–Life-saving benefit of CABG now clear in long-term trial follow-up
Finally, after 10 years of follow-up, the life-saving benefits of coronary artery bypass graft (CABG) surgery in heart failure patients with coronary artery disease are clear.
More than 15 years ago, the NIH funded the original STICH trial to answer a question that was already old and the subject of considerable disagreement: Should heart failure patients with coronary artery disease receive CABG? After 56 months, there were no significant differences in mortality between the surgery arm and the medical arm, although there were trends toward reductions in cardiovascular mortality and other endpoints.
Now, the main 10-year results of the Surgical Treatment for Ischemic Heart Failure Extension Study (STICHES) have been presented at the American College of Cardiology meeting in Chicago and published simultaneously in the New England Journal of Medicine.
Dramatic Benefit At 10 Years
At 10 years, death from any cause was reduced by a relative 16% in the CABG group. The mortality rate was 58.9% (359 of 610) in the CABG group compared with 66.1% (398 of 602) in the control group (hazard ratio 0.84, 95% confidence interval 0.73-0.97, P=0.02), resulting in an absolute 8% difference in survival. The median survival gain was 1.44 years, with an average of 6.29 years in the medical therapy group versus 7.73 years in the CABG group. CABG patients also had a 21% reduction in the risk of death from cardiovascular causes and a 23% reduction in the risk of death or hospitalization for cardiovascular causes.
In the group randomized to CABG, 91% underwent the procedure. Nearly 20% of the medical therapy group ended up having CABG during the 10-year follow-up period.
A likely explanation for the long delay before the benefits of CABG became manifest was the early increase in events associated with the surgery, the authors wrote. The benefits of CABG only started to a emerge after 2 years. “It appears that the operative risk associated with CABG is offset by a durable effect that translates into increasing clinical benefit to at least 10 years.”
The “lasting benefits of CABG” might be even greater, because the per-protocol analysis indicated that for patients in either group who actually received CABG mortality was reduced by 20% to 25%.
The durable benefits of CABG were likely related to the widespread use of the left internal mammary artery as a conduit and the increased uptake of statins, the authors speculated.
In an interview, lead author Eric Velazquez, MD, of Duke University in Durham, N.C., said that the results of STICHES help answer an ancillary question. “We’ve debated for years whether we should look for coronary disease in these patients. So this answers that question. You have to look for disease.”
He said that every heart failure patient for whom a survival benefit might be anticipated should undergo angiographic evaluation for coronary disease.
But, Velazquez made clear, physicians need to carefully talk with patients about both the early hazard as well as the potential for long-term benefit. “If you have a patient whose major goal is to live the next few months, then CABG may not be right for him or her. But if that person has a goal for 10 years, then CABG may be the right choice.”
Implications for PCI
Percutaneous coronary intervention (PCI) played no role in STICH or STICHES. But Milton Packer, MD, of Baylor University Medical Center at Dallas, predicted that interventional cardiologists will surely use the trial to help justify percutaneous revascularization in heart failure patients. Packer intended this remark as a statement of fact, not an endorsement.
Velazquez, like Packer, pointed out that PCI has never been tested in this context and this population. In observational studies, CABG was significantly better than PCI, he said.
In an interview, Judith Hochman, MD, of NYU Langone Medical Center in New York City, said that “we don’t have the data yet and we can’t extrapolate.” It is widely believed that CABG protects more of the vessel and for a longer period than PCI, she said.