Operation for acute postinfarction mitral insufficiency and cardiogenic shock.

Since 1973, 11 patients have had emergency valve replacement for severe mitral insufficiency and cardiogenic shock within 1 month (mean 10.0 days) of acute myocardial infarction. Mean age was 60 years (range 44 to 71 years). Nine infarcts affected the inferior wall, one patient had a prior myocardial infarction, and only two patients had a history of cardiac symptoms. Ten patients had pulmonary edema, five were oliguric (less than 0.5 ml/kg/hr for 12 hours), four required endotracheal intubation, nine required preoperative intra-aortic balloon support, and three had had a cardiac arrest. Preoperative cardiac index averaged 1.7 L/m2/min even with pharmacologic and circulatory support. Eight patients had cardiac catheterization and nine had echocardiograms. Left ventricular ejection fraction varied from 23% to 83% (mean 51%) and was not prognostic. Five patients had papillary muscle rupture and six patients had papillary muscle dysfunction. The mitral valve was replaced with a mechanical prosthesis in all patients. Five had simultaneous coronary artery bypass grafts. Three of five patients with papillary muscle rupture and two of six with papillary muscle dysfunction survived hospitalization. Two patients could not be weaned from cardiopulmonary bypass, two patients died within 24 hours of low cardiac output, and two patients died 3 weeks postoperatively of acute tubular necrosis and sepsis following prolonged preoperative cardiogenic shock. The interval from onset of shock to operative therapy averaged 1.7 days for survivors versus 9.3 days for nonsurvivors. Although the amount of viable left ventricular mass cannot be measured preoperatively, we recommend early operation, before other organ systems fail, for patients having severe mitral insufficiency and cardiogenic shock within 30 days of acute myocardial infarction.