Predictive value of coronary lesion functional assessment using an OCT computational algorithm in the CLIMA study

Background: Optical flow ratio (OFR) has recently been described to accurately compute coronary fractional flow reserve using optical coherence tomography (OCT), yet its prognostic impact remains unclear. The present study aimed to investigate the predictive value of coronary functional assessment, alone and combined with plaque morphology, by OCT. Methods: In the present study, OFR software was applied to untreated coronary lesions undergoing OCT analysis in the multicenter, international, prospective CLIMA study. The primary endpoint was target-vessel failure (TVF) at 1 year, defined as a composite of cardiac death, target-vessel myocardial infarction (TV-MI) or target-vessel revascularization (TVR). The secondary endpoint was a composite of cardiac death or target segment MI. Results: Overall, 983 patients were included (median age 66 years, 24.8 % women). Lesions with OFR ≤0.80 (n = 120) showed more frequently a minimum lumen area < 3.5 mm2 (p < 0.001), a thin-cap fibroatheroma (TCFA) (p = 0.023) and a large lipid arc >180° (p = 0.001) as compared to OFR-preserved lesions. TVF was significantly more frequent in patients with versus without OFR-detected flow-limiting lesions (10.8 % and 4.8 %; HR 2.25, 95 %CI 1.21–4.21). This association was directionally consistent for TV-MI and TVR. Patients with both TCFA and impaired OFR lesions were at the highest risk of the primary (HR 6.47, 95 %CI 2.79–15.02) and secondary endpoint (HR 5.78, 95 %CI 1.92–17.43). Conclusions: The presence of OFR-detected flow limitation was associated with high-risk morphological features and a higher incidence of adverse events. The combined presence of TCFA and OFR-derived flow limitation was associated with the highest incidence of primary and secondary endpoints.