RISK-FACTORS FOR OPERATIVE MORTALITY IN ELDERLY PATIENTS UNDERGOING INTERNAL MAMMARY ARTERY GRAFTING

From January 1986 through June 1992, 512 elderly patients (70 years and older) underwent internal mammary artery grafting (IMAG). The operative mortality in these patients was 7.62% (39 of 512), which was significantly higher than that (1.97% [60 of 3,047]; p < 0.0001) in younger patients (under 70 years old). To investigate the risk factors in the elderly, the data from the 512 patients were evaluated by univariate analysis and multiple logistic regression. Of 53 variables analyzed, nine preoperative variables (age, smoking history, congestive heart failure, myocardial infarction, New York Heart Association functional class, ejection fraction, left main artery disease, stenosis of the left anterior descending artery, and reoperation), three intraoperative variables (emergency operation, bilateral IMAG, and right IMAG), and nine postoperative variables were significantly associated with the higher mortality (p < 0.05). In particular, the operative mortality was significantly higher in the patients undergoing right IMAG (21.62% [8 of 37]) than that in patients only undergoing left IMAG (6.53% [31 of 475]; p < 0.004). The significant preoperative and intraoperative variables and the variables that have a tendency for correlation (p < 0.2) to mortality were included in a stepwise multiple logistic regression. The regression analysis demonstrated that right IMAG, reoperation, history of myocardial infarction, age, left main artery disease, history of smoking, and postoperative complications are the risk factors for the elderly undergoing IMAG. Therefore, particular care should;be taken in those patients scheduled to undergo IMAG. The role of right IMAG in the elderly should be further clarified before universal acceptance of the technique in these patients.