Murray law-based quantitative flow ratio for assessment of nonculprit lesions in patients with ST-segment elevation myocardial infarction.

Introduction: Revascularization of nonculprit arteries in patients with ST-Segment Elevation Myocardial Infarction (STEMI) is now recommended based on several trials. However, the optimal therapeutic strategy of nonculprit lesions remains unknown. Murray law-based Quantitative Flow Ratio (μQFR) is a novel, non-invasive, vasodilator-free method for evaluating the functional severity of coronary artery stenosis, which has potential applications for nonculprit lesion assessment in STEMI patients.

Material and methods: Patients with STEMI who received staged PCI before hospital discharge were enrolled retrospectively. μQFR analyses of nonculprit vessels were performed based on both acute and staged angiography.

Results: Eighty-four patients with 110 nonculprit arteries were included. The mean acute μQFR was 0.76 ± 0.18, and the mean staged μQFR was 0.75 ± 0.19. The average period between acute and staged evaluation was 8 days. There was a good correlation (r = 0.719, P < 0.001) between acute μQFR and staged μQFR. The classification agreement was 89.09%. The area under the receiver operator characteristic (ROC) curve for detecting staged μQFR ≤ 0.80 was 0.931.

Conclusions: It is feasible to calculate the μQFR during the acute phase of STEMI patients. Acute μQFR and staged μQFR have a good correlation and agreement. The μQFR could be a valuable method for assessing functional significance of nonculprit arteries in STEMI patients.