Mitral valve replacement with small-sized tilting-disc mechanical prostheses may lead to moderate stenosis

Background. Analyzing the hemodynamics of small-sized tilting-disc mechanic al prostheses implanted in the mitral position. Methods. Experimental design: this is a retrospective study. The mean follo w-up of patients was 114 +/- 27 months (range 68-152 months). Setting: departments of Cardiovascular Surgery and Cardiology in a general community hospital. Patients: this study includes 9 survivors of 17 patients undergoing mitral valve replacement with this type of device between May, 1982 and July, 1991 . Interventions: all subjects underwent mitral valve replacement with size 25 mm Sorin tilting-disc mechanical prostheses, Measures: all patients underw ent transthoracic echocardiography. Five consenting patients also underwent transoesophageal echocardiography, The following parameters were measured: peak gradient, mean gradient, peak velocity, mean velocity, pressure half- time and Doppler area. Results. The ejection fraction was 50% or more in all patients. The followi ng mean results were obtained: peak gradient: 17.4 +/- 2.5 mmHg; mean gradi ent: 8.2 +/- 0.6 mmHg; peak velocity: 2.1 +/- 0.1 m/sec; mean velocity: 1.4 3 +/- 0.06 m/sec; pressure half-time: 135.9 +/- 29.7 msec; Doppler area: 1. 7 +/- 0.3 cm(2). Conclusions. Valve replacement with Sorin 25 mm tilting-disc mechanical pro stheses appears to originate a moderate degree of mitral stenosis and, ther efore, we do not recommend their use if at all possible.