Residual ischemia after percutaneous coronary intervention (PCI) may help identify acute coronary syndrome (ACS) patients at higher long-term risk. A post hoc analysis from the FAVOR III China trial, published in the Journal of the American College of Cardiology, evaluated the prognostic utility of residual global Murray law–based quantitative flow ratio (μQFR).

The analysis included patients with ST-segment elevation myocardial infarction, non–ST-segment elevation myocardial infarction, and unstable angina. Residual global μQFR combined post-PCI values from treated vessels with baseline values from vessels not undergoing intervention. Patients were categorized using a cutoff of 2.71.

Among 2,428 ACS patients, 2,241 (92.3%) had analyzable μQFR data. High-risk patients (≤2.71; n=407) had higher 3-year major adverse cardiac events (MACE) than low-risk patients (21.2% vs 10.4%; adjusted hazard ratio [aHR] 1.53; 95% confidence interval [CI] 1.10-2.13; P=0.01). Excluding periprocedural myocardial infarction, rates remained higher (16.2% vs 7.8%; aHR 1.72; P=0.006).

Associations were consistent across QFR-guided and angiography-guided PCI subgroups. Among patients with low residual ischemia, QFR-guided PCI showed lower MACE rates than angiography guidance (8.8% vs 11.9%; hazard ratio 0.73; 95% CI 0.55-0.97). 

Residual global μQFR identified post-PCI ischemic burden and long-term risk, while QFR-guided PCI with low residual ischemia showed the best 3-year outcomes.