Hypoxemia in patients with idiopathic or heritable pulmonary arterial hypertension

• Published in: PloS one 2018-01, Vol.13 (1), p.e0191869-e0191869
• Main Authors: Khirfan, Ghaleb, Naal, Tawfeq, Abuhalimeh, Batool, Newman, Jennie, Heresi, Gustavo A, Dweik, Raed A, Tonelli, Adriano R
• Format: Article
• Language: English
• Subjects: Adult; Aged; Biology and Life Sciences; Body mass; Body mass index; Body size; Cardiovascular diseases; Critical care; Female; Gases; Health risks; Heart failure; Humans; Hypertension; Hypertension, Pulmonary - complications; Hypertension, Pulmonary - genetics; Hypertension, Pulmonary - physiopathology; Hypoxemia; Hypoxia - complications; Hypoxia - physiopathology; Lung diseases; Male; Medicine; Medicine and Health Sciences; Middle Aged; Oximetry; Patients; Physical Sciences; Pulmonary arteries; Pulmonary functions; Pulmonary hypertension; Research and Analysis Methods; Respiratory function; Respiratory Function Tests; Retrospective Studies; Risk analysis; Risk factors; Standard deviation; Survival; Survival Analysis; Veins & arteries
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0191869

The prevalence and prognostic implications of hypoxemia either at rest or during six-minute walk test (6MWT) in patients with idiopathic or heritable pulmonary arterial hypertension (IPAH or HPAH) have not been systemically studied. We sought to determine the prevalence, phenotypic and prognostic implications of hypoxemia in patients with IPAH and HPAH. Patients with IPAH or HPAH were identified from the Cleveland Clinic Pulmonary Hypertension Registry. Pulse oximetry (SpO2) at rest and during 6MWT was used to define hypoxemia at rest or during activities when measurements were lower than 90%, respectively. A total of 292 patients (age 50.6 ± 18.0 years, 73% females) with IPAH (88%) and HPAH (12%) were included. Of them, 143 (49%) had SpO2 >90% at rest and during 6MWT, 89 (31%) subjects had hypoxemia during 6MWT and 60 (20%) had hypoxemia at rest. Patients with hypoxemia had older age, greater body mass index, higher prevalence of cardiovascular risk factors, worse functional capacity and pulmonary function tests but less severe pre-capillary pulmonary hypertension. Individuals with hypoxemia either at rest or during the initial 6MWT had worse long-term survival when compared to subjects without hypoxemia, even when adjusting for a great number of potential confounders. (HR: 2.5 (95% CI: 1.54-3.98)). Hypoxemia in patients with IPAH and HPAH is associated with more comorbidities, less severe pre-capillary pulmonary hypertension and worse survival.