Coronary-Artery Bypass Surgery in Patients with Ischemic Cardiomyopathy

Abstract

Background: The survival benefit of a strategy of coronary-artery bypass grafting (CABG) added to guideline-directed medical therapy, as compared with medical therapy alone, in patients with coronary artery disease, heart failure, and severe left ventricular systolic dysfunction remains unclear.

Methods: From July 2002 to May 2007, a total of 1212 patients with an ejection fraction of 35% or less and coronary artery disease amenable to CABG were randomly assigned to undergo CABG plus medical therapy (CABG group, 610 patients) or medical therapy alone (medical-therapy group, 602 patients). The primary outcome was death from any cause. Major secondary outcomes included death from cardiovascular causes and death from any cause or hospitalization for cardiovascular causes. The median duration of follow-up, including the current extended-follow-up study, was 9.8 years.

Results: A primary outcome event occurred in 359 patients (58.9%) in the CABG group and in 398 patients (66.1%) in the medical-therapy group (hazard ratio with CABG vs. medical therapy, 0.84; 95% confidence interval [CI], 0.73 to 0.97; P=0.02 by log-rank test). A total of 247 patients (40.5%) in the CABG group and 297 patients (49.3%) in the medical-therapy group died from cardiovascular causes (hazard ratio, 0.79; 95% CI, 0.66 to 0.93; P=0.006 by log-rank test). Death from any cause or hospitalization for cardiovascular causes occurred in 467 patients (76.6%) in the CABG group and in 524 patients (87.0%) in the medical-therapy group (hazard ratio, 0.72; 95% CI, 0.64 to 0.82; P<0.001 by log-rank test).

Conclusions: In a cohort of patients with ischemic cardiomyopathy, the rates of death from any cause, death from cardiovascular causes, and death from any cause or hospitalization for cardiovascular causes were significantly lower over 10 years among patients who underwent CABG in addition to receiving medical therapy than among those who received medical therapy alone. (Funded by the National Institutes of Health; STICH [and STICHES] ClinicalTrials.gov number, NCT00023595.).

Figure 1. Randomization and Follow-up

CABG denotes coronary-artery bypass grafting.

Figure 2

Kaplan–Meier Estimates of the Rates of Death from Any Cause, Death from Cardiovascular Causes, and Death from Any Cause or Hospitalization for Cardiovascular Causes.

Figure 3. Subgroup Analyses of Death from Any Cause

Age, sex, race, region, New York Heart Association (NYHA) heart failure class, left ventricular ejection fraction (LVEF), stratum, Canadian Cardiovascular Society (CCS) angina class, and number of diseased vessels are prespecified subgroup factors. All other variables are post hoc subgroup factors. All subgroups are based on values measured at baseline. Data on ESVI were missing for 97 patients, data on the number of vessels with 75% or greater stenosis and on the degree of stenosis of the left main coronary artery (LM) and proximal left anterior descending artery (PLAD) were missing for 1 patient, and data on mitral regurgitation were missing for 3 patients. The Canadian Cardiovascular Society (CCS) angina classes range from I to IV, with higher classes indicating more disabling pain due to angina. New York Heart Association (NYHA) heart failure classes range from I to IV, with higher values indicating greater disability. The divisions between the LVEF and the end-systolic volume index subgroups were based on the median values. Patients who met the eligibility criteria for random assignment to the CABG group or medical-therapy group but did not meet the criteria for eligibility for surgical ventricular reconstruction were enrolled in stratum A; patients who did meet the criteria for eligibility for surgical ventricular reconstruction were enrolled in stratum B.