Background: Lipoprotein (a) (Lp(a)) is an independent risk factor for atherosclerotic cardiovascular disease. The atherogenic potential of Lp(a) may be by impairment of endothelial function. Objectives. We investigated the relation of Lp(a) plasma levels to endothelium dependent and independent dilatation of the brachial artery in healthy postmenopausal women.
Methods: One hundred and five healthy postmenopausal women aged 52-67 years were included in the study. Endothelial function was assessed non-invasively by measuring percent lumen diameter change in the brachial artery after reactive hyperemia and sublingual nitroglycerine spray.
Results: Flow mediated dilatation was inversely related to the plasma logLp(a) level. Mean change per unit logLp(a) increase:-2.83% (95% CI: -5.22--0.43). Elevated Lp(a) (>239 mg/l) (upper quartile) was associated with an impaired flow mediated vasodilatation (2.4%+/-1. 2) compared to Lp(a) < or =239 mg/l (5.2%+/-0.7). Adjustment for other cardiovascular risk factors did not change the magnitude of the association. Nitroglycerine-induced vasodilatation was not significantly lower in the high Lp(a) level group, compared to the group with normal levels of Lp(a) (< or =239 mg/l) (8.0+/-1.2 vs. 11.4%+/-0.8).
Conclusion: Elevated lipoprotein (a) levels are associated with an impaired endothelial function in healthy postmenopausal women, independent of conventional risk factors for cardiovascular disease. Since Lp(a) may be pathogenetically important for early vascular damage, elevated Lp(a) levels might contribute to the increased cardiovascular risk seen in postmenopausal women.