INTRODUCTION: Patients with rheumatoid arthritis (RA) are at an increased risk for cardiovascular disease (CVD). One of the earliest manifestations of CVD is endothelial dysfunction (ED). ED can occur in both the microcirculation and the macrocirculation, and these manifestations might be relatively independent of each other. Little is known about the association between endothelial function in the microcirculation and the macrocirculation in RA. The objectives of the present study were to examine the relationship between microvascular and macrovascular endothelial function in patients with RA.

METHODS: Ninety-nine RA patients (72 females, mean age (± SD) 56 ± 12 years), underwent assessments of endothelial-dependent (acetylcholine) and endothelial-independent (sodium nitroprusside) microvascular vasodilatory function (laser Doppler imaging with iontophoresis), as well as endothelial-dependent (flow-mediated dilation) and endothelial-independent (glyceryl trinitrate-mediated dilation) macrovascular vasodilatory function. Vasodilatory function was calculated as the percentage increase after each stimulus was applied relative to baseline values.

RESULTS: Pearson correlations showed that microvascular endothelial-dependent function was not associated with macrovascular endothelial-dependent function (r (90 patients) = 0.10, P = 0.34). Similarly, microvascular endothelial-independent function was not related to macrovascular endothelial-independent function (r (89 patients) = 0.00, P = 0.99).

CONCLUSIONS: Microvascular and macrovascular endothelial function were independent of each other in patients with RA, suggesting differential regulation of endothelial function in these two vascular beds. Assessments of both vascular beds may provide more meaningful clinical information on vascular risk in RA, but this hypothesis needs to be confirmed in long-term prospective studies.