TIMING OF SURGERY AFTER ACUTE MYOCARDIAL-INFARCTION

Objective. We wished to determine if timing of surgery, when other co- morbid variables are controlled, influenced outcome after operations f or acute myocardial infarction. Design. Between 3/20/1990 and 6/17/199 4, data was prospectively collected on 338 patients undergoing operati on for either evolving infarcts (n=73) or up to 21 days after infarcti on (mean 7.9 days). Setting. Tertiary hospital referral center. Patien ts. Infarction was diagnosed by CK enzymes or EKG Q-waves preoperative ly in 338 patients undergoing surgery. The mean age of the patients wa s 66.1 years (SD+/-10.5 years), 76 had emergency operations immediatel y after catheterization (50 following PTCA complications), 223 had urg ent operations, and 39 were elective. Interventions. Seventy-three had preoperative balloon pumps, and 259 had one or more mammary artery by passes with a mean of 3.27 (SD+/-1.0) distal anastomoses. Results. In- hospital and 30-day survival rate was 95.6% (323/338). Of the 73 varia bles evaluated by step-wise logistic regression analysis, the multivar iate independent preoperative predictors of death were: aortic valve r egurgitation, chronic pulmonary disease, preoperative diuretic adminis tration, preoperative balloon pump, preoperative inotropes, and the ne ed for additional concomitant noncardiac surgery. Including the operat ive variables, the predictors were: preoperative balloon pump, preoper ative inotropes, the presence of left main stenosis, preoperative rena l failure, chronic pulmonary disease, valve disease, ischemic arrhythm ia, pump perfusion time, valve surgery, and homologous blood transfusi on volume required. When the postoperative variables mere included, th e predictors were: preoperative inotropes, postoperative balloon pump, postoperative epinephrine, postoperative permanent stroke, and postop erative acute renal failure. The time between infarction and operation was not an independent prediction (p>0.4) in any of the logistic regr ession models. Conclusion. Early operation after acute infarction is n ot in itself a risk factor, rather comorbid disease and preoperative h emodynamic status determine outcome after surgery.