STICHES at 10 Years: CABG Ups Survival in Severe LV Dysfunction

Marlene Busko

April 04, 2016

CHICAGO, IL — Patients who were around 60 years old and had ischemic cardiomyopathy were more likely to survive the next decade if they received CABG plus optimal medical therapy vs optimal medical therapy alone, in the Surgical Treatment for Ischemic Heart Failure (STICH) extension study (STICHES)[1]. Previously, the 5-year results from STICH had shown that CABG reduced mortality, but this did not reach statistical significance.

Dr Eric J Velazquez (Duke Clinical Research Institute, Durham, NC) presented these latest findings in a press conference and in a clinical-research session here at the American College of Cardiology (ACC) 2016 Scientific Sessions, and the study was simultaneously published in the New England Journal of Medicine.

"We believe these results have the immediate clinical implication that the presence of severe left ventricular dysfunction should prompt an evaluation of the extent and severity of angiographic lesions in patients with ischemic cardiomyopathy, and CABG should be strongly considered, to improve long-term survival, said Velazquez.

"These findings should prompt strong consideration of coronary bypass as an addition to medical therapy in shared decision making" for certain patients with coronary artery disease, heart failure, and severe left ventricular systolic dysfunction, Drs Robert A Guyton and Andrew L Smith (Emory University, Atlanta, GA) echo, in an accompanying editorial[2].

Invited to comment, two panel members at the session agreed. The researchers "showed very clearly" that revascularization can improve outcomes in patients with a reduced ejection fraction, Dr Jeroen J Bax (Leiden University, the Netherlands) told heartwire from Medscape.

Dr Howard C Herrmann (Perelman School of Medicine, University of Pennsylvania, Philadelphia) added that "now with 10-year data, it's a positive trial; it allows us to rethink that concept of who should be operated on with left ventricular dysfunction and multivessel coronary artery disease."

Controversial Surgery in High-Risk Patients

Dr Eric Velazquez

"Advances in the management of coronary artery disease and heart failure have increased survival for patients with severe left ventricular dysfunction, but whether surgical revascularization leads to improved survival beyond guideline-recommended therapy remains controversial," said Velasquez.

STICH evaluated the 5-year effects of CABG in patients with ischemic cardiomyopathy. From 2002 to 2007 the researchers enrolled 1212 patients with an ejection fraction of 35% or less and CAD amenable to CABG at 99 sites in 22 countries.

The patients had a median age of 60, and 12% were women. Three-quarters had had a previous MI; 39% had known type 2 diabetes; and they had a median body-mass index (BMI) of 27. Most (89%) were in NYHA class 2 or worse, and three-quarters had multivessel disease. They had a median LVEF of 28%.

A total of 610 patients received CABG plus medical therapy and 602 patients received medical therapy alone.

CABG was associated with lower all-cause mortality (the primary end point) as well as lower cardiovascular mortality and other secondary end points, including combined all-cause death or hospitalization for cardiovascular causes.

10-Year Outcomes, CABG Group vs Medical Therapy

Outcome CABG group (%) Medical-therapy group (%) HR (95%CI) P
Death from any cause 58.9 66.1 0.84 (0.73–0.97) 0.02
Death from cardiovascular causes 40.5 49.3 0.79 (0.66–0.93) 0.006
Death from any cause or hospitalization for heart failure 76.6 87.0 0.72 (0.64–0.82) <0.001

Overall, CABG was associated with an incremental median survival benefit of nearly 18 months. The number needed to treat to prevent one death was 14, and the number needed to treat to prevent one cardiovascular death was 11.

Candidates for CABG

"Does that mean that we need to revascularize everybody?" Bax asked rhetorically. The current study was not designed to determine which patients would benefit most. Improved survival after CABG could be related to fewer lethal ventricular arrhythmias or to reverse remodeling or to removing the ischemia by doing the revascularization, he suggested.

"I think it's a very clear indication that if you have low ejection fraction that you should seriously consider whether revascularization is feasible."

Guyton and Smith describe how a patient's risk profile affects the decision on whether to have CABG.

"A patient with few risk factors—for example, age 60 years, an ejection fraction of 30%, and NYHA class 3 heart failure—would have a predicted risk of CABG-related death of 0.7% calculated with the use of the STS risk calculator, as compared with the 3.6% mean mortality found in STICH, which makes the choice of CABG extremely compelling.

"A different patient, with several major risk factors—for example, age 70 years, previous CABG, an ejection fraction of 30%, moderate mitral regurgitation, a creatinine level of 2.4 mg/dL, and NYHA class 3 heart failure—would have an STS-predicted risk of death in excess of 7%, which would make the decision more difficult."

These "relatively young but quite ill patients had average ejection fraction of less than 30%," Herrmann noted. The low survival rate despite successful revascularization suggests "that there are still opportunities for new ideas and new ways to treat these patients."

STICHES was supported by a grant from the National Institutes of Health. Velazquez reports grant support from the National Heart, Lung,  and Blood Institute during the conduct of the study; grant support from Abbott Laboratories, Medtronic, Alnylam Pharmaceuticals, and Pfizer; grant support and personal fees from Amgen and Novartis; and personal fees from Merck and Spire Learning outside the submitted work. Disclosures for the coauthors are list on the journal website . Guyton reports personal fees from Medtronic. Smith has no relevant financial relationships.

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