Cobalt Chromium EES Compared to CABG in Patients With Diabetes Mellitus

June 17, 2014—A new generation of drug-eluting stents may bridge the gap in outcomes currently seen with percutaneous coronary intervention (PCI) versus coronary artery bypass graft surgery (CABG) to treat patients with diabetes mellitus, according to a study by Sripal Bangalore, MD, et al. The study was published online ahead of print in Circulation: Cardiovascular Interventions.

The investigators advised that although this hypothesis needs to be tested in future trials, evidence from an indirect comparison shows similar mortality between CABG and PCI using a cobalt chromium everolimus-eluting stent (EES). CABG was shown to be associated with numerically excess stroke. PCI with the cobalt chromium EES was associated with numerically increased repeat revascularization.

The background of this study is that CABG compared with PCI has been shown to reduce mortality in patients with diabetes mellitus. However, previous trials compared CABG with balloon angioplasty or older-generation stents. It is not known if the gap between CABG and PCI can be reduced by newer-generation drug-eluting stents.

As summarized in Circulation: Cardiovascular Interventions, the investigators conducted a PubMed/Embase/Central search for randomized trials comparing modes of revascularization in patients with diabetes mellitus. The primary outcome was all-cause mortality. Secondary outcomes were myocardial infarction, repeat revascularization, and stroke. Mixed treatment comparison analyses were performed using a random-effects Poisson regression model. 

The investigators’ inclusion criteria were met by 68 randomized trials that enrolled 24,015 diabetic patients with a total of 71,595 patient-years of follow-up satisfied. When compared with CABG (reference rate ratio [RR] = 1), PCI with a paclitaxel-eluting stent (RR = 1.57 [1.15–2.19]) or a sirolimus-eluting stent (RR = 1.43 [1.06–1.97]) was associated with an increase in mortality. However, PCI with a cobalt chromium EES (RR = 1.11 [0.67–1.84]) was not associated with a statistically significant increase in mortality. 

When compared with CABG, there was excess repeat revascularization with PCI, which progressively declined from plain old balloon angioplasty (341% increase) to bare-metal stent (218% increase) to paclitaxel-eluting stent (81% increase) and to sirolimus-eluting stent (47% increase). However, for PCI with a cobalt-chromium EES (RR = 1.31 [0.74–2.29]), the excess repeat revascularization was not statistically significant, but the point estimate favored CABG. CABG was associated with numerically higher stroke, stated the investigators in Circulation: Cardiovascular Interventions.