Impaired Brachial Artery Reactivity in Young Adults With Clinically Quiescent Juvenile Dermatomyositis.

This study characterized brachial artery reactivity, an ultrasound indicator of endothelial function, in young adults who had clinically quiescent juvenile dermatomyositis (JDM) compared with matched controls. Twenty young adults with previous documentation of JDM 14.2 ± 3.9 years (mean ± SD) after onset of their JDM symptoms, who were no longer taking medications were enrolled, with 20 healthy control participants matched for age, race, sex and body mass index. They obtained ultrasound brachial artery reactivity testing and nailfold end row capillary loop count. Participants were 21.8 ± 4.2 years old (70% female) and were aged 7.6 ± 3.7 years at JDM onset. The JDM Disease Activity Score (DAS) was 1.9 ± 2.5 and primarily based on active skin symptoms. Compared to controls, participants with JDM had fewer end row capillary loops/mm (mean ± SD 6.35 ± 1.29 vs 7.40 ± 0.58; P = 0.002) and were shorter in stature (mean ± SD 163.68 ± 9.69 cm vs 170.49 ± 9.60 cm; P = 0.032). Their end row capillary loop count was associated with their DAS (r = -0.401, P = 0.011). After adjusting for height, age, sex, and resting brachial artery diameter, the brachial artery reactivity in the adults with JDM was significantly lower than that in controls (β = 2.51%, 95% CI -4.62 to -0.40, P = 0.026). This pilot study provides new evidence of endothelial dysfunction, as assessed by brachial artery reactivity, in asymptomatic adults who had classic JDM symptoms in childhood.