The prognostic effect of QFR-based functionally complete versus incomplete revascularization: a systematic review and meta-analysis

Background The assessment of post-percutaneous coronary intervention revascularization completeness with anatomic parameters and physiological indices is a significant parameter towards quantifying post-procedural residual ischemia, as functionally incomplete revascularization could increase post-interventional adverse events. This assessment can be performed with the use of the residual functional SYNTAX Score (rFSS), which accounts for both anatomic- and physiology parameters. Recently, the use of the quantitative flow ratio (QFR), which is a non-invasive functional indice correlating well with invasive assessment, has been evaluated as the physiology parameter included in the rFSS. Purpose The aim of this systematic review and meta-analysis is to evaluate the prognostic significance of functionally complete and incomplete revascularization (FCR and FIR, respectively) in cardiovascular events after PCI, based on QFR-rFSS. Methods We performed a systematic search in 3 different databases (MEDLINE/PubMed, Web of Science and Scopus). After selecting all appropriate studies according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a random effect meta-analysis was performed. Results A total of 5 studies and 6,698 patients were included, with a mean follow-up of 24 months. Of the included patients, 5,228 had a FCR (rFSS=0), whereas 1,470 had an FIR. Patients with a FCR had a significantly lower risk for all-cause [Risk Ratio (RR): 0.38; 95% Confidence Interval (CI): 0.14-0.99] and cardiovascular morality (RR: 0.20; 95%CI: 0.08-0.50). Furthermore, patients with complete revascularization had significantly lower major adverse cardiovascular events (RR: 0.36; 95%CI: 0.26-0.49) as well as myocardial infarction (RR: 0.27; 95%CI: 0.21-0.36). Finally, in respect to revascularization events, patients in the FCR cohort also had significantly lower events of ischemia-driven revascularization (RR: 0.30; 95%CI: 0.20-0.46) and non-infarct lesion ischemia driven revascularization (RR: 0.22; 95%CI: 0.15-0.31). Conclusion This meta-analysis shows that, achieving a post-PCI complete revascularization based in both angiography and non-invasive physiology criteria, is associated with significantly lower mortality and cardiovascular events at 2 years follow-up. Therefore, QFR-rFSS could be a significant tool in post-PCI lesion evaluation, assisting PCI optimization.