[15O]H2O myocardial perfusion PET: Added value of relative stress perfusion deficit in the prediction of significant coronary artery stenosis in a mixed population

Abstract

BackgroundIt remains unknown whether estimation of the relative stress perfusion deficit offers added value in the prediction of significant coronary artery stenosis in myocardial perfusion imaging with [15O]H2O PET in a population with high prevalence of established cardiac disease. MethodsDuring eight months, we consecutively included all patients undergoing [15O]H2O PET and subsequent invasive coronary angiography (ICA). Significant stenosis was defined from ICA as fractional flow reserve ≤0.8 or coronary artery narrowing of ≥70%. We calculated absolute and relative total perfusion deficits (aTPD and rTPD, respectively) as semiquantitative measures of the extent and severity of reduced stress perfusion. A multivariate logistic regression analysis was performed to test the adjusted associations (odds ratio (OR) with 95% CI) with significant coronary artery stenosis. ResultsOf 800 patients undergoing [15O]H2O PET, 144 underwent ICA, where 142 patients had an aTPD ≥3% and 79 (55%) of these had at least one significant stenosis. In an adjusted analysis rTPD (OR10% increase = 2.12 (1.44-3.12), P<0.001), previous coronary artery bypass grafting (CABG) (OR = 0.11 (0.03-0.36), P<0.001) and reduced left ventricular ejection fraction (LVEF) (OR = 0.25 (0.08-0.84), P=0.02) were independently associated with significant stenosis, whereas the association with aTPD (OR10% increase = 1.14 (0.98-1.32), P=0.08) was modest. ConclusionsIn the presence of an absolute perfusion deficit (aTPD ≥3%), rTPD may improve the prediction of significant stenosis in a heterogeneous population of patients examined with [15O]H2O PET. Furthermore, previous CABG and reduced LVEF are associated with non-stenotic perfusion deficiencies suggesting caution when interpreting myocardial perfusion imaging in such patients.