The purpose of this study is to determine whether CPAP is effective in the treatment of systemic hypertension.

It is now well known that cardiovascular risks are increased in patients with obstructive sleep apnea syndrome (OSAS). Also a link has already been demonstrated between OSAS and hypertension.

Nowadays, the most efficient treatment of the OSAS is the continuous Positive Airway Pressure (cPAP). Several studies have also shown that cPAP could reduce arterial blood pressure in OSAS patients. But level of blood pressure (BP), drug treatment were not equal between groups and it`s difficult to single out independent role of cPAP.

Our study has the objective to compare the effects of cPAP on hypertension in OSAS patients. After 3-9 weeks of antihypertensive treatment (valsartan and amlodipine) those one who reached target level of BP will be randomized either in the group "treatment by cPAP" or in the group "treatment by cham-cPAP" for 3 weeks and then we`ll perform cross-over.

• Obstructive Sleep Apnea Syndrome
• Hypertension

• 1: Active Comparator
  Intervention: Device: cPAP
• 2: Sham Comparator
  Intervention: Device: cPAP

Inclusion Criteria:

• male/female over than 18 years old
• patient with an obstructive sleep apnea (apnea-hypopnea index > or equal to 15)
• patient with weak or moderate hypertension (140 <= SBP < 180 mmHg and 90 <= DBP < 110 mmHg)
• negative pregnancy test
• ambulatory patient
• patient who have signed the informed consent form

Exclusion Criteria:

• pregnant or nursing woman
• woman who refuses to use contraceptive method
• acute hepatic failure, biliary cirrhosis, cholestasis
• clearance of Cockcroft < 30 ml/min/1.73m2
• kaliemia >= 5.5 mmol/l
• acute hypertension (SBP>= 180 mmHg and/or DBP >= 110 mmHg)
• acute daytime sleepiness (Epworth rating scale > 15)
• patient with a profession that is inconsistent with the continuous positive airway pressure (CPAP) treatment
• known cardiovascular pathologies
• contraindication to CPAP
• allergy to valsartan and/or amlodipine
• patient treated with lithium
• patient on tutelle or curatelle
• patient kept in detention, major protected by the law, hospitalized person patient currently participating in another clinical trial