Comparison of Stress-rest and Stress-LGE analysis strategy in patients undergoing stress perfusion cardiovascular magnetic resonance

ABSTRACTBACKGROUNDStress perfusion cardiovascular magnetic resonance (CMR) is increasingly used without rest perfusion for the quantification of ischemia burden. However, the optimal method of analysis is uncertain.METHODSWe identified 666 patients from Clinical Evaluation of MAgnetic Resonance imaging in Coronary heart disease (CE-MARC) with complete stress perfusion, rest perfusion, late gadolinium enhancement (LGE) and quantitative coronary angiography (QCA) data. For each segment of the 16-segment model, perfusion was visually graded during stress and rest imaging, with infarct transmurality assessed from LGE imaging. In the “Stress-LGE” analysis a segment was defined as ischemic if it had a subendocardial perfusion defect with no infarction. Rest perfusion was not used in this analysis. We compared the diagnostic accuracy of “Stress-LGE” analysis against QCA and the “Stress-rest” method validated in the original CE-MARC analysis. The diagnostic accuracy of the “Stress-LGE” method was evaluated with different thresholds of infarct transmurality, used to define whether an infarcted segment had peri-infarct ischemia.RESULTSThe optimal “Stress-LGE” analysis classified all segments with a stress perfusion defect as ischemic unless they had >75% infarct transmurality (AUC 0.843, sensitivity 75.6%, specificity 93.1%, P<0.001). This analysis method has superior diagnostic accuracy to the “Stress-rest” method (AUC 0.834, sensitivity 73.6%, specificity 93.1%, P<0.001, P-value for difference=0.02). Patients were followed up for median 6.5 years for major adverse cardiovascular events (MACE), with the presence of inducible ischemia by either the “Stress-LGE (>75%)” or “Stress-rest” analysis being similar and strongly predictive (Hazard Ratio 2.65, P<0.0001, for both).CONCLUSIONSThe optimum definition of inducible ischemia was the presence of a stress-induced perfusion defect without transmural infarction. This definition improved the diagnostic accuracy compared to the “Stress-rest” analysis validated in CE-MARC without the need for rest perfusion imaging. The absence of ischemia by either analysis strategy conferred a favorable long-term prognosis.CLINICAL PERSPECTIVEWhat is new?Functional ischemia testing, specifically with stress perfusion cardiovascular magnetic resonance (CMR), is an established step in the evaluation of patients with chest pain. This study demonstrates that the rest perfusion imaging can safely be removed from the acquisition and analysis, without compromising imaging diagnostic and prognostic accuracy. For the highest diagnostic accuracy, all segments with stress-induced subendocardial hypoperfusion without transmural infarction should be considered ischemic.What are the clinical implications?Removal of rest imaging from the stress perfusion CMR examination reduces study duration which could potentially reduce costs, increase throughput, and build capacity to increase access to CMR.