Ultrasonic flow ratio versus Murray law-based quantitative flow ratio for predicting target vessel failure after IVUS-guided PCI

Residual ischemia after percutaneous coronary intervention (PCI) is closely associated with adverse clinical outcomes. Murray law-based quantitative flow ratio (μQFR), derived from coronary angiography, has demonstrated prognostic value after PCI. Ultrasonic flow ratio (UFR), derived from intravascular ultrasound (IVUS), integrates intravascular imaging with computational physiological assessment; however, its prognostic performance relative to μQFR in patients undergoing IVUS-guided PCI remains insufficiently defined. This retrospective single-center study included 127 patients who underwent IVUS-guided PCI at the Sandun Campus of Zhejiang Hospital between January 2021 and December 2022 and completed follow-up coronary angiography during the follow-up period. UFR and μQFR were measured at the distal exit of the most distal stent. The primary endpoint was target vessel failure (TVF). Receiver operating characteristic curve analysis and Cox proportional hazards regression were performed. Among the 127 included patients, 19 developed TVF and 108 remained free of TVF. Compared with the non-TVF group, the TVF group had significantly lower minimum stent expansion rate, mean stent expansion rate, and post-PCI UFR. UFR showed the highest discriminatory ability for TVF and significantly outperformed μQFR. In multivariable analysis, only post-PCI UFR remained independently associated with TVF. These findings suggest that IVUS-derived anatomical-functional assessment may provide additional value for post-PCI risk stratification.