Article

The effects of stenting on shear stress: relevance to endothelial injury and repair

Biomedical Engineering, Department Cardiology, ErasmusMC, Rotterdam, The Netherlands.
Cardiovascular Research (Impact Factor: 5.81). 04/2013; 99(2). DOI: 10.1093/cvr/cvt090
Source: PubMed

ABSTRACT Stent deployment following balloon angioplasty is used routinely to treat coronary artery disease (CAD). These interventions cause damage and loss of endothelial cells (EC), and thus promote in-stent thrombosis and restenosis. Injured arteries are repaired (intrinsically) by locally-derived EC and by circulating endothelial progenitor cells (EPC) which migrate and proliferate to re-populate denuded regions. However, re-endothelialisation is not always complete and often dysfunctional. Moreover, the molecular and biomechanical mechanisms that control EC repair and function in stented segments are poorly understood. Here we propose that stents modify endothelial repair processes, in part, by altering fluid shear stress, a mechanical force that influences EC migration and proliferation. A more detailed understanding of the biomechanical processes that control endothelial healing would provide a platform for the development of novel therapeutic approaches to minimise damage and promote vascular repair in stented arteries.

Full-text

Available from: Frank Gijsen, Sep 24, 2014
2 Followers
 · 
109 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Three-dimensional design simulations of coronary metallic stents utilizing mathematical and computational algorithms have emerged as important tools for understanding biomechanical stent properties, predicting the interaction of the implanted platform with the adjacent tissue, and informing stent design enhancements. Herein, we demonstrate the hemodynamic implications following virtual implantation of bioresorbable scaffolds using finite element methods and advanced computational fluid dynamics (CFD) simulations to visualize the device-flow interaction immediately after implantation and following scaffold resorption over time. CFD simulations with time averaged wall shear stress (WSS) quantification following virtual bioresorbable scaffold deployment in idealized straight and curved geometries were performed. WSS was calculated at the inflow, endoluminal surface (top surface of the strut), and outflow of each strut surface post-procedure (stage I) and at a time point when 33% of scaffold resorption has occurred (stage II). The average WSS at stage I over the inflow and outflow surfaces was 3.2 and 3.1 dynes/cm(2) respectively and 87.5 dynes/cm(2) over endoluminal strut surface in the straight vessel. From stage I to stage II, WSS increased by 100% and 142% over the inflow and outflow surfaces, respectively, and decreased by 27% over the endoluminal strut surface. In a curved vessel, WSS change became more evident in the inner curvature with an increase of 63% over the inflow and 66% over the outflow strut surfaces. Similar analysis at the proximal and distal edges demonstrated a large increase of 486% at the lateral outflow surface of the proximal scaffold edge. The implementation of CFD simulations over virtually deployed bioresorbable scaffolds demonstrates the transient nature of device/flow interactions as the bioresorption process progresses over time. Such hemodynamic device modeling is expected to guide future bioresorbable scaffold design.
    12/2014; 2014(4):428-36. DOI:10.5339/gcsp.2014.56
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Innovations in drug-eluting stents (DES) have substantially reduced rates of in-segment restenosis and early stent thrombosis, improving clinical outcomes following percutaneous coronary interventions (PCI). However a fixed metallic implant in a vessel wall with restored patency and residual disease remains a precipitating factor for sustained local inflammation, in-stent neo-atherosclerosis and impaired vasomotor function increasing the risk for late complications attributed to late or very late stent thrombosis and late target lesion revascularization (TLR) (late catch-up). The quest for optimal coronary stenting continues by further innovations in stent design and by using biocompatible materials other than cobalt chromium, platinum chromium or stainless steel for engineering coronary implants. Bioresorbable scaffolds made of biodegradable polymers or biocorrodible metals with properties of transient vessel scaffolding, local drug-elution and future restoration of vessel anatomy, physiology and local hemodynamics have been recently developed. These devices have been utilized in selected clinical applications so far providing preliminary evidence of safety showing comparable performance with current generation drug-eluting stents (DES). Herein we provide a comprehensive overview of the current status of these technologies, we elaborate on the potential benefits of transient coronary scaffolds over permanent stents in the context of vascular reparation therapy, and we further focus on the evolving challenges these devices have to overcome to compete with current generation DES. : The quest for optimizing percutaneous coronary interventions continues by iterative innovations in device materials beyond cobalt chromium, platinum chromium or stainless steel for engineering coronary implants. Bioresorbable scaffolds made of biodegradable polymers or biocorrodible metals with properties of transient vessel scaffolding; local drug-elution and future restoration of vessel anatomy, physiology and local hemodynamics were recently developed. These devices have been utilized in selected clinical applications providing preliminary evidence of safety showing comparable intermediate term clinical outcomes with current generation drug-eluting stents.
    12/2014; 2014(4):409-27. DOI:10.5339/gcsp.2014.55
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent studies have indicated that coronary artery bypass grafting (CABG) outcomes in patients with prior stents are suboptimal. We aimed to study the impact of prior percutaneous coronary intervention (PCI) with stenting (PCI-S) on late CABG mortality in diabetic patients with triple-vessel disease. We reviewed the primary nonemergency CABG experience from a single U.S. institution (n = 7005; 1996-2007, Toledo, Ohio). Diabetics with triple-vessel disease (n = 1583) were identified and divided into 2 groups: (1) prior PCI-S (n = 202); and (2) no prior PCI (No-PCI [n = 1381]). Hierarchic Cox proportional hazards models were used to assess the effect of prior PCI-S on 5-year mortality after CABG. A propensity score for PCI-S and No-PCI patients was derived using a nonparsimonious logistic regression and used to generate a 1:1 (PCI-S to No-PCI) matched cohort. In model 1, after adjusting for preoperative clinical characteristics, medications, off-pump surgery, and isolated CABG surgery status, prior PCI-S was associated with a 39% increased risk of mortality (hazard ratio [HR] = 1.39, with 95% confidence interval [CI; 1.02, 1.90]; P = .04). Further adjustment for date of surgery (model 2) (HR = 1.39, with 95% CI [1.02, 1.91]; P = .04) or operative parameters (model 3) (HR = 1.38, with 95% CI [1.01, 1.88]; P = .046) did not alter the association. The 1:1 matched-cohort analysis confirmed the increased risk associated with PCI-S (HR = 1.61, with 95% CI [1.03, 2.51]; P = .037). Patients who have both diabetes and triple-vessel disease, and have undergone prior PCI-S, have poorer long-term outcomes after CABG compared with those who have had no prior PCI-S. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
    Journal of Thoracic and Cardiovascular Surgery 02/2015; DOI:10.1016/j.jtcvs.2015.01.051 · 3.99 Impact Factor