Dynamic Luminal Topography: A Potential Strategy to Prevent Vascular Graft Thrombosis

Abstract

Aim: Biologic interfaces play important roles in tissue function. The vascular lumenblood interface represents a surface where dynamic interactions between the endothelium and circulating blood cells are critical in preventing thrombosis. The arterial lumen possesses a uniform wrinkled surface determined by the underlying internal elastic lamina. The function of this structure is not known, but computational analyses of artificial surfaces with dynamic topography, oscillating between smooth and wrinkled configurations, support the ability of this surface structure to shed adherent material (Genzer and Groenewold, 2006; Bixler and Bhushan, 2012; Li et al., 2014). We hypothesized that incorporating a luminal surface capable of cyclical wrinkling/flattening during the cardiac cycle into vascular graft technology may represent a novel mechanism of resisting platelet adhesion and thrombosis. Methods and Results: Bilayer silicone grafts possessing luminal corrugations that cyclically wrinkle and flatten during pulsatile flow were fabricated based on material strain mismatch. When placed into a pulsatile flow circuit with activated platelets, these grafts exhibited significantly reduced platelet deposition compared to grafts with smooth luminal surfaces. Constrained wrinkled grafts with static topography during pulsatile flow were more susceptible to platelet accumulation than dynamic wrinkled grafts and behaved similar to the smooth grafts under pulsatile flow. Wrinkled grafts under continuous flow conditions also exhibited marked increases in platelet accumulation. Conclusion: These findings provide evidence that grafts with dynamic luminal topography resist platelet accumulation and support the application of this structure in vascular graft technology to improve the performance of prosthetic grafts. They also suggest that this corrugated structure in arteries may represent an inherent, self-cleaning mechanism in the vasculature.

Topographic de-adhesion in the viscoelastic limit

“…The initial theory was limited to an elastic response regime for the fouling layer [8]. Nevertheless, the mechanism shows promising applications in medical device design, specifically anti-thrombotic vascular grafts [9,10]. The application of actuation into medical devices requires precise knowledge of target strains, which will inform the choice of graft materials, sources of actuation loading, and range of biofoulants that the mechanism will effectively remove from the surface.…”

“…For optimal design of self-cleaning surfaces in contact with viscoelastic biofoulants, the interaction of the time-dependent characteristics of the viscoelastic foulant layer with the geometry set by the wrinkled topography and the surface energy needs to be understood, especially for dynamic topography-driven anti-fouling strategies in biomaterials and medical devices [6,7,9,10]. In this paper, we tackle the complex interaction between foulant layer’s viscoelasticity, rate of topographic changes, mechanical instability and surface adhesion in the wrinkle-induced delamination model [8].…”

Tissue‐Engineered Vascular Grafts: Emerging Trends and Technologies

“…In a follow‐up study, the same research group revealed that the antithrombotic property of the wrinkled luminal topography depends on its dynamic behavior, and constrained luminal corrugations are susceptible to platelet adhesion. [ 99 ] These observations could epitomize the self‐cleaning ability of natural blood vessel intima.…”

Parametric excitation of wrinkles in elastic sheets on elastic and viscoelastic substrates

“…In many cases wrinkles appear when the sheet is supported on a softer substrate, a scenario which is relevant to a range of applications (e.g., coatings, paints) and naturally occurring structures (e.g., skin and tissue linings). Studies have been directed more recently at active wrinkling [4,5,6,7,8]. The interplay between the topography of supported thin sheets and their delamination off the support [9,10,11,12,13] suggests active wrinkling as an anti-fouling strategy adopted by Nature and mimicked in man-made systems [3,5,6,8].…”

“…Studies have been directed more recently at active wrinkling [4,5,6,7,8]. The interplay between the topography of supported thin sheets and their delamination off the support [9,10,11,12,13] suggests active wrinkling as an anti-fouling strategy adopted by Nature and mimicked in man-made systems [3,5,6,8].…”