Quantitative flow ratio in predicting residual angina: is it better than the eye?

Abstract Background/Introduction Percutaneous coronary intervention (PCI) guided by functional coronary stenosis severity has been associated with fewer clinical adverse events compared to plain coronary angiography. Quantitative flow ratio (QFR) has proven to be a reliable tool for the functional assessment of coronary lesions. Purpose To investigate the predictive role of disagreement between plain coronary angiography and QFR in PCI guiding regarding symptom relief. Methods We performed an offline QFR analysis in all vessels of consecutive patients who underwent coronary angiography and prospectively followed up the patients for a median follow-up period of 30.5 (26.4-33.7) months. Patients were divided into two groups according to the concordance or discordance of the two methods. Patients with at least one vessel with QFR value ≥ 0.80 treated with PCI and/or at least one vessel with QFR value 0.80 not treated with PCI were included in the discordance group. The remaining patients formed the concordance group. Endpoint was the presence of angina stratified by the Canadian Cardiovascular Society (CCS) angina score at follow-up the composite outcome of cardiovascular death, myocardial infraction and ischemia-driven revascularization. Results Overall, we included 549 patients in the study. Concordance between plain coronary angiography and QFR was present in 404 (73.6%) patients, while discordance between the two methods was found in 145 patients (26.4%). Baseline patient characteristics are displayed in Figure 1. Patients in the discordance group were older, with more extended coronary artery disease and higher SYNTAX score. More patients in the discordance group reported severe angina (CCS 3-4) compared to the concordance group (22.1% vs 14.4% p=0.036). Furthermore, discordance between the two methods was an independent risk factor for major clinical adverse events (6.9% vs 23.4% OR: 2.975 95%CI 1.782-4.967, p0.001). Conclusion In our study, discordance between plain coronary angiography and QFR in revascularization guidance was associated with a higher rate of severe angina and clinical adverse events, suggesting proper functional selection of patients to undergo PCI is crucial for both symptom relief and improved clinical outcomes.