The Effects of Obstructive Sleep Apnea and Its Intervention on Coronary Heart Disease
Condition: Hypertension; Metabolic Disorder
MeSH terms: Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Hypertension; Heart Diseases; Coronary Disease; Coronary Artery Disease; Myocardial Ischemia; Metabolic Diseases
Study type: Interventional

Summary: 
      Obstructive sleep apnea(OSA) is an important identifiable cause of hypertension. Previous
      study has suggested that OSA significantly increases cardiovascular morbidity and mortality,
      especially in patients with pre-existing cardiovascular disease.The standardized treatment of
      moderate/severe OSA is continuous positive airway pressure (CPAP). Most of short-term trials
      indicated that CPAP treatment reduced BP in patients with OSA. But relevant studies have a
      relative short duration with only but few more than one year. In our opinion, they are not
      sufficient to detect the real effect of CPAP on reduction in BP. Besides, the impact of OSA
      on metabolic disorder is still unclear.We hypothesized that long-term CPAP treatment could
      reduce blood pressure and improve metabolic disorder in patients with coronary heart disease
      (CHD)and OSA.
    

Detailed description: 
      Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive partial
      (hypopnea) or complete (apnea) occlusion of the upper airway during sleep caused by collapse
      of the pharyngeal airway, resulting in sleep fragmentation and oxyhemoglobin desaturation.
      Kiely and colleague's study showed that over 20% of hypertensive patients exhibit OSA,
      whereas prevalence of hypertension in the setting of OSA exceeds 50%. One study confirmed
      that OSA is an important identifiable cause of hypertension. OSA is considered as one of the
      most common risk factors of resistant hypertension. Previous study has suggested that OSA
      significantly increases cardiovascular morbidity and mortality, especially in patients with
      pre-existing cardiovascular disease. Several studies confirmed that CPAP reduced systolic
      blood pressure (SBP) and diastolic blood pressure (DBP) in patients with OSA. Additionally,
      some papers reported that there was a protective effect of CPAP therapy against death from
      cardiovascular disease in patients with severe OSA. Other researches regarding the
      antihypertensive effect of CPAP therapy, however, showed that CPAP had no antihypertensive
      effect. But relevant studies have a relative short duration with only but few more than one
      year. In our opinion, they are not sufficient to detect the real effect of CPAP on reduction
      in BP. According to our knowledge, there is no report about long-term effect of CPAP on BP in
      hypertensive patients with coronary revascularization (CRV) and OSA under conventional
      antihypertensive medications. Therefore, we conducted a long-term, prospective controlled
      study to investigate the effects of CPAP on BP, metabolic disorder, clinical symptoms,
      cardiovascular and cerebrovascular events in patients with CHD and OSA on conventional
      treatment.
    

Intervention name(s): continuous positive airway pressure
Intervention type(s): Device
Intervention description(s): mean continuous positive airway pressure use was at least 4 hours per night;continuous positive airway pressure group received fixed-level continuous positive airway pressure titration using an automated pressure
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Treatment
Keywords: continuous positive airway pressure; hypertension; coronary heart disease; metabolic disorder; obstructive sleep apnea