Prognostic Impact of Quantitative Flow Ratio-Derived Physiology for Intermediate Non-Infarct-Related Artery in Acute Myocardial Infarction.

BACKGROUND

The optimal treatment for functionally insignificant intermediate stenosis in non-infarct-related artery (IRA) after acute myocardial infarction (AMI) remains controversial. We identified high-risk non-IRAs using quantitative flow ratio (QFR)-derived physiological indices and evaluated their prognostic and therapeutic implications.

METHODS AND

RESULTS

We retrospectively assessed QFR-derived physiology in 240 non-IRAs (189 deferred [Defer group], 51 treated [percutaneous coronary intervention (PCI) group]) with diameter stenosis ≥40% and QFR ≥0.8 in 205 AMI patients treated between January 2014 and December 2023. In the Defer group, physiological indices associated with target vessel failure (TVF) were identified, and their discriminative performance and optimal cut-off values were determined using time-dependent receiver operating characteristic curve analysis with the Youden index. Adding QFR pressure pullback gradient (PPG) to QFR significantly enhanced time-dependent risk reclassification, as reflected by net reclassification improvement (P=0.039) and integrated discrimination improvement (P=0.023). After stratification using Youden-derived 3-year optimal cut-off values of 0.88 for QFR and 0.78 for QFR-PPG, deferred non-IRAs with high-risk physiology (QFR <0.88 and QFR-PPG <0.78) had a significantly higher 3-year TVF rate than those without high-risk physiology (42.1% vs. 9.9%; P<0.001). Among high-risk non-IRAs, the TVF rate was significantly higher in the Defer than PCI group, whereas it was similar among non-IRAs without high-risk physiology (P for interaction=0.040).

CONCLUSIONS

QFR-derived physiology, including QFR and QFR-PPG, can stratify high-risk non-IRAs and guide optimal treatment in patients with AMI.