Flow-mediated vasodilation in the popliteal artery was significantly greater than in the brachial artery when the shear rate was experimentally matched (4.5% vs -0.4%, P<0.05).
Cross-Sectional (n=12)
Are there limb-specific differences in flow-mediated dilation between the brachial and popliteal arteries when accounting for shear rate in young healthy subjects?
Flow-mediated dilation differs between the upper and lower limbs, highlighting the importance of assessing the specific shear stimulus to which each vessel is exposed.
Absolute Event Rate: 4.5% vs -0.4%
p-value: p=<0.05
We sought to examine flow-mediated vasodilation (FMD) in both the arm brachial artery (BA) and lower leg popliteal artery (PA) of 12 young, healthy subjects. Vessel diameter, blood velocity, and calculated shear rate were determined with ultrasound Doppler following a suprasystolic cuff occlusion (5 min) in both the BA and PA and an additional reduced occlusion period (30–120 s) in the BA to more closely equate the shear stimulus observed in the PA. The BA revealed a smaller diameter and larger postischemic cumulative blood velocity area under curve (AUC) than the PA, a combination that resulted in an elevated postcuff cumulative shear rate (AUC) in the BA (BA: 25,419 ± 2,896 s −1 ·s, PA 8,089 ± 1,048 s −1 ·s; P < 0.05). Thus, when expressed in traditional terms, there was a tendency for the BA to have a greater FMD than the PA (6.5 ± 1.0 and 4.5 ± 0.8%, respectively; P = 0.1). However, when shear rate was experimentally matched (PA: 4.5 ± 0.8%; BA: −0.4 ± 0.4%) or mathematically normalized (PA: 6.8 × 10 −4 ± 1.6 × 10 −4 %Δ/s −1 ·s; BA: 2.5 × 10 −4 ± 0.4 × 10 −4 %Δ/s −1 ·s), the PA revealed a greater FMD per unit of shear rate than the BA ( P < 0.05). These data highlight the importance of assessing the shear stimulus to which each vessel is exposed and reveal limb-specific differences in flow-mediated dilation.
Nishiyama et al. (Fri,) conducted a cross-sectional in Healthy (n=12). Suprasystolic cuff occlusion in popliteal artery vs. Suprasystolic cuff occlusion in brachial artery (matched shear rate) was evaluated on Flow-mediated vasodilation (FMD) with experimentally matched shear rate (p=<0.05). Flow-mediated vasodilation in the popliteal artery was significantly greater than in the brachial artery when the shear rate was experimentally matched (4.5% vs -0.4%, P<0.05).