DOPPLER-ECHOCARDIOGRAPHIC DETERMINATION OF GEOMETRIC ORIFICE AREAS INMECHANICAL AORTIC-VALVE PROSTHESES

In 63 St. Jude bileaflet and 34 Bjoerk-Shiley tilting disk aortic valv e prostheses, Doppler continuity areas were compared to their correspo nding geometric areas defined by the opening angle of the occluders. C ontinuity areas correlated significantly with geometric areas in Bjoer k-Shiley (p = 0.68) and St. Jude prostheses (p = 0.86). Differences be tween continuity and geometric areas were greater in St. Jude than in Bjoerk-Shiley valves (0.87 +/- 0.45 cm(2) vs. 0.06 +/- 0.47 cm(2), p < 0.0001). Exclusion of patients with atrial fibrillation, with a posto perative interval of less than 1 year or valve sizes of 19 and 21 mm d id not change the results: Thus, underestimation of geometric areas is present in the St. Jude bileaflet aortic valves, while geometric and continuity areas are not significantly different in Bjoerk-Shiley pros theses. These results are attributable to the effect of valve-type-dep endent velocity profiles.