives of the study is to explore and describe the extent to which patients with CAD adapt their lifestyles following CABG surgery, PTCA or insertion of a i coronary stent, the comparison of the extent of these lifestyle adaptations after two and four months and to set guidelines to improve the extent and contingency of lifestyle adaptations. An explorative and descriptive study was done in order to explore and describe the extent to which patients with CAD, who underwent CABG surgery, PTCA or insertion of coronary a stent, adapted their lifestyle, and to determine the maintenance of these lifestyle adaptations. For the purpose of this study questionnaires, based on a conceptual framework, were designed. The questionnaires enabled the researcher to explore and describe the lifestyle adaptations that patients with CAD underwent. The study was conducted in five private hospitals in Gauteng. The data obtained confirmed that patients suffering from CAD do adapt their lifestyle after having CABG surgery, PTCA or insertion of a coronary stent. Data also showed that the presence of a cardiac rehabilitation centre at the hospital where participants were treated, has a significant influence on patients’ ability to adapt their lifestyle and to maintain this new lifestyle.Dr. W.O.J. Nel Ms. W. Jacobs