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Coronary flow reserve can explain some of FFR and iFR discrepancies. Results from international, multicenter and prospective trial


 
 
 The trial collected prospective data from physiology measurements of borderline lesions in five Czech, one Japan and one Argentinian cathlabs. The main purposes were to analyze diagnostic agreement between FFR (fractional flow reserve) and iFR (instantaneous wave free ratio) examinations and to find possible explanations for discrepant results.
 
 
 
 FFR and iFR examinations were analyzed using Philips-Volcano console and coronary flow reserve (CFR) was analyzed by using Combomap machine Philips-Volcano. Hyperemia for FFR and CFR measurements was induced by intracoronary administration of adenosine. We used CFR as a truth for comparison between FFR and iFR, because CFR has higher impact on patients prognosis than pressures indices.
 
 
 
 Data were collected from February 2016 to June 2019 and the database includes 1.789 examinations from 1.492 patients (282 of them, 15.8%, with ACS). CFR were measured in 343 lesions in 293 patients. (ACS 31.2%). Overall correlation between FFR and iFR is high (R=0.86 p<0.0001). The FFR/iFR discrepancy occurred in 84 measurements (24.5%), more frequently it was FFRp (positive) / iFRn (negative) type of discrepancy (65, 18.9%) compare to FFRn/iFRp (19, 5.5%) one. There was no difference in occurrence of FFR/iFR discrepancy in stable patients and ACS ones (25.1%vs. 22.4%, p=0.59). The CFR correlated better with iFR than with FFR (R=0.56, p<0.0001 vs. R= 0.36, p<0.0001) (see table). In lesions with FFRp/iFRn type of discrepancy we found substantially higher CFR value compared to FFR/iFR agreement group (2.4±0.7 vs. 1.5±0.5, p<0.0001). Unlike to FFRn/iFRp discrepancy, where CFR value was similar with agreement group (1.4±0.1 vs. 1.5±0.1, p=0.25)
 
 
 
 The FFR/iFR discrepancy occurred in almost one quarter of examinations. Correlation between CFR and iFR is better than between CFR and FFR. High flow is probably one of the main reason for FFRp/iFRn type of discrepancy.
 
 
 
 Type of funding source: Public grant(s) – National budget only. Main funding source(s): Czech Health Research Council
