Assessment Of Peak Peripheral Artery Conduit And Resistance Artery Structure In Humans: Does Occluding Cuff Position Matter?

Abstract

PURPOSE: To determine whether the position of an occluding cuff on the lower and upper limbs modifies conduit artery diameter and blood flow responses to peak vasodilator stimuli. Edge-detection and wall tracking of high resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, was used to calculate conduit artery blood flow (BF) and diameter responses continuously across the cardiac cycle. METHODS: Thirty-six healthy subjects (47.4±3 yrs; 42.2±2 ml.kg-1.min-1) underwent assessment of popliteal and brachial artery blood flow and diameter responses to periods of ischemic exercise and glyceryl trinitrate (GTN) administration. Ischemia was induced with occluding cuff placement both proximal and distal to the imaged artery. RESULTS: The peak popliteal artery diameter response (PADpeak) was observed following a 5 minute period of ischemic combined with 3 minutes of exercise, with the occluding cuff placed above the imaged artery (12.8±1.1% vs 9.7±0.9%, thigh vs calf cuff placement, P<0.05). Peak brachial artery diameter response (BADpeak) was observed following a similar ischemic handgrip exercise stimulus with upper arm cuff placement (17.9±1.3% vs 11.2±0.9%, arm vs forearm cuff placement, P<0.0001). No significant effect of cuff placement was evident for either peak brachial (BAFpeak) or popliteal artery flow (PAFpeak) or conductance responses. CONCLUSIONS: These data indicate that cuff position modifies peak diameter responses through both the popliteal and brachial arteries. Future studies should utilize proximal cuff placement if the aim is to determine peak arterial vasodilation responses as an index of conduit arteriogenic adaptation.