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

University of Sao Paulo20 enrolled

Overview

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)

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

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

Eligibility

Sex: MALEMin age: 30 YearsMax age: 60 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

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.

Time frame: 3 months

Secondary Outcomes

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)