Smoking after coronary artery bypass: high three-year mortality

Coronary artery bypass grafting (CABG) is carried out for prognosis and symptomatic relief. Smoking is associated with increased postoperative complications, although its precise influence on long-term survival is unclear. We examined the influence of smoking and other risk factors on survival and myocardial ischaemia seven years after CABG.

208 patients underwent elective CABG; 25 % were persistent smokers. 165 were alive at seven years. 128 (78 % of survivors) agreed to reexamination and 79 had thallium scans.

Angina and dyspnoea were reported by 52 % and 69 %, respectively, of survivors; these were associated with smoking ( P = 0.029 and 0.0 009) but with no other risk factors. Smokers had higher stress thallium scores ( P = 0.057) and ischaemia scores (10.6 +/- 6.5 vs. 6.8 +/- 6.0; P = 0.036); ejection fractions were equivalent. Obesity was prevalent and worsened in men. 33 patients (17 %) died during follow-up. Initially there was no survival difference between smokers and nonsmokers but as early as three years postoperation smoking was associated with an increased mortality ( P = 0.011; log-rank test).

Patients experienced almost universal improvement with the operation. However, persistent smoking completely removed the prognostic benefits of CABG by accelerating late mortality which was higher than previously reported. Higher indices of ischaemia in smokers were suggested by symptoms and confirmed by perfusion scans.