Conference Coverage

Coronary bypass shows compelling advantages in ischemic cardiomyopathy




CHICAGO – Coronary artery bypass grafting plus guideline-directed medical therapy resulted in significantly lower all-cause mortality than did optimal medical therapy alone at 10 years of follow-up in the Surgical Treatment for Ischemic Heart Failure Extension Study (STICHES), Dr. Eric J. Velazquez reported at the annual meeting of the American College of Cardiology.

“We believe these results have the immediate clinical implications that the presence of severe left ventricular dysfunction should prompt an evaluation for the extent and severity of angiographic CAD, and that among patients with ischemic cardiomyopathy, CABG should be strongly considered in order to improve long-term survival,” declared Dr. Velazquez, professor of medicine in the division of cardiology at Duke University, Durham, N.C.

Dr. Eric J. Velazquez Bruce Jancin/Frontline Medical News

Dr. Eric J. Velazquez

STICHES included 1,212 patients in 22 countries, all with heart failure and an ejection fraction of 35% or less along with CAD deemed suitable for surgical revascularization. They were randomized to CABG plus guideline-directed medical therapy or to the medical therapy alone. The 98% successful follow-up rate over the course of 10 years in this trial drew audience praise as a herculean effort.

At a median 9.8 years of follow-up, all-cause mortality – the primary study endpoint – had occurred in 58.9% of the CABG group and 66.1% of medically managed patients. That translates to a 16% relative risk reduction and an absolute 8% difference in favor of CABG. The median survival extension conferred by CABG was 1.4 years. The number of patients needed to treat with CABG in order to prevent one death from any cause was 14.

The CABG group also did significantly better in terms of secondary endpoints. The cardiovascular mortality rate was 40.5% in the CABG group versus 49.3% with medical therapy, for a 21% relative risk reduction favoring CABG and a number needed to treat of 11. The composite endpoint of all-cause mortality or cardiovascular hospitalization occurred in 76.6% of the CABG group and 87% of the medically treated patients.

In an earlier analysis based upon 56 months of follow-up, there was a trend favoring CABG in terms of all-cause mortality, but it didn’t reach statistical significance (N Engl J Med. 2011;364:1607-16). With an additional 5 years of prospective follow-up, however, the divergence in outcome between the two study arms increased sufficiently that the difference achieved statistical significance. But the more impressive study finding, in Dr. Velazquez’s view, was the durability of the CABG benefits out to 10 years.

Discussant Dr. Jeroean J. Bax of Leiden (the Netherlands) University commented that while the solid advantage in outcomes displayed by the CABG group was noteworthy, he finds it sobering that even though the STICHES participants averaged only 60 years of age at entry, the majority were dead at 10 years’ follow-up. What, he asked, is the likely mechanism for the very high mortality seen in this population?

“My take-home after many years working with our team is that I believe these patients have very low reserve, and they are at risk any time they take a hit. I don’t believe just one mechanism is involved. In our previous analysis of the 5-year follow-up data, we showed the results can’t be explained solely by viability, ischemia, or functional recovery. I think the issue of arrhythmia reduction and substrate reduction is important. But for me, it’s a combination of many factors. Any additional hit for this high-risk population is not well tolerated; that’s what leads to death,” Dr. Velazquez replied.

Asked how he thinks multivessel percutaneous coronary intervention would perform as an alternative to CABG in patients with ischemic cardiomyopathy, Dr. Velazquez responded that he has no idea because it hasn’t been studied.

“I can picture reasons for and against PCI providing benefits similar to CABG,” he added.

Simultaneous with Dr. Velazquez’s presentation at ACC 16, the STICHES results were published online (N Engl J Med. 2016 April 3. doi:10.1056/NEJMoa1602001).

In an accompanying editorial, Dr. Robert A. Guyton and Dr. Andrew L. Smith of Emory University in Atlanta asserted that these strong results from STICHES make a compelling case that CABG for patients with ischemic cardiomyopathy should be upgraded in the ACC/AHA heart failure management guidelines from its current status as a class IIb recommendation that “might be considered” to class IIa, indicating it is “probably beneficial” (N Engl J Med. 2016 April 3. doi:10.1056/NEJMe1603615).

STICHES was funded by the National Institutes of Health. The study presenter reported having no financial conflicts regarding the study.

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