Comparison of FFR, iFR, and QFR assessment in patients with severe aortic stenosis and coronary heart disease

Introduction
Some patients with coronary heart disease are diagnosed with severe aortic stenosis. For further treatment, coronary angiography is performed in these patients. For intermediate lesions, obtaining coronary artery physiological data can facilitate clinical decision-making regarding revascularization. Aim: The study compared the physiological significance of coronary artery stenosis using the fractional flow reserve (FFR) method with instantaneous wave-free pressure ratio (iFR) and quantitative flow ratio (QFR) in patients qualified for aortic valve replacement.

Material and methods
Data were collected on patients hospitalized in the years 2019–2020 at the 2nd Department of Cardiology, University Hospital in Krakow.

Results
Twelve patients with severe aortic stenosis and borderline lesions in the coronary artery were qualified for physiological assessment. There were 6 women, whose mean age was 73.8 ±7.5 years. The mean left ventricular ejection fraction was 52 ±15%. The mean aortic valve area was 0.80 ±0.16 cm2. The left anterior descending artery was assessed in 12 from 13 cases (92%). In comparison to FFR, all iFR measurements were concordant with FFR. The total agreement between QFR and FFR/iFR assessment was 69%.

Conclusions
Despite the controversy and uncertainty of some operators regarding the interpretation of the FFR test in patients with severe aortic stenosis, we obtained complete agreement of FFR with iFR assessment. This fact suggests that in patients with severe aortic stenosis the choice of an invasive method to assess the physiological significance of the stenosis in the coronary artery is not crucial – both iFR and FFR allow comparable results.