INTRODUCTION: The concomitant presence of myocardial necrosis with myocardial ischemia, stunning and hibernation may complicate appraisal of left ventricular (LV) function and patient management. Several imaging modalities have been proposed for the accurate assessment of myocardial necrosis, viability, stunning and hibernation, with mixed results. We aimed to review the evidence base on myocardial necrosis, stunning and hibernation by conducting an umbrella review (i.e. overview of systematic reviews).
EVIDENCE ACQUISITION: We searched PubMed and The Cochrane Library for meta-analyses focusing on the diagnostic, prognostic, or management appraisal of myocardial necrosis, viability, stunning and hibernation. Diagnostic test accuracy, prognostic yield, and clinical outcomes were systematically abstracted from shortlisted reviews.
EVIDENCE SYNTHESIS: From an initial set of 6069 citations, 12 systematic reviews were finally included, encompassing 286 studies and 201,680 patients. Cardiac magnetic resonance imaging (CMR) had favorable results in 4 reviews that focused on the diagnosis of myocardial stunning or hibernation in patients followed-up for 6±4 months after coronary revascularization (sensitivity 96% and specificity 91%). Positron emission tomography (PET), single photon emission tomography (SPECT) and CMR in 6 meta-analyses had each a significant and independent prognostic role for the prediction of fatal and non-fatal cardiovascular events in patients with follow-up of 2.8±1.7 years. Finally, 2 reviews with 2.3±1.1 years of follow-up showed moderate quality evidence in favor of coronary revascularization in patients with objective signs of myocardial viability.
CONCLUSIONS: The appraisal of myocardial necrosis and residual viability remains a cornerstone of the modern management of patients with CAD. Current imaging modalities, (echocardiography, PET, SPECT and CMR) are widely used. Further trials using contemporary methods are warranted to further clarify the impact of viability assessment on patient management, and the cumulative risk of morbidity and mortality.