The aim of this study is to examine how effective CPAP treatment and treatment with nebivolol are respectively on reducing blood pressure and on endothelial dysfunction in patients suffering from obstructive sleep apnea and hypertension.

Inclusion Criteria:

• male/female ≥ 18 years old
• patient with obstructive sleep apnea (apnea-hypopnea index ≥ 20) naïve for CPAP treatment
• patient with weak or moderate hypertension (140 <= systolic blood pressure (SBP) < 180 mmHg and 90 <= diastolic blood pressure (DBP) < 110 mmHg naïve for any antihypertensive treatment
• negative pregnancy test
• ambulatory patient
• patient who have signed the informed consent form
• patient affiliated to social security

Exclusion Criteria:

• pregnant or nursing woman
• acute hepatic failure, biliary cirrhosis, cholestasis
• clearance of Cockcroft < 30 ml/min/1.73m2
• sick sinus syndrome, including sino-atrial block
• second and third degree heart block (without a pacemaker)
• history of bronchospasm and bronchial asthma
• bradycardia (heart rate< 60bpm prior to start therapy)
• severe peripheral circulatory disturbances
• acute hypertension (SBP>= 180 mmHg and/or DBP >= 110 mmHg)
• severe daytime sleepiness (Epworth rating scale > 15)
• known cardiovascular pathologies
• contraindication to CPAP
• allergy to nebivolol
• patient treated with antihypertensive drug(s), with class I antiarrhythmics (quinidine, hydroquinidine, cibenzoline, flecainide, disopyramide, lidocaine, mexiletine, propafenone)
• patient treated with CPAP
• patient kept in detention, major protected by the law, hospitalised person
• patient currently participating in another clinical trial