title: Exercise hypoxaemia as a predictor of pulmonary hypertension in COPD patients without severe resting hypoxaemia.
abstract: 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.
  
  
  
  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).
  
  
  
  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 (DLCO, r = -0.40, P < 0.001), 6MWD (r = -0.40, P < 0.001) and SpO2at the end of the 6MWT (r = -0.74, P < 0.001). In stepwise regression analysis, SpO2at the end of the 6MWT and 6MWD remained as independent predictors of mPAP (R2= 0.60). In receiver operating characteristic (ROC) analysis, SpO2at 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%.
  
  
  
  In addition to 6MWD, exercise hypoxaemia indicates PH in patients with COPD without resting hypoxaemia.
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.|Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Nakahara
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Respiratory Medicine and Allergy, Tosei General Hospital, Seto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kondoh
authors.affiliation: School of Rehabilitation Sciences, Seirei Christopher University, Hamamatsu, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Arizono
authors.affiliation: Department of Pulmonary Medicine, National Center for Geriatrics and Gerontology, Obu, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishimura
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sakamoto
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Ito
authors.affiliation: Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ando
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hasegawa
mesh_terms: D000368:Aged; D015444:Exercise / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D000860:Hypoxia / Q000175:diagnosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011237:Predictive Value of Tests; D011379:Prognosis; D011652:Pulmonary Circulation; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D012372:ROC Curve; D012189:Retrospective Studies; D000070857:Walk Test / Q000379:methods
chemical_list: D010100:Oxygen
keywords: chronic obstructive pulmonary disease; exercise; pulmonary circulation; pulmonary hypertension; pulmonary rehabilitation