Continuous positive airway pressure improves visit-to-visit blood pressure variability in patients with severe obstructive sleep apnea

Abstract

Background: Recent studies have shown that visit-to-visit blood pressure variability (VVV) is a powerful risk factor for cardiovascular disease. Obstructive sleep apnea (OSA) was associated with high blood pressure variability hypertension (eg, mornig surge, masked hypertension, resistant hypertension) and cardiovascular risk. Purpose: The aims of this study were to examine 1) the association of the severity of OSA with VVV; 2) the effect of continuous positive airway pressure (CPAP) on VVV in patients with OSA. Methods: 76 patients with hypertension (HT) were divided into 3 groups: HT without OSA (controls) (n=26), HT with mild to moderate OSA (n=20), HT with severe OSA (n=30). Age, body mass index and blood pressure levels were matched in three groups. All of the patients underwent polysomnography. Blood pressure was measured 5 times, and VVV was expressed as the standard deviation (SD) of systolic blood pressure and coefficient of variation (CV). In patients with OSA, VVV was obtained at both before and after CPAP (figur presented) Results: Compared with controls and mild to moderate OSA group, VVV was significantly higher in severe OSA group (P<0.05) (figure left panel). In severe OSA group, CPAP significantly reduced SD and CV of systolic blood pressure (11.8±5.8→5.8±4.5 mmHg, P<0.001, 9.2±5.0→3.5±2.2%, P<0.001, respectively) (figure right panel). Conclusions: Severe OSA significantly increased VVV, and CPAP significantly improved VVV in patients with severe OSA. These results may partially explain the increased risk of cardiovascular disease in OSA and benefit of CPAP for decreasing these risks.