In this single-center, prospective, cross-sectional study we examined brachial artery flow-mediated dilation (FMD), a nitric oxide-mediated, endothelial-dependent response, in children with IPAH and matched controls. FMD measurements were compared with clinical and echocardiographic measures of IPAH severity.
Thirteen patients and 13 controls were studied, ranging in age from 6 to 20 years. FMD was decreased in IPAH subjects compared with controls (5.1 卤 2.1%vs 9.7 卤 2.0%; p < 0.0001). In IPAH subjects, FMD correlated directly with cardiac index (R2 = 0.34, p = 0.035), and inversely with tricuspid regurgitation velocity (R2 = 0.57, p = 0.019) and right ventricular myocardial performance index (R2 = 0.44, p = 0.028).
The presence of systemic endothelial dysfunction in children with IPAH and its strong association with IPAH severity demonstrate that IPAH is a global vasculopathy. Although morbidity in IPAH is typically associated with pulmonary vascular disease, systemic vascular changes may also relate to disease pathogenesis and progression. Further study into shared mechanisms of systemic and pulmonary endothelial dysfunction may contribute to future therapies for IPAH.