Endothelial function in patients with rheumatoid arthritis without classical cardiovascular risk factors is determined by subclinical lipid disturbances and compensatory vascular adaptation.

Endothelial dysfunction has been reported in rheumatoid arthritis (RA) patients without classical cardiovascular risk factors, but findings remain inconsistent. To assess whether endothelial function is impaired in RA with moderate inflammatory burden in the absence of established cardiovascular risk factors. This cross-sectional study was conducted in 64 patients with RA without classical CV risk factors and 60 healthy age- and sex-matched controls. Endothelial function was evaluated in the brachial artery by flow-mediated dilation (FMD), in peripheral and skin microcirculation by peripheral arterial tonometry (RH-PAT), and flow-mediated skin fluorescence (FMSF), respectively. There were no significant differences in endothelial function parameters between patients with RA and healthy controls. However, patients with RA had increased augmentation index: 3.0 (-9.0-10.0) vs -6.5 (-16.0-2.0), P = 0.003. 29 patients with RA that displayed lowered FMD (<7%) had higher total cholesterol (5.09 mmol/l [0.85] vs 4.47 [0.77], P = 0.005) and higher low-density lipoprotein cholesterol (LDL-C: 2.92 mmol/l [0.86] vs 2.42 [0.75], P = 0.02). Surprisingly, a subgroup with FMD >7% had higher C-reactive protein (CRP) (1.11, [1.0-8.46] vs 1.0 [1.0-1.0], P = 0.03) in contrast to patients with FMD <7%. Furthermore, microvascular responses measured by FMSF techniques (RHR%) were augmented in patients with higher LDL-C levels as compared with the group of RA with lower LDL-C level. RA, even with a moderate inflammatory burden, may facilitate the detrimental effect of lipoproteins on macrovascular endothelial function. Interestingly, compensatory vascular responses were detected that may precede overt vascular dysfunction. Their monitoring may be useful in endothelial-guided therapy.