Performance of quantitative flow ratio in patients with aortic stenosis undergoing transcatheter aortic valve implantation

Objectives: This study aims to evaluate the diagnostic performance of quantitative flow ratio (QFR) pre transcatheter aortic valve implantation (TAVI) in patients with aortic valve stenosis (AS) and coronary artery disease (CAD). Post-TAVI fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) was used as reference.

Background: CAD is prevalent in patients with AS, but the hemodynamics of AS confounds evaluation using pressure wire-based assessments. QFR might be less sensitive to the presence of AS thereby allowing for CAD evaluation before aortic valve replacement. Further, QFR does not require the use of pressure wire and therefore has the potential for reducing costs and complications related to insertion of a coronary pressure wire.

Methods: The diagnostic performance of QFR in coronary angiograms from 28 patients undergoing TAVI was evaluated. In all patients, both FFR and iFR were measured pre- and immediately post-TAVI while QFR was measured pre-TAVI.

Results: Using post-TAVI FFR and iFR as reference the diagnostic accuracy of pre-TAVI QFR were 83% (95%CI; 68-97) and 52% (95%CI; 30-74) p = .008, respectively.

Conclusions: Pre-TAVI QFR showed a good diagnostic performance using post-TAVI FFR as reference. QFR could become a wire-free, safe, and quick way of evaluating CAD in patients with severe AS undergoing TAVI.