A 5 year experience with the Medtronic-Hall disc valve prosthesis.

Throughout the period from 1977 to 1982, 426 patients underwent aortic valve replacement, 106 patients underwent mitral valve replacement, and 56 patients had double valve replacement with the Medtronic-Hall (previous Hall-Kaster) valve. Early and late mortality was 4% and 9% in the aortic group, 8% and 11% in the mitral group, and 7% and 13% in the double valve group. There was an 81% probability of surviving 5 years after aortic or double valve replacement, and a 75% probability of surviving 5 years after mitral valve replacement. Postoperative follow-up studies revealed low pressure gradients across the aortic as well as across the mitral valve prosthesis, irrespective of valve size. Exercise studies indicated good tolerance of increasing cardiac output during strenuous exercise tests in patients with aortic valve prosthesis. Thromboembolic complications in the aortic series included two cases of valve thrombosis and 11 thromboembolic episodes in 10 patients. In the mitral series an aspergillus thrombus was found on the valve at autopsy in a patient dying from multiple cerebral aspergillus abscesses, and five thromboembolic episodes occurred in four additional patients in the mitral series. In the double valve series there was one valve thrombosis and one patient had a thromboembolic episode.