Heme Effects in Lowering Patient Discomfort in Radial Artery Verapamil Injection.

Background: The primary objective of this study was to evaluate whether diluting verapamil with heme as compared to normal saline reduces patient discomfort during radial artery injection. Following radial artery access, verapamil is frequently administered to reduce the incidence of radial artery spasm. The injection of verapamil via the radial artery is associated with a temporary "burning" discomfort. It has been hypothesized that the dilution of verapamil with heme rather than saline leads to less patient discomfort during administration.

Methods: This prospective, single-center, randomized study enrolled patients undergoing coronary angiography via radial artery access between August 2017 and April 2018. Patients were randomized 1:1 to receive either verapamil/heme or verapamil/saline administration. Patient discomfort was assessed at the time of injection, and 1-h post procedure.

Results: A total of 214 patients were enrolled in the study. Of these, 103 patients were included in the verapamil/heme group and 100 in the verapamil/saline group. For the primary objectives, there were no statistically significant differences in patient discomfort at the time of verapamil injection (P = 0.15), or 1-h post injection (P = 0.48). However, in the verapamil/heme group, there was a trend towards a lower post-injection pain score (M = 2.83, standard deviation (SD) = 3.18) compared to the verapamil/saline group (M = 3.48, SD = 3.01) (P = 0.15).

Conclusion: There was no significant difference in immediate or 1-h post-procedure patient discomfort with verapamil diluted with heme as compared to dilution with saline. While there was a trend towards lower immediate patient discomfort in the verapamil/heme group, larger studies are needed to further evaluate this trend.