Thrombogenic evaluation of two mechanical heart valve prostheses using a new in-vitro test system

The continued risk of thrombus formation and subsequent thromboembolism remains a major problem with prosthetic mechanical heart valves, and patients must undergo lifelong anticoagulation therapy. Thus, it is necessary to localize and analyze critical thrombogenic regions in heart valves for their optimal design. The study aim was to verify the application of a new in-vitro test system for thrombogenic investigation, and to assess two different types of prosthetic mechanical heart valves for the detection of thrombus formation and regions of thrombogenic potential in prosthetic valves.

The test system was specifically designed and manufactured at the Helmholtz Institute Aachen for the in-vitro determination of thrombogenic effects in mechanical heart valves. Porcine whole blood was used as a test fluid. In order to examine the state of the blood and function of the valves, the activated clotting time (ACT) and pressure differences across the valves were measured during testing.

The local thrombogenic areas within the tested valves, and consequent thrombus formation caused by the valves, were detected using the test system. The in-vitro test results correlated well to reported in-vivo animal test results with these valves.

Correlation of the present in-vitro results with previously reported in-vivo results confirmed the reliability of the new system to detect local thrombogenic areas in mechanical heart valves. The new system represents a cost-effective method for optimizing the design and development of new prosthetic mechanical heart valves.