Relationship of Coronary Angiography-Derived Radial Wall Strain With Functional Significance, Plaque Morphology, and Clinical Outcomes.

BACKGROUND: Coronary angiography-derived radial wall strain (RWS) is a newly developed index that can be readily accessed and describes the biomechanical features of a lesion. OBJECTIVES: The authors sought to investigate the association of RWS with fractional flow reserve (FFR) and high-risk plaque (HRP), and their relative prognostic implications. METHODS: We included 484 vessels (351 patients) deferred after FFR measurement with available RWS data and coronary computed tomography angiography. On coronary computed tomography angiography, HRP was defined as a lesion with both minimum lumen area <4 mm2 and plaque burden ≥70%. The primary outcome was target vessel failure (TVF), a composite of target vessel revascularization, target vessel myocardial infarction, or cardiac death. RESULTS: The mean FFR and RWSmax were 0.89 ± 0.07 and 11.2% ± 2.5%, respectively, whereas 27.7% of lesions had HRP, 15.1% had FFR ≤0.80. An increase in RWSmax was associated with a higher risk of FFR ≤0.80 and HRP, which was consistent after adjustment for clinical or angiographic characteristics (all P < 0.05). An increment of RWSmax was related to a higher risk of TVF (HR: 1.23 [95% CI: 1.03-1.47]; P = 0.022) with an optimal cutoff of 14.25%. RWSmax >14% was a predictor of TVF after adjustment for FFR or HRP components (all P < 0.05) and showed a direct prognostic effect on TVF, not mediated by FFR ≤0.80 or HRP in the mediation analysis. When high RWSmax was added to FFR ≤0.80 or HRP, there were increasing outcome trends (all P for trend <0.001). CONCLUSIONS: RWS was associated with coronary physiology and plaque morphology but showed independent prognostic significance.

Clinical outcomes of Fractional Flow Reserve-Guided Percutaneous Coronary Intervention By Coronary Flow Capacity Status in Stable Lesions.

BACKGROUND: Coronary flow capacity (CFC) provides integrated information about coronary flow reserve (CFR) and hyperaemic coronary flow and is useful for identifying coronary flow limitation. AIMS: The aim of this study was to investigate the effect of percutaneous coronary intervention (PCI) on vessel-related major adverse cardiovascular events (MACE) according to CFC status in stable coronary lesions. METHODS: From a global, multicentre registry of comprehensive physiological assessment, a total of 1,397 patients (1,694 vessels) were analysed. Low CFC was defined for lesions with reduced CFR and inverse of hyperaemic mean transit time (1/hTmn). A predefined definition of CFC (CFR <2.0 and 1/hTmn less than the corresponding percentile) was assessed first in a multivariable marginal Cox proportional model with the interaction term between CFC status and PCI (performed or not), and then the optimal definition of CFC was explored. RESULTS: We observed a significant interaction between predefined low CFC and PCI (p=0.067). With the optimal definition of CFC (CFR ≤3.2 and 1/hTmn ≤2.8), the HR (95% CI) of PCI was 0.278 (0.103-0.751) and 1.393 (0.783-2.478) in lesions with low and normal CFC, respectively. If lesions with fractional flow reserve (FFR) ≤0.8 and normal CFC had been deferred, the number of PCI would have decreased by 64%. CONCLUSIONS: FFR-guided PCI for low CFC lesions was associated with reduced incidence of MACE in low CFC but not in normal CFC lesions. Our results suggest the potential use of CFC in combination with FFR for optimising the indication for PCI by reducing potentially unbeneficial PCI. CLINICAL TRIALS REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03690713.