Inverse Modified Allen’s Test: an Inaccurate Predictor of Radial Artery Occlusion Compared to Doppler Ultrasound after Transradial Catheterization: Case Series and Review of Literature

Introduction: There is ever increasing evidence to suggest that transradial catheterization is associated with fewer access site complications, shorter length of stay, and improved patient comfort. A principle concern remains the potential for radial artery occlusion (RAO) with a reported incidence ranging from 10-30%. One of the traditional methods used to diagnose radial artery occlusion is inverse modified Allen test with pulse plethysmography which is then graded as Barbeau A-D according to increasing severity of occlusion. Methods: We describe a series of patients undergoing transradial catheterization in whom we performed inverse modified Allen’s testing with pulse plethysmography and compared this with Doppler ultrasound in determining the presence of a radial artery occlusion. Results: Three patients demonstrated a Barbeau grade of D on inverse modified Allen’s test following a successful diagnostic and interventional procedures; however, Doppler ultrasound demonstrated a patent radial artery with antegrade flow and no evidence of occlusion. Conclusions: Inverse modified Allen test with pulse plethysmography is an inaccurate method to diagnose to radial artery occlusion and may yield false positive or negative results in comparison to Doppler ultrasound. The clinical presentation and diagnostic methods are discussed.