Effect of Smoking Status on Mortality and Morbidity Following Coronary Artery Bypass Surgery[*]

Abstract

Background: We aimed to examine the effect of smoking on outcomes following coronary artery bypass grafting (CABG). Methods: We retrospectively analysed 6 367 consecutive patients who underwent CABG between April 1997 and March 2003. Logistic regression was used to risk adjust in-hospital outcomes, while Cox proportional hazards analysis was used to risk adjust Kaplan-Meier survival curves. Outcomes were adjusted for variables suggested by the American Heart Association and American College of Cardiology. Results: 947 (14.9 %) patients were current smokers (smoking within 1 month of surgery), while 3857 (60.6 %) were ex-smokers and 1 563 (24.5 %) were non-smokers. After adjusting for differences in case-mix, current smokers were more likely to develop chest infections (p < 0.001), atelectasis (p < 0.001), and require ventilation longer than 48 hours (p = 0.003). Current smokers were also more likely to stay in intensive care for more than 3 days (p < 0.001). Ex-smokers were not associated with excess mortality (p = 0.11), while current smokers had significantly increased mortality during follow-up (p = 0.029). Conclusions: Patients should be encouraged to stop smoking to maximise the long-term benefits of CABG.

Smoking - coronary artery bypass grafting - mortality - morbidity - risk adjustment

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1 Presented at the 4th joint meeting of the German, Austrian, and Swiss Society of Thoracic and Cardiovascular Surgery, Hamburg, February 2004