Continuous positive airway pressure and measures of cardiovascular risk in men with OSAS

¹ Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, UK; and Joint first authors
² Dept of Respiratory Medicine, Musgrove Park Hospital, Taunton, UK; and Joint first authors
³ Dept of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, UK
⁴ Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, UK
⁵ Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, UK; and Joint senior authors

^* To whom correspondence should be addressed. E-mail: Malcolm.Kohler{at}orh.nhs.uk.

	Abstract

Obstructive sleep apnoea syndrome (OSAS) has been associated with hypertension, stroke and myocardial ischemia in epidemiological and observational studies. Continuous positive airway pressure (CPAP) is the treatment of choice for OSAS, but the impact of this intervention on established risk factors for cardiovascular disease remains incompletely understood.

102 men with moderate-severe OSAS were randomised to therapeutic (n=51) or subtherapeutic (n=51) CPAP treatment for 4 weeks to investigate effects of active treatment on 24-hour urinary catecholamine excretion, baroreflex sensitivity (BRS), arterial stiffness (augmentation index) and 24-hour ambulatory blood pressure (ABP).

Results are expressed as mean (SD). Four weeks of therapeutic CPAP significantly reduced urine normetanephrine excretion (from 179.7 (80.1) to 132.7 (46.5) µmol·mol^-1 creatinine) and augmentation index (from 14.5 (11.3) to 9.1 (13.8) %) compared to the subtherapeutic control group (two-way ANOVA, p=0.004 and p=0.001 respectively, between interventions). Furthermore, therapeutic CPAP significantly improved BRS (from 7.1 (3.3) to 8.8 (4.2) ms·mmHg^-1; two-way ANOVA, p=0.001, between interventions) and reduced mean arterial ABP by 2.6 (5.4) mmHg (two-way ANOVA, p=0.02, between interventions).

In conclusion, treatment of obstructive sleep apnoea with CPAP may lower cardiovascular risk by reducing sympathetic nerve activity, ambulatory blood pressure, arterial stiffness and by increasing sensitivity of the arterial baroreflex.

This article has been cited by other articles:

				M. Enoz and H. M. Inancli CPAP and measures of cardiovascular risks in patients with OSAS Eur. Respir. J., June 1, 2009; 33(6): 1520 - 1520. [Full Text] [PDF]

				S. D West, H. A McBeath, and J. R Stradling Obstructive sleep apnoea in adults BMJ, April 7, 2009; 338(apr07_1): b1165 - b1165. [Full Text]