Quantitative flow ratio-Meta-analysis and systematic review

Area of Science:

• Cardiovascular Medicine
• Interventional Cardiology
• Medical Imaging

Background:

• Fractional flow reserve (FFR) is the gold standard for assessing coronary artery stenosis significance, but its invasive nature limits widespread use.
• Quantitative flow ratio (QFR) offers a non-invasive, angiography-based alternative for functional assessment.
• Current evidence on QFR's diagnostic accuracy and feasibility compared to FFR needs comprehensive evaluation.

Purpose of the Study:

• To systematically review and meta-analyze the diagnostic accuracy of QFR against FFR.
• To compare the feasibility and potential biases between retrospective and prospective QFR analyses.
• To describe the current evidence base for QFR in guiding percutaneous coronary intervention.

Main Methods:

• Systematic literature review and meta-analysis of studies comparing QFR and FFR.
• Calculation of pooled diagnostic test values (sensitivity, specificity, PPV, NPV) and summary receiver operating characteristic (ROC) curves.
• Evaluation of factors affecting QFR analysis success rates, differentiating between retrospective and prospective study designs.

Main Results:

• Sixteen studies were included, demonstrating good correlation and agreement between QFR and FFR.
• Pooled diagnostic accuracy metrics for QFR were: sensitivity 0.84, specificity 0.89, positive predictive value (PPV) 0.80, and negative predictive value (NPV) 0.92.
• 18% of evaluated vessels could not be analyzed by QFR, with significant differences in non-analysis rates and causes between retrospective and prospective studies.

Conclusions:

• QFR exhibits excellent correlation and agreement with FFR for assessing coronary stenosis significance.
• Prospective analysis of QFR, guided by a dedicated protocol, enhances its feasibility and reliability.
• QFR represents a promising functional index for guiding percutaneous coronary intervention, potentially improving upon traditional angiography.