Optimal Starting Time of Acquisition and Feasibility of Complementary Administration of Nitroglycerin With Intravenous β-Blocker in Multislice Computed Tomography

OBJECTIVES: We determined the optimal starting time of acquisition after sublingual nitroglycerin (NTG) administration and evaluated the effects on multislice computed tomographic (MSCT) images of a complementary administration of sublingual NTG with beta-blocker. METHODS: Sixty patients who underwent MSCT coronary angiography (CA) were randomly divided into 2 groups as follows: 30 patients given an intravenous administration of beta-blocker (landiolol hydrochloride, mean dose of 0.032 mg/kg per minute; group B); and 30 patients given a coadministration of intravenous beta-blocker and sublingual NTG (0.3 mg; group N). Blood pressure and heart rate were recorded every 1 minute after NTG administration. In addition, the maximum diameters of the proximal and distal lesions in each coronary artery were measured, and the number of assessable segments was calculated. RESULTS: Blood pressure significantly decreased and heart rate significantly increased 4 minutes after NTG administration. The number of assessable segments was significantly greater in group N than in group B. The maximum diameters of the distal lesions of the left anterior descending and left circumflex arteries and both proximal and distal lesions of the right coronary artery were significantly larger in group N than in group B. CONCLUSIONS: It is advisable to obtain MSCT images after sublingual NTG administration because nitrates are always given during conventional CA and may prevent beta-blocker-induced coronary spasm. The optimal starting time for MSCT CA is approximately 3 minutes after sublingual NTG administration.