Significance of the lipid profile and endothelium-dependent vasodilatation in the pathogenesis of microvascular angina

Background: To investigate the significance of lipid disorders and endothelial dysfunction in the pathogenesis of microvascular angina. Methods: Levels of plasma lipids, lipoproteins and apolipoproteins were assessed in 21 patients with microvascular angina and 24 healthy subjects as controls. Also, the endothelium-dependent vasodilatation function was determined with high-resolution ultrasound in both groups. Results: Levels of serum total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), apolipoprotein B100 (ApoB100) and lipoprotein(a) [Lp(a)] in microvascular angina group were significantly higher than those in healthy subjects (each p < 0.05). The flow-mediated dilatation (FMD) in brachial arteries in patients with microvascular angina declined significantly as compared with that in control subjects (4.7 &#177; 1.9% vs. 12.8 &#177; 3.7%, p < 0.001). However, no significant difference was observed in response to nitroglycerin between groups (19.7 &#177; 8.1% vs. 21.2 &#177; 6.6%; p > 0.05). Linear correlation analysis revealed a significant negative correlation between the FMD of brachial arteries and the serum levels of LDL-C and Lp(a) in the microvascular angina group (r = -0.5125 and -0.4271, respectively, both p < 0.001). Subsequently, all subjects were pooled and divided into two groups (groups A and B) according to the degree of FMD in brachial arteries (A &#163; 4% and B > 4%). The serum LDL-C level was found to be significantly higher in group A than in group B (4.09 &#177; 0.65 mmol/L vs. 2.59 &#177; 0.49 mmol/L; p < 0.05). Conclusions: Plasma lipid disorders and vascular endothelial dysfunction may play important roles in the development of microvascular angina. The dysfunction of endothelium-dependent vasodilation was mainly associated with anomalies in LDL-C and Lp(a), and myocardial endothelial dysfunction was aggravated by lipid abnormalities in patients with microvascular angina