At 1 year following intervention, there apparently is no difference between coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in treating diabetic patients with multivessel disease, as measured by the incidence of a composite of death, myocardial infarction (MI), and stroke.

The CARDia (Coronary Artery Revascularization in Diabetes Trial; ISRCTN19872154) trial results were presented in Munich at the 2008 European Society of Cardiology Congress by Akhil Kapur, MD, London Chest Hospital, Barts and the London NHS Trust, London, UK.

“We saw more repeat revascularization in the PCI group, but with similarity in other major outcomes at 1 year, we can now consider PCI a reasonable strategy in diabetic patients with multivessel disease. But longer follow-up is still needed,” said Dr. Kapur.

Dr. Kapur emphasized that even though the trial was designed to test the hypothesis that PCI is noninferior to CABG (n=254) in these patients, the targeted enrollment of 600 subjects was not met, and the noninferiority of PCI could not be formally, statistically established by the outcome of the trial. “The trial was, finally, underpowered to test this endpoint,” he said. Noninferiority trials are intended to show that the effect of one treatment, in this case PCI, is not worse than that of an active control, in this case CABG, by a statistically significant margin. Investigators randomized 510 diabetic patients (mean age 64 years, 74% men, average weight 84 kg) with multivessel disease to CABG (n=254) or PCI (n=256). Nearly one-quarter of the admissions were considered acute (23.7% CABG group vs 21.5% in the PCI cohort). Similar numbers of patients required insulin to treat diabetes (31.4% of CABG vs 30.6% of PCI). All patients in the PCI group were treated with aspirin, clopidogrel, and GP IIb/IIIa inhibitors.

Of the CABG group, 229 underwent the procedure. Of the PCI group, 252 underwent the procedure. There was 96% (n=245) subject follow-up at 1 year in the CABG group and 98% (n=251) in the PCI group.

The investigators reported that for the composite primary endpoint of death, MI, and stroke at 1 year, there was a rate of 10.2% for CABG veruss 11.6% for PCI (OR=1.15, 95% CI, 0.65–2.03; p=0.63). This result was not statistically significant enough to establish the noninferiority of PCI.

The rate for revascularization at 1 year was 2.0% for CABG versus 9.9% for PCI (OR=5.31, 95% CI, 2.00–14.11; p=0.001).

The rate of death at 1 year was 3.3% for CABG versus 3.2% for PCI (OR=0.98, 95% CI, 0.36–2.64; p=0.83). The rate of nonfatal MI was 5.7% for CABG versus 8.4% for PCI (OR=1.51, 95% CI, 0.75–3.03; p=0.25). The rate of nonfatal stroke was 2.5% for CABG versus 0.4% for PCI (OR=0.16, 95% CI, 0.02–1.33; p=0.09). The composite outcome of death, MI, stroke, and repeat revascularization was 11% for CABG versus 17.5% for PCI (OR=1.72, 95% CI, 1.02–2.87; p=0.04).

For CABG (n=245) versus the PCI-DES (n=179; 71% of total) subgroup, the primary composite outcome of death, nonfatal MI, and nonfatal stroke at 1 year was 10.2% for CABG versus 10.1% for PCI-DES (p=0.98). The rate for revascularization at 1 year was 2.0% for CABG versus 7.3% for PCI-DES (p=0.013). The rate of death at 1 year was 3.3% for CABG versus 3.9% for PCI-DES (p=0.723). The rate of nonfatal MI was 5.7% for CABG versus 6.2% for PCI-DES (p=0.852). The rate of nonfatal stroke was 2.5% for CABG versus 0% for PCI-DES (p=0.041). The composite outcome of death, nonfatal MI, nonfatal stroke, and repeat revascularization at 1 year was 11% for CABG versus 15.1% for PCI-DES (p=0.217).

Dr. Kapur noted that the findings are preliminary and that several clinical events still need to be adjudicated.