Radiation-Dose-Lowering Effects of Landiolol Hydrochloride in Coronary Angiography Using Computed Tomography (DELIGHT)　- A Prospective Multicenter Study.

Background: Controlling and decreasing the heart rate (HR) of patients during coronary computed tomography angiography (CCTA) is necessary to reduce radiation exposure and improve image quality. This prospective multicenter study aimed to investigate whether HR control with landiolol hydrochloride is useful for reducing radiation exposure during CCTA. Methods and Results: We investigated 219 patients with suspected ischemic heart disease whose pretest HRs were 50-80 beats/min. We measured the HR before and after administration of landiolol hydrochloride and compared the estimated exposure inferred from the HR before administration of landiolol hydrochloride with the actual dose. After administration of landiolol hydrochloride, the mean HR (59.9 +/- 6.4 beats/min) at the time of CCTA was significantly lower than before administration (69.3 +/- 7.3 beats/min; P<0.001); 80% of the patients had controlled HRs at <= 65 beats/min. HR and blood pressure of all the patients recovered after the scan. The mean radiation dose in all patients was approximately 50% derived from the inferred dose before use of landiolol hydrochloride (4.5 +/- 3.2 vs. 9.0 +/- 3.7 mSv; P<0.001). There were no adverse events during this study. Conclusions: The use of landiolol hydrochloride during CCTA was safe and resulted in approximately 50% decrease in radiation exposure dose, suggesting the clinical usefulness of this drug.