Risk factors for intermediate-term survival after coronary artery bypass grafting

Background. Risk factors for short-term mortality after coronary artery byp ass grafting are well established, but little is known about risk factors f or intermediate-term mortality. Methods. We analyzed the outcomes of 11,815 patients undergoing coronary ar tery bypass grafting in one of the 43 cardiac surgery programs of the Depar tment of Veteran Affairs. Risk factors for intermediate- and short-term mor tality were determined using Cox proportional hazards regression models. Ef fects of risk factors during these two periods were explicitly compared. Results. We found important differences in mortality risk-factor sets betwe en the intermediate- and short-term periods after coronary artery bypass gr afting. The majority of predictors of intermediate-term mortality were nonc ardiac-related variables, whereas the majority of predictors of short-term mortality were cardiac-related variables. Impaired functional status, chron ic obstructive pulmonary disease, and renal dysfunction had greater effects in the intermediate-term period. Previous heart operation, angina class II I or IV, previous myocardial infarction, and preoperative use of an intraao rtic balloon pump had greater effects in the short-term period. Conclusions. The risk factors for intermediate-term mortality identified in this study can augment preoperative risk assessment and counseling of pati ents. Clinicians should be aware of the importance of noncardiac-related va riables as predictors of mortality in the intermediate-term period after co ronary artery bypass grafting. (C) 2001 by The Society of Thoracic Surgeons .