Utility of a Smart Phone Application in Assessing Radial Artery Patency - the CAPITAL iRADIAL Study

The Modified Allen's Test (MAT) will be performed in a well-lit room on both of the participant's hands. This technique will involve compression of both the radial and ulnar arteries by the investigator to assess patency of the contralateral artery. The participant will then be asked to clench and open their hand several times. The participant will then be asked to maintain their hand in an open position. The investigator will then release the compression over the ulnar artery and observe for palmar blush. The length of time to achieve maximal palmar blush will be recorded. This technique will then be repeated by maintaining compression over the ulnar artery and releasing of the compression over the radial artery.

The iRADIAL iPhone app (Heart Rate, Azumio software) will be used to assess radial and ulnar artery patency. Briefly, the iPhone camera will be placed over the participant's thumb and patency assessed before and immediately following isolated contralateral artery compression for a maximum of two minutes.