Numerical comparison between reliability of instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in diagnosis severity of stenosis in coronary arteries

Due to increased atherosclerosis-caused mortality, timely and accurate diagnosis of cardiovascular disease is required.Fractional flow reserve (FFR) is the current gold standard diagnostic measure for clinically assessing the severity of moderate stenosis. However, to measure this parameter, a drug should be injected for producing hyperemic condition which has several side effects for the patients. Recently, an alternative diagnostic adenosine-free index called instantaneous wave-free ratio (iFR) is introduced as a novel and less risky method to assess the ischemic of coronary artery disease. However, there are doubts about the reliability of results of iFR in accurate diagnosis the coronary disease than FFR. In addition, clinical procedures for measuring both FFR and iFR are invasively and costly. In this paper, FFR and iFR for three patient specific geometries of Tehran Heart Center (THC) are calculated byusing computational fluid dynamic (CFD) as a non-invasive and cost reducing method. Also, the reliability of iFR than FFR is investigated numerically for the mentioned patients. Results indicate a discordance between calculated FFR and sensitivity of iFR to coronary hyperemia is interrogated. The result of this survey show that iFR is not completely independent of coronary hyperemia. Due to theseuncertainties of iFR results, a hybrid method including iFR and FFR tests is recommended to use which has minimumrisk and cost factor and maximum accuracy among all clinical approaches.

Keywords:

Heart disease , Coronary artery , Fractional flow reserve (FFR) , Instantaneous wave-free ratio (iFR)