The Effects of Continuous Positive Airway Pressure (CPAP) on Sympathetic Activity in Different Sites of Activation
Recruitment status was Active, not recruiting
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)
Radionuclide Imaging (MIBG Scintigraphy)
Blood Pressure Monitoring, Ambulatory
Sympathetic Nerve Activity
|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|
- improvement in sympathetic activity in muscle sympathetic nerve activity (MSNA) [ Time Frame: 3 months ] [ Designated as safety issue: No ]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.
- improvement in sympathetic activity evaluated in different sites of activation [ Time Frame: 3 months ] [ Designated as safety issue: No ]
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)
|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)|
OSA treatment with CPAP
No Intervention: control
Please refer to this study by its ClinicalTrials.gov identifier: NCT01336335
|São Paulo, Brazil|
|Principal Investigator:||Rodrigo Pedrosa, MD, PhD||Heart Institute (InCor)|