Six-Minute Walk Test in Evaluation of Children with Pulmonary Arterial Hypertension.

Six-minute walk test (6MWT) is a submaximal exercise test applied for evaluation of adults with pulmonary arterial hypertension (PAH). It was widely used as an endpoint in the clinical trials. The aim of the study was to assess the usefulness of 6MWT in management of children with PAH and to establish correlations with other clinical features. 164 6MWT were performed in 15 children between 5 and 18 years with PAH confirmed by right heart catheterization (102 in patients with shunt, 62 without shunt). Distance in 6MWT (6MWD)-% of predicted for age and gender, desaturation at the maximum effort, peak heart rate (HR)-% of maximal HR, were compared to the level of NTproBNP, WHO-FC, echocardiography parameters, and events of PAH treatment intensification. 6MWD had low negative correlation with peak HR (τ -0.1 p = 0,03), negative correlation with NTproBNP (τ -0.17 p = 0.002), and no dependence on echocardiography parameters. The presence of shunt was associated with lower 6MWD, lower blood saturation at rest, and higher desaturation after effort. Patients in III/IV WHO-FC achieved higher rest HR and maximal HR in comparison to patients in I/II WHO-FC (63.1 vs. 55.2% p < 0.01) and lower 6MWD (64.3 vs. 77.5% p < 0.01). In 14 out of 20 6MWT performed after treatment intensification, increase of distance was observed. The results of 6MWT were consistent with clinical status (WHO-FC, NTproBNP) but not with echocardiography parameters. 6MWT may be the source of additional information in management of children with PAH.