Coronary artery bypass grafting (CABG): reassessing efficacy,safety, and cost

Based on randomized clinical trials begun in the 1970s showing the superiority of coronary artery bypass grafting (CABG) to medical management for patients with coronary artery disease (CAD), CABG has been routinely used to reduce angina and improve chances of survival in patients with CAD. Since CABG became a recognized standard treatment of CAD, considerable evidence has accumulated concerning the pathogenesis of CAD; the efficacy, risks, and costs of CABG; and the effectiveness of CAD risk factor reduction. To re-evaluate efficacy, safety, and cost of CABG, a MEDLINE search was performed to locate randomized trials comparing CABG vs nonsurgical management, CAD pathogenesis studies, and articles evaluating efficacy of coronary artery risk factor reduction behaviors. The extent of revascularization with CABG bore no relationship to relief of angina or survival. Randomized CABG vs medical management studies revealed that only patients with the most advanced CAD had improved survival, and this advantage vanished after 12 years. Researchers kept little coronary risk factor reduction data in the original CABG vs medical management randomized trials. However, in the Bypass Angioplasty Revascularization Intervention (BARI) study, surgically treated patients adopted lifestyles associated with lower coronary risk significantly more than patients treated with angioplasty. Factors other than revascularization cause the improvement in angina associated with CABG. Temporary survival advantages of CAD high-risk subgroups after CABG may be better explained by risk factor reduction rather than by revascularization. Using the BARI data, including lifestyle factors, a multivariate analysis of the influences determining survival and quality-of-life end points would test this hypothesis.