Towards Non-thrombogenic Performance of Blood Recirculating Devices

Abstract

Implantable blood recirculating devices have provided life saving solutions to patients with severe cardiovascular diseases. However, common problems of hemolysis and thromboembolism remain an impediment to these devices. In this article, we present a brief review of the work by several groups in the field that has led to the development of new methodologies that may facilitate achieving the daunting goal of optimizing the thrombogenic performance of blood recirculating devices. The aim is to describe work which pertains to the interaction between flow-induced stresses and the blood constituents, and that supports the hypothesis that thromboembolism in prosthetic blood recirculating devices is initiated and maintained primarily by the non-physiological flow patterns and stresses that activate and enhance the aggregation of blood platelets, increasing the risk of thromboembolism and cardioembolic stroke. Such work includes state-of-the-art numerical and experimental tools used to elucidate flow-induced mechanisms leading to thromboembolism in prosthetic devices. Following the review, the paper describes several efforts conducted by some of the groups active in the field, and points to several directions that should be pursued in the future in order to achieve the goal for blood recirculating prosthetic devices becoming more effective as destination therapy in the future.

Comparison of Symmetric Hemodialysis Catheters Using Computational Fluid Dynamics

“…An important phenomenon in these devices is that of flow separation, whereby coherent patterns of laminar flow become disrupted by blood flowing in a direction opposite to the main direction of flow, forming a low-velocity recirculation eddy. The resultant slowing and stagnation of the bloodstream can promote thrombus formation and development (24). The Palindrome catheter was found to have the largest regions of flow separation, with these regions most prominent around the distal tip and the side slots of the catheter.…”

Three‐dimensional quantification of vorticity and helicity from 3D cine PC‐MRI using finite‐element interpolations

“…is the vector with all unknown nodal vorticity values to be solved for our domain. To evaluate the integrals in Equations [8] and [9], we used a four-point quadrature scheme (42), and considered the the fact that v ðxÞ was optimally approximated by v FEM ij ðxÞ at the Gauss points. To reduce the computational effort to solve Equation [7] without compromising its accuracy, the matrix M was replaced by a diagonal lumped matrix M~, where…”

“…A few studies of vorticity and helicity-related parameters have shown that these parameters have a direct relationship with geometric changes of the vessels and the reappearance of different diseases (7,8). Studies based on 3D cine PC-MRI performed on phantom data have revealed that vortex and helical flow can induce vessel wall injury and vascular remodeling (7,(9)(10)(11). Additionally, other studies have demonstrated that standard surgical procedures induce local and global hemodynamic changes of the treated section, altering the secondary flow patterns, which could lead to the reappearance of the pathology and the need for re-intervention (12)(13)(14)(15)(16)(17)(18)(19).…”

Maintenance of Endothelial Cell Function in Liquid Based Antithrombotic Surface Coating

“…These devices are highly effective and applied frequently in patients with CVD. However, the host responses following deployment could induce complications like thrombosis and restenosis [1,2]. To minimize these responses, a protective surface coating is crucial for the safety as well as the lifetime of an implanted device.…”