Hemodynamic and physical performance during maximal exercise in patients with an aortic bioprosthetic valve - Comparison of stentless versus stented bioprostheses

OBJECTIVES The objective of this study was to compare stentless bioprosthes es with stented bioprostheses with regard to their hemodynamic behavior dur ing exercise. BACKGROUND Stentless aortic bioprostheses have better hemodynamic performan ces at rest than stented bioprostheses, but very few comparisons were perfo rmed during exercise. METHODS Thirty-eight patients with normally functioning stentless (n = 19) or stented (n = 19) bioprostheses were submitted to a maximal ramp upright bicycle exercise test. Valve effective orifice area and mean transvalvular pressure gradient at rest and during peak exercise were successfully measur ed using Doppler echocardiography in 30 of the 38 patients. RESULTS At peak exercise, the mean gradient increased significantly less in stentless than in stented bioprostheses (+5 +/- 3 vs. +12 +/- 8 mm Hg; p = 0.002) despite similar increases in mean flow rates (+137 +/- 58 vs. +125 +/- 65 ml/s; p = 0.58); valve area also increased but with no significant d ifference between groups. Despite this hemodynamic difference, exercise cap acity nas not significantly different, but left ventricular (LV) mass and f unction were closer to normal in stentless bioprostheses. Overall, there wa s a strong inverse relation between the mean gradient during peak exercise and the indexed Valve area at rest (r = 0.90). CONCLUSIONS Hemodynamics during exercise are better in stentless than stent ed bioprostheses due to the larger resting indexed valve area of stentless bioprostheses. This is associated with beneficial effects with regard to LV mass and function. The relation found between the resting indexed valve ar ea and the gradient during exercise can be used to project the hemodynamic behavior of these bioprostheses at the time of operation. It should thus be useful to select the optimal prosthesis given the patient's body surface a rea and level of physical activity. (C) 1999 by the American College of Car diology.