Clinical and echocardiographic assessment of the Medtronic-Hall valve: experience with 370 implanted valves

During a 34-month period, 370 Medtronic-Hall valves were implanted into 310 patients. Twenty-four percent of patients had additional operative procedures. Hospital mortality was 7% and late mortality to date is 3%. No deaths were due to thromboembolic complications or mechanical failure of the valve. The overall embolic rate was 2.5 per 100 patient years. For mitral valve replacement, the embolic rate was 3.5 per 100 patient years. Patients with isolated mitral valve replacement were subjected to detailed clinical and echocardiographic assessment. Eighty-nine percent of patients with 29 or 31 mm mitral prostheses improved one NYHA class or more and 33% improved 2 classes or more. For the 25 mm mitral prostheses, the figures were 91% and 38% respectively. The peak rate of increase of left ventricular dimension in diastole (dD/dt) was measured echocardiographically in subjects with normal native mitral valves and in patients with 29 or 31 mm Medtronic-Hall valves, Björk-Shiley valves and Starr-Edwards valves. Peak dD/dt in the native valves was 15.8 +/- 0.8, in Medtronic-Hall valves 13.9 +/- 0.8, in Björk-Shiley 11.6 +/- 1.0 and in Starr-Edwards 9.5 +/- 0.6. The Björk-Shiley and Starr-Edwards valves differed significantly from normal (p less than 0.05 and less than 0.001 respectively) but there was no significant difference between the Medtronic-Hall valves and the native ones. We conclude that the Medtronic Hall valve is a safe and hemodynamically effective valve in the mitral position.