Assessment of collateral hand circulation by modified Allen's test in normal Indian subjects

Allen's test (AT) and Modified Allen's Test (MAT) are used as screening methods for assessment of the hand circulation. Few people lack the dual blood supply of hand and are at risk of hand ischemia after any intervention on radial artery. The Purpose of the study was to assess the collateral circulation of hand using MAT in normal Indian subjects and in elderly population to know the prevalence of positivity of Allen's test.

900 participants (1800 hands) were divided in two groups. Group I had participants with age <50 years and group II had participants with age ≥50 years. MAT was performed in all participants and results were compared between the two groups.

In group I (n = 450, 900 hands), 313 were males and 137 were females, with mean age of 35.04 years. The relative percentages of a normal, equivocal, borderline and abnormal MAT were 77.8%, 16.6%, 3.7% and 1.6%, respectively. In group II (n = 450, 900 hands), 248 were males and 202 were females, with mean age of 60.4 years. The relative percentages of a normal, equivocal, borderline and abnormal MAT were 69.0%, 18.6%, 6.60% and 5.66%, respectively. A positive/abnormal test was significantly more common (5.66% Vs 1.66%, P < 0.00001) in older group.

MAT is simple, time tested and non invasive test to assess collateral circulation of the hand. A negative MAT safely selects patients for radial artery harvest; however, if the test is positive and in older patients then a second objective test may be needed.