Quantitative flow ratio modulated by intracoronary optical coherence tomography for predicting physiological efficacy of percutaneous coronary intervention

BackgroundThe combination of coronary imaging assessment and blood flow perturbation estimation has the potential to improve percutaneous coronary intervention (PCI) guidance. ObjectivesWe aimed to evaluate a novel method for fast computation of Murray law-based quantitative flow ratio (mu QFR) from coregistered optical coherence tomography (OCT) and angiography (OCT-modulated mu QFR, OCT-mu QFR) in predicting physiological efficacy of PCI. MethodsPatients treated by OCT-guided PCI in the OCT-arm of the Fractional Flow Reserve versus Optical Coherence Tomography to Guide RevasculariZAtion of Intermediate Coronary Stenoses trial (FORZA, NCT01824030) were included. Based on angiography and OCT before PCI, simulated residual OCT-mu QFR was computed by assuming full stent expansion to the intended-to-treat segment. Plaque composition was automatically characterized using a validated artificial intelligence algorithm. Actual post-PCI OCT-mu QFR pullback was computed based on coregistration of angiography and OCT acquired immediately after PCI. Suboptimal functional stenting result was defined as OCT-mu QFR <= 0.90. ResultsPaired simulated residual OCT-mu QFR and actual post-PCI OCT-mu QFR were obtained in 76 vessels from 74 patients. Simulated residual OCT-mu QFR showed good correlation (r = 0.80, p < 0.001), agreement (mean difference = -0.02 +/- 0.02, p < 0.001), and diagnostic concordance (79%, 95% confidence interval: 70%-88%) with actual post-PCI OCT-mu QFR. Actual post-PCI in-stent OCT-mu QFR had a median value of 0.02 and was associated with left anterior descending artery lesion location (beta = 0.38, p < 0.001), higher baseline total plaque burden (beta = 0.25, p = 0.031), and fibrous plaque volume (beta = 0.24, p = 0.026). ConclusionsThis study based on patients enrolled in a prospective OCT-guidance PCI trial shows that simulated residual OCT-mu QFR had good correlation, agreement, and diagnostic concordance with actual post-PCI OCT-mu QFR. In OCT-guided procedures, OCT-mu QFR in-stent pressure drop was low and was significantly predicted by pre-PCI vessel/plaque characteristics.