While the efficacy of CABG in improving both morbidity and mortality in patients with severe coronary artery disease and angina was established in the 1970’s, the majority of patients who took part in these initial ground-breaking studies had normal or near normal ventricular function. The role of CABG in treating patients with poor systolic LV function is less well established, especially in light of modern alternatives such as medical and device management.
The STICH trial was designed to assess these questions, and while the surgical ventricular reconstruction arm has already reported no benefit, the study also examined the role of CABG vs medical therapy alone. This multi-centre prospective randomised trial recruited 1212 patients with an ejection fraction of 35% or less and coronary artery disease amenable to CABG, without significant symptoms of angina (CCS class 0-II), with the majority having NYHA class II-III symptoms of heart failure. Of these, 601 underwent assessment of myocardial viability. Patients were assigned in a 1:1 fashion to either medical therapy or CABG and followed up for an average of 5 years. 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.
There was no difference in the primary outcome of the study with 244 patients (41%) in the medical-therapy group and 218 (36%) in the CABG group dying (HR with CABG, 0.86; 95% CI, 0.72 to 1.04; P=0.12). The results were similar in the viability substudy when after adjustment for baseline variables there was no significant difference between the CABG and medical therapy groups regardless of whether the presence of hibernating myocardium was found (P=0.21). However, the secondary outcomes of death from a cardiovascular cause and death from any cause or hospitilisation for cardiovascular causes did favour CABG (P=0.05 and P<0.001 respectively).
In patients with severe systolic heart failure and coronary disease without significant symptoms of angina there is no significant mortality difference between medical therapy and medical therapy plus CABG. Pre-operative identification of viable myocardium also fails to identify a sub-group who might benefit from CABG.
- Valezquez EJ, Lee KL, Deja MA et al. Coronary -artery bypass surgery in patients with left ventricular dysfunction. N Engl J Med 2011;364:1607-1616.