Radial Access Strategies: Focus on Coronary Function Testing for Angina With Nonobstructive Coronary Arteries.

Invasive coronary function testing (CFT) allows comprehensive assessment of the mechanisms of angina with nonobstructive coronary arteries, which can include coronary microvascular dysfunction, coronary vasospasm, endothelial dysfunction, or myocardial bridging. There is significant heterogeneity in approaches to CFT, including in the selection of arterial access site for the procedure. Transradial arterial access is associated with less bleeding and fewer vascular complications, but can be challenging in patients with chest pain and nonobstructive coronary arteries, as they are disproportionately of female sex, with higher risks of radial spasm and crossover. Radial vasodilators for radial spasm prophylaxis may lower the diagnostic yield of CFT. In this review, we highlight strategies to ensure diagnostic fidelity while enabling radial-first CFT, including conscious sedation, left radial arterial access, atraumatic wire advancement, pressure-mediated vasodilation using a saline "mocktail," selective use of short-acting arterial vasodilators when needed, mother-and-daughter catheter advancement, balloon-assisted tracking techniques, and the use of long hydrophilic sheaths. A pragmatic approach to radial vasodilators is reasonable when CFT is performed ad hoc, whereas withholding prophylactic radial vasodilators is preferred in patients electively referred for definitive CFT. Although the access site should be selected based on anatomic considerations and patient preference, a cocktail-free radial-first strategy is feasible for most patients undergoing CFT.