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

Study Overview
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Brief Summary
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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)

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

Conditions
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Radionuclide Imaging (MIBG Scintigraphy), Exercise Test, Blood Pressure Monitoring, Ambulatory, Sympathetic Nerve Activity, Catecholamines

Intervention / Treatment
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* Device: CPAP


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Severe OSA males Exclusion Criteria: Smoking Sustained Hypertension Heart failure Diabetes Renal diseases Under use of any medication Under treatment for OSA

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: CPAP<br>OSA treatment with CPAP | Device: CPAP<br>* CPAP<br>|
| No Intervention: control<br>no intervention | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| improvement in sympathetic activity in muscle sympathetic nerve activity (MSNA) | 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. | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| improvement in sympathetic activity evaluated in different sites of activation | 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) | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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treatment, sleep apnea, obstructive, sympathetic nerve activity