HEMODYNAMIC PERFORMANCE OF SMALL AORTIC-VALVE BIOPROSTHESES - IS THERE A DIFFERENCE

Background. There is the potential for left ventricular outflow obstru ction when small aortic valve bioprostheses are employed in normal-siz ed or large adults. It has been hoped that bovine pericardial valves w ould improve hemodynamic performance in the smaller tissue valve sizes . Methods. To determine in vivo hemodynamic performance of heterograft aortic valve prostheses, we analyzed echocardiographic data from pati ents receiving 21- or 23-mm Carpentier-Edwards pericardial, Medtronic Intact, and Carpentier-Edwards porcine bioprostheses. In addition, dat a from 19-mm Carpentier-Edwards pericardial valves were included for c omparison of hemodynamic performance between valve sizes. Doppler echo cardiography was performed in 151 patients within 2 weeks of operation . Left ventricular outflow gradient was derived from continuous Dopple r measurements of flow velocity, and effective orifice area was calcul ated by the continuity equation. Results. There were statistically sig nificant differences in hemodynamic performance of different sized pro stheses for each valve type (effective orifice area, p < 0.01; valvula r gradient, p < 0.03). There were, however, no significant differences in effective orifice area or mean gradient for different valve types within each size category. Conclusions. The in vivo hemodynamic perfor mance of these three different aortic valve heterograft bioprostheses is similar. Patient-prosthesis mismatch with heterograft prostheses, a s demonstrated by the indexed effective orifice area can be avoided by appropriate sizing and use of annular enlarging techniques when neces sary. (C) 1997 by The Society of Thoracic Surgeons.