Clinical and Hemodynamic Studies in Patients

Debate continues regarding the long-term clinical and hemodynamic benefit of homograft replacement of the diseased mitral valve. The results of valve replacement with mitral homografts in the 120 patients who have had operation at the Stanford Medical Center from May 1967 to November 1970 are given. The operative mortality rate has been 5% and the late mortality rate 6%. Anticoagulants were stopped 6 weeks following surgery and there has been only one thromboembolic complication. Ninety percent of the surviving patients are improved clinically. Thirteen of these patients have been restudied 25 to 41 months after receiving homograft mitral valve replacement. Hemodynamic studies showed a 43% decrease in mean left atrial pressure and 42% decrease in mean pulmonary artery pressure with a 10% increase in mean resting cardiac output. Early diastolic gradients between the left atrium and left ventricle averaging 3.0 mm Hg at rest and 6.0 mm Hg during moderate exercise were present. Left ventricular angiography showed a trace of mitral insufficiency in three patients, moderate to severe in three others, and poor contractility in three other patients with normal homograft functioin. Mitral insufficiency, when present, was thought to result from poor mounting of the homograft on the metal strut rather than primary deterioration of the valve leaflets. These data indicate that fresh homograft replacement of the mitral valve provides good long-term clinical and hemodynamic benefit in most patients.