Six-minute walking distance and decrease in oxygen saturation during the six-minute walk test in pediatric pulmonary arterial hypertension

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• 作者：Johannes M. Douwes^a ; ¹ ; ^{j.m.douwes@umcg.nl" class="auth_mail" title="E-mail the corresponding author} ; Anneke K. Hegeman^b ; ¹ ; Merel B. van der Krieke^a ; ¹ ; Marcus T.R. Roofthooft^a ; ¹ ; Hans L. Hillege^c ; ¹ ; Rolf M.F. Berger^a ; ¹
• 关键词：6-MWD ; 6-minute walking distance ; 6-MWT ; 6-minute walk test ; HR ; heart rate ; IPAH/HPAH ; idiopathic/hereditary pulmonary arterial hypertension ; PAH ; pulmonary arterial hypertension ; PAH-CHD ; pulmonary arterial hypertension associated with congenital heart disease ; TcSO2 ; transcutaneous oxygen saturation ; WHO-FC ; World Health Organization&mdash ; functional class
• 刊名：International Journal of Cardiology
• 出版年：2016
• 出版时间：1 January 2016
• 年：2016
• 卷：202
• 期：Complete
• 页码：34-39
• 全文大小：497 K

文摘

To investigate the prognostic value of the 6-minute walking distance (6-MWD), transcutaneous saturation (tcSO2) and heart rate (HR) obtained during the 6-minute walk test (6-MWT) in pediatric pulmonary arterial hypertension (PAH).

Methods

This was an observational study with forty-seven pediatric PAH patients, aged ≥ 7 years, and diagnosed and followed at the national referral center for pediatric PAH in the Netherlands. All patients performed a comprehensive 6-minute walk test (6-MWT), which measures 6-MWD and tcSO2 and HR before (“baseline”), during (“exercise”) and 5 min after (“recovery”) the walk test.

Results

The 6-MWD expressed either in meters or in sex- and age-corrected z-scores, was associated with transplant-free survival, independently from sex, age, and the presence of a shunt-defect. Shorter 6-MWD correlated with higher WHO-FC and increased NT-pro-BNP. Absolute tcSO2 at exercise and tcSO2-decrease during 6-MWT were associated with transplant-free survival, independent from 6-MWD. Combining tcSO2-decrease with 6-MWD provided the strongest prognostic model. Patients with 6-MWD > 352 m (the median 6-MWD) had a better outcome than those with smaller 6-MWD. A large tcSO2-decrease during 6-MWT (> 19% for patients with and > 5% for patients without a shunt defect) identified patients with worse transplant-free survival both in patients with a 6-MWD above and below the median 6-MWD.

Conclusions

The 6-MWD is an independent predictor of prognosis in pediatric PAH, that reflects disease severity and clinically relevant exercise-tolerance and therefore qualifies as a treatment goal. The magnitude of tcSO2-decrease during 6-MWT, adjusted for the presence of a shunt, indicates an additional risk factor for prognosis in children with PAH.