Improved survival in asymptomatic diabetic patients with high-risk SPECT imaging treated with coronary artery bypass...

The Bypass Angioplasty Revascularization Investigation trial demonstrated that symptomatic diabetics with multivessel coronary artery disease had a survival advantage with initial coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI). No published study has examined different treatments and outcome in asymptomatic diabetics.

This study group consisted of 826 asymptomatic diabetics (age 62+/-12 years; 76% men) without known coronary artery disease who had abnormal myocardial perfusion during stress single photon emission computed tomography (SPECT). SPECT images were classified as low-, intermediate-, and high-risk. Early revascularization (CABG or PCI < or =4 months after SPECT) was performed in 76 patients. Survival (follow-up, 5.3+/-3.3 years) was compared in patients treated with CABG, PCI, or medical therapy. Revascularization (CABG or PCI) was performed in 54 of 261 patients with high-risk scans and was independently associated with improved survival (chi2=4.55; P=0.03 after multivariate adjustment). Subset analysis demonstrated that the survival advantage was confined to patients treated with CABG (n=39), with a 5-year survival CABG at 85%, PCI at 72%, and medical therapy at 67% (P=0.02 for 3 groups). Although CABG was associated with better survival, mortality remained high (3% per year). There was no survival advantage by treatment for patients with less-severe SPECT abnormalities.

These nonrandomized data suggest that CABG improves survival in asymptomatic diabetic patients with high-risk SPECT, although revascularization was performed infrequently in these patients. These results parallel those of the Bypass Angioplasty Revascularization Investigation trial in symptomatic diabetic patients.