Endothelial function, arterial wall mechanics and intima media thickness in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a chronic inflammatory disease of children which might persist into adulthood. Systemic inflammation seen in adult RA patients has been shown to be associated with alteration in endothelial function, arterial wall mechanics and intima media thickness. Our study was planned to assess similar changes in JIA patients.

Thirty-one newly diagnosed JIA patients and a similar number of age- and sex-matched controls were enrolled in the study. Endothelial function was assessed by measuring flow mediated dilation and glyceryl trinitrate (GTN)-mediated dilation of the brachial artery. To assess arterial stiffness, various arterial wall mechanic parameters such as cross-sectional compliance, cross-sectional distensibility, shear stress and elastic modulus were derived. Intima media thickness of the common carotid artery was measured as a marker of subclinical atherosclerosis.

The brachial artery diameter at rest was found to be slightly lower in the patients than controls (0.258 ± 0.042 vs. 0.264 ± 0.039; p=0.54). No significant difference was found in flow mediated dilation (17.71 ± 9.26 vs. 16.31 ± 8.23; p=0.53), GTN mediated dilation (25.25 ± 10.02 vs. 23.66 ± 9.79; p=0.53) or FMD: GTN mediated dilation ratio (0.730 ± 0.432 vs. 0.717 ± 0.280; p=0.89) between the cases and controls. There was also no significant difference in carotid artery intima media thickness (0.065 ± 0.0068 vs. 0.068 ± 0.007; p=0.084) between cases and controls. Cases in different subsets of JIA were also analysed separately with regards to FMD, GTN mediated dilation and cIMT but no difference was found between cases in each subset and their controls. Cross-sectional compliance was significantly lower in cases than controls (0.0016 ± 0.0005 vs. 0.002 ± 0.001; p=0.034). Cross-sectional distensibility (0.009 ± 0.003 vs. 0.011 ± 0.006; p=0.14) was also found to be lower whereas diastolic wall shear stress (299.9 ± 47.08 vs. 294.9 ± 59.5; p=0.72) and elastic modulus (1138.5 ± 1085.8 vs. 911 ± 453; p=0.19) were found to be higher in cases as compared to controls. But these differences were not statistically significant. When the subsets were analysed separately for vessel wall indices, cross-sectional compliance was found to be significantly lower in systemic arthritis patients as compared to controls. A high level of intra- and inter-observer agreement was found for all the ultrasonographically evaluated parameters.

Arterial wall indices were found altered in JIA patients indicating increased arterial stiffness. Larger studies are required to assess endothelial dysfunction, intima media thickness and arterial stiffness in each subset of JIA patients.