Novel application of quantitative flow ratio for predicting microvascular dysfunction after ST-segment-elevation myocardial infarction

OBJECTIVES This study evaluated quantitative flow ratio (QFR) to predict microvascular dysfunction (MVD) in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND QFR is a novel approach for the rapid computation of fractional flow reserve based on three-dimensional quantitative coronary angiography. We hypothesized that QFR computation could be used to predict MVD after STEMI. METHODS Indexes such as contrast-flow QFR (cQFR), fixed-flow QFR (fQFR), and hyperemic flow velocity (HFV) were calculated in 130 STEMI patients with culprit lesion with ≥50% diameter stenosis and TIMI flow grade 2/3 in the spontaneously recanalized culprit artery on initial angiography. MVD was defined as microvascular obstruction determined by contrast-enhanced cardiac magnetic resonance at a median of 5 days after percutaneous coronary intervention. RESULTS Patients were divided into the MVD group (76/130, 58.5%) and non-MVD group (54/130, 41.5%). Patients with MVD had higher cQFR-fQFR value (0.080 ± 0.058 vs. 0.038 ± 0.039, p