A Randomized, Double-Blind, Placebo-Controlled, Phase III Study of the Short-Acting β1-Adrenergic Receptor Blocker Landiolol Hydrochloride for Coronary Computed Tomography Angiography in Japanese Patients with Suspected Ischemic Cardiac Disease

OBJECTIVES AND BACKGROUND The objective of this study was to investigate the image quality-improving and heart rate-lowering effects of landiolol hydrochloride (a short-acting β1-adrenergic receptor blocker) on coronary computed tomography angiography (CCTA). During CCTA, β-adrenergic receptor blockers have been commonly used to lower heart rate and improve image quality. METHODS A total of 258 subjects suspected of having ischemic cardiac disease and requiring CCTA were randomized to either a landiolol hydrochloride 0.125 mg/kg group or placebo group to study the efficacy and safety of landiolol hydrochloride in a multicenter, double-blind, randomized parallel study. The primary endpoint was the diagnosable proportion (proportion of subjects whose coronary stenosis was diagnosable). RESULTS The diagnosable proportions about the reconstruction images at mid-diastole were 68.2 and 38.2 % in the landiolol hydrochloride and placebo group, respectively, indicating significant superiority of landiolol hydrochloride over placebo (p < 0.0001). The diagnosable proportions about the optimal reconstruction images were 81.4 and 54.2 % in the landiolol hydrochloride and placebo group, respectively, indicating significant superiority of landiolol hydrochloride over placebo (p < 0.0001). The mean heart rate-lowering effect was first observed soon after administration of landiolol hydrochloride, was most marked at 3-5 min, and disappeared 30 min after completion of administration. The mean heart rate-lowering proportion at that time was -19.1 ± 8.1 % and -5.9 ± 9.7 % in the landiolol hydrochloride and placebo groups, respectively, showing a significantly higher proportion in the landiolol hydrochloride group. CONCLUSIONS Landiolol hydrochloride was confirmed to significantly and rapidly lower heart rate after intravenous injection, suggesting that it is a safe and useful agent for improving the image quality of CCTA.