Coronary bypass surgery with or without surgical ventricular reconstruction

Abstract

Background: Surgical ventricular reconstruction is a specific procedure designed to reduce left ventricular volume in patients with heart failure caused by coronary artery disease. We conducted a trial to address the question of whether surgical ventricular reconstruction added to coronary-artery bypass grafting (CABG) would decrease the rate of death or hospitalization for cardiac causes, as compared with CABG alone.

Methods: Between September 2002 and January 2006, a total of 1000 patients with an ejection fraction of 35% or less, coronary artery disease that was amenable to CABG, and dominant anterior left ventricular dysfunction that was amenable to surgical ventricular reconstruction were randomly assigned to undergo either CABG alone (499 patients) or CABG with surgical ventricular reconstruction (501 patients). The primary outcome was a composite of death from any cause and hospitalization for cardiac causes. The median follow-up was 48 months.

Results: Surgical ventricular reconstruction reduced the end-systolic volume index by 19%, as compared with a reduction of 6% with CABG alone. Cardiac symptoms and exercise tolerance improved from baseline to a similar degree in the two study groups. However, no significant difference was observed in the primary outcome, which occurred in 292 patients (59%) who were assigned to undergo CABG alone and in 289 patients (58%) who were assigned to undergo CABG with surgical ventricular reconstruction (hazard ratio for the combined approach, 0.99; 95% confidence interval, 0.84 to 1.17; P=0.90).

Conclusions: Adding surgical ventricular reconstruction to CABG reduced the left ventricular volume, as compared with CABG alone. However, this anatomical change was not associated with a greater improvement in symptoms or exercise tolerance or with a reduction in the rate of death or hospitalization for cardiac causes. (ClinicalTrials.gov number, NCT00023595.)

Conflict of interest statement

Dr. Velazquez reports receiving grant support from Cardiokinetix; Dr. O’Connor, receiving grant support from Scios and NovaCardia; and Dr. Rouleau, receiving consulting fees from Novartis, Pfizer, and Scios. No other potential conflict of interest relevant to this article was reported.

2009 Massachusetts Medical Society

Figures

Figure 1. Enrollment and Outcomes in the STICH Hypothesis 1 and Hypothesis 2 Trials

Eligible patients who had an ejection fraction of 35% or less and coronary artery disease that was amenable to coronary-artery bypass grafting (CABG) were stratified for randomization on the basis of protocol criteria regarding eligibility for medical therapy and for surgical ventricular reconstruction (SVR). Patients who were eligible for medical therapy with or without CABG but not for CABG with SVR were randomly assigned within stratum A. Data from these patients are being collected in the ongoing Hypothesis 1 component of the Surgical Treatment of Ischemic Heart Failure (STICH) trial. Patients who were eligible for medical therapy with or without CABG or for CABG with SVR were randomly assigned within stratum B. Patients who were not eligible for medical therapy alone but who were eligible for CABG or CABG with SVR were randomly assigned within stratum C. Patients in stratum B and stratum C who were then randomly assigned to undergo CABG with or without SVR are included in the 1000-patient cohort that was evaluated in the Hypothesis 2 trial.

Figure 2. Angina and Heart-Failure Symptoms at Baseline and at the Last Follow-up Visit

Symptoms of angina, classified according to criteria of the Canadian Cardiovascular Society (CCS), and symptoms of heart failure, classified according to criteria of the New York Heart Association (NYHA), improved significantly for the 499 patients who underwent coronary-artery bypass grafting (CABG) alone and for the 501 patients who under-went CABG with surgical ventricular reconstruction (SVR) between baseline and the latest follow-up visit, at a median of 48 months. Angina symptoms improved by an average of 1.7 classes in both cohorts (P = 0.84) (Panel A). Heart-failure symptoms improved by an average of one class in both cohorts (P = 0.70) (Panel B).

Figure 3. Kaplan–Meier Estimates of Outcomes

Panel A shows the probability of the primary outcome (death from any cause or hospitalization for cardiac causes), which did not differ significantly between the two groups. The primary outcome occurred in 292 patients (59%) assigned to undergo coronary-artery bypass grafting (CABG) alone and in 289 patients (58%) assigned to undergo CABG with surgical ventricular reconstruction (SVR) (hazard ratio, 0.99; 95% CI, 0.84 to 1.17). Panel B shows the probability of death from any cause, which occurred in 141 patients (28%) assigned to undergo CABG and in 138 patients (28%) assigned to undergo CABG with SVR (hazard ratio, 1.00; 95% CI, 0.79 to 1.26).

Figure 4. Primary Outcome in Subgroups of Interest

Hazard-ratio plots for selected characteristics of patients at baseline show no significant interaction with the study-group assignment. CABG denotes coronary-artery bypass grafting, CCS Canadian Cardiovascular Society, LAD left anterior descending coronary artery, LM left main coronary artery, LVEF left ventricular ejection fraction, NYHA New York Heart Association, and SVR surgical ventricular reconstruction.