Chronic Disease

Coronary artery bypass surgery may be better than angioplasty for older patients and those with diabetes

Patients with several blocked coronary arteries (multivessel disease) who also have diabetes or are older may have a significant survival advantage if they select coronary artery bypass graft (CABG) over percutaneous coronary intervention (PCI, angioplasty). That's the finding from an analysis of 10 randomized trials comparing the effectiveness of CABG with PCI (use of a balloon-tipped catheter or metal stent to open a blocked artery) for patients with several blocked arteries. While long-term mortality was similar with both procedures for some patients, researchers found a decided advantage in survival for CABG among patients suffering from diabetes or who were 65 years of age.

Through an extensive literature search, the researchers identified 10 randomized, comparison trials with at least 3 years of followup. Each study's principal investigator was then asked to join a collaborative analysis of individual patient data on a set of core clinical variables. From information obtained on 7,812 patients, randomly assigned to either CABG or PCI, the researchers determined if survival was modified by patients' baseline clinical characteristics. During a median followup of 5-9 years, the 3,889 patients who underwent CABG had a 15 percent mortality rate and the 3,923 patients who underwent PCI had a 16 percent mortality rate. The mortality rate was similar between groups in patients without diabetes. Among patients with diabetes, however, the mortality rate was significantly lower in the CABG group (23 percent) compared with the PCI group (29 percent). Age was found to have a graded effect on mortality after CABG or PCI. For example, in patients age 65 years and older, the mortality rate was 20 percent for CABG and 24 percent for PCI compared with 10 percent and 8 percent, respectively, for patients younger than 55 years. The interaction between age and treatment effect remained even after the researchers adjusted for such clinical factors as diabetes, smoking, and three-vessel coronary artery disease. The study was supported by the Agency for Healthcare Research and Quality (Contract No. 290-02-0017).

See "Coronary artery bypass surgery compared with percutaneous coronary interventions for multivessel disease: A collaborative analysis of individual patient data from ten randomised trials," by Mark A. Hlatky, M.D., Derek B. Boothroyd, Ph.D., Dena M. Bravata, M.D., and others in the April 2009 Lancet 373, pp. 1190-1194.

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