Prevalence of pathological FFR${}_{CT}$ values without coronary artery stenosis in an asymptomatic marathon runner cohort

To evaluate computed tomography fractional flow reserve (FFR${}_{CT}$) values in distal parts of the coronaries in an asymptomatic cohort of marathon runners without any coronary stenosis for potentially false-positive values. Ninety-eight asymptomatic male marathon runners (age 53 $\pm$ 7 years) were enrolled in a prospective monocentric study and underwent coronary computed tomography angiography (CCTA). CCTA data were analyzed for visual coronary artery stenosis. FFR${}_{CT}$ was evaluated in 59 participants without coronary artery stenosis in proximal, mid, and distal coronary sections using an on-site software prototype. In participants without coronary artery stenosis, abnormal FFR${}_{CT}$ values $\le$0.8 in distal segments were found in 22 participants (37%); in 19 participants in the LAD; in 5 participants in the LCX; and in 4 participants in the RCA. Vessel diameters in participants with FFR${}_{CT}$ values > 0.80 compared to $\le$0.80 were 1.6 $\pm$ 0.3 mm versus 1.5 $\pm$ 0.3 mm for distal LAD (p = 0.025), 1.8 $\pm$ 0.3 mm versus 1.6 $\pm$ 0.5 mm for distal LCX (p = 0.183), and 2.0 $\pm$ 0.4 mm versus 1.5 $\pm$ 0.2 mm for distal RCA (p < 0.001). Abnormal FFR${}_{CT}$ values of $\le$0.8 frequently occurred in distal coronary segments in subjects without any anatomical coronary artery stenosis. This effect is only to some degree explainable by small distal vessel diameters. Therefore, the validity of hemodynamic relevance evaluation using FFR${}_{CT}$ in distal coronary artery segment stenosis is reduced.