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The Effects of Continuous Positive Airway Pressure (CPAP) on Sympathetic Activity in Different Sites of Activation

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified July 2010 by University of Sao Paulo.
Recruitment status was:  Active, not recruiting
Information provided by:
University of Sao Paulo Identifier:
First received: April 13, 2011
Last updated: NA
Last verified: July 2010
History: No changes posted
Recent evidences suggest that obstructive sleep apnea (OSA) can contribute to cardiovascular disease even in the absence of hypertension. However, there are few data regarding the impact of OSA on the sympathetic system in apparently normotensive patients with OSA as well as the impact of treatment with continuous positive airway pressure in different sites of activation (heart, peripheral nerves and circulating catecholamines)

Condition Intervention Phase
Radionuclide Imaging (MIBG Scintigraphy)
Exercise Test
Blood Pressure Monitoring, Ambulatory
Sympathetic Nerve Activity
Device: CPAP
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Effects of Continuous Positive Airway Pressure (CPAP) on Sympathetic Activity in Different Sites of Activation

Further study details as provided by University of Sao Paulo:

Primary Outcome Measures:
  • improvement in sympathetic activity in muscle sympathetic nerve activity (MSNA) [ Time Frame: 3 months ]
    Improvement in MSNA will be quantified as burst frequency over time (bursts per minute) and as burst frequency corrected for heart rate values (bursts per 100 heartbeats)in the begining and after 3 months.

Secondary Outcome Measures:
  • improvement in sympathetic activity evaluated in different sites of activation [ Time Frame: 3 months ]

    All measurement will be performed at the begining and after 3 months. Blood: blood and 24 hour urine will be collected for norepinephrine quantification.

    Heart: Early (15 min) and delayed (3 hr) planar images will be taken after injection of (123)I-MIBG. The mean counts of the whole heart and the mediastinum will be obtained to calculate heart-to-mediastinum count ratios from the early images (H/Me) and from the delayed images (H/Md) and the myocardial washout rate (WR).

    Blood pressure: 24 hour ambulatory blood pressure monitoring and blood pressure during exercise test (treadmill test)

Estimated Enrollment: 20
Study Start Date: July 2010
Estimated Study Completion Date: July 2011
Estimated Primary Completion Date: July 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: CPAP
OSA treatment with CPAP
Device: CPAP
No Intervention: control
no intervention


Ages Eligible for Study:   30 Years to 60 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Severe OSA males

Exclusion Criteria:

  • Smoking

    • Sustained Hypertension
    • Heart failure
    • Diabetes
    • Renal diseases
    • Under use of any medication
    • Under treatment for OSA
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Please refer to this study by its identifier: NCT01336335

Heart Institute
São Paulo, Brazil
Sponsors and Collaborators
University of Sao Paulo
Principal Investigator: Rodrigo Pedrosa, MD, PhD Heart Institute (InCor)
  More Information

Responsible Party: Geraldo Lorenzi-Filho, Universidade de São Paulo Identifier: NCT01336335     History of Changes
Other Study ID Numbers: Sympathetic activity and OSA
Study First Received: April 13, 2011
Last Updated: April 13, 2011

Keywords provided by University of Sao Paulo:
sleep apnea, obstructive
sympathetic nerve activity
treatment processed this record on May 23, 2017