Effects of contrast media selection upon heart rate and heat sensation during coronary computed tomographic angiography

Background: Coronary computed tomographic angiography (CCTA) image quality is dependent on heart rate (HR). Beta blockers are commonly administered before CCTA to lower HR and minimize variability. However, contrast media may also impact upon HR and image quality. Since iso-osmolar contrast media induce less vasodilation, this may decrease a patient's sensation of heat, minimizing patient discomfort and improving HR control and variability. Objectives: The aim of the study was to compare the impact of contrast media selection in CCTA upon HR and image quality. Patients and Methods: A total of 173 patients undergoing CCTA between February and April 2011 were allocated to different contrast media (Iodixanol, Iohexol, and Iopamidol) in 2-week blocks. The groups were analyzed for differences in baseline characteristics, imaging parameters, image quality, HR, and HR variability. Patients were also surveyed for perception of heat. Results: Baseline HR was similar across the patients assigned to Iohexol, Iopamidol, and Iodixanol (65.3 ± 9.7, 66.9 ± 10.9, and 65.3 ± 13.3, respectively; P = NS). Compared to Iohexol and Iopamidol, Iodixanol use was associated with lower HR at the time of image acquisition and immediately after CCTA (53.2 ± 8.0 bpm, 56.3 ± 7.8 bpm, and 56.8 ± 6.5 bpm; P = 0.069 and P = 0.032). A greater proportion of patients achieved HR ≤ 55 beats per minute (bpm) with Iodixanol (63%) than with Iohexol (42%; P = 0.025) and Iopamidol (39%; P = 0.011). As was expected, Iodixanol (2.34 ± 2.02) was associated with a lower perception of heat than Iohexol (6.13 ± 1.89; P < 0.001) and Iopamidol (5.22 ± 2.10; P < 0.001). Image quality was similar in all three groups. Conclusions: Compared to Iohexol and Iopamidol, Iodixanol use was associated with a lower patient perception of heat and lower HR while maintaining similar contrast-to-noise and signal-to-noise ratios.