The ulnar artery is the continuation of the brachial artery and was the initial access site used by Zimmerman in 1949 for retrograde catheterization of the left ventricle. It is often larger and has a straighter course compared with the radial artery and rarely has anomalies. A case series from a high-volume center demonstrated the feasibility and safety of utilizing ipsilateral ulnar access even if initial radial artery access fails. Procedural success via the ulnar artery was 97% with 3% of patients necessitating crossover to femoral access. The rate of ulnar artery occlusion (UAO) was 3.1% at 30 days, which was asymptomatic. The SWITCH registry, in which an attempt at ipsilateral ulnar access was mandated in case of inability to place an introducer sheath in the radial artery, strengthens these data.
Indication for Ulnar Artery Access
The transulnar approach may provide alternative wrist access in a patient with a strong pulsation of the ulnar artery with a small caliber radial artery and thin radial pulse. Furthermore, it can be used when there was a failed radial artery puncture (only puncture without sheath insertion) and confirmed complex, challenging loops and curvatures or severe spasm of the radial artery. Transulnar access may be used in patients that previously had multiple transradial interventions with the patent radial artery and in cases with previous large bore (7 Fr/8 Fr sheath) transradial interventions with confirmed radial artery patency.