Preoperative assessment of the radial artery for coronary artery bypass grafting: Is the clinical Allen test adequate?

Background. The clinical Allen test (AT) is widely adopted as the only preoperative assessment of the hand collateral circulation before radial artery (RA) harvest as a coronary artery bypass graft. Nevertheless, in some cases it may be misleading because of clinically undetectable anatomic anomalies of the forearm arteries. Methods. We evaluated the nondominant forearm arterial circulation by echo color Doppler (ECD) technique and by performing static and dynamic tests such as the AT, snuffbox test (SBT), and palmar arch test (PAT) in 150 patients who underwent elective coronary artery revascularization with a RA graft. Results. Although the clinical AT was normal in all patients, in 8 patients (5.3%) preoperative ECD AT, SBT, and PAT did contraindicate RA harvesting. We did not harvest the RA in these patients. In the remaining 142 patients the RA was harvested. We did not observe any case of postoperative forearm or hand ischemia. We examined the blood flow to the hand in all patients at both 5 days and 24 months after surgery. In all patients ECD showed adequate hand perfusion and a significant increase of the peak flow velocity in the ulnar artery at both follow-up times. Conclusions. The clinical AT may be not sufficient to assess the hand collateral flow and the quality of the RA as a coronary artery bypass graft in at least 5% of patients. The ECD technique, performed during static and dynamic tests, does offer a safer and more objective preoperative noninvasive evaluation and it may have an important role also from the medicolegal point of view. (C) 2005 by The Society of Thoracic Surgeons.