Ischemia-reperfusion injury significantly reduced flow-mediated dilation (7.9 to 4.7, p=0.0001) but did not affect microvascular function measures like hyperemic velocity or PAT index.
Does ischemia-reperfusion injury affect microvascular function (PAT hyperemic index and VTI) and conduit vessel function (FMD) in healthy volunteers?
Ischemia-reperfusion injury impairs conduit vessel endothelial function but does not affect resistance vessel function as measured by PAT index and hyperemic VTI.
Absolute Event Rate: 4.7% vs 7.9%
p-value: p=0.0001
BACKGROUND: Ischemia-reperfusion injury results in conduit vessel endothelial dysfunction as assessed by flow-mediated dilatation (FMD). The effect on the potentially more important microvascular circulation has not been well studied. The objective of our study was to assess the effect of ischemia-reperfusion injury on microvascular function including peripheral arterial tonometry (PAT) hyperemic index. METHODS: 45 healthy volunteers free of cardiovascular disease were recruited (mean age 35 ± 14 yrs, 29 men). Using ultrasound, the flow-mediated dilation (FMD) and hyperemic velocity (VTI) of the brachial artery were measured following a 5-minute forearm cuff occlusion. Simultaneously, the PAT hyperemic index was measured. Ischemia was then induced by a 15-minute upper arm occlusion and within 15 minutes of recovery the vascular measures were repeated. RESULTS: Ischemia caused a significant reduction in FMD (7.9 ± 4.0 to 4.7 ± 3.5, p = 0.0001). The hyperemic VTI, a measure of microvascular function, was unaffected following ischemia-reperfusion (92 ± 30 vs. 97 ± 37 cm, p = 0.236). Finally, PAT index was also unchanged by the intervention (2.07 ± 0.8 vs. 2.04 ± 0.7, p = 0.742). CONCLUSIONS AND DISCUSSIONS: Ischemia-reperfusion caused conduit and not resistance vessel endothelial dysfunction. The PAT-index was unchanged suggesting that this measure is more closely aligned with resistance than conduit vessel function. This has implications for its use as a measure of vascular function in clinical research.
Alhejily et al. (Wed,) conducted a other in Healthy (n=45). Ischemia-reperfusion injury vs. Baseline (pre-ischemia) was evaluated on Flow-mediated dilation (FMD) (p=0.0001). Ischemia-reperfusion injury significantly reduced flow-mediated dilation (7.9 to 4.7, p=0.0001) but did not affect microvascular function measures like hyperemic velocity or PAT index.