Echo-phonocardiographic evaluation of the Björk-Shiley mitral prosthesis

Ninety patients were studied with combined echophonocardiography after Björk-Shiley disc prosthetic mitral valve replacement. They were evaluated every 6 months (mean follow-up 6 years). Nine cases of left ventricular (LV) failure and 6 cases of prosthetic malfunction (5 paravalvular leaks and 1 thrombosis) were detected; 1 case was confirmed at necropsy and the other 5 cases were surgically verified and repaired. The following measures of prosthetic malfunction were evaluated: opening and closing velocity, maximal amplitude of the prosthesis, septal motion 6 months after operation, LV diastolic diameter, protodiastolic hump, variations during same record of the interval between aortic valve closure sound to the phono and mitral valve opening to the echo, and interval between aortic valve closure sound and maximal excursion of the LV posterior wall. All measures studied were useful for detecting prosthetic malfunction, but 2 are more useful in individual cases: variations of the interval between second heart sound and mitral valve opening and the interval between the aortic valve closure sound and LV posterior wall motion. These 2 intervals also allow discrimination between normal function, prosthetic malfunction and LV failure.