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