Extent of coronary and myocardial disease and benefit from surgical revascularization in ischemic LV dysfunction [Corrected]

Abstract

Background: Patients with ischemic left ventricular dysfunction have higher operative risk with coronary artery bypass graft surgery (CABG). However, those whose early risk is surpassed by subsequent survival benefit have not been identified.

Objectives: This study sought to examine the impact of anatomic variables associated with poor prognosis on the effect of CABG in ischemic cardiomyopathy.

Methods: All 1,212 patients in the STICH (Surgical Treatment of IsChemic Heart failure) surgical revascularization trial were included. Patients had coronary artery disease (CAD) and ejection fraction (EF) of ≤35% and were randomized to receive CABG plus medical therapy or optimal medical therapy (OMT) alone. This study focused on 3 prognostic factors: presence of 3-vessel CAD, EF below the median (27%), and end-systolic volume index (ESVI) above the median (79 ml/m(2)). Patients were categorized as having 0 to 1 or 2 to 3 of these factors.

Results: Patients with 2 to 3 prognostic factors (n = 636) had reduced mortality with CABG compared with those who received OMT (hazard ratio [HR]: 0.71; 95% confidence interval [CI]: 0.56 to 0.89; p = 0.004); CABG had no such effect in patients with 0 to 1 factor (HR: 1.08; 95% CI: 0.81 to 1.44; p = 0.591). There was a significant interaction between the number of factors and the effect of CABG on mortality (p = 0.022). Although 30-day risk with CABG was higher, a net beneficial effect of CABG relative to OMT was observed at >2 years in patients with 2 to 3 factors (HR: 0.53; 95% CI: 0.37 to 0.75; p<0.001) but not in those with 0 to 1 factor (HR: 0.88; 95% CI: 0.59 to 1.31; p = 0.535).

Conclusions: Patients with more advanced ischemic cardiomyopathy receive greater benefit from CABG. This supports the indication for surgical revascularization in patients with more extensive CAD and worse myocardial dysfunction and remodeling. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease [STICH]; NCT00023595).

Keywords: coronary artery disease; heart failure; left ventricular dysfunction; myocardial ischemia; outcomes.

Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Time-varying hazard ratios for all-cause mortality in patients randomized to CABG or OMT in the STICH trial

OMT= optimal medical therapy; CABG= coronary artery bypass graft surgery.

Figure 2. Kaplan-Meier estimates of all-cause (panel A) and cardiovascular (panel B) mortality rates

In each panel, study patients are divided according to the presence of 0–1 or 2–3 prognostic factors, regardless of treatment allocation.

Figure 2. Kaplan-Meier estimates of all-cause (panel A) and cardiovascular (panel B) mortality rates

In each panel, study patients are divided according to the presence of 0–1 or 2–3 prognostic factors, regardless of treatment allocation.

Figure 3. Kaplan-Meier rate estimates of all-cause mortality among patients with 2–3 (top panel) and 0–1 (bottom panel) prognostic factors

In each panel, study patients are divided according to the treatment arm (CABG or OMT) to which they were randomized.

Figure 4. Kaplan-Meier estimates of all-cause mortality rates among patients randomized to optimal medical therapy alone (OMT; top panel) or to coronary artery bypass surgery (CABG; bottom panel)

In each panel, study patients are divided according to the presence of 0–1 or 2–3 prognostic factors.

Figure 4. Kaplan-Meier estimates of all-cause mortality rates among patients randomized to optimal medical therapy alone (OMT; top panel) or to coronary artery bypass surgery (CABG; bottom panel)

In each panel, study patients are divided according to the presence of 0–1 or 2–3 prognostic factors.

Figure 5. Time-dependent hazard ratios of all-cause (top panel) and cardiovascular (bottom panel) mortality for CABG vs. OMT

Study patients are divided according to the presence of 2–3 (upper part of each panel) or 0–1 (lower part of each panel) prognostic factors.

Figure 5. Time-dependent hazard ratios of all-cause (top panel) and cardiovascular (bottom panel) mortality for CABG vs. OMT

Study patients are divided according to the presence of 2–3 (upper part of each panel) or 0–1 (lower part of each panel) prognostic factors.

CENTRAL ILLUSTRATION. Schematic Representation of the Clinical Implications of the Present Study Findings

*These thresholds are simply the medians of the LV function variables in the present study and have not been validated prospectively in an independent patient population. This algorithm should only be applied conceptually to support the notion that, among patients with ischemic LV systolic dysfunction, the benefit of surgical revascularization is greater when the disease process is more advanced (see text for more detail). CAD= coronary artery disease; EF= ejection fraction; ESVI= end-systolic volume index.