COMPUTATIONAL HEMODYNAMIC ASSESSMENT OF A NOVEL MODULAR ANASTOMOTIC VALVE DEVICE FOR IMPROVING HEMODIALYSIS VASCULAR ACCESS PATENCY

摘要

End-stage renal disease (ESRD) occurs as a result of any renal injury that chronically decreases renal excretory and regulatory function. ESRD patients are most commonly treated with hemodialysis (HD) to manage their renal failure while awaiting kidney transplant. Current practices for maintenance of HD vascular access consist of arteriovenous fistulas (AVFs) or grafts (AVGs), which are both fraught with problems that compromise the patency and use of these surgically created shunts. The major cause of shunt failure is thrombosis caused by occlusion of the outflow venous anastomosis and draining vein. Intimal hyperplasia (IH), which consists of the thickening of the innermost layer of the vessel wall, is the initial pathological event leading to shunt stenosis/thrombosis and has been associated with the presence of flow disturbances and abnormal wall shear stress (WSS) at the graft-vein anastomosis. Therefore, the improvement of HD via the enhancement of vascular access patency requires the development of a novel vascular access technology preserving the normal hemodynamics of the native vein. In pursuit of this goal, a novel vascular access technology based on a modular anastomotic valve device was developed to improve AVG patency by limiting the development of IH. The principle of the device is to isolate the graft from the systemic circulation between dialysis periods. The device (Fig. 1) can be sewn onto the native vessels and hemostatically coupled to conventional graft material, while the modular design allows the surgeon to achieve a custom fit in each patient. The MAVD features a shuttle valve system which moves from the open to the closed position (or vice-versa) in order to block (or allow) AVG access to systemic blood flow. The goal of this study was to quantify the hemodynamics of the MAVD mounted in the venous position during and between hemodialysis periods.