Effects of continuous positive airway pressure on early signs of atherosclerosis in obstructive sleep apnea

Abstract

Rationale: Obstructive sleep apnea (OSA) is associated with adverse cardiovascular outcomes, including myocardial infarction and stroke. Atherosclerosis is a key mechanism for these cardiovascular events. Recent cross-sectional studies showed the presence of early signs of atherosclerosis in patients with OSA who were free of comorbidities.

Objectives: To determine the impact of treatment with continuous positive airway pressure (CPAP) on atherosclerosis.

Methods: We randomly assigned 24 patients with severe OSA (age, 46 +/- 6 yr) who were free of comorbidities to receive no treatment (control, n = 12) or CPAP (n = 12) for 4 months. Carotid intima-media thickness, arterial stiffness (evaluated by pulse-wave velocity), carotid diameter, 24-hour blood pressure monitoring, C-reactive protein, and catecholamines were determined at baseline and after 4 months.

Measurements and main results: At baseline, all measurements were similar in both groups and did not change in the control group after 4 months. In contrast, a significant decrease occurred in carotid intima-media thickness (707 +/- 105 vs. 645 +/- 95 microm, P = 0.04), pulse-wave velocity (10.4 +/- 1.0 vs. 9.3 +/- 0.9 m/s, P < 0.001), C-reactive protein (3.7 +/- 1.8 vs. 2.0 +/- 1.2 mg/L, P = 0.001), and catecholamines (365 +/- 125 vs. 205 +/- 51 ng/ml, P < 0.001) after 4 months of CPAP. Carotid diameter did not change significantly. Regarding the whole group, changes in carotid intima-media thickness were correlated with changes in catecholamines (r = 0.41, P < 0.05). Changes in pulse-wave velocity were correlated with changes in C-reactive protein (r = 0.58, P < 0.01) and catecholamines (r = 0.54, P < 0.01).

Conclusions: The treatment of OSA significantly improves early signs of atherosclerosis, supporting the concept that OSA is an independent risk factor for atherosclerosis. Clinical trial registered with www.clinicaltrials.gov (NCT 00400543).

Trial registration: ClinicalTrials.gov NCT00400543.