Anatomic assessment of hand circulation in harvesting the radial artery

F or the radial artery (RA) to be harvested safely, a careful assessment of the adequacy of the remaining blood supply of the hand is essential. The modified Allen test and Doppler ultrasound are the two tests commonly used for this purpose. The modified Allen test involves assessing the perfusion of the hand and fingers before and after occluding the RA and the ulnar artery 1 to 2 cm proximal to the wrist. However, alternative channels may still perfuse the hand and fingers. Two anatomic variations in which this may occur are (1) a superficial dorsal branch of the RA and (2) a persistent median artery as a branch derived from the ulnar artery (or even the RA) proximally. Noninvasive tests such as the Allen test and ultrasound may produce a false negative result in the presence of these variations.