Quantitative flow ratio-Meta-analysis and systematic review

Despite of the wide evidence of use fractional flow reserve (FFR), isolated angiography evaluation is still the main tool to indicate percutaneous coronary intervention. Quantitative flow ratio (QFR) is a new functional index to assess functional significance. Recently, few studies have showed the capacity of QFR to predict significance stenosis. The aim of this research has been to describe the evidence of QFR in this clinical setting, to analyze the global diagnosis accuracy of QFR versus FFR and to compare the difference in feasibility between retrospective and prospective analysis.

Systematic review of literature was performed. Eligible studies for the meta-analysis were considered those directly evaluating de QFR versus FFR. Pooled values of diagnosis test and summary receiver operator curve were calculated. Main causes of not-perform QFR analysis according to study design were also evaluated. Sixteen studies were included. Good correlation and agreement were showed. Global sensibility, specificity, PPV, and NPV were 0.84, 0.89, 0.80, and 0.92, respectively. Then, 18% of evaluated vessels could not be analyzed. Significant differences were found in the percentage of discarded vessels and the cause of nonperformed analysis between retrospective or prospective analysis.

Excellent correlation and agreement between QFR and FFR was demonstrated. QFR assessment could be improved by its prospective analysis with a dedicated protocol.