Abstract 13636: Identification of Therapeutic Benefit from Revascularization in Patients with Left Ventricular Systolic Dysfunction: Inducible Ischemia versus Hibernating Myocardium

Abstract

Background: The strategy of revascularization of myocardium deemed viable by standard techniques was ineffective in a recent STICH trial substudy. These results were limited by the viability imaging technique used as well as by the lack of information regarding inducible ischemia. We examined the relative impact of stress-rest rubidium-82/ F-18 fluorodeoxyglucose positron emission tomography (PET) identified ischemia, scar and hibernating myocardium on the survival benefit associated with revascularization in patients with systolic dysfunction.

Methods and Results: The extent of perfusion defects and metabolism-perfusion mismatch was measured with an automated quantitative method in 648 consecutive patients (age 65±12 years, 23% female, mean LVEF 31±12%) undergoing PET. Cox proportional hazards modeling was used to adjust for potential confounders, including a propensity score to adjust for nonrandomized treatment allocation. Revascularization was performed within 90 days of PET in 222 patients (34%). During a follow-up of 2.8±1.4 years, there were 213 (33%) deaths. The proportion of hibernating myocardium was significantly associated with all cause death (<0.0001), while the proportions of ischemic (p=0.37) and nonviable myocardium (p=0.51) were not. An interaction between treatment and hibernating myocardium extent was present such that revascularization in the setting of significant hibernating myocardium was associated with improved survival compared to medical therapy (p<0.0009), especially when the extent of viability exceeded 20% of the myocardium.

Conclusions: Among patients with ischemic cardiomyopathy, the extent and severity of hibernating, but not ischemic, myocardium identifies which patients may accrue a survival benefit with revascularization versus medical therapy.