Reproducibility of instantaneous wave-free ratio and angiography coregistration in patients with coronary heart disease and diffuse and multilevel coronary artery lesion

Aim. To determine the reproducibility of the results of instantaneous wavefree ratio (iFR) and angiography coregistration in patients with coronary heart disease (CAD) with multilevel and diffuse lesions of the coronary arteries.Materials and methods. The study included 34 patients with chronic ischemic heart disease (CAD) with diffuse and/or multilevel coronary stenoses >50%. In 41 coronary arteries, two consecutive iFR pullback of the conductor were performed and paired iFR angio-coregistrations were formed, reflecting changes in iFR gradients (Δ iFR) along the entire length of the studied artery. To compare the results of paired studies, the following values were used: 1) indices of distal iFR; 2) maximum Δ iFR; 3) Δ iFR of all stenoses ˃50%.Results. Comparable values of distal iFR were obtained 0,84 [0,78; 0,89] vs. 0,85 [0,77; 0,88]) with an average difference of the first and second measurements of 0,001, maximum ΔiFR (0,08 [0,05; 0,14] vs. 0,08 [0,05; 0,13]) with a mean difference of -0,004 and ΔiFR of all stenoses >50% (0,05 [0,02; 0,11] vs. 0,05 [ 0,02; 0,10]) with an average difference of -0.001. Lin’s concordance correlation coefficient and Intraclass Correlation Coefficients calculated for the three parameters studied showed a good level of agreement (0,97; 0,98; 0,98) with excellent reliability (0,97; 0,98; 0,97).Conclusion. In patients with multilevel and diffuse lesions of the coronary artery, iFR angio-coregistration has a fairly high reproducibility.