Does obstructive sleep apnoea influence BNP concentrations in atrial fibrillation patients?

Abstract

Background B-type natriuretic peptide (BNP) is a biomarker commonly used in diagnosing and assessing prognosis in heart failure patients. Its concentration can be elevated in various conditions associated with excessive heart wall stretch including atrial fibrillation and obstructive sleep apnoea (OSA). The aim of the study was to assess if BNP levels in atrial fibrillation patients are associated with the value of apnoea-hypopnea index (AHI).

Material and methods Study population were consecutive patients with atrial fibrillation, who underwent overnight sleep study, and had blood taken for BNP concentration assessment. Subsequently, patients were divided into group according to AHI: Group I (< 5/h), Group II (5–15/h), and Group III (> 15/h).

Results Analysis covered 158 patients (males, 64.6%; mean age, 58.3 ± 9.2 years). 83 (52.5%) patients had AHI < 5/h, Group II consisted of 44 (27.9%), and Group III of 31 (19.6%) patients. Mean BMI and neck circumference rose with AHI value severity. BMI was as follows 28.7 ± 4.3, 30.7 ± 4.7, and 31.8 ± 5.2 kg/m² (p for trend < 0.01), while neck circumference was 39.2 ± 3.5, 41.5 ± 3.9, and 41.2 ± 3.2 cm, (p for trend = 0.001) for Group I, II, and III respectively. BNP concentration was the lowest in Group I (53.0 ± 57.0 pg/mL), in middle ranges in Group II (69.2 ± 89.9 pg/mL), and the highest in patients with AHI > 15 (104.0 ± 150.8 pg/mL; p for trend = 0.03).

Conclusions Majority of patients with atrial fibrillation have AHI < 5/h and these generally have lower BMI, and neck circumference. Patients who have AHI exceeding ≥ 5/h BNP levels tend to be elevated, and its values rise along with AHI.