Feasibility and safety of intracoronary nicorandil infusion as a novel hyperemic agent for fractional flow reserve

Fractional flow reserve (FFR) is a useful modality to assess the functional significance of coronary stenoses. Although adenosine triphosphate (ATP) is gen- erally used as the hyperemic stimulus, we sometimes encounter adverse events like hypotension during FFR measurement. Nicorandil, an ATP-sensitive potassium channel opener, recognized as an epicardial and resistance vessel dilator, has not been fully evaluated as a possible alternative hyperemic agent. The aim of this study was to evaluate the feasibility and safety of intracoronary nico- randil infusion compared to intravenous ATP for FFR measurement in patients with coronary artery disease. A total of 102 patients with 124 intermediate lesions (diam- eter stenosis (40 and \70 % by visual assessment) were enrolled. All vessels underwent FFR measurements with both ATP (150 lg/kg/min) and nicorandil (2.0 mg) stim- ulus. FFR, hemodynamic values, and periprocedural adverse events between the two groups were evaluated. A strong correlation was observed between FFR with ATP and FFR with nicorandil (r = 0.954, p\0.001). The agreement between the two sets of measurements was also high, with a mean difference of 0.01 ± 0.03. The mean aortic pressure drop during pharmacological stimulus was significantly larger with ATP compared to nicorandil (9.6 ± 9.6 vs. 5.5 ± 5.8 mmHg, p\0.001). During FFR measurement, transient atrioventricular block was fre- quently observed with ATP compared to nicorandil (4.0 vs. 0% ,p = 0.024). This study suggests that intracoronary nicorandil infusion is associated with clinical utility and safety compared to ATP as an alternative hyperemic agent for FFR measurement.