PCI Fails to Match CABG in Diabetic Patients with Multivessel Disease

MUNICH, Germany—There is no clear evidence to support the use of routine percutaneous coronary intervention (PCI) over coronary artery bypass graft (CABG) surgery in patients with diabetes and multivessel disease, according to late-breaking clinical trial results presented on August 27, 2012, at the European Society of Cardiology Congress.

For the CARDia (Coronary Artery Revascularization in Diabetes) trial, Roger Hall, MD, of the University of East Anglia Medical School (Norwich, United Kingdom), and colleagues randomized 510 diabetic patients with multivessel disease and either stable angina or NSTE ACS to CABG (n = 254) or PCI (n = 256) at 24 centers in Britain and Ireland. Enrollment began in January 2002 and final follow-up was completed in April 2012.

Noninferiority Not Seen

After a median of 5.1 years, 14 patients originally slated for CABG had crossed over to PCI and 1 original PCI patient switched to CABG. Of patients receiving PCI, 69% were implanted with DES.

In an intention to treat analysis, PCI trended higher in the primary endpoint, failing to fall within the prespecified noninferiority margin of 12% (5.9% difference; 95% CI -2%-13%). CABG-treated patients had less nonfatal MI and repeat revascularization (table 1).

Table 1. Five-Year Outcomes

“We cannot declare noninferiority, and certainly the impression is slight superiority for CABG,” Dr. Hall said. “This trial was not powered to show superiority using a conventional analysis and indeed it did not show it. Strikingly, the death rates were very similar in the 2 groups and I think this is an extremely important point.”

The important clinical message, he concluded, is that CABG should remain the preferred method of revascularization in diabetic patients “unless there are clinical features that make it clear that PCI is preferable. If one has such a patient, then the fact that the mortality is so similar means that it’s reasonable to carry out PCI in such patients. But as a trend, I think that across Europe and certainly in the UK, this should be done after appropriate consultation with colleagues, including surgeons, and also the patient.”

Limited Potential for Impact

Commentating after the presentation, Patrick W. Serruys, MD, PhD, of Erasmus Medical Center (Rotterdam, The Netherlands), raised several issues with the study design. First, “the noninferiority margin was set far too wide,” he stressed, noting that the US Food and Drug Administration (FDA) has proven to be exceedingly strict regarding margins in other similar trials like SYNTAX, EXCEL, and RESOLUTE. “Today the FDA would insist on a noninferiority margin of 3.5%, maximum 4% if there is no revascularization.”

Dr. Serruys congratulated the investigators on the use of neurological imaging in stroke, but again said that would be insufficient for the FDA, which would now require that a neurologist  make the diagnosis.

Next, he took issue with the study’s definition of MI. “I’ve been struggling with the different [cardiac] biomarkers to detect periprocedural myocardial infarction in contemporary coronary stent trials and their impact on outcome reporting,” Dr. Serruys noted. “Understanding cardiac biomarkers is really vital to prevent over or under diagnosis of myocardial infarction.”

Referring to the SYNTAX trial, which has already shown a substantial difference between PCI and CABG in this population, Dr. Serruys concluded that there is no longer a need to conduct similar trials in the future. “Would this study impact guidelines?” Dr. Serruys asked. “I’ll let you judge.”

Study Details

Baseline characteristics were well balanced between the treatment groups. The average age of all patients was 64 years, and three-quarters were male. About 60% of patients had 3-vessel disease.

 

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Source:
Hall R. CARDia: Coronary artery revascularization in diabetes trial. Presented at: European Society of Cardiology Congress; August 27, 2012; Munich, Germany.

 

 

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• Study Compares Stents, Surgery in Diabetics with Multivessel Disease
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• Studies Support DES Use in Diabetics, But Results Vary by Device