CARDia: Coronary Artery Revascularisation in Diabetes trial

List of Authors: Akhil Kapur, Dr Andreas Baumbach (UK), Dr Kevin Beatt (UK), Dr Peter Crean (ROI), Dr Adam De Belder (UK), Dr Farzin Fath-Ordoubadi (UK), Prof Marcus Flather (UK), Professor Roger Hall (UK), Dr Iqbal Malik (UK)

The purpose of this study was to compare the safety and efficacy of percutaneous coronary intervention (PCI) with stenting against coronary artery bypass grafting (CABG) in patients with diabetes and symptomatic multivessel coronary artery disease.

CABG is the established method of revascularization in patients with diabetes and multivessel coronary disease, but with advances in PCI, there is uncertainty whether CABG remains the preferred method of revascularization.

The primary outcome was a composite of all-cause mortality, myocardial infarction (MI), and stroke, and the main secondary outcome included the addition of repeat revascularization to the primary outcome events. A total of 510 diabetic patients with multivessel or complex single-vessel coronary disease from 24 centers were randomized to PCI plus stenting (and routine abciximab) or CABG. The primary comparison used a noninferiority method with the upper boundary of the 95% confidence interval (CI) not to exceed 1.3 to declare PCI noninferior. Bare-metal stents were used initially, but a switch to Cypher (sirolimus drug-eluting) stents (Cordis, Johnson & Johnson, Bridgewater, New Jersey) was made when these became available.

At 5.1 median years of follow-up, the composite rate of death, MI, and stroke was 20.5% in the CABG group and 26.6% in the PCI group (hazard ratio [HR]: 1.34, 95% confidence interval [CI] 0.94 to 1.93; p=0.11), all-cause mortality rates were 12.6% and 14% respectively (HR: 1.17, 95% CI 0.73 to 1.87; p=0.53), and the rates of death, MI, stroke, or repeat revascularization 26% and 37.5% (HR: 1.56, 95% CI 1.14 to 2.14; p=0.005), respectively. 

Stroke rate was numerically higher in the CABG group (4.3% vs 3.1%, HR: 0.72, 95% CI 0.29 to 1.79; p=0.48), and MI rate significantly higher in the PCI group (6.3% CABG vs 14% PCI, HR: 2.26, 95% CI 1.25 to 4.08; p=0.007).

The CARDia (Coronary Artery Revascularization in Diabetes) trial is the first randomized trial of coronary revascularization in diabetic patients. The 5-year results did not confirm that PCI is non-inferior to CABG. However, the CARDia trial did show that multivessel PCI is feasible in patients with diabetes. Data from other trials will provide a more precise comparison of the efficacy of these 2 revascularization strategies.