Revascularization with CABG or PCI had no Difference on Outcomes of Death, non-fatal MI, or CVA for Diabetics with Multi-Vessel Coronary Disease: Results of the CARDia Trial
September 1, 2008 by Leah H. Biller 
ESC Congress 2008- Munich, Germany:  European investigators reported that for diabetes patients with coronary artery disease, treatment with coronary artery bypass graft surgery (CABG) provided no significant benefit over percutaneous coronary intervention (PCI) in terms of the composite variable of death, non-fatal myocardial infarction (MI), and cerebrovascular accident (CVA) at 1 year .  These results from the CARDia (Coronary Artery Revascularization in Diabetes) Trial were presented by Dr. Akhil Kapur as part of the ESC 2008 Congress Hot Line II Session .
Diabetes patients represent an important and burgeoning population with a high risk of coronary heart disease (CHD); by 2015, scientists predict that 30% of all coronary revascularizations will be performed on diabetics .  The CARDia trial aimed to investigate whether the strategy of revascularization , either CABG or PCI, would affect  clinical outcomes for diabetes patients with multi-vessel coronary disease.
The results of previous studies of revascularization procedures, with subgroup analyses of the diabetes population, have guided clinical practice toward CABG.  The BARI (Bypass Angioplasty Revascularization Investigation) trial (1988 -1991) reported a significantly lower 5-year cumulative survival rate for diabetic patients receiving percutaneous transluminal coronary angioplasty (PTCA) than for those receiving CABG (65.5 for PTCA , 80.6 for CABG , p=0.003) .   A higher repeat revascularization rate was found in the PTCA group as well.  However, the benefits of decreased mortality in the CABG arm were seen primarily in patients with a left internal mammary artery (LIMA) graft to the left anterior descending (LAD) artery , and no significant advantage over angioplasty was found for non-LIMA graft procedures .
The CARDia trial is the largest prospective investigation specifically into the optimal strategy for revascularization of diabetic coronary artery disease, with 510 patients randomized into either PCI or CABG treatment arms in sites throughout England and Ireland.  The primary endpoint of the 1-year analysis was the composite variable of death, non-fatal MI, and CVA.
Investigators found no significant difference between the two treatment arms for the composite clinical endpoint (11.6% for PCI, 10.2% for CABG, p=0.63), or for the individual variables of death (3.2% for PCI, 3.3% for CABG, p=0.83), non-fatal MI (8.4% for PCI, 5.7% for CABG, p=0.25), and CVA (0.4% for PCI, 2.5% for CABG, p=0.09).  As was found in the BARI trial, the rate of repeat revascularization was higher for patients receiving PCI (9.9%) versus those in the CABG arm (2.0%) .
In this modestly sized trial with short term follow-up at one year, the CARDia findings suggest that modern PCI practices may not in fact be inferior to CABG in terms of outcomes of death, non-fatal MI and CVA for diabetics.  While it was generally thought that the inherent risks of surgery were less than the benefits from this strategy of revascularization, the CARDia trial indicates that PCI may be an equally effective tool for treating diabetics with multi-vessel coronary disease.  Long-term follow-up in 3-5 years should offer additional information about the optimal method of revascularization for this patient population.
Reviewed by C. Michael Gibson, M.S., M.D.