Loading...
Gas exchange responses during 6-min walk test in patients with pulmonary arterial hypertension
Morris, Norman R. Seale, Helen Harris, Julie Hall, Kathleen Lin, Aaron C. W. Kermeen, Fiona
Morris, Norman R.
Seale, Helen
Harris, Julie
Hall, Kathleen
Lin, Aaron C. W.
Kermeen, Fiona
Abstract
Background and objective The 6‐min walk test (6MWT) is the most widely utilized method of assessing exercise capacity in pulmonary arterial hypertension (PAH). Cardiopulmonary exercise testing has the advantage of providing additional physiological information over 6MWT. The goals of our study were to describe the addition of gas exchange measurements to 6MWT and to determine how these parameters were related to the severity of PAH in three major subgroups of PAH (idiopathic (IPAH), connective tissue disease‐related (CTPAH) and congenital heart disease‐related (CHPAH)). Methods Seventy‐six PAH patients (IPAH, n = 28; CTPAH, n = 24; CHPAH, n = 24) completed the 6MWT with simultaneous gas exchange measurements. The 6‐min walk distance (6MWD), oxygen uptake (urn:x-wiley:resp:media:resp12868:resp12868-math-0001 O2 ), carbon dioxide production (urn:x-wiley:resp:media:resp12868:resp12868-math-0001 CO2 ), oxygen saturation, minute ventilation to carbon dioxide output (urn:x-wiley:resp:media:resp12868:resp12868-math-0001 E/urn:x-wiley:resp:media:resp12868:resp12868-math-0001 CO2 ) and end‐tidal partial pressure for carbon dioxide (PETCO2 ) were compared between subgroups, different functional classes (FCs) and pharmacotherapy. Results Whilst no significant difference in 6MWT was observed, absolute urn:x-wiley:resp:media:resp12868:resp12868-math-0001 O2 and urn:x-wiley:resp:media:resp12868:resp12868-math-0001 CO2 were higher for IPAH (P < 0.05). Differences were removed when urn:x-wiley:resp:media:resp12868:resp12868-math-0001 O2 and urn:x-wiley:resp:media:resp12868:resp12868-math-0001 CO2 were expressed relative to body mass (i.e. mL/kg/min). CHPAH had the most significant desaturation during 6MWT (CPAH: 73 ± 15%; CTPAH: 90 ± 8%, IPAH: 92 ± 8%, P < 0.01). There was no difference in urn:x-wiley:resp:media:resp12868:resp12868-math-0001 E/urn:x-wiley:resp:media:resp12868:resp12868-math-0001 CO2 and PETCO2 between groups; however, New York Health Association (NYHA) FC II performed better than FC III subjects in 6MWT with lower urn:x-wiley:resp:media:resp12868:resp12868-math-0001 E/urn:x-wiley:resp:media:resp12868:resp12868-math-0001 CO2 and higher end‐exercise PETCO2 . Similarly, individuals on more advanced pharmacotherapy (triple therapy vs monotherapy) had poorer gas exchange during exercise. Conclusion Whilst 6MWT and gas exchange did not differentiate between PAH groups, individuals with more severe disease and on more advanced pharmacotherapy had poorer gas exchange during exercise.
Keywords
Date
2017
Type
Journal article
Journal
Respirology
Book
Volume
22
Issue
1
Page Range
165-171
Article Number
ACU Department
School of Allied Health
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
License
File Access
Controlled