BACKGROUND AND AIMS OF THE STUDY: The hemodynamics of five designs of 19 mm pericardial aortic valve bioprosthesis were examined by Doppler echocardiography in 48 resting patients at medium or long term follow up.METHODS: The salient differences among the five designs are that valve leaflets are mounted inside the support frame in one (the Carpentier-Edwards valve, evaluated in five patients) and outside the frame in the other four (the Ionescu-Shiley (14 patients), Mitroflow (six patients), Bioflo (eight patients) and Labcor-Santiago (15 patients)); and that two models have either total (Bioflo) or partial (Labcor-Santiago) protective pericardial sheaths on the stent, while the other three do not. The hemodynamic parameters determined included transvalvular pressure drop, valve area, left ventricular outflow tract diameter, subvalvular/valvular velocity ratio and subvalvular/valvular velocity-time integral ratio.RESULTS: There were no significant differences among the various valves as regards left ventricular outflow tract diameter, subvalvular/valvular velocity ratio or subvalvular/valvular velocity-time integral ratio. Negative correlation between left ventricular outflow tract diameter and subvalvular velocity (r = -0.63, p < 0.001) confirmed the need to correct for prevalvular velocities when using the Bernoulli equation to calculate the pressure drop across small pericardial aortic valve bioprostheses. The Bioflo design caused significantly greater pressure drops (peak 49.6 +/- 11.3 mmHg, mean 28.1 +/- 6.1 mmHg) and provided smaller areas (0.80 +/- 0.16 cm2) than the Ionescu-Shiley (26.7 +/- 6.6 and 15.2 +/- 4.1 mmHg, 1.17 +/- 0.17 cm2) and Labcor-Santiago (24.8 +/- 5.9 and 15.1 +/- 3.7 mmHg, 1.24 +/- 0.12 cm2) valves.CONCLUSIONS: Of the currently available 19 mm bovine pericardium heart valve bioprostheses, the Mitroflow and Labcor-Santiago valves, in both of which the leaflets are mounted outside the stent, have better hemodynamics in the aortic position than the Carpentier-Edwards valve, which has internal leaflet mounting. Sheathing the stent totally in pericardium, as in the withdrawn Bioflo valve, gives rise to relatively poor hemodynamics.
Aged Animals