Reduced risk of coronary artery bypass surgery for unstable angina during a 6-year period

Objective: To assess the risk of early death or acute myocardial infarction in patients undergoing isolated coronary artery bypass surgery for unstabl e coronary artery disease. Methods: Retrospective observational study of 85 3 patients operated on because of unstable coronary artery disease during 1 990-1995. Results: There were 5.9% deaths and 13.0% nonfatal infarctions le ss than or equal to 30 days. These figures declined during the observation period and were 2.6% and 6.2%, respectively, in 1995. The relative risk of early death or myocardial infarction was 50% less during 1994-1995 than dur ing 1990-1991, after multivariate adjustment for several patient risk facto rs. The risk of death or infarction was almost twice as high in patients gr eater than or equal to 50 years than in those < 50 years of age. Multivaria te analysis showed that aortic-cross-clamp time <greater than or equal to> 60 min, previous bypass surgery, pre-operative heart failure, emergency sur gery, worse Braunwald class and non-use of an internal mammary artery graft were associated with an increased risk of death or infarction. Early morta lity was 3.4% (23/702) in unstable patients without symptoms of congestive heart failure, who were not operated on emergently after failed percutaneou s coronary intervention and had not had previous cardiac surgery. Conclusio ns: We observed a marked reduction of the: risk of early death or myocardia l infarction after surgery for unstable angina during the 6-year period 199 0-1995. The risk reduction was not explained from operations performed on p atients with less risk and indicates improved peri-operative patient manage ment. (C)2000 Elsevier Science B.V. All rights reserved.