In vitro examination for the hemodynamic performance and calcification behavior of aortic valve prostheses

Aims: The aim of this study was to compare calcification behavior and influence of calcification on hydrodynamics and leaflet kinematics of two types of bovine pericardium heart valve prostheses.

Methods: Five fresh Edwards Perimount Magna (EPM) and five St. Jude Trifecta (SJT) aortic heart valves (23 mm) were investigated in an artificial circulatory system. Valves were then exposed to a calcium-phosphate solution at a constant pulse rate of 300 beats/min for a total of three weeks. After that, repeated testing in three different hemodynamic situation (3, 5 and 8 l/min Cardiac Output (CO) by 120, 70 and 110 beats/min heart rate (HR)) was performed. Leaflet kinematics was documented using a high-speed camera and analyzed.

Results: SJT valves demonstrated significantly lower transvalvular gradient (5.6 mmHg vs. 26.9 mmHg) and total regurgitation volume (3.6% vs. 6.3%) and lager effective orifice area (EOA) (2.14 cm² vs. 1.45 cm²) after calcification in all hemodynamic situation then EPM valves (Table 1, 2 and 3). The EPM valves calcified faster and more severely. Evaluations of the leaflet kinematic videos show a reduced EOA in stronger calcified EPM valves. There was no difference between SJT and EPM in opening and closing times before and after calcification.

Conclusions: In vitro EPM calcified faster and more severe than SJT leading to increased mean systolic pressure difference and smaller EOAs, which was also documented in high speed video films. These findings may have clinical relevance for valve choice in different clinical settings.