Preoperative assessment of hand circulation by means of Doppler ultrasonography and the modified Allen test

Objective: The aims of this study were as follows: (1) to evaluate Doppler ultrasonography in assessing hand collateral circulation; (2) to define the criteria for an abnormal Doppler ultrasonography dynamic test result; and (3) to validate the modified Alien test. Methods: The hand circulation of 71 patients scheduled for coronary artery bypass grafting was assessed by means of the Alien test and Doppler ultraso nography. The flow in the superficial palmar branch of the radial artery, t he ulnar artery, and the dorsal digital thumb artery with and without radia l artery compression were recorded. Flow patterns in the superficial palmar branch of the radial artery, the ulnar artery, and the dorsal digital thum b artery with radial artery compression were categorized into 4 groups: (1) no flow; (2) decreased flow; (3) reversed flow; and (4) increased how. Results: Among the 71 hands, 4 (5.6%) had an abnormal Alien test result (>1 0 seconds). Seven (10.6%) of 66 superficial palmar branches of the radial a rtery, 3 (4.2%) of 71 ulnar arteries, and 2 (2.8%) of 71 dorsal digital thu mb arteries showed no flow with radial artery compression, as measured by D oppler ultrasonography. There were significant differences among the 4 grou ps (superficial palmar branch of the radial artery: F = 7.0, P < .001; ulna r artery: F = 13.1, P < .001; and dorsal digital thumb artery: F = 8.4, P < .001) for the Alien test. Pairwise comparisons showed that when subjected to an Alien test, category 1 patients (no flow) had significantly longer re covery times compared with the other groups (P < .02 in all cases) for the superficial palmar branch of the radial artery, the ulnar artery, and the d orsal digital thumb artery. Conclusion: Absence of flow in the dorsal digital thumb artery with radial artery compression is considered an absolute contraindication to radial art ery harvesting. An increased recovery time with the modified Alien test pre dicts absence of flow in the dorsal digital thumb artery in Doppler ultraso nographic flow patterns. This demonstrates the validity of the modified Ali en test for primary screening.