Impact of height difference between coronary ostium and location of intracoronary pressure sensor on fractional flow reserve measurements

Abstract

Abstract Background Fractional flow reserve (FFR) is the most verified index to date in invasively evaluating lesion-specific myocardial ischemia. During FFR measurements, distal coronary pressure (Pd) can be influenced by hydrostatic pressure change resulted from the height difference (HD) between coronary ostium and location of distal pressure sensor. We aimed to investigate the impact of aorto-coronary HD on FFR measurement in each coronary artery. Methods We retrospectively analyzed 257 patients who underwent FFR measurement and coronary computed tomography angiography (CCTA) within a year. HD was measured by CCTA as the vertical distance between coronary ostium and a matched point of distal coronary pressure sensor identified on coronary angiography. Results The location of Pd sensor was higher in left anterior descending artery (LAD) (-4.47±1.33cm), whereas lower in left circumflex artery (LCX) (2.54±1.05cm) and right coronary artery (RCA) (2.05±1.25cm) than the coronary ostium. Compared with the original FFR values, corrected FFR by HD was higher in LAD (0.79±0.09, 0.82±0.09, P<0.05) and tended to be lower in LCX and RCA (0.87±0.07, 0.85±0.08, p=0.21; 0.87±0.10, 0.86±0.10, p=0.49, respectively). Based on FFR cut-off value of 0.8, the concordance rate between the FFR and corrected FFR was 77.8%, 92.5%, and 100% in LAD, LCX, and RCA, respectively. Conclusion During FFR measurements, HD between coronary ostium and distal pressure sensor may affect interpretation of disease severity and FFR-guided treatment decision of coronary artery disease.