Chest
Volume 144, Issue 3, September 2013, Pages 896-902
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Original Research
Sleep Disorders
CPAP Improves Endothelial Function in Patients With Minimally Symptomatic OSA: Results From a Subset Study of the MOSAIC Trial

https://doi.org/10.1378/chest.13-0179Get rights and content

Background

Minimally symptomatic OSA is a highly prevalent disorder, and the effects of CPAP on vascular function in these patients are unknown. This trial aimed to investigate whether CPAP improves vascular function in minimally symptomatic OSA.

Methods

In two centers taking part in the MOSAIC (Multicentre Obstructive Sleep Apnoea Interventional Cardiovascular) trial, 253 patients with minimally symptomatic OSA were randomized to 6 months of CPAP or standard care. Two hundred eight patients attended their follow-up visit within the predefined time window and had complete measurements of arterial stiffness (augmentation index [AIx]), and 64 patients had endothelial function measurements by brachial artery flow-mediated dilatation (FMD). Multivariable analyses adjusting for baseline measurements and minimization factors were performed to assess the effect of CPAP treatment on FMD (% dilatation) and AIx (% augmentation) compared with standard care.

Results

The mean ± SD baseline oxygen desaturation index and Epworth Sleepiness Score (ESS) of the 208 patients (age 58 ± 7.3 years, 31 women) were 13.7 ± 12.8 events/h and 8.3 ± 4.2, respectively. There was no CPAP treatment effect on arterial stiffness (AIx, −1.4%; 95% CI, −3.6 to +0.9%; P = .23), but CPAP improved endothelial function (FMD, +2.1%; 95% CI, +1.0 to +3.2%; P < .0001). CPAP reduced daytime sleepiness (ESS, −2.2; 95% CI, −3.0 to −1.5; P < .0001) compared with standard care. There was a larger improvement in FMD in patients using CPAP for > 4 h/night than those who used it less (P = .013).

Conclusions

CPAP improves endothelial function, but not arterial stiffness, in minimally symptomatic OSA. Thus, minimally symptomatic OSA may be a cardiovascular risk factor.

Trial registry

ISRCTN Register; No.: ISRCTN 34164388; URL: http://isrctn.org

Cited by (0)

Funding/Support: This study was supported by an unrestricted project grant from The British Heart Foundation; research salaries were paid for by Oxford Health Services Research Committee; an unrestricted charitable donation was made by ResMed UK to support research work in the Oxford Sleep Unit in 1998 and 2006; and ResMed UK supplied the CPAP machines for this trial. Prof Kohler was a recipient of a European Respiratory Society [No. 118] and University of Zurich research fellowship.

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