Clinical value of single projection angiography-derived FFR in non-infarct related artery

Abstract Background Murray law-based quantitative flow ratio (μFR) is an emerging technique which requires only one projection of coronary angiography with similar accuracy with quantitative flow ratio (QFR). However, it has not been validated for evaluation of non-infarct related artery (non-IRA) in acute myocardial infarction (AMI) setting. Therefore, our study aimed to evaluate the diagnostic accuracy of μFR and the safety of deferring non-IRA lesion with μFR>0.80 in the setting of AMI. Methods μFR and QFR were analyzed for non-IRA lesions of AMI patients enrolled in the FRAME-AMI trial, consisting of fractional flow ratio (FFR)-guided PCI and angiography-guided PCI groups. Diagnostic accuracy of μFR was compared to QFR and FFR. Patients were classified by non-IRA μFR values 0.80 as a cutoff value. The primary outcome was vessel-oriented composite outcomes (VOCO), a composite of cardiac death, non-IRA-related MI, and non-IRA-related repeat revascularization. Results 443 patients (552 lesions) were eligible for μFR and QFR analysis. μFR showed acceptable correlation with FFR (R=0.777, P<0.001), comparable C-index with QFR to predict FFR≤0.80 (μFR vs. QFR: 0.926 vs. 0.961, P=0.070), and shorter total analysis time (mean 32.7sec vs. 186.9sec, P<0.001). Non-IRA with μFR>0.80 and deferred PCI had significantly lower risk of VOCO than non-IRA with performed PCI (3.4% vs. 10.5%; HR, 0.37; 95% CI, 0.14-0.99; P=0.048). Conclusion In multivessel AMI patients, μFR of non-IRA showed acceptable diagnostic accuracy comparable to that of QFR to predict FFR≤0.80. Deferred non-IRA with μFR>0.80 showed lower risk of VOCO than revascularized non-IRA.