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 μm, 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 (NCT00400543).