[Comparison of noninvasive techniques in evaluation of the Björk-Shiley and the St. Jude Medical valve prostheses in mitral position].

Pressure gradients and left ventricular function were assessed by Doppler echocardiography in 50 patients with Björk-Shiley mitral valve and 50 patients with St. Jude Medical valve prosthesis. There was correlation between pressure gradient and valve size, and between effective valve orifice area and valve size for St. Jude Medical valve. These correlations were not found in Björk-Shiley valve. Clinical improvement and cardiac function were quite satisfactory in 20 patients with Björk-Shiley valve and in 32 patients with St. Jude Medical valve whose pressure gradients were less than 10 mmHg. Twenty eight of 50 patients with Björk-Shiley valve and 42 of 50 patients with St. Jude Medical valve showed good response to the exercise test. Eight patients underwent reoperation because of unacceptably high gradient caused by thrombus and pannus formation. The patients who show high pressure gradient across the valve prosthesis should be followed up cautiously.