Established preoperative risk factors do not predict long-term survival in isolated coronary artery bypass grafting patients.

Background: Use of isolated coronary artery bypass grafting (CABG) is expected to increase as the population ages. Short-term adverse outcomes models and their application to the decision-making process have greatly increased the safety and effectiveness of CABG. However, similar tools addressing long-term survival have not been developed. We examined the effect of the preoperative risk factors included in short-term outcomes models on long-term survival in patients who survive CABG.

Methods: A Cox survival model considering preoperative risk factors identified by The Society of Thoracic Surgeons was developed for 8,529 consecutive patients who underwent isolated CABG between January 1, 1997, and August 31, 2010, at Baylor University Medical Center (Dallas, Texas) and were alive 30-days post-CABG.

Results: There were 2,388 (27.9%) deaths during follow-up (≤14 years). Unadjusted survival was 83.8% and 65% at 5 and 10 years, respectively. The Cox model showed that most established preoperative risk factors were significantly associated with survival. Their effect was minimal, however; the variation explained by their cumulative effect in predicting survival was 16.8% (R2=0.168).

Conclusions: Established operative risk factors may not be good predictors of long-term post-CABG survival. Late mortality may be attributable to many causes, not necessarily related to patients' cardiovascular and general health at the time of operation. Discussions with cardiothoracic surgeons and long-term shared decision making with primary care physicians/cardiologists should therefore not focus solely on patients' preoperative risk profile but should also emphasize the importance of preventing/controlling other diseases through a healthy lifestyle and compliance with disease management protocols.