Exercise hypoxaemia as a predictor of pulmonary hypertension in COPD patients without severe resting hypoxaemia

Yoshio Nakahara; Hiroyuki Taniguchi; Tomoki Kimura; Yasuhiro Kondoh; Shinichi Arizono; Koichi Nishimura; Koji Sakamoto; Satoru Ito; Masahiko Ando; Yoshinori Hasegawa

doi:10.1111/resp.12863

Exercise hypoxaemia as a predictor of pulmonary hypertension in COPD patients without severe resting hypoxaemia

Respirology. 2017 Jan;22(1):120-125. doi: 10.1111/resp.12863. Epub 2016 Jul 28.

Authors

Affiliations

¹ Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
² Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
³ School of Rehabilitation Sciences, Seirei Christopher University, Hamamatsu, Japan.
⁴ Department of Pulmonary Medicine, National Center for Geriatrics and Gerontology, Obu, Japan.
⁵ Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Japan.

PMID: 27471142
DOI: 10.1111/resp.12863

Abstract

Background and objective: Pulmonary hypertension (PH) in COPD is associated with morbidity and mortality. Previous studies showed a relationship between resting hypoxaemia and PH, but little is known about the relationship between exercise hypoxaemia and PH in COPD without resting hypoxaemia.

Methods: A retrospective observational study of COPD patients without resting hypoxaemia was conducted to evaluate the relationships between exercise hypoxaemia and pulmonary haemodynamics. Clinical characteristics, pulmonary function, blood gas analysis, 6-min walk distance (6MWD) and oxygen saturation of peripheral artery (SpO₂ ) at the end of the 6-min walk test (6MWT) were reviewed. Correlation analysis and stepwise regression analysis were performed to identify the predictor of mean pulmonary artery pressure (mPAP).

Results: Eighty-four consecutive patients with a mean predicted forced expiratory volume in 1 s (FEV₁ ) of 47 ± 21% were evaluated. In univariate analysis, mPAP had negative correlations with age (r = -0.27, P < 0.05), arterial partial pressure of oxygen (PaO₂ , r = -0.24, P < 0.05), % predicted forced vital capacity (FVC, r = -0.28, P < 0.05), % predicted FEV₁ (r = -0.40, P < 0.001), FEV₁ /FVC ratio (r = -0.33, P < 0.005), % predicted diffusion capacity for carbon monoxide (DL_CO , r = -0.40, P < 0.001), 6MWD (r = -0.40, P < 0.001) and SpO₂ at the end of the 6MWT (r = -0.74, P < 0.001). In stepwise regression analysis, SpO₂ at the end of the 6MWT and 6MWD remained as independent predictors of mPAP (R² = 0.60). In receiver operating characteristic (ROC) analysis, SpO₂ at the end of the 6MWT presented an area under the curve of 0.896 for the prediction of PH, with a sensitivity of 0.86 and specificity of 0.84 for the cut-off point of 81%.

Conclusion: In addition to 6MWD, exercise hypoxaemia indicates PH in patients with COPD without resting hypoxaemia.

Keywords: chronic obstructive pulmonary disease; exercise; pulmonary circulation; pulmonary hypertension; pulmonary rehabilitation.

Publication types

Observational Study

MeSH terms

Aged
Exercise / physiology*
Exercise Tolerance / physiology
Female
Forced Expiratory Volume
Humans
Hypertension, Pulmonary* / diagnosis
Hypertension, Pulmonary* / etiology
Hypertension, Pulmonary* / physiopathology
Hypoxia* / diagnosis
Hypoxia* / etiology
Male
Middle Aged
Oxygen / blood
Predictive Value of Tests
Prognosis
Pulmonary Circulation
Pulmonary Disease, Chronic Obstructive* / complications
Pulmonary Disease, Chronic Obstructive* / diagnosis
Pulmonary Disease, Chronic Obstructive* / physiopathology
ROC Curve
Retrospective Studies
Walk Test / methods

Substances

Oxygen