Quantitative flow ratio for immediate assessment of nonculprit lesions in patients with ST‐segment elevation myocardial infarction—An iSTEMI substudy

Abstract

Objectives We evaluated the diagnostic performance of quantitative flow ratio (QFR) assessment of nonculprit lesions (NCLs) based on acute setting angiograms obtained in patients with ST‐segment elevation myocardial infarction (STEMI) with QFR, fractional flow reserve (FFR), and instantaneous wave‐free ratio (iFR) in the staged setting as reference. Background QFR is an angiography‐based approach for the functional evaluation of coronary artery lesions. Methods This was a post‐hoc analysis of the iSTEMI study. NCLs were assessed with iFR in the acute setting and with iFR and FFR at staged (median 13 days) follow‐up. Acute and staged QFR values were computed in a core laboratory based on the coronary angiography recordings. Diagnostic cut‐off values were ≤0.80 for QFR and FFR, and ≤0.89 for iFR. Results Staged iFR and FFR data were available for 146 NCLs in 112 patients in the iSTEMI study. Among these, QFR analysis was feasible in 103 (71%) lesions assessed in the acute setting with a mean QFR value of 0.82 (IQR: 0.73–0.91). Staged QFR, FFR, and iFR were 0.80 (IQR: 0.70–0.90), 0.81 (IQR: 0.71–0.88), and 0.91 (IQR: 0.87–0.96), respectively. Classification agreement of acute and staged QFR was 93% (95%Cl: 87–99). The classification agreement of acute QFR was 84% (95%CI: 76–90) using staged FFR as reference and 74% (95%CI: 65–83) using staged iFR as reference. Conclusions Acute QFR showed a very good diagnostic performance with staged QFR as reference, a good diagnostic performance with staged FFR as reference, and a moderate diagnostic performance with staged iFR as reference.

Contrast medium Pd/Pa ratio in comparison to fractional flow reserve, quantitative flow ratio and instantaneous wave-free ratio for evaluation of intermediate coronary lesions

“…In a study by Sejr-Hansen et al, the authors compared online and offline QFR in patients presenting with acute coronary syndromes, yielding similar results and good diagnostic performance with staged FFR as a reference, and a moderate diagnostic performance with staged iFR [27]. In our study, surprisingly, cFFR correlated well with QFR, even more strongly than with iFR, even though QFR and iFR are both non-hyperemic methods.…”

Quantitative flow ratio—Meta‐analysis and systematic review

“…In staged procedure lesions appear less severe; a cut‐off point of 0.82 in index procedure has been proposed to avoid staged procedure with a NPV of 87%. The largest series evaluating the efficacy of QFR in nonculprit lesions is a substudy of iSTEMI trial 34 . A total of 112 patients (142 lesions) with multivessel diseases were retrospectively evaluated by QFR.…”

Comparison of quantitative flow ratio and fractional flow reserve with myocardial perfusion scintigraphy and cardiovascular magnetic resonance as reference standard. A Dan-NICAD substudy

“…QFR does not require induction of hyperemia or the use of pressure wires and can be computed within the time of conventional FFR measurement [5][6][7]. QFR approaches FFR with an overall good diagnostic accuracy (ranging from 80 to 95%) [5,6,[8][9][10][11] and recent studies reported a good agreement between QFR and myocardial perfusion scintigraphy, MPS [1,5,12].…”