Prognostic value of Murray law-based quantitative flow ratio after percutaneous coronary intervention.
Verbatim Formal Study Abstract
Post-percutaneous coronary intervention (PCI) physiological indices have prognostic relevance. Murray law-based quantitative flow ratio (μQFR) enables wire-free, rapid, single-view functional assessment, yet its long-term prognostic value after PCI remains incompletely established.
We sought to evaluate the prognostic value of post-PCI μQFR for long-term adverse outcomes.
This prespecified subgroup analysis of the FAVOR III China trial included 3,825 patients. All PCI-treated vessels with a reference diameter ≥2.5 mm and 50-90% diameter stenosis were analysed for offline post-PCI μQFR. The primary endpoint was 5-year major adverse cardiovascular events (MACE; including death from any cause, myocardial infarction, or ischaemia-driven revascularisation).
Post-PCI μQFR was successfully analysed in 4,196 vessels from 3,455 patients, with similar distributions between the randomised treatment groups. At 5 years, a low post-PCI μQFR was associated with a higher incidence of MACE compared with the intermediate and high post-PCI μQFR tertiles (23.1% vs 19.0% vs 17.2%; p=0.001). Using the highest tertile (μQFR>0.95) as a reference, adjusted hazard ratios (aHR) were 1.08 (95% confidence interval [CI]: 0.87-1.34) for the intermediate tertile (0.92-0.95) and 1.30 (95% CI: 1.06-1.60) for the lowest tertile (μQFR ≤0.91). Using a receiver operating characteristic-derived cutoff, MACE occurred more frequently in patients with post-PCI μQFR <0.94 (22.3% vs 17.4%, aHR 1.23, 95% CI: 1.04-1.47; p=0.02) than in those with post-PCI μQFR ≥0.94. No significant interaction was observed between treatment strategy and post-PCI μQFR (p for interaction=0.23).
Post-PCI μQFR distributions were similar between treatment groups, but lower values were associated with higher 5-year adverse event risk without significant treatment interaction. Its limited binary discrimination supports use as a continuous metric for post-PCI physiological risk stratification. (ClinicalTrials.gov: NCT03656848).