Aims: We sought to assess the reliability of the most frequently used intracoronary physiologic indices (including intravenous adenosine FFR [IV-FFR], intracoronary low-dose adenosine FFR [LD-IC-FFR], intracoronary high-dose adenosine FFR [HD-IC-FFR], Pd/Pa and iFR). We also sought to analyse factors affecting their reproducibility in a real-world patient population.
Methods and results: A total of 91 lesions in 86 consecutive patients were included. Measurements of all physiological indices were repeated within a systematic standardised prospective protocol. All measured indices showed excellent test-retest reliability, with intraclass correlation coefficient (ICC) over 0.96. IV-FFR showed the highest coefficient of variation (CV) values among the studied measurements (Pd/Pa: 0.05; iFR: 0.10; LD-IC-FFR: 0.10; HD-IC-FFR: 0.08; IV-FFR: 0.12). Pd/Pa was significantly less variable than the other indices. On multivariate analysis, female gender, distal lesion location, history of hypertension or kidney failure, as well as presentation as an acute coronary syndrome, were associated with more variability in all physiological intracoronary measurements.
Conclusions: The reliability of most frequently used intracoronary physiologic indices is high. Clinical and anatomic factors significantly influence the reliability of these physiologic indices.