Predictive value of the QFR combined with early exercise tolerance testing for long-term prognosis after coronary intervention

To evaluate the predictive value of the quantitative flow ratio (QFR) combined with early exercise tolerance testing (CPET) for long-term prognosis after coronary intervention. Patients with unstable angina (UA) and 50–90% stenosis scheduled for elective PCI were randomly assigned to the QFR group (undergoing intervention if QFR < 0.80) or the conventional group (empirical PCI). Cardio-Pulmonary Exercise Test (CPET) was performed 1–3 weeks postoperatively to record the anaerobic threshold (AT), peak metabolic equivalent (MET), peak oxygen uptake (peakVO2), VE/VCO2 slope, oxygen uptake/work rate (VO2/WR), oxygen uptake/heart rate (VO2/HR), Weber cardiac function classification, and cardiac reserve function. One-year follow-up assessed MACE events (including cardiovascular death, non-fatal arrhythmia, ischemia-driven revascularization, and rehospitalization for unstable angina). The QFR group demonstrated superiority over the conventional group in key CPET parameters including AT, peak MET, peak VO2, and VO2/HR (p < 0.05). Ischemia-driven revascularization was significantly lower in the QFR group (8.6% vs 19.5%, p = 0.046), with significantly shorter stent lengths (20 mm vs 26 mm, p = 0.001) and higher postoperative QFR values (0.92 vs 0.90). Logistic regression analysis demonstrated that improved QFR values significantly reduced MACE risk. PeakVO2 was an independent protective factor for MACE (OR = 0.47, p = 0.017). ROC curve analysis revealed that the QFR curve had an area under the curve (AUC = 0.928), peakVO2 AUC = 0.948). Optimal cutoff values were set at QFR = 0.885 and peakVO2 = 16.8 mL kg−1 min−1. Patients were reclassified into four groups based on these cutoffs: dual-normal, single-abnormal, and dual-abnormal groups. Logistic regression analysis showed combined indicator p = 0.081 < 0.05, with combined indicator AUC 0.977 indicating good calibration (HL P = 0.624, Brier 0.049). Decision curve analysis demonstrated superiority over single-indicator models. QFR-guided PCI enables precise ischemia localization, reduces implantations, and enhances exercise tolerance. Combining QFR with peakVO2 accurately identifies high-risk patients, and intensive rehabilitation improves long-term outcomes.