Association of postoperative complications and outcomes following coronary artery bypass grafting.

ABSTRACT

BACKGROUND: The long-term effects of postoperative complications following coronary artery bypass grafting (CABG) are unknown. METHODS: Medicare-linked records from the Society of Thoracic Surgeons Adult Cardiac Surgery Database were queried for isolated CABG records from 2007 through 2012. Unadjusted and adjusted associations between individual postoperative complications and both mortality and all-cause rehospitalization were evaluated to 7 years using Cox proportional-hazards models and cumulative incidence functions. Because of nonproportional hazards, associations are presented as early (0 to 90 days) and late (90 days to 7 years). RESULTS: Of the 294,533 isolated CABG patients who had records linked to Medicare for long-term follow-up (median age, 73 years; 30% female), 120,721 (41%) experienced at least 1 of the complications of interest, including new-onset atrial fibrillation (30.0%), prolonged ventilation (12.3%), renal failure (4.5%), reoperation (3.5%), stroke (1.9%), and sternal wound infection (0.4%). Each of the 6 postoperative complications was associated with a significantly increased risk of mortality and rehospitalization to 7 years despite adjustment for baseline characteristics and the presence of multiple complications. Although the predominant effect of postoperative complications was observed in the first 90 days, the increased risk-adjusted hazard for death and rehospitalization continued through 7 years. CONCLUSIONS: Postoperative complications are associated with an increased risk of both early and late mortality and all-cause rehospitalization, particularly during the "value" window within 90 days of CABG. These findings underscore the need to develop avoidance strategies as well as cost-adjustment methods for each of these complications.