Mitral valve replacement: a nine-year follow-up of risks and survivals.

Experience with mitral valve replacement over a nine-year period is reviewed. Hospital mortality was 8.9%, with an additional late mortality of 18.5% during a mean follow-up period of 4.34 years. Study of the factors influencing the results of valve replacement revealed a direct correlation between long-term survival and New York Heart Association (NYHA) Functional Class, as judged preoperatively, as well as left ventricular end-diastolic pressure, cardiac index, type of valve lesion, and presence of associated coronary artery disease. Hospital mortality was 32% (p less than 0.01) for those patients in NYHA Functional Class IV before operation, compared with 3% for Class III patients. Untreated concomitant coronary artery disease was associated with a significantly higher perioperative mortality of 28% (p = 0.002) compared with an 8% mortality in patients with coronary artery disease treated by vein bypass at the time of mitral valve replacement. Patients with normal coronary arteries documented angiographically before operation had a 1% hospital mortality. Seventy-two percent of all patients are still alive at a maximum follow-up of nine years. Eighty-three percent of those survivors who were in Functional Class III or IV before operation are now considered to be in Class I or II. We conclude that patients should undergo mitral valve replacement before the development of the advanced functional stage of valve disease. In addition, coronary arteriograms should be performed on all patients who are more than 40 years old at the time of cardiac catheterization, and revascularization considered at the time of mitral valve replacement for those patients with significant coronary disease.