iFR diagnostic accuracy using FFR as gold standard : insights from a 5-year experience

Abstract

Background: Functional coronary lesion assessment by fractional flow reserve (FFR) is commonly employed worldwide. Recently, several studies have focused on a new parameter, the instantaneous wave free ratio (iFR), as an alternative or complementary method to FFR which does not require the use of adenosine. The use of iFR, however, is not consensual: its ideal cut-off and interpretation are still not completely established.

Purpose: We aimed to analyse the diagnostic accuracy of iFR using FFR as gold standard.

Methods: Retrospective analysis of all patients undergoing functional coronary lesion assessment during 5 years. FFR was used as a gold standard for assessing the diagnostic accuracy of iFR in every patient who underwent measurements with both techniques. The decision was made on an individual patient basis according to the operator's decision. For statistical analysis we used Receiver Operating Characteristics (ROC) curve. The test was undertaken for 2 FFR cut-offs: ≤0,80 and <0,75.

Results: Functional testing was undertaken in 326 patients (67±11 years, 65,6% male), encompassing 402 lesions. 154 lesions underwent assessment with both techniques, 222 by FFR only and 26 cases iFR only.