Abstract 16450: Impact of LV Remodeling on the Threshold of Jeopardized Myocardium Needed for a Survival Benefit with CABG in Patients with Left Ventricular Systolic Dysfunction: was STICH too Simplistic?

Abstract

Aims The recent STICH trial showed lack of prognostic benefit for revascularization (RVS) in pts with viable myocardium. However, identification of pts who may accrue a prognostic benefit from RVS in ischemic LV dysfunction is a complex multifactorial process in which hibernation (H), ischemia (I), scar, remodeling, and mitral regurgitation (MR) status are substrates. We evaluated the impact of scar, LV remodeling, MR, and jeopardized myocardium (JM=I+H) on RVS benefit in pts with reduced LVEF.

Methods: 513 consecutive pts (age 66±11, 78% men, LVEF 28±9%) with known or suspected coronary disease and LVEF<50% who underwent gated stress/rest Rb/ F-18-fluorodeoxyglucose PET and echocardiography (echo) were evaluated. An automated quantitative method was applied to the PET images to measure the extent of I, H, LV volumes [end-systolic volume index (ESVI)], and LVEF reserve. Cox proportional hazards model (CPH) was used to model the association of PET and echo metrics with all cause death after adjustment for confounders. A propensity score model (PS) was developed to predict RVS within 90 days of PET.

Results: During a mean follow-up of 2.7 years, 172 (34%) deaths, 114 CABG (22%), and 74 PCI (14%) occurred. CPH revealed that after adjustment for multiple factors, Euroscore, JM, ESVI, and use of CABG or ICD were associated with survival (chisq 2 96, p<.001). Interactions were present between JM and Euroscore (p=0.02), JM and CABG (<0.02), and between CABG and ESVI (p<0.05) such that improved survival was present with CABG at higher levels of JM. With increasing ESVI, more JM was necessary for CABG benefit (Figure). Relative benefit with CABG increased with higher Euroscore.

Conclusions: In pts with reduced LVEF, the survival benefit of CABG is proportionate to the amount of JM despite MR or remodeling. The JM threshold for this benefit is greater with worsening remodeling.