Relationship between optical coherence tomography-derived morphological criteria and functional relevance as determined by fractional flow reserve.

Background: Although several previous studies have indicated that optical coherence tomography (OCT)-derived minimal lumen area (MLA) correlates with fractional flow reserve (FFR) severity, other morphologic criteria for functionally significant coronary stenosis assessed by FFR have not been fully elucidated. This study aimed to identify OCT-based morphological predictors of physiologically significant ischemia assessed by FFR in angiographically intermediate coronary lesions.

Methods: We investigated 194 de novo intermediate coronary lesions in 178 patients with stable angina pectoris who underwent OCT imaging and FFR measurement. The lesions were divided into two groups according to an FFR threshold: ischemia group, FFR <0.75 (n=69) and non-ischemia group, FFR ≥0.75 (n=125). Clinical characteristics, angiographic, and OCT findings were compared between these two groups. Predictors of significant ischemia defined as FFR <0.75 were identified by logistic regression analyses.

Results: Patient age, statin use, lesion in left anterior descending artery (LAD), OCT-derived MLA, and lipid volume index (LVI) (averaged lipid arc multiplied by lipid length) were independent predictors of FFR <0.75 in multivariate logistic regression analysis. Receiver operating characteristic analysis suggested that age <64 years old, OCT-derived MLA ≤1.39mm, and LVI ≥733 are the best cut-off values for predicting FFR <0.75. Multiple logistic regression models, including the MLA combined with the LAD location, LVI, age, and statin use, provided superior predictive efficacy for physiologically significant ischemia compared with the model that only employed MLA.

Conclusions: Information on OCT-derived LVI and lesion locations facilitates better identification of coronary lesions that cause ischemia than OCT-derived MLA analysis alone.