Key Points Vascular dysfunction at the level of the brachial artery after transradial cardiac catheterization appears transient and resolves within a week Chemo‐toxicity from procedural cocktails in addition to catheter‐mediated barotrauma directly to the brachial artery or indirectly from radial trauma may play a role in its etiology. Further work is needed to better define the causes of vascular damage from the transradial procedures to develop safer techniques for the future.