Patients with coronary heart disease (CHD) who refrain from smoking over a 2-year follow-up period decrease their relative risk (RR) for morbidity and mortality by about one third (strength of recommendation [SOR]: A, meta-analysis of 20 cohort studies). People who maintain abstinence after coronary artery bypass surgery are more likely to avoid angina, repeat revascularization, significant physical impairment, and CHD-related hospital admissions than patients who continue to smoke (SOR: A, 4 cohort studies with 1- to 20-year follow-up)