Effects of Continuous Positive Airway Pressure (CPAP) in Patients With Resistant Hypertension and Obstructive Sleep Apnea (OSA)

Sponsor

University of Sao Paulo (Other)

Overall Status

Completed

CT.gov ID

NCT00812695

Collaborator

(none)

Enrollment

Location

Arms

28.9

Duration (Months)

1.4

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Obstructive sleep apnea (OSA) is an important cause of refractory hypertension but the impact of treatment with continuous positive airway pressure (CPAP) is not completely understood. The aim of this project is to study the effects of CPAP on blood pressure control and its influences on cardiac remodeling and arterial stiffness in patients with refractory hypertension and moderate or severe OSA.

Condition or Disease	Intervention/Treatment	Phase
Obstructive Sleep Apnea Refractory Hypertension	Device: CPAP	Phase 3

Detailed Description

Study design Interventional, open-label, randomized.

Patients selection

Fifty refractory hypertensive patients with moderate-to-severe OSA, aged between 30 to 65 years old will be recruited from the outpatient clinics of the Heart Institute by the hospital staff.

Refractory hypertension will be defined as usually: blood pressure higher than or equal to 140x90 mmHg after a regimen of three drugs, including a diuretic for a minimum of 3 months. Initial evaluation will consist on ambulatory blood pressure measurement for 24 hours and a detailed clinical examination. Moderate to severe OSA will be defined as an apnea-hypopnea index > 15 evens per hour, after an overnight polysomnography.

Exclusion criteria include BMI >40 kg/m2; diabetes mellitus; aortic, heart and valve diseases; renal failure; other identifiable causes of hypertension, no adherence, use of cocaine, amphetamines, other illicit drugs, sympathomimetics (decongestants, anorectics), oral contraceptive hormones, nonsteroidal anti-inflammatory drugs.

Refractory hypertension Secondary causes of hypertension will be excluded using usual procedures from the Hypertension Unit.

Polysomnography All participants will be submitted to standard overnight polysomnography (EMBLA - Flagra hf. Medical Devices, Reykjavik, Iceland). The apnea-hypopnea index will be calculated as the total number of respiratory events (apneas plus hypopneas) per hour of sleep.

Apnea will be defined as an air flow cessation greater than 10 seconds and hypopnea as a reduction grater than 50% with oxygen saturation fall grater than 4% or arousal.

After recruitment, patients will be instructed about CPAP working by an experimented professional and another polysomnography will be done to adjust pressures. Hour counter will be used to check the adherence to CPAP.

Intervention Patients will be divided in two groups: medical treatment plus CPAP or medical treatment alone for 6 months without drug dose changing.

Twenty-four hour blood pressure monitoring Twenty-four hour blood pressure monitoring (system SpaceLabs 90207) will be used in all patients in the beginning and at the end of the study.

Arterial Stiffness Carotid-femoral arterial stiffness will be determined by Complior.

Echocardiography Echocardiography will be performed by using a commercially available machine.

Study Design

Study Type:

Interventional

Actual Enrollment :

40 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

None (Open Label)

Primary Purpose:

Treatment

Official Title:

Effects of Continuous Positive Airway Pressure in Patients With Resistant Hypertension and Obstructive Sleep Apnea

Study Start Date :

Oct 1, 2008

Actual Primary Completion Date :

Mar 1, 2011

Actual Study Completion Date :

Mar 1, 2011

Arms and Interventions

Arm	Intervention/Treatment
No Intervention: 1
Active Comparator: 2 CPAP	Device: CPAP Gold standard treatment for Obstructive sleep apnea

Arm

Intervention/Treatment

No Intervention: 1

Active Comparator: 2

CPAP

Device: CPAP

Gold standard treatment for Obstructive sleep apnea

Outcome Measures

Primary Outcome Measures

Ambulatory blood pressure monitoring [Change from Baseline in Blood Pressure at 6 months]

Secondary Outcome Measures

Change from Baseline in Arterial stiffness at 6 months [baseline and 6 months]
change from baseline in heart remodeling at 6 months [baseline and 6 months]

Eligibility Criteria

Criteria

Ages Eligible for Study:

30 Years to 65 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Refractory hypertensive patients with moderate-to-severe OSA, aged between 30 to 65 years old.

Exclusion Criteria:

Aortic, heart and valve diseases
Renal failure
Other identifiable causes of hypertension, no adherence, use of cocaine, amphetamines, other illicit drugs, sympathomimetics (decongestants, anorectics), oral contraceptive hormones, nonsteroidal anti-inflammatory drugs.