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

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

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.

Study Overview

• Status: Completed
• Conditions: Obstructive Sleep Apnea; Refractory Hypertension
• Intervention / Treatment: Device: CPAP

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 Type: Interventional
• Enrollment (Actual): 40
• Phase: Phase 3

Contacts and Locations

Study Locations

• Brazil
  • Sao Paulo, Brazil, 05403-904
    • Heart Institute (InCor)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Ambulatory blood pressure monitoring	Change from Baseline in Blood Pressure at 6 months

Secondary Outcome Measures

Outcome Measure	Time Frame
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

Collaborators and Investigators

• Sponsor: University of Sao Paulo

Publications and helpful links

General Publications

• Pedrosa RP, Drager LF, de Paula LKG, Amaro ACS, Bortolotto LA, Lorenzi-Filho G. Effects of OSA treatment on BP in patients with resistant hypertension: a randomized trial. Chest. 2013 Nov;144(5):1487-1494. doi: 10.1378/chest.13-0085.

Study record dates

Study Major Dates

• Study Start: October 1, 2008
• Primary Completion (Actual): March 1, 2011
• Study Completion (Actual): March 1, 2011

Study Registration Dates

• First Submitted: December 19, 2008
• First Submitted That Met QC Criteria: December 19, 2008
• First Posted (Estimate): December 22, 2008

Study Record Updates

• Last Update Posted (Estimate): November 23, 2011
• Last Update Submitted That Met QC Criteria: November 21, 2011
• Last Verified: November 1, 2011

More Information

Terms related to this study

• Keywords: Obstructive sleep apnea; Arterial stiffness; CPAP; Refractory hypertension; Heart remodeling
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Signs and Symptoms, Respiratory; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Hypertension; Apnea
• Other Study ID Numbers: RH-OSA