title: Vascular communications of the hand in patients being considered for transradial coronary angiography: is the Allen's test accurate?
abstract: OBJECTIVE
  The purpose of this study was to assess the accuracy of the Allen's test (AT) in predicting hand ischemia in patients undergoing transradial coronary angiography.
  
  
  BACKGROUND
  Patients with poor vascular communications between the radial artery (RA) and ulnar artery (UA), as indicated by an abnormal AT, are usually excluded from transradial coronary angiography to avoid ischemic hand complications.
  
  
  METHODS
  Over a four-month period, patients undergoing coronary angiography were screened for AT time. Circulation in the RA, UA, principal artery of the thumb (PAT), and thumb capillary lactate were measured before and after 30 min of RA occlusion.
  
  
  RESULTS
  Fifty-five patients were studied (20 normal, 15 intermediate, 20 abnormal). Three patients with an abnormal AT were excluded, owing to absence of detectible flow in the distal UA. Patients with an abnormal AT were all men, had a larger RA (3.4 vs. 2.8 mm; p <0.001), and smaller UA (1.9 vs. 2.5 mm; p <0.001), compared with patients with a normal AT. After 30 min of RA occlusion in patients with abnormal AT, blood flow to the PAT improved (3.2 to 7.7 cm/s; p <0.001) yet remained reduced relative to patients with normal AT (7.7 vs. 21.4 cm/s; p <0.001. Thumb capillary lactate was elevated in patients with an abnormal AT (2.0 vs. 1.5 mmol/l; p = 0.019).
  
  
  CONCLUSIONS
  After 30 min of RA occlusion, patients with an abnormal AT showed significantly reduced blood flow to the thumb and increased thumb capillary lactate (compared with patients with a normal AT) suggestive of ischemia. Transradial cardiac catheterization should not be performed in patients with an abnormal AT.
authors.affiliation: Victoria Heart Institute, Victoria, British Columbia, Canada. greenie3@bigpond.net.au
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Greenwood
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Della-Siega
authors.forename: Eric B
authors.initials: EB
authors.lastname: Fretz
authors.forename: David
authors.initials: D
authors.lastname: Kinloch
authors.forename: Peter
authors.initials: P
authors.lastname: Klinke
authors.forename: Richard
authors.initials: R
authors.lastname: Mildenberger
authors.forename: Malcolm B
authors.initials: MB
authors.lastname: Williams
authors.forename: David
authors.initials: D
authors.lastname: Hilton
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D003097:Collateral Circulation; D003250:Constriction; D005260:Female; D006225:Hand / Q000098:blood supply*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D017534:Radial Artery / Q000502:physiology*; D012039:Regional Blood Flow; D013933:Thumb / Q000098:blood supply / Q000000981:diagnostic imaging; D017535:Ulnar Artery / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color
chemical_list: D019344:Lactic Acid