Sleep Disordered Breathing in Group 1 Pulmonary Arterial Hypertension
What are the prevalence and clinical correlates of sleep disordered breathing (SDB) and group I pulmonary arterial hypertension (PAH)?
This was a retrospective, cross-sectional, single-center review of consecutive subjects with known PAH, referred for assessment of SDB. Subjects had overnight polysomnography and right heart catheterization data within 6 months of each other as well as routine clinical evaluation, including a 2-D echocardiogram and 6-minute walk distance (6MWD) and B-type natriuretic peptide (BNP). Subjects previously diagnosed with SDB were excluded.
Between 2006 and 2011, 152 patients with group I PAH were screened and 52 met criteria. SDB was present in 71% of the PAH patients: 56% had obstructive sleep apnea (OSA) and 44% central sleep apnea. A high prevalence of OSA occurred in both male (50%) and female (60%) subjects. No differences in cardiopulmonary hemodynamics or survival between those with and without SDB were observed. They were followed for median (range) duration of 1,719 (92–2,504) days. At the time of study, 32 subjects were alive (62%) and 18 were deceased (38%). Treatment for PAH at the time of initial sleep study or treatment of SDB were associated with survival. However, only 50% of those initially treated with positive airway pressure for OSA continued compliance with therapy. Survival was associated with lung function, fewer heart failure symptoms, BNP, and duration of 6MWD. On multiple regression analysis, only BNP remained independently associated with survival outcome (p = 0.014).
The authors concluded that routine testing for SDB should be done in the PAH population, given the high prevalence reported here.
Obvious limitations exist with all retrospective cross-sectional studies; however, the gender ratio here is different from those previously reported large PAH registries, and may simply be a sampling bias. The large clinical question in this group remains unclear. To what extent does SDB contribute to a PAH patient’s symptoms, right ventricular failure, or disease progression? Future studies in this population are needed to elucidate this important problem in order to know whether treatment of SDB will impact outcomes.
Keywords: Polysomnography, Cardiac Catheterization, Sleep Apnea, Central, Hypertension, Pulmonary, Heart Failure, Sleep Apnea, Obstructive, Natriuretic Peptide, Brain
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