A Randomized Controlled Study of the Long-term Effects of Nasal Continuous Positive Airway Pressure on Systemic Blood Pressure, Coagulability and Carotid Intima-media Thickness in Obstructive Sleep Apnea Syndrome
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 100
- 试验地点
- 1
- 主要终点
- Blood Pressure measurement
研究概览
简要总结
Sleep-disordered breathing (SDB) briefly means cessation of breathing during sleep at least 5 times per hour. Sleep-disordered breathing affects 9 to 24% of the middle-aged and overall 4% of the middle-aged males suffers from Obstructive sleep apnea syndrome (OSAS) i.e. SDB with associated daytime sleepiness. Several major epidemiological studies have shown that SDB is not only an independent risk factor for systemic hypertension but it is also associated with cardiovascular complications such as heart failure, stroke, and sudden death.
The mechanisms for the linkage between Sleep-disordered breathing and cardiovascular diseases are not fully determined but surges in sympathetic nerve activity are seen at the end of each apneic episode accompanied by large rises in systemic arterial blood pressure (BP). The increased levels of muscle sympathetic nerve activity are diminished by nasal continuous positive airway pressure (CPAP) therapy. Numerous studies have found a hypercoagulable state in terms of increased clotting factor and platelet activities, and impaired fibrinolysis in coronary artery disease, ischaemic stroke, and sleep-disordered breathing. Common carotid artery intima-media thickness (IMT) has been shown to correlate with traditional vascular risk factors and may predict the likelihood of acute coronary events and stroke. Recently, carotid artery intima-media thickness has been shown to have positive correlations with the severity of sleep disordered breathing.
Despite robust evidence showing improvement of symptoms, cognitive function and quality of life in patients with obstructive sleep apnea treated with nasal continuous positive airway pressure, there are conflicting short-term data whether continuous positive airway pressure can reduce blood pressure in patients with obstructive sleep apnea. This randomized controlled study aims to assess the long-term effects of nasal continuous positive airway pressure on 1) 24 hr systemic blood pressure; 2) Coagulation state; and 3) Carotid artery intimal media thickness.
详细描述
Subjects and Methods: We propose to carry out a prospective, randomized controlled study on 100 consecutive patients newly diagnosed with obstructive sleep apnea syndrome, as defined by overnight sleep study showing Apnea- hypopnoea index (AHI) >or=5 per hour of sleep plus Epworth sleepiness scale (ESS) ≥10.1 The patients will be recruited from the Respiratory Clinic, Prince of Wales Hospital (PWH), Shatin.
Sleep assessment: Overnight diagnostic polysomnography(PSG) [Healthdyne Alice 4, USA] will be performed at Prince of Wales Hospital, Hong Kong for every subject on the first night recording electroencephalogram, electro-oculogram, submental electromyogram, bilateral anterior tibial electromyogram, electrocardiogram, chest and abdominal wall movement by inductance plethysmography, airflow measured by a nasal pressure transducer [PTAF2, Pro-Tech, Woodinville, WA, USA]and supplemented by oronasal airflow thermister, and finger pulse oximetry as in our previous studies.2,3 Sleep stages will be scored according to standard criteria by Rechtshaffen and Kales.4 Apnoea is defined as cessation of airflow for > 10 seconds and hypopnea as a reduction of airflow of > 50% for > 10 seconds plus an oxygen desaturation of > 3% or an arousal.
Ambulatory Blood Pressure Monitoring (ABPM):
All patients with obstructive sleep apnea syndrome will be fitted with the Ultralite Ambulatory Blood Pressure Monitoring (Spacelabs Medical, Redmond, WA) via an arm cuff as out-patients during normal activities and monitored for 48 hrs prior to commencement of continuous positive airway pressure or conservative treatment. The patients' arm circumference will be measured at the biceps level and an appropriate sized arm cuff will be applied. The machine will be programmed for cuff inflation measurement every 30 minutes for 48 hrs and can only be removed for bathing. Patients will be asked to abstain from caffeine-containing products during this time but to continue their normal daily activities. Patients will record the time they retire to bed and the subsequent time of waking in order to identify the sleep period. Data gathered before 6pm on the second evening will be discarded to allow for acclimatization and the analysis will be performed with the second 24 hr of data (6pm to 6am).5 Data will be manually checked for artifact by our respiratory fellow, who will be blinded to the treatment status of the patient. Ambulatory Blood Pressure Monitoring will be repeated for all patients with significant OSAS at 3, 6, and 12 months of the study.
Conservative treatment 6 months followed by continuous positive airway pressure 6 months vs Concurrent continuous positive airway pressure+ Conservative treatment for 12 months:
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 20 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age 20 to 80 yrs
- •Apnoea Hypopnea index ≥5/hr on Polysomnography with Epworth Sleepiness Scale ≥10
排除标准
- •Predominantly central sleep apnoea
- •Recent myocardial infarction 3 months before the study
- •Unstable angina
- •Underlying malignancy
- •Professional drivers and those handling dangerous machinery
- •Patients will be considered dropouts if anti-hypertensive medication is accidentally changed by the patients or their general practitioners
结局指标
主要结局
Blood Pressure measurement
时间窗: 6 and 12 months
次要结局
- serial changes of carotid intimal media thickness between the two treatment groups over 12 months(12 months)
- serial changes in haemostatic assays(6 and 12 months)
- Changes in systolic and diastolic Blood pressure between the 2 groups at 6 & 12 months(6 and 12 months)
研究者
Fanny W.S. Ko
Dr
Chinese University of Hong Kong