Diagnostic performance of intracoronary optical coherence tomography-based versus angiography-based fractional flow reserve for the evaluation of coronary lesions

Aims: The aim of this study was to evaluate the diagnostic performance of OCT-based optical flow ratio (OFR) in unselected patients and compare it with angiography-based quantitative flow ratio (QFR), using wire-based FFR as reference standard.

Methods and results: All patients with OCT and FFR assessment prior to revascularisation were analysed. OFR and QFR were computed in a blinded fashion and compared with FFR, applying the same cut-off value of ≤0.80 to all to define ischaemia. Paired comparison between OFR and QFR was performed in 212 vessels from 181 patients. Average FFR was 0.82±0.10 and 40.1% of vessels had an FFR ≤0.80. OFR showed a significantly better correlation and agreement with FFR than QFR (r=0.87 versus 0.77, p<0.001; SD of the difference=0.05 versus 0.07, p<0.001). The AUC was 0.97 for OFR, higher than for QFR (difference=0.05, p=0.017), and much higher than the minimal lumen area (difference=0.15, p<0.001) and diameter stenosis (difference=0.17, p<0.001). Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio for OFR to identify FFR ≤0.80 were 92%, 86%, 95%, 92%, 91%, 18.2 and 0.2, respectively. The diagnostic accuracy of OFR was not significantly different in MI-related vessels (95% versus 90%, p=0.456), or in vessels with and without previously implanted stents (90% versus 93%, p=0.669).

Conclusions: OFR had an excellent agreement with FFR in consecutive patients with coronary artery disease. OFR was superior to QFR, and much better than conventional morphological parameters in determining physiological significance of coronary stenosis. The diagnostic performance of OFR was not influenced by the presence of prior myocardial infarction or implanted stents.