CABG BETTER THAN ANGIOPLASTY FOR DIABETICS

Diabetes patients with multivessel coronary artery disease fare better after coronary artery bypass graft (CABG) surgery than following angioplasty, even when the most contemporary drug-eluting stents (DES) are employed, says the lead author of a new study. Masoor Kamalesh, MD, from Roudebush VA Medical Center, Indianapolis, Indiana and colleagues report their findings, from the VA CARDS study in US veterans, in the February 26 issue of the Journal of the American College of Cardiology.

"The overriding conclusion is that surgery is better; it's clearly the way to go in diabetics," Dr. Kamalesh told Medscape Medical News.

The findings corroborate those of the Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease (FREEDOM) trial, presented at the end of last year and following which most observers felt the debate was finally settled in favor of surgery, he said.

However, FREEDOM primarily involved first-generation DES, and Dr. Kamalesh said the new trial is the first to compare the most contemporary surgical techniques with the newest-generation DES in a significant number of cases: "It's a state-of-the-art study. As soon as everolimus/zotarolimus-eluting stents were FDA approved and available, we used them."

Writing in an accompanying editorial, Stephen G. Ellis, MD, from the Cleveland Clinic, Ohio, agrees that surgery is the best option: "On the basis of the current body of evidence, CABG should be preferred over [percutaneous coronary intervention] PCI in patients with diabetes and multivessel disease with complex anatomy exemplified by SYNTAX scores >22 and perhaps even all patients with diabetes with multivessel disease."

First Trial to Use Newer DES Underpowered but 'Still Meaningful'

VA CARDS was a prospective, multicenter study conducted at VA centers around the US between 2006 and 2010, in which 198 eligible patients with diabetes with severe coronary artery disease were randomly assigned to either CABG (n=97) or PCI with DES (n=101).

Patients were eligible if they had diabetes and multivessel disease including either the left anterior descending (LAD) coronary artery or isolated proximal LAD. Objective evidence of ischemia was required for stenoses between 50% and 70%.

The choice of stent was at the operator's discretion, but a single stent type per patient was recommended; all commercially available DES were allowed once they were approved by the FDA. The stents used were Taxus (Boston Scientific; n=35), Cypher (Cordis; n=20), Xience/Promus (Abbott Vascular; n=18), Endeavor (Medtronic; n =2), mixed drug-eluting stents (n=16), and mixed bare-metal stents (n=1).

Patients were followed for at least 2 years; the primary outcome measure was a composite of nonfatal MI or death. Secondary-outcome measures included all-cause mortality, cardiac mortality, nonfatal MI, and stroke.

The study was stopped because of slow recruitment, however, after enrolling only 25% of the intended sample size, leaving it severely underpowered for the primary end point.

Dr. Kamalesh acknowledges that his study did fall short but says the results are still "meaningful," particularly when added to those from FREEDOM and data from the ASCERT and New York registries.

"Our results are statistically significant, but they won't be taken as definitive because of the wide confidence intervals," he said. However, "they will contribute to the literature; for example, they can be included in meta-analyses."

Questions Over Mortality Findings, Definitions of Nonfatal MI

The primary end point of nonfatal MI or death came out in favor of CABG, albeit that it was underpowered (hazard ratio, 0.89; 95% confidence interval [CI], 0.47 – 1.71). All-cause mortality was 5% for CABG and 21% for PCI (hazard ratio, 0.30; 95% CI, 0.11 – 0.80), while the risk for nonfatal MI was 15% for CABG and 6.2% for PCI (hazard ratio, 3.32; 95% CI, 1.07 – 10.30).

In his editorial, Dr. Ellis wonders, "Why, particularly when the VA system has contributed many important randomized trials in the field of CAD, could the VA system not complete such an important study?" The authors don't provide an adequate answer to this question, he states.

And although this means that the all-cause mortality findings could "be due to the play of chance," he observes that "at last count" from four relatively contemporary trials — SYNTAX, CARDIA, FREEDOM, and now VA CARDS — there were 159 deaths in the CABG groups and 244 deaths in the PCI groups, and "one cannot ignore these findings."

Still, it would have "been useful if the [VA CARDS] investigators had provided the causes of death for these patients," he noted. It is also difficult to interpret the higher rate of nonfatal MI in the CABG group in VA CARDS because a "novel definition" of this outcome was used, he adds.

Dr. Kamalesh acknowledges the problems they had recruiting patients to their study, which indicates that "international trials are the way to go, because we found we couldn't enroll enough patients in a timely manner." However, he points out there is a drawback to trials conducted in more than one country, such as FREEDOM, because there are often different techniques for CABG and PCI in different places, he says, "so it's a leap of faith to compare them."

Surgery Generally Favored, but Individual Needs Must Be Considered

Dr. Kamalesh says the totality of evidence in support of surgery for diabetics with CAD "applies to patients with two- or three-vessel disease," and the only exception is diabetic patients with just one lesion in the circumflex or right coronary; "they are better off with stenting."

Dr. Ellis says further data are needed "regarding the important interaction between lesion number and complexity and clinical outcomes" with the two approaches. "The best recommendations will contextualize an individual’s needs relative to the body of data generally favoring surgery."

Dr. Kamalesh has disclosed no relevant financial relationships ; disclosures for the coauthors are listed in the article. Dr. Ellis has disclosed no relevant financial relationships.

J Am Coll Cardiol . 2012;61:808-816, 817-819.