Multicenter Registry for Angiography-Derived Quantitative Flow Ratio

Multicenter Registry for Diagnostic Accuracy of Angiography-Derived Quantitative Flow Ratio to Evaluate the Hemodynamic Significance of Coronary Artery Stenosis

1. to investigate the feasibility and diagnostic performance of contrast quantitative flow ratio (QFR) for identifying the functional significance of intermediate degree stenotic lesions in all-comer patients with coronary artery disease (CAD) including presentation of acute myocardial infarction (AMI) with non-culprit lesion.
2. to compare the changes of contrast QFR and fractional flow reserve (FFR) according to severity of percent diameter stenosis (%DS)
3. to evaluate prognostic implication of contrast QFR in comparison with FFR

Despite potential clinical benefits and abundant evidences of FFR-guided percutaneous coronary intervention (PCI), adoption rate of FFR is still low in real world practice, most likely due to use of additional resource and to concern about side effects of hyperemic agent. Therefore, several tools to derive FFR non-invasively has been developed based on computational fluid dynamics to overcome the limitations. One of the novel methods, the contrast quantitative flow ratio (QFR) is a computation of FFR based on 3-dimensional quantitative coronary angiography (QCA) combined with Thrombolysis in Myocardial Infarction (TIMI) frame counts adjustment without hyperemic agent infusion.

Although diagnostic performance of contrast QFR for evaluation of functional significance, using FFR as reference standard, is well validated in patients with stable ischemic heart disease (SIHD), there have been lack of evidence regarding the reliability of QFR for non-culprit stenosis in patients with AMI.

Therefore, the investigators sought to investigate the feasibility and diagnostic performance of contrast QFR for identifying the functional significance of coronary stenosis in all-comer patients with CAD. In addition, prognostic implication of contrast QFR will be also compared with that of FFR.

Inclusion Criteria:

• Subject must be ≥18 years
• Patients suspected with ischemic heart disease
• Patients with intermediate degree of coronary artery stenosis (40-70% stenosis by visual estimation) in major epicardial coronary artery with FFR measurement
• Patients who were able to analyze QFR
• Subject is able to verbally confirm understandings of risks, benefits and treatment alternatives of receiving invasive physiologic evaluation and he/she or his/her legally authorized representative provides

Exclusion Criteria:

• Left main (LM) or right coronary artery (RCA) ostial lesion
• Severe overlap of stenotic segments
• Severe tortuosity of target vessel
• Poor angiographic image quality precluding contour detection
• No optimal images with angles ≥ 25o