Sleep-related breathing disorders in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension
Background. The data evidence that in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) nocturnal hypoxemia is associated with poor prognosis. Although, data regarding sleep-related breathing disorders (SRBD) prevalence and their association with pulmonary hypertension (PH) severity are scarce.Objective. To evaluate the prevalence and the structure of SRBD in patients with PAH and CTEPH and the relationship of SRBD with PH severity. Design and methods. In a prospective, single-center study we examined 31 patients (45 % male (n = 14)) with a verified diagnosis of precapillary PH: 22,6 % with IPAH; 9,7 % with PAH associated with congenital heart disease; 64,5 % with CTEPH; 3,2 % with PAH associated with connective tissue disease. Patients underwent a general clinical examination, questionnaires, respiratory tests, full videopolysomnography, electrocardiogram, and heart ultrasound (ECHO) examination, clinical and biochemical blood tests, including the assessment of ADMA and NT-proBNP levels.Results. No differences in SRBD pattern in patients with PAH and CTEPH were observed as well as with the severity of PH. A positive correlation was found between the apnea-hypopnea index (AHI) and the end-diastolic left ventricular dimension (ρ = 0,54; p = 0,005); the ventricular diameter ratio (RV/LV) negatively correlated with AHI (ρ = -0,41; p = 0,05). Low peripheral blood oxygen saturation negatively correlated with NT-proBNP level (ρ = -0,40; p = 0.035). ADMA level was increased in all patients, nevertheless no association between ADMA and SRBD severity was found (χ2 = 2,97; p = 0,085).Conclusions. SRBD often occurs among patients with PAH and CTEPH, while the presence of SRBD is not associated with the severity of PH. The severity of SRBD is associated with left heart remodeling. The severity of nocturnal hypoxemia in our group is associated with the increased NT-proBNP level, which is consistent with the idea of a negative prognostic value of nocturnal hypoxemia in patients with PAH and CTEPH.