Comparison Of The Brachial And Popliteal Artery Vascular Responses To The Consumption Of A High Fat Meal

Abstract

Results from earlier studies indicate that the consumption of a high fat meal (HFM) significantly reduces the vascular reactivity (i.e. decreased vasodilatory response) in the brachial artery. Given the prevalence of vascular disease in the lower extremities, it is interesting that there is little data to date comparing the effect of consuming a HFM on the vascular responses of the upper and lower limbs. PURPOSE: To compare the vascular response of the brachial (BA) and popliteal (PA) arteries following the consumption of a HFM. It is hypothesized that endothelial dysfunction induced by the consumption of a HFM will be greater in the PA than in the BA, consistent with the findings that the lower extremities are more susceptible to endothelial dysfunction and vascular disease compared to the upper extremities. METHODS: Eight healthy (23.8 ± 1.8 yrs (±SD)) men (n=3) and women (n=5) reported to the facility following a 12 h fast. Each subject rested in either the supine (BA) or prone position (PA) to obtain baseline measurements of the artery of interest. Endothelial-dependent vascular function was assesses using the flow-mediated vasodilation (FMD) technique. Each subject consumed a high fat meal consisting of 90g total fat (63 g saturated fat), 364 mg cholesterol, 17 g carbohydrate and 139 mg sodium. BA and PA FMD responses were obtained 60 min following ingestion of the HFM. Longitudinal images of the BA and PA were obtained in B-mode using a linear array probe with an operating frequency of 7.0 MHz. Images were captured (10 fps) and analyzed using a commercially available system that incorporates an automated wall detection program. FMD (%) was calculated as the difference between baseline diameter and the maximal diameter measured following release of the occlusion cuff (250 mmHg) placed around the forearm for 5 min. RESULTS: Compared to baseline, consumption of a HFM resulted in a decrease (p<0.05) in vascular reactivity for both the BA (pre, 10.6 ± 3.7 vs. post, 6.2 ± 2.2 %FMD) and the PA (pre, 4.8 ± 2.1 vs. post, 2.1 ± 1.2 %FMD). When expressed as relative to the change in FMD within a limb, the decrease in the PA (55.3%) was greater (p<0.05) than for the BA (42.4%). CONCLUSIONS: While the differences in the FMD response to a HFM between the BA and PA artery are apparent, the mechanism behind this difference warrants further investigation