Quantitative flow ratio functional Syntax Score in predicting severity of angina

Background/Introduction Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) score takes into consideration only the anatomy of the coronary network, while the Functional Syntax Score based on Quantitative Flow Ratio (FSSQFR) combines all the information derived from both anatomy and physiology of coronary arteries. Purpose We sought to investigate the predictive value of FSSQFR regarding the severity of angina in patients undergoing coronary angiography Methods Consecutive patients who underwent coronary angiography from our single center included in this study. Offline QFR analysis estimated for each patient. FSSQFR counted by summing the individual scores only in ischemia-producing lesions (vessel QFR ≤0.8). Patients were divided into low-, intermediate- and high-risk according to SS and FSS with the same cutoff. The endpoint was the impact of FSSQFR classification for clinical adverse events and the severity of angina stratified by CCS angina score. Results 410 patients included in this study. Mean age was 65.7 (±10.9) and 83% of patients were male. 26.6% of patients were high- risk, 36.6% were intermediate-risk, and 36.8% were low-risk regarding as SS. After calculating FSSQFR, risk stratification changed in 10% of the study population, specifically 21.2%, 36.6%, and 42.2% of patients were classified as high-, intermediate- and low-risk correspondingly. During a median 30-month follow-up period, 37 patients died. Of the remaining population (N = 373) 82.6% presented without angina or CCS grade I, while 14.7 and 2.7% suffered from angina CCS grade II and III, correspondingly. No patient reported angina CCS grade IV. Patients classified as high-risk FSSQFR group presented more often with moderate to severe angina (CSS II or III) independently of the treatment strategy compared to low-risk FSSQFR group (adjusted OR: 6.99 95% CI 2.94–16.63, p < 0.001). Patients complaining of angina CCS grade III had mean FSSQFR = 24.9, while patients with angina CCS grade II or I had lower mean FSSQFR values of 18.6 and 13.0, respectively. Patients without angina symptoms had the lowest mean FSSQFR. Figure shows that the higher the value of baseline FSSQFR, the more severe the angina at follow-up (p < 0.0001). Conclusion In our study, patients stratified in the high-risk FSSQFR group presented eight-fold more often with severe angina (CSS II or III) independently of the treatment strategy compared to the low-risk FSSQFR group.