Restenosis after Vascular Reconstruction

Nikkari, Seppo T.; Clowes, Alexander W.

doi:10.3109/07853899409147335

Cited by 44 publications

(21 citation statements)

References 51 publications

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“…8,18,26,38,50 Nevertheless, the overexpansion of the lesions during angioplasty still induces mechanical injury, which triggers pathological responses such as neointimal hyperplasia. 14,17 These responses are key factor in in-stent restenosis, 6,19,30,39 the most important longterm limitation of stent implantation. It is important to note that the mechanical injury to the vessels is not eliminated by drug-eluting stents.…”

Section: Introductionmentioning

confidence: 98%

Experimental Studies and Numerical Analysis of the Inflation and Interaction of Vascular Balloon Catheter-Stent Systems

2008

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Balloon angioplasty with stenting is a well-established interventional procedure to treat stenotic arteries. Despite recent advances such as drug eluting stents, clinical studies suggest that stent design is linked to vascular injury. Additionally, dilation of the medical devices may trigger pathological responses such as growth and migration of vascular smooth cells, and may be a potent stimulus for neointimal hyperplasia. The purpose of this study is to experimentally investigate the mechanical characteristics of the transient expansion of six commercially available balloon-expandable stent systems, and to develop a robust finite element model based on the obtained experimental results. To reproduce the inflation of stent systems as in clinical practice, a pneumatic-hydraulic experimental setup is built, able to record loads and deformations. Characteristic pressure-diameter diagrams for the balloon-expandable stents and the detached balloons are experimentally obtained. Additionally, typical measures such as the burst opening pressure, the maximum dog-boning and foreshortening, and the elastic recoil are determined. The adopted constitutive models account for elastoplastic deformation of the stent, and for the nonlinear and anisotropic behavior of the balloon. The employed contact algorithm, based on a C(2)-continuous surface parametrization, efficiently simulates the interaction of the balloon and stent. The computational model is able to successfully capture the experimentally observed deformation mechanisms. Overall, the numerical results are in satisfactory agreement with experimental data.

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Section: Introductionmentioning

confidence: 98%

Experimental Studies and Numerical Analysis of the Inflation and Interaction of Vascular Balloon Catheter-Stent Systems

2008

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“…The operative mortality rate for coronary artery bypass graft ͑CABG͒ surgery is around 3%, and clinical outcomes include restenosis, renal failure, ischemia, and myocardial infarction. 1,2 However, approximately 15%-30% of saphenous vein grafts occlude within the first year of surgery, increasing to over 50% after ten years. 3 The influence of geometry on hemodynamics has been quantitatively studied for CABG.…”

Section: Introductionmentioning

confidence: 99%

The impact of uncertainty on shape optimization of idealized bypass graft models in unsteady flow

Sankaran

Marsden

2010

Physics of Fluids

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It is well known that the fluid mechanics of bypass grafts impacts biomechanical responses and is linked to intimal thickening and plaque deposition on the vessel wall. In spite of this, quantitative information about the fluid mechanics is not currently incorporated into surgical planning and bypass graft design. In this work, we use a derivative-free optimization technique for performing systematic design of bypass grafts. The optimization method is coupled to a three-dimensional pulsatile Navier-Stokes solver. We systematically account for inevitable uncertainties that arise in cardiovascular simulations, owing to noise in medical image data, variable physiologic conditions, and surgical implementation. Uncertainties in the simulation input parameters as well as shape design variables are accounted for using the adaptive stochastic collocation technique. The derivative-free optimization framework is coupled with a stochastic response surface technique to make the problem computationally tractable. Two idealized numerical examples, an end-to-side anastomosis, and a bypass graft around a stenosis, demonstrate that accounting for uncertainty significantly changes the optimal graft design. Results show that small changes in the design variables from their optimal values should be accounted for in surgical planning. Changes in the downstream ͑distal͒ graft angle resulted in greater sensitivity of the wall-shear stress compared to changes in the upstream ͑proximal͒ angle. The impact of cost function choice on the optimal solution was explored. Additionally, this work represents the first use of the stochastic surrogate management framework method for robust shape optimization in a fully three-dimensional unsteady Navier-Stokes design problem.

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“…1 At the same time, activated platelets secrete growth factors, namely, platelet-derived growth factor (PDGF), which diffuses into the media of the adjacent vessel to initiate the migration of smooth-muscle cells (SMC) from the media into the intima. 2,3 The SMC produce a fibrous connective tissue, which accounts for the bulk of the intimal thickness.…”

Section: Introductionmentioning

confidence: 99%

Heparin immobilized on proteins usable for arterial prosthesis coating: Growth inhibition of smooth-muscle cells

Laemmel

Penhoat

Warocquier-Clerout

et al. 1998

J. Biomed. Mater. Res.

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Gelatin or a mixture of albumin and gelatin has been proposed for the coating of vascular grafts according to their surface thrombogenicity and biocompatibility, and the possibility of biodegradation. Heparin treatment of hemocompatible surfaces improved the patency of prostheses. In this study, different amounts of heparin were immobilized on these protein gels using a water-soluble carbodiimide [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide]. The results showed a coupling of heparin with gelatin and/or albumin at the surface of the gels, stable for as long as 1 month. From 0.20 to 3.60 microg x cm(-2), heparin could be immobilized. The antiproliferative activity of immobilized heparin was controlled toward bovine smooth-muscle cells grown on these gels. Cell growth inhibition was dose dependent, but the percentages of inhibition were lower at day 8 than at day 4 at any heparin concentration used under experimental conditions. Referring to heparin in solution, immobilized heparin displayed an antiproliferative activity that improved the potential interest for coating.

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Restenosis after Vascular Reconstruction

Cited by 44 publications

References 51 publications

Experimental Studies and Numerical Analysis of the Inflation and Interaction of Vascular Balloon Catheter-Stent Systems

Experimental Studies and Numerical Analysis of the Inflation and Interaction of Vascular Balloon Catheter-Stent Systems

The impact of uncertainty on shape optimization of idealized bypass graft models in unsteady flow

Heparin immobilized on proteins usable for arterial prosthesis coating: Growth inhibition of smooth-muscle cells

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