Role of Heme-oxygenase (HO) and Nitric Oxide (NO) Pathway in Patients With Obstructive Sleep Apnea (OSA) and Pulmonary Hypertension (PH)

NCT ID: NCT02368171

Last Updated: 2015-02-20

Basic Information

• Recruitment Status: UNKNOWN
• Total Enrollment: 60 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2015-03-31

Brief Summary

Research design: This is a controled prospective study.

Methodology:

Patients with newly diagnosed and untreated OSA with total apnea-hypopnea index (AHI) >5/h, and control (AHI<5/h) will be recruited from the Long Beach VA sleep center. Controls are subjects without OSA or other sleep disorders and no sign of pulmonary hypertension based on echo. The investigators also measure pulmonary artery pressure by 2D Echo and exclude patient with any sign of left heart dysfunction. PH will be defined as RVSP > 35 mmHg or mean PA pressure>25 mmHg. The investigators will recruit subjects with and without PH and OSA in three separate groups:

1. group one : OSA+ PH,

2. group two: normal individual with no OSA and no PH,

3. group three: OSA with no PH Pulmonary function test will be done to exclude patients with underlying lung disease.

The inclusion criteria is: Age >20, AHI >5, AHI <5 (as control), RVSP > 35 mmHg OR Mean PA pressure>25 mmHg, RVSP < 35 mmHg OR Mean PA pressure < 25 mmHg (as control).

Subjects will be excluded if they had known peripheral vascular disease, liver disease, hemolytic anemia, inflammatory disease, active infection, or if they were pregnant, on therapy for OSA, on chronic steroid treatment, or younger than 20 years of age, patients with left heart failure (systolic or diastolic), patients are on PH medications including sildenafil, active smokers, COPD and asthma, active infection or inflammatory disease and collagen vascular disease.

Nocturnal polysomnography will be performed and scored according to the American Academy of Sleep Medicine.

Exhaled Carbon monoxide (CO) will be measured with a calibrated fuel cell type electrochemical device with sensor sensitivity of 1 ppm. The mean of three reproducible measurements will be recorded and corrected for ambient CO.

Exhaled Nitric Oxide (NO) will be measured. At each testing session, at least three flow-regulated FENO measurements will be performed.

The investigators will repeat 2D Echo and measurements of above factors after 3 months of CPAP treatment. The investigators also check patient's compliance with the treatment by downloading data off of their CPAP device.

Each subject will be informed of the experimental procedures, which is approved by the Human Investigation Committee of the VA-Long Beach.

Finding:

The investigators hypothesize that HO pathway causing perturbation of pulmonary endothelial function by inhibition of nitric oxide.

Clinical significance:

OSA is associated with PH, but exact mechanism is not well known. In the past, I have shown that increased endogenous CO in the setting of elevated NO concentration is associated with endothelial dysfunction in patient with OSA. Therefore, the investigators sought to investigate the roles of HO and NO pathways in patients with OSA associated with PH.

Impact/significance:

It addresses a fundamental gap in our understanding of how OSA results in increase the pulmonary artery pressure and if substantiated, will provide the basis for the design and testing of new approaches to prevention and treatment of OSA.

Conditions

Obstructive Sleep Apnea; Pulmonary Hypertension

Study Design

• Observational Model Type: CASE_CONTROL
• Study Time Perspective: PROSPECTIVE

Study Groups

Obstructive sleep apnea with pulmonary hypertension

Patients with AHI\> 5/h and pulmonary hypertension with RVSP\>35 mmHg on Echo

measure exhaled carbon monoxide and nitric oxide

Intervention Type: OTHER

control

patients with AHI\<5/h and RVSP\<35 mmHg on Echo

measure exhaled carbon monoxide and nitric oxide

Intervention Type: OTHER

OSA with no Pulmonary hypertension

patients with AHI\>5/h, but RVSP\<35 mmHg on Echo

measure exhaled carbon monoxide and nitric oxide

Intervention Type: OTHER

Interventions

measure exhaled carbon monoxide and nitric oxide

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

1. participants must satisfy diagnostic criteria for Obstructive sleep apnea.

2. evidence of pulmonary hypertension disease base upon one or more of the following: RVSP > 35 mmHg OR Mean PA pressure>25 mmHg, RVSP < 35 mmHg OR Mean PA pressure < 25 mmHg (as control).

3. age greater than or equal to 20 years.

4. no significant alcohol use (7 or fewer drinks per week).

Exclusion Criteria

1. peripheral vascular disease

2. liver disease

3. Pregnancy. A serum pregnancy test must be performed and negative in all women of child bearing potential within 2 weeks prior to enrollment.

4. Any medical or psychosocial condition that, in the opinion of the investigator, could jeopardize the subject's participation, and compliance with the study criteria.

5. hemolytic anemia

6. inflammatory disease

7. active infection,

8. on therapy for OSA,

9. on chronic steroid treatment,

10. younger than 20 years of age,

11. patients with left heart failure (systolic or diastolic),

12. patients are on pulmonary hypertension medications including sildenafil,

13. active smokers,

14. COPD and asthma,

15. active infection or inflammatory disease

16. collagen vascular disease.

• Minimum Eligible Age: 20 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Southern California Institute for Research and Education

OTHER

Sponsor Role: lead

Responsible Party

Behrouz Jafari

Assisstant professore of medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Other Identifiers

OSA-PH-001

Identifier Type: -

Identifier Source: org_study_id