Highlights
- •Several composite indices can integrate 6MWD and arterial oxygenation changes.
- •These composite indexes predict mortality in some chronic respiratory diseases.
- •Arterial oxygenation during exercise does not add prognostic value to that of the 6MWD in PAH.
Abstract
Background
The 6-min walking distance (6MWD) is often used to assess prognosis in pulmonary arterial
hypertension (PAH) patients. Whether or not changes in arterial oxygen saturation
(SpO2) during exercise add prognostic value to the 6MWD in these patients is unclear. The
objective of this study was to investigate if SpO2 changes during exercise adds prognostic value to the 6MWD in PAH patients.
Methods
Ambispective study that includes 137 patients with PAH: 38 idiopathic/heritable (i/h
PAH), 42 with connective tissue disease (CTD-PAH), 34 with porto-pulmonary hypertension
(PoPH), 21 with HIV-associated PAH and 2 with pulmonary venous occlusive disease (PVOD).
Patients were characterized and, treated according to international recommendations,
and were followed-up for 5 years. To integrate SpO2 changes during exercise, we calculated the desaturation distance ratio (DDR) either
in its original form (from a maximal theoretical value of 100%) or the actual resting
SpO2 value of the patient (new DDR) as well as the distance saturation product (DSP).
Results
(1) during follow-up, 40 patients died (29.2%); (2) results confirmed the prognostic value of the 6MWD (AUC 0.913 [IQR 0.868–0.958];
p < 0.0001), original DDR (AUC 0.923 [0.881–0.966]; p < 0.001), New DDR (AUC 0.917
[0.872–0.961], p < 0.001), and DSP (AUC 0.914 [0.869–0.959], p < 0.001); and, (3) neither the original or new DDR or DSP added significant prognostic value to 6MWD
in these patients.
Conclusions
Consideration of three different composite indices of arterial oxygenation changes
during exercise does not add prognostic value to that of the 6MWD in patients with
PAH.
Keywords
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Article info
Publication history
Published online: December 03, 2022
Accepted:
December 1,
2022
Received in revised form:
November 30,
2022
Received:
May 26,
2022
Identification
Copyright
© 2022 Published by Elsevier Ltd.
