A study was executed to decipher the best cut-off point for a positive Allen’s test. Ninety-three hands of 47 patients undergoing coronary artery bypass surgery were screened. The average age of the patients was 63.3 years. Independent observers examined these procedures using the Allen’s Test and a Doppler ultrasound test.
Results of six second cut-off point:
- Sensitivity = 54.5%
- Specificity = 75.8%
- Diagnostic accuracy = 78.5%
Results of five second cut-off point:
- Sensitivity = 75.8%
- Specificity = 81.7%
- Diagnostic accuracy = 79.6%
Results of three second cut-off point:
- Sensitivity = 100%
- Specificity = 27%
- Diagnostic accuracy = 52%
This study showed poor coorelation between abnormal Allen’s test and adverse outcomes from radial artery harvesting.
During another study, 942 patients were screened while undergoing transradial access. Of those patients, 83 had normal Allen’s test results, 60 had intermediate results, and 60 had abnormal results. To analyze the patency of ulnopalmar arches the patients underwent thumb capillary lactate, thumb plethysmography, and ulnar frame count. Also, to determine isometric strength of the hand and forearm muscles and discomfort ratings the patients underwent a handgrip strength test. Overall, the data showed poor correlation between abnormal Allen’s test and adverse outcomes during transradial coronary catheterization.
Both of these studies collectively determine that Radial artery catheterization may be safely performed without first performing a Modified Allen’s Test.
