Cardiac outcome after peripheral vascular surgery - Comparison of general and regional anesthesia

Background: Despite evidence that regional anesthesia may be associated with fewer perioperative complications than general anesthesia, most studies that have compared cardiac outcome after general or regional anesthesia alone have not shown major differences. This study examines the impact of anesthetic choice on cardiac outcome in patients undergoing peripheral vascular surgery who have a high likelihood of associated coronary artery disease. Methods: Four hundred twenty-three patients, between 1988 and 1991, were randomly assigned to receive general (n = 138), epidural (n = 149), or spinal anesthesia (n = 136) for femoral to distal artery bypass surgery. All patients were monitored with radial artery and pulmonary artery catheters. Postoperatively, patients were in a monitored setting for 48-72 h and had daily electrocardiograms for 4-5 days and creatine phosphokinase/isoenzymes every 8 h X 3, then daily for 4 days. Cardiac outcomes recorded were myocardial infarction, angina, and congestive heart failure. Results: Baseline clinical characteristics were not different between anesthetic groups. Overall, the patient population included 86% who were diabetic, 69% with hypertension, 36% with a history of a prior myocardial infarction, and 41% with a history of smoking. Cardiovascular morbidity and overall mortality were not significantly different between groups when analyzed by either intention to treat or type of anesthesia received. In the intention to treat analysis, incidences of cardiac event or death for general, spinal, and epidural groups were 16.7%, 21.3%, and 15.4%, respectively. The absolute risk difference observed between general and all regional anesthesia groups for cardiac event or death was -1.6% (95% confidence interval -9.2%, 6.1%) This reflected a nonsignificant trend for lower risk of postoperative events with general anesthesia. Conclusions: The choice of anesthesia, when delivered as described, does not significantly influence cardiac morbidity and overall mortality in patients undergoing peripheral vascular surgery.