Studies on prolonged acute regional ischemia: VI. Myocardial infarction with left ventricular power failure: A medical/surgical emergency requiring urgent revascularization with maximal protection of remote muscle

Abstract

Eighty consecutive patients receiving maximum inotropic and intraaortic balloon support underwent emergency coronary artery bypass grafting 3.4 +/- 1 days (mean +/- standard error) after infarction for severe left ventricular power failure (stroke work index less than 25 gm-m, left atrial pressure greater than 20 mm Hg). All underwent induction of cardioplegia with a 37 degrees C glutamate/aspartate blood cardioplegic solution, multidose cold (4 degrees C) replenishment, and warm reperfusate. Viable areas were grafted first to ensure cardioplegic distribution. Left ventricular power failure was reversed in 94% of patients; 75 of 80 patients had discontinuation of inotropic drugs and intraaortic balloon support. The early mortality rate (less than 30 days) was only 7% (3/45) with early operation (less than 18 hours) and rose to 31% (11/35, p less than 0.05) if operation was delayed more than 18 hours. Six of 14 early deaths were due to progression of preoperative organ failure despite reversal of shock. Eighteen of 66 early survivors died of end-stage heart failure (21/80), a 26% late mortality rate. Nonsurvivors (early and late) had a higher incidence of extending versus evolving infarction (33/64 versus 2/16, p less than 0.05), a longer delay from shock to operation (11/45 versus 24/35, p less than 0.05), more preoperative organ failure (9/9 versus 26/71, p less than 0.05), and a greater incidence of previous infarction (22/43 versus 13/37, p greater than 0.05). Thirty of 45 late survivors (67%) remain physically active. We conclude that left ventricular power failure should be considered a medical/surgical emergency that necessitates prompt angiography and can be reversed in selected patients. Postoperative mortality (early and late) is due principally to delay of operation leading to progression of preoperative organ failure or progression of underlying cardiac disease if infarction becomes established.