An Age-Old Question: What Is Too Old for Coronary Artery Bypass Grafting in Heart Failure?

Selecting the appropriate patients for coronary artery bypass grafting in ischemic cardiomyopathy-importance of myocardial viability

Patients who undergo coronary artery bypass graft (CABG) surgery in ischemic cardiomyopathy have a survival advantage over medical therapy at 10 years. The survival advantage of CABG over medical therapy is due to its ability to reduce future myocardial infarction, and by conferring electrical stability. The presence of myocardial viability does not provide a differential survival advantage for CABG over medical therapy. Presence of angina and inducible ischemia are also less predictive of outcome. Moreover, CABG is associated with significant early mortality. Hence, careful patient selection is more important for reducing the early mortality and improving the long-term outcome than relying on results of myocardial viability. Younger patients with good exercise tolerance benefit the most, while patients who are frail and patients with renal dysfunction and dysfunctional right ventricle seem to have very high operative mortality. Elderly patients, because of poor life expectancy, do not benefit from CABG, but the age cutoff is not clear. Patients also need to have revascularizable targets, but this decision is often based on experience of the surgical team and heart team discussion. These recommendations are irrespective of the myocardial viability tests. Optimal medical treatment remains the cornerstone for management of ischemic cardiomyopathy.

Understanding the role of coronary artery revascularization in patients with left ventricular dysfunction and multivessel disease

Coronary artery disease (CAD) is the most common cause of heart failure with reduced ejection fraction (HFrEF). Advances and innovations in medical therapy have been shown to play a crucial role in improving the prognosis of patients with CAD and HFrEF; however, mortality rate in these patients remains high, and the role of surgical and/or percutaneous revascularization strategy is still debated. The Surgical Treatment for Ischemic Heart Failure (STICH) trial and the Revascularization for Ischemic Ventricular Dysfunction (REVIVED) trial have attempted to provide an answer to this issue. Nevertheless, the results of these two trials have generated further uncertainties. Their findings do not provide a definitive answer about the ideal clinical phenotype for surgical or percutaneous coronary revascularization and dispute the historical dogma on myocardial viability and the theory of myocardial hibernation, raising new questions about the proper selection of patients who are candidates for coronary revascularization. The aim of this review is to provide an overview on the actual available evidence of coronary artery revascularization in patients with CAD and left ventricular dysfunction and to suggest new insights on the proper selection and management strategies in this high-risk clinical setting.

Change in Left Ventricular Ejection Fraction With Coronary Artery Revascularization and Subsequent Risk for Adverse Cardiovascular Outcomes

BACKGROUND

Coronary revascularization is recommended to treat ischemic cardiomyopathy. However, the relations of revascularization-associated ejection fraction (EF) change to subsequent outcomes have not been elucidated.

METHODS

In 10 071 veterans (mean age 67 years; 1% women; 15% non-White) who underwent a first percutaneous coronary intervention (PCI) or coronary artery bypass grafting between January 1, 1995, and December 31, 2010, and had prerevascularization and postrevascularization EF measured, we calculated delta-EF (postprocedure EF-preprocedure EF). We related delta-EF as a continuous measure and as categories (≤-5, -5<delta-EF<0, delta-EF=0, 0<delta-EF<5, and delta-EF≥5) to death (using Cox regression) and heart failure hospitalization days (using negative binomial regression) in multivariable-adjusted models, for total sample, and PCI and coronary artery bypass grafting strata.

RESULTS

Over follow-up (mean/maximum 5/14 years) 56% died. Each 5% improvement in delta-EF was associated with statistically significant reductions in death and heart failure hospitalization days of 5% (95% CI, 3%-7%) and 10% (95% CI, 5%-15%), respectively, in the total sample and 6% (95% CI, 4%-8%) and 10% (95% CI, 5%-16%), respectively, in the PCI subgroup. Patients in the highest delta-EF category had 27% (95% CI, 19%-34%) lower mortality (30% [95% CI, 21%-37%] lower in PCI stratum) and ≈40% lower heart failure hospitalization days in total sample and PCI stratum, compared with those in the lowest category. Relations of delta-EF and outcomes in coronary artery bypass grafting subgroup did not reach statistical significance.

CONCLUSIONS

Revascularization-associated EF improvement was associated with significant reductions in mortality and heart failure hospitalization burden, particularly in the PCI subgroup.