ROME – Coronary artery bypass surgery reduces cardiovascular mortality in heart failure patients with ischemic cardiomyopathy to a consistent extent regardless of age at the time of surgery, according to a secondary analysis from the landmark STICH trial, Eric J. Velazquez, MD, reported at the annual congress of the European Society of Cardiology.
“Cardiologists and cardiac surgeons can confidently offer patients CABG in addition to optimal medical therapy with the knowledge that cardiovascular mortality is reduced by CABG to a similar extent across all age groups in this trial through 10 years of follow-up,” said Dr. Velazquez, professor of medicine at Duke University in Durham, N.C.
However, that’s only part of the story. Cardiovascular mortality was a secondary endpoint in STICH (Surgical Treatment for Ischemic Heart Failure). The primary endpoint was all-cause mortality. And CABG’s impact on all-cause mortality was diminished in older STICH participants because of their greater comorbidity burden and the competing risk of noncardiovascular death, he added.
The take-home message is that cardiologists and heart surgeons need to carefully assess competing mortality risks before pursuing CABG in older patients, according to Dr. Velazquez.
Session cochair Kim A. Williams, MD, professor and chief of cardiology at Rush University Medical Center in Chicago, posed a direct question: “Is there an age cutoff for your group for bypass surgery?”
No, Dr. Velazquez replied. He pointed out that cardiovascular mortality remained the No. 1 cause of mortality across all age groups.
“If the expectation is that the major cause of fatal events is going to be cardiovascular, and CABG plus medical therapy reduces that risk consistently regardless of age, we think that there really is no particular age cutoff. There is a point at which the noncardiovascular risk predominates, but in the population we studied we did not see that point,” Dr. Velazquez added.
STICH was a 22-nation trial in which 1,212 patients with a left ventricular ejection fraction of 35% or less and coronary artery disease amenable to CABG were randomized to CABG plus optimal medical therapy or optimal medical therapy alone and followed for a median of 9.8 years (JACC Heart Fail. 2013;1:400-8). For purposes of this secondary analysis, participants were divided into quartiles according to baseline age: Quartile 1 patients were up to 54 years old; quartile 2 were ages 55-60; quartile 3 were ages 61-67; and quartile 4 were ages 68 and up.
Older subjects had more comorbidities. All-cause mortality was significantly higher in older than younger patients: for CABG, 68% vs. 48% in quartiles 4 and 1, respectively; for medical therapy, 79% vs. 60% in the same two quartiles. In contrast, cardiovascular mortality did not differ significantly by age: It was 39% in quartile 4 and 35% in quartile 1 in the CABG group, and 53%, compared with 49%, in medically managed patients in quartiles 4 and 1.
For the secondary composite endpoint of all-cause mortality or cardiovascular hospitalization, the benefit of CABG plus medical management over medical management alone was significantly greater in younger than in older patients.
The rate of noncardiovascular mortality was 5.8% in quartiles 1 and 2, then leapt to 14.7% in quartile 3 and 21.1% in quartile 4.
Although the main focus of Dr. Velazquez’s presentation was the impact of CABG with advancing age, he said he found an important lesson in the younger population as well.
“We saw roughly a 40% relative risk reduction in all-cause mortality with CABG in the youngest quartile, compared with the three older groups. My interpretation of that data is that it’s probably not appropriate to avoid CABG in favor of another strategy in a younger patient when you see this kind of mortality benefit,” the cardiologist said.
One limitation of the STICH analysis, said session cochair Stephan Achenbach, MD, is that the study population was relatively young overall. The oldest patients in STICH were roughly the same age as the average patients undergoing CABG for left ventricular systolic dysfunction today at most centers, according to Dr. Achenbach, professor of cardiology at the University of Erlangen-Nuremberg (Germany).
Dr. Velazquez agreed. “I can’t speak as to whether these trial results would apply to the very elderly, patients age 90 and above,” he said.
Simultaneously with the presentation , the new STICH analysis was published online (Circulation. 2016 Aug 29. doi: 10.1161/CIRCULATIONAHA.116.024800).
STICH was funded by the National Institutes of Health. Dr. Velazquez reported having no relevant financial conflicts.