HEMODYNAMICS OF VARIOUS DESIGNS OF 19 MM PERICARDIAL AORTIC-VALVE BIOPROSTHESIS

The hemodynamics of five designs of 19 mm pericardial aortic valve bio prostheses were examined in 47 resting patients by Doppler echocardiog raphy, The salient differences among the five designs are that valve l eaflets are mounted inside the support frame in one (the Carpentier-Ed wards valve, evaluated in 4 patients) and outside the frame in the oth er four (the Ionescu-Shiley (16 patients), Mitroflow (4), Bioflo (8) a nd Labcor-Santiago (15)); and that two models have either total (Biofl o) or partial (Labcor-Santiago) protective pericardial sheaths on the stent, while the other three do not. The hemodynamic parameters determ ined included transvalvular pressure drop, valve area, left ventricula r outflow tract diameter, subvalvular/valvular velocity ratio and subv alvular/valvular velocity-time integral ratio. There were no significa nt differences among the various valves as regards left ventricular ou tflow tract diameter, subvalvular/valvular velocity ratio or subvalvul ar/valvular velocity-time integral ratio. Negative correlation between left ventricular outflow tract diameter and subvalvular velocity (r = -0.66, P < 0.001) confirmed the need to correct for prevalvular veloc ities when using the Bernouilli equation to calculate the pressure dro p across small pericardial aortic valve bioprostheses. The Bioflo desi gn caused significantly greater pressure drops (peak 38.3 +/- 8.3 mmHg , mean 24.6 +/- 4.8 mmHg) and smaller areas (0.82 +/- 0.17 cm(2)) than the Ionescu-Shiley (20.3 +/- 5.6 and 11.7 +/- 3.8 mmHg, 1.19 +/- 0.18 cm(2)) and Labcor-Santiago (19.3 +/- 5.3 and 10.1 +/- 3.1 mmHg, 1.27 +/- 0.12 cm(2)) valves.