Importance of angina in patients with coronary disease, heart failure, and left ventricular systolic dysfunction: insights from STICH

Abstract

Background: Patients with left ventricular (LV) systolic dysfunction, coronary artery disease (CAD), and angina are often thought to have a worse prognosis and a greater prognostic benefit from coronary artery bypass graft (CABG) surgery than those without angina.

Objectives: This study investigated: 1) whether angina was associated with a worse prognosis; 2) whether angina identified patients who had a greater survival benefit from CABG; and 3) whether CABG improved angina in patients with LV systolic dysfunction and CAD.

Methods: We performed an analysis of the STICH (Surgical Treatment for Ischemic Heart Failure) trial, in which 1,212 patients with an ejection fraction ≤35% and CAD were randomized to CABG or medical therapy. Multivariable Cox and logistic models were used to assess long-term clinical outcomes.

Results: At baseline, 770 patients (64%) reported angina. Among patients assigned to medical therapy, all-cause mortality was similar in patients with and without angina (hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 0.79 to 1.38). The effect of CABG was similar whether the patient had angina (HR: 0.89; 95% CI: 0.71 to 1.13) or not (HR: 0.68; 95% CI: 0.50 to 0.94; p interaction = 0.14). Patients assigned to CABG were more likely to report improvement in angina than those assigned to medical therapy alone (odds ratio: 0.70; 95% CI: 0.55 to 0.90; p < 0.01).

Conclusions: Angina does not predict all-cause mortality in medically treated patients with LV systolic dysfunction and CAD, nor does it identify patients who have a greater survival benefit from CABG. However, CABG does improve angina to a greater extent than medical therapy alone. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease [STICH]; NCT00023595).

Keywords: coronary artery bypass grafting; coronary artery disease; heart failure; mortality.

Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1. Kaplan-Meier Estimates: Cumulative Incidence of All-Cause Mortality in Medically Treated Patients With and Without Angina

Amongst patients assigned to medical therapy, all-cause mortality was similar in patients with and without angina (HR: 1.05; 95% CI: 0.79 to 1.38).

Figure 2. Adjusted Cox Proportional Hazards Estimates of the Cumulative Risk of All-Cause Mortality According to Angina Status and Treatment Arm

The effect of CABG was similar whether the patient had angina (HR: 0.89; 95% CI: 0.71 to 1.13) or not (HR: 0.68; 95% CI: 0.50 to 0.94) (p interaction = 0.14). Analyses adjusted for LVEF, age, BMI (above or below 35), log of creatinine (0 to 0.4), peripheral vascular disease, mitral regurgitation, beta-blockers at baseline, atrial fibrillation/flutter. BMI = body mass index; CABG = coronary artery bypass graft; CI = confidence interval; LVEF = left ventricular ejection fraction.

Central Illustration. The STICH Angina Substudy: The Interaction of Angina, Revascularization, and Outcomes in Patients With LV Systolic Dysfunction and Coronary Artery Disease

The presence of angina does not confer a markedly poorer prognosis in medically treated patient. By intention-to-treat, mortality rates are similar in patients assigned to CABG or to medical therapy, whether angina is present or not. Patients treated with CABG had greater improvement in CCS angina class compared to patients treated with medical therapy only, but the treatment effect diminishes over time. Angina, unless recalcitrant to medical therapy, does not appear useful in selecting patients with CAD, heart failure and LV systolic dysfunction for CABG. CABG = coronary artery bypass graft; CAD = coronary artery disease; CCS = Canadian Cardiology Society; LV = left ventricular.