COMPARATIVE EARLY AND LATE CARDIAC MORBIDITY AMONG PATIENTS REQUIRINGDIFFERENT VASCULAR-SURGERY PROCEDURES

Purpose: The evaluation of coronary artery disease (CAD) in patients u ndergoing vascular surgery can provide information with respect to per ioperative and long-term risk for CAD-related events. However, the ext ent to which the required surgical procedure itself imparts additional risk beyond that dictated by the presence of CAD determinants remains in question. The purpose of this study was to quantify the relative c ontributions of specific vascular procedures and CAD markers on periop erative and long-term cardiac risk. Methods: The study cohort comprise d 547 patients undergoing vascular surgery from two medical centers wh o underwent clinical evaluation, dipyridamole thallium testing, and ei ther aortic (n = 321), infrainguinal (n = 177), or carotid (n = 49) va scular surgery between 1984 and 1991. Perioperative and late cardiac r isk of fatal or nonfatal myocardial infarction (MI) was compared for t he three procedures before and after adjustment for the influence of c omorbid factors. These adjusted estimates may be regarded as the compo nent of risk because of type of surgery. Results: Perioperative MI occ urred in 6% of patients undergoing aortic and carotid artery surgery, and in 13% of patients undergoing infrainguinal procedures (p = 0.019) . Significant (p < 0.05) predictors of MI were history of angina, fixe d and reversible dipyridamole thallium defects, and ischemic ST depres sion during testing. Although patients undergoing infrainguinal proced ures exhibited more than twice the risk for perioperative MI compared with patients undergoing aortic surgery (relative risk: 2.4[1.2 to 4.5 , p = 0.008]), this value was reduced to insignificant levels (1.6[0.8 to 3.2, p = 0.189]) after adjustment for comorbid factors. There was little change in comparative risk between carotid artery and aortic pr ocedures before (1.0[0.3 to 3.6, p = 0.95]) or after (0.6[0.2 to 2.3, p = 0.4]) covariate adjustment. The 4-year cumulative event-free survi val rate was 90% +/- 2% for aortic, 74% +/- 5% for infrainguinal, and 78% +/- 7% for carotid artery procedures (p = 0.0001). Predictors of l ate MI included history of angina, congestive heart failure, diabetes, fixed dipyridamole thallium defects, and perioperative MI. Patients u ndergoing infrainguinal procedures exhibited a threefold greater risk for late events compared with patients undergoing aortic procedures (r elative risk: 3.0[1.8 to 5.1, p = 0.005]), but this value was reduced to 1.3(0.8 to 2.3, p = 0.32) after adjustment. Long-term risk among pa tients undergoing carotid artery surgery was less dramatically altered by risk factor adjustment. Conclusion: In current practice, among pat ients referred for dipyridamole testing before operation; observed dif ferences in cardiac risk of vascular surgery procedures may be primari ly attributable to readily identifiable CAD risk factors rather than t o the specific type of vascular surgery. Thus the cardiac and diabetic status of patients should be given careful consideration whenever pos sible, regardless of surgical procedure to be performed.