The modified Allen test and a novel objective screening algorithm for hand collateral circulation using differential...

Area of Science:

• Vascular Surgery
• Medical Devices
• Diagnostic Techniques

Background:

• Hand artery cannulation and grafting carry risks of ischemia and thrombosis.
• Current screening methods like the Modified Allen Test (MAT) lack objectivity or availability.
• Objective screening is crucial for reducing complications in hand artery interventions.

Purpose of the Study:

• To introduce a novel, objective, reliable, and inexpensive method for screening hand arterial patency.
• To develop an artery selection algorithm based on differential photo-plethysmography (PPG) measurements.
• To evaluate the efficacy of PPG in assessing hand blood circulation and identifying risks.

Main Methods:

• Conducted a pilot study on 11 participants undergoing the Modified Allen Test (MAT).
• Recorded differential photo-plethysmography (PPG) measurements from thumb and little fingers of both hands.
• Applied a proprietary artery selection algorithm to analyze PPG data for each hand.

Main Results:

• The PPG method demonstrated results congruent with known vascular anatomy.
• Identified two participants with >50% blood reduction due to arterial occlusion.
• Indicated an elevated risk of accessing an artery in 8 out of 11 participants.

Conclusions:

• Differential PPG measurement combined with an artery selection algorithm shows promise as an objective screening tool.
• This method may offer insights into hand blood circulation and the impact of arterial occlusion.
• Further validation in larger studies could establish this technique for safer artery access selection.