Physiologically-based testing system for the mechanical characterization of prosthetic vein valves

Abstract

Due to the relatively limited amount of work done to date on developing prosthetic vein (as opposed to cardiac) valves, advances in this topic require progress in three distinct areas: 1) improved device design, 2) relevant device testing conditions, and, 3) appropriate parameters for evaluation of results. It is the purpose of this paper to address two of these issues (#2 and #3) by: 1) performing a study of normal volunteers to quantify the anatomy and hemodynamic features of healthy venous valves, 2) construction of a 2-step, in vitro testing procedure, which simulates both physiologic and postural conditions seen in the lower extremity venous system, and, 3) defining several modified and new parameters which quantify dynamic valve characteristics.

Figure 1

A schematic of the vertical column 2:1 Mock-Up System.

Figure 2

A schematic of the horizontal 1:1 Pulsatile Flow System.

Figure 3

Prototype design of venous valve in the Open (left) and Closed (right) positions consisting of a solid circular base, frame struts with uniquely shaped flanges, and a flexible leaflet material.

Figure 4

Actual 2:1 scale device with optimized frame and shaped Biospan^® leaflet. A threaded extension from the base (not shown) screwed into the test section fixture to improve alignment and prevent leakage.