Vasodilation in resistance arteries is related to the apolipoprotein B/A1 ratio in the elderly: the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.

BACKGROUND: Recent studies have shown the apolipoprotein B to apolipoprotein A1 ratio (apoB/A1) to be superior to LDL-cholesterol measurements to predict cardiovascular events. The present study aims to relate apoB/A1 to endothelium-dependent vasodilation, an early marker of atherosclerosis, in the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study.

METHODS AND RESULTS: In this population-based study, 1016 subjects aged 70 years were evaluated by the invasive forearm technique with acetylcholine (EDV), brachial artery ultrasound to assess flow-mediated vasodilation (FMD) and pulse wave analysis with a beta-2 receptor agonist challenge, terbutaline. EDV and the pulse wave response, but not FMD, were related to apoB/A1 levels (r=-0.11, p=0.0038 for EDV, r=-0.16, p<0.0001 for the pulse wave analysis and r=0.01, p=0.65 for FMD). Neither LDL-cholesterol, nor non-HDL-cholesterol, was significantly related to the measurements of endothelium-dependent vasodilation. Also endothelium-independent vasodilation (EIDV) evaluated by the invasive forearm technique with sodium nitroprusside was related to apoB/A1 levels (r=-0.12, p<0.0016).

CONCLUSION: The apoB/A1 levels, but not LDL-cholesterol, were inversely related to endothelium-dependent vasodilation evaluated by EDV and pulse wave analysis, but not by FMD. Also EIDV showed the same pattern, suggesting a general deterioration in vasoreactivity mainly in resistance arteries in elderly subjects with high apoB/A1 levels.