Consider CABG in patients with diabetes, multivessel disease

Score one for CABG over PCI in patients with diabetes and multivessel disease. According to a meta-analysis published online Sept. 13 in The Lancet, CABG reduces the long-term risk of death by about a third in these patients, regardless of the type of stent used.

Randomized controlled trials that assessed revascularization approaches for patients with diabetes and multivessel disease often were either small or based on subpopulation analyses of trials that also enrolled patients without diabetes, observed Subodh Verma, MD, of the cardiac surgery division at St. Michael’s Hospital in Toronto, and colleagues. To better assess CABG vs. PCI in this patient population in the modern stent era, they conducted a review and meta-analysis of randomized trials that compared the two approaches.

They identified eight trials using Ovid Medline, Embase and Cochrane Central Registry of Controlled Trials between Jan. 1, 1980, and March 12, 2013, that included data on outcomes in patients with diabetes at a minimum one-year follow-up. The primary outcome was all-cause mortality at five years; secondary outcomes included one-year or closest follow-up for all-cause mortality, nonfatal MI, revascularization and nonfatal stroke.

The eight trials enrolled 7,468 participants (3,612 with diabetes). Four trials assessed the use of bare metal stents (BMS) and four looked at drug-eluting stents (DES). Seven trials reported five-year all-cause mortality results and the remaining study listed two-year mortality findings.

Based on pooled data, at five years the risk of all-cause mortality in patients with diabetes and multivessel disease was about 30 percent lower with CABG vs. PCI (risk ratio 0.67). “Importantly, the mortality benefit of CABG was quantitatively much the same in trials that used either BMS or DES with no difference noted between PCI strategies, and was only present in patients with diabetes, with a statistically significant subgroup effect for the comparison with diabetes versus without diabetes,” Verma et al wrote.

CABG was associated with a 60 percent reduction in the need for repeat revascularization (50 percent with DES alone) at five years or longest follow-up. CABG vs. PCI also showed benefits at one-year.

Nonfatal MI was defined in various ways—which the researchers noted made assessment challenging—while the risk of stroke increased with CABG, particularly at one-year follow-up. The authors attributed the higher risk to perioperative events or possibly lower use of antiplatelet therapy in patients who received CABG.  

They wrote that the results tip the scale in favor of CABG over PCI for patients with diabetes and multivessel disease and recommended assembling a heart team approach for caring for these patients.

“Physicians involved in making these recommendations must provide patients with informed consent and fully disclose the mortality benefits of CABG compared with PCI with DES. Since the decision to recommend revascularisation strategies often resides in the hands of the invasive or interventional cardiologist, and not with the cardiac surgeon, there is an inherent bias built into the algorithm that might lead to inferior recommendations.”

Verma and colleagues pointed out several limitations related to differences in the trials, including variations in definitions. They also emphasized that the results help inform population-level recommendations and that recommendations for an individual patient should incorporate other relevant factors.