When is it appropriate to perform catheterization though the ulnar artery in place of the radial artery?

Cardiac catheterization via ulnar access is uncommonly performed in our lab however this approach may be considered if the following 2 criteria are fulfilled: patent dual arterial supply to the hand and anatomic difficulties that render radial access difficult. The typical scenario in which this may occur is the patient who has a normal plethysmography-based Allen test and then is found at the time of attempted radial access to have radial disease/anomalies by angiography. When there is difficulty advancing the guidewire through the 20g Angiocath (prior to sheath insertion), I will typically advance the Angiocath into the radial artery and perform a radioulnar angiogram to evaluate the caliber, course and flow in both radial and ulnar vessels. If the ulnar artery appears more favorable and the radial artery has not been traumatized, ulnar access may be considered.  more