Echocardiography. 2019;1–10. wileyonlinelibrary.com/journal/echo | 1 © 2019 Wiley Periodicals, Inc. Received: 30 January 2019 | Revised: 6 March 2019 | Accepted: 21 March 2019 DOI: 10.1111/echo.14337 ORIGINAL INVESTIGATION Coronary flow reserve is related to the extension and transmurality of myocardial necrosis and predicts functional recovery after acute myocardial infarction Roberta Montisci MD 1 | Massimo Ruscazio MD 1 | Francesco Tona MD, PhD 2 | Francesco Corbetti MD 3 | Cristiano Sarais MD 2 | Maria Francesca Marchetti MD 1 | Luisa Cacciavillani MD 2 | Sabino Iliceto MD 2 | Martina Perazzolo Marra MD, FACC, FESC 2 | Luigi Meloni MD 1 1 Clinical Cardiology, Department of Medical Science and Public Health, University of Cagliari, Cagliari, Italy 2 Clinical Cardiology, Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy 3 Euganea Medica, Padova, Italy Correspondence Roberta Montisci, Clinical Cardiology, Department of Medical Science and Public Health, University of Cagliari, Cagliari, Italy. Email: rmontisc@gmail.com Abstract Background: Few studies have examined the effect of transmurality of myocardial necrosis on coronary microcirculation. The aim of this study was to examine the influ- ence of cardiac magnetic resonance-derived (GE-MRI) structural determinants of coronary flow reserve (CFR) after anterior myocardial infarction (STEMI), and their predictive value on regional functional recovery. Methods: Noninvasive CFR and GE-MRI were studied in 37 anterior STEMI patients after primary coronary angioplasty. The wall motion score index in the left de- scending anterior coronary artery territory (A-WMSI) was calculated at admission and follow-up (FU). Recovery of regional left ventricular (LV) function was defined as the difference in A-WMSI at admission and FU. The necrosis score index (NSI) and transmurality score index (TSI) by GE-MRI were calculated in the risk area. Baseline (BMR) and hyperemic (HMR) microvascular resistance, arteriolar resist - ance index (ARI), and coronary resistance reserve (CRR) were calculated at the Doppler echocardiography. Results: Bivariate analysis indicated that the CPK and troponin I peak, heart rate, NSI, TSI, BMR, the ARI, and CRR were related to CFR. Multivariable analysis revealed that TSI was the only independent determinant of CFR. The CFR value of >2.27, identified as optimal by ROC analysis, was 77% specific and 73% sensitive with accuracy of 76% in identifying patients with functional recovery. Conclusions: Preservation of microvascular function after AMI is related to the ex- tent of transmurality of myocardial necrosis, is an important factor influencing re- gional LV recovery, and can be monitored by noninvasive CFR. KEYWORDS acute myocardial infarction, cardiac magnetic resonance imaging, coronary flow reserve, transthoracic echocardiography