Nuclear myocardial perfusion studies do not predict vascular or myocardial architecture in advanced heart failure

Objectives To determine predictors of tissue that would benefit from improved blood flow in subjects with advanced heart disease. Background Advanced regeneration and percutaneous revascularization strategies including revascularization of chronic total occlusions (CTO) are being used to potentially restore myocardial function in the growing population of patients with advanced heart disease. Predictors of myocardial recovery in this population have not been established. Methods Cardiac tissue was collected from 27 subjects undergoing LVAD or cardiac transplantation who had nuclear perfusion imaging prior to procedure. Histologic analysis for fibrosis, vascular density and inflammation was performed and correlated with nuclear perfusion images from the same areas. In a subset of subjects, correlations of nuclear perfusion with TIMI flow by coronary arteriography was also performed. Results Areas of both normal and abnormal epicardial coronary blood flow had a large variation in radiotracer uptake. There were no statistically significant correlations between uptake of radiotracer at rest and degree of cardiac fibrosis, vascular density or inflammation and the matched area of myocardium. Fibrosis varied from 5-50% in areas with severe defects and areas of normal radiotracer uptake. Endothelial density correlated with inflammation in end-stage heart disease. Conclusions Radiotracer uptake poorly predicted both areas of severe fibrosis that will not benefit from increased blood flow and areas of minimal fibrosis that may recover. Correlation of inflammation and endothelial density support a hypothesis that inflammatory cytokines augment vascularity in myocardium. Novel strategies to improve function in advanced heart disease are in need of better markers of recovery.