Effectiveness of a portable device and the need for treatment of mild-to-moderate obstructive sleep-disordered breathing in patients with cardiovascular disease

Background and purpose: In Japan, there are two sleep-disordered breathing (SDB)-related problems, which include diagnosing SDB using a portable device (PD) and treating mild-to-moderate SDB (mm-SDB) using continuous positive airway pressure (CPAP) for severe SDB (s-SDB) in obstructive sleep apnea (OSA) patients. Our aims were to evaluate the effectiveness of a PD in diagnosing SDB in patients with cardiovascular disease (CVD), and to assess the difference between mm-SDB [apnea-hypopnea index (AHI): 20-40h(-1)] and s-SDB (AHI: >40h(-1)) using brain natriuretic peptide (BNP) in OSA patients.

Methods and subjects: After their underlying CVD was treated, full-night sleep studies using polysomnography (PSG) and PD were performed on the same day.

Results: Eighty-three patients underwent full-night PSG simultaneously with PD. The average duration of the sleep study was 8.6+/-6.2 days. There was a tendency for a higher AHI value obtained with PSG (PSG, 28.9+/-24.3h(-1); PD, 22.3+/-16.7h(-1); p=0.05). However, the specificity and sensitivity of diagnosing SDB using PD were 86% and 81%, respectively. Using PD, twenty-nine OSA patients had mm-SDB and eleven patients had s-SDB. The BNP value was higher in the mm-SDB patients (318+/-550pg/ml) than in the s-SDB patients (202+/-160pg/ml).

Conclusions: The PD was effective in diagnosing SDB in patients with CVD. The BNP value was higher in the mm-SDB patients. Therefore, they need to be treated with CPAP to treat underlying CVD.