"Reversibility of Cardiovascular Injury With CPAP Use: Mechanisms Involved"

University of Wisconsin, Madison90 enrolled

Overview

The purpose of this study is to determine the factors that are associated with improved cardiovascular function with the use of CPAP therapy on subjects diagnosed with moderate to severe obstructive sleep apnea.

We will monitor non-invasively changes in arterial stiffness, cardiac mass, pulmonary pressures, endothelial function, etc. We will also assess the reversibility of these changes after only 5-7 days of not using the CPAP mask. In a subgroup of subjects we will explore changes in coronary flow response after 12 weeks of CPAP use compared with baseline.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Sleep Apnea, Obstructive Hypoxia Hypercapnia Sleep Disorders Obesity

Eligibility

Sex: ALLMin age: 21 YearsMax age: 50 Years

Medical Language ↔ Plain English

Inclusion Criteria: * subjects naïve of CPAP therapy just recently diagnosed with moderate to severe obstructive sleep apnea (OSA). The degree of OSA is defined by results of a comprehensive polysomnogram requiring an apnea hypopnea index (AHI) \>15 events/hour and Epworth score \>10, or an AHI \>20 events/hour * either sex * any race * between 21-50 years old. Exclusion Criteria: * Systolic blood pressure \>160 mmHg, or diastolic blood pressure \>100 mmHg * Changes in antihypertensive medications in the last 6 weeks * Restless leg syndrome * Average overnight oxygen saturation below 80% * Current use of beta-blockers * History of coronary artery disease * History of Stroke * Atrial fibrillation * Peripheral vascular disease * Suspected cardiac valve abnormality * Ejection fraction \<50% * Type I and type II Diabetes Mellitus (DM) * Asthma or confirmed Chronic Obstructive Pulmonary Disease * Cigarette smoking in the last 6 months * Raynaud's disease * Pregnancy (the normal hormonal changes that occur in pregnancy affect greatly arterial stiffness parameters) If a subject becomes pregnant we will discontinue data collection. * Physically incapable of resting on left lateral decubitus for 40 minutes. * Mastectomy with lymph node removal that might preclude us to monitor blood pressures on both arms

Outcomes

Primary Outcomes

Changes in endothelium mediated response to brachial artery reactivity test between baseline and 4 and 12 weeks after CPAP therapy

Ultrasound based brachial artery reactivity tests will be performed at entry before CPAP therapy and at 4, 12 weeks post CPAP use and 5-7 days after CPAP withdrawal

Time frame: 14 weeks

Secondary Outcomes

Changes in arterial stiffness between baseline and after CPAP treatment

Subjects will undergo pulse wave velocity testing with applanation tonometry. tonometry recordings will be at entry and after 4 and 12 weeks of CPAP use and 5-7- days after withdrawal.

Time frame: 14 weeks

Changes in coronary artery flow under a cold pressor test

A subset of subjects with abnormal endothelial function determined during the baseline scan and good echocardiographic images will be invited to participate on this portion of the test. We will record the response to a cold pressor test (submerging their hand in ice water for 1.5 minutes) on left anterior descending coronary artery velocities with transthoracic echocardiography at baseline and after 12 weeks of CPAP therapy.

Time frame: 13 weeks