Usefulness and safety of intracoronary administration of nicorandil for evaluating fractional flow reserve in Japanese patients.

BACKGROUND

Fractional flow reserve (FFR) is useful for determining the functional significance of epicardial coronary stenosis and may facilitate clinical decision making in patients with an equivocal coronary stenosis for coronary revascularization. Therefore, determining an efficient and safe method to achieve hyperemia is important for evaluating FFR. We investigated the usefulness and safety of intracoronary bolus administration of nicorandil compared with intravenous administration of adenosine triphosphate (ATP) for evaluating FFR in Japanese patients with suspected angina pectoris.

METHODS

First, we evaluated the most appropriate hyperemic dose of nicorandil in the first 11 consecutive patients out of 101 Japanese patients. Next, we compared the FFR induced by ATP and by 2 mg of nicorandil in 130 vessels of the 101 patients.

RESULTS

FFR was measured according to nicorandil dose in 14 vessels among 11 of the 101 patients; 92.9% of the patients achieved hyperemia with 2 mg of nicorandil. The FFR values obtained with ATP were significantly correlated with those obtained with 2 mg of nicorandil (regression coefficient = 0.974, R(2) = 0.933, P < 0.001). There were no hypotension cases needing a vasopressor after ATP or nicorandil administration, and there was 1 case of transient second-degree atrioventricular block after ATP administration. The time taken to achieve hyperemia after nicorandil administration (18.9 ± 9.6 seconds) was significantly shorter than that after ATP administration (197.9 ± 23.8 seconds) (P < 0.001).

CONCLUSIONS

Intracoronary nicorandil administration is more useful than and as safe as intravenous administration of ATP for evaluating FFR in Japanese patients.