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NCT Number: NCT03246022

Characteristics of Obstructive Sleep Apnea Syndrome Related Hypertension and the Effect of Continuous Positive Airway Pressure Treatment on Blood Pressure

Obstructive sleep apnea syndrome (OSAS) causes nocturnal chronic intermittent hypoxia (CIH) that contributes to the development of hypertension. CIH profiles, including the its length, speed and intensity were widely different in individuals. Until recently, the influence of OSAS-related IH profiles on hypertension development has not been fully explored. The present study aimed to investigate the effects of different CIH properties on blood pressure (BP) and short-term blood pressure variability (BPV) in severe OSAS patients.

Continuous positive airway pressure (CPAP) prevents the airway collapse, avoids the occurrence of intermittent hypoxemia and arousal, is the preferred treatment for OSAS and has been widely used in clinical. In theory, CPAP maintains upper airway patency and preserves ventilation, thereby inhibits the chain reaction over activation of the sympathetic nervous system and blood pressure regulating mechanism, thus CPAP treatment have adequate scientific basis to cause a substantial reduction arterial blood pressure, but controlled studies showed either no effect or only a minor decrease in arterial blood pressure by 1.4 and 2.5 mmHg respectively.The current, which type of combination of hypertension OSA patients can obtain the best antihypertensive benefit from CPAP therapy is still under debate.

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Key information

Conditions

Hypertension Secondary Cardiovascular Diseases Hypertension Vascular Diseases

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Department Of Respiratory Medicine,Huai'an First People's Hospital,Nanjing Medical University

Huai'an, Jiangsu, 223300, China

About this study

Nocturnal BP was continuously monitored via measurement of pulse transmit time (PTT). The value of apnea-related systolic BP elevation (△BP) was used to reflect short-term BPV. Beat-to-beat RR interval data were incorporated in polysomnography for heart rate variability analysis. LF/HF band ratio was compared between two groups which used to reflect sympatho-vagal balance. The length of the desaturation event was measured to the nearest 0.5 second (△t). The fall in SpO2 during apnea was calculated as the gap from start of the desaturation to the nadir of the desaturation. The rate of fall in SpO2 was counted as the change in the percentage of SpO2 per second (△SpO2 /△t) and expressed as oxygen desaturation rate (ODR), which reflected the speed and efficacy of oxygen desaturation during an apnea event. One hundred and two severe OSAS subjects were divided into two groups according to the their median ODR: faster ODR and slower ODR.

In addtion,patient were categorized into three groups: Group l: systolic blood pressure index was less than 30% of AHI; Group 2: systolic blood pressure index was less than 60% but more than 30%; Group 3: systolic blood pressure index is more than 60% of AHI. The investigator would compare the effect of CPAP treatment on awake and sleep BP level at the first night and 2 weeks therapy among three groups. Moreover, whether or not the sympathetic-parasympathetic nerve balance and the renin-angiotensin-aldosterone system are different in three groups would also be evaluated. The main purpose of study is to confirm the OSA with hypertension and OSA secondary hypertension are two different concepts. Basis for the clinical treatment, the former, CPAP might have no effect or only a minor decrease in arterial blood pressure, while the latter CPAP treatment might achieve significant antihypertensive effect.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • BP≤180/110mmHg,but≥140/90mmHg
  • without taking oral antihypertensive drugs. Exclusion criteria.

(1) patients who had been hospitalized for cardiac or respiratory exacerbation<6wk prior to recruiting; (2) with autonomic nervous system diseases or endocrine disorders which might influence BP; (3) unwilling to participate in the study.

Treatment and study plan

Continuous Positive Airway Pressure

Other

Continuous positive airway pressure (CPAP) prevents the airway collapse, avoids the occurrence of intermittent hypoxemia and arousal, is the preferred treatment for OSAS and has been widely used in clinical. The investigator would compare the effect of CPAP treatment on awake and sleep BP level at the first night and 2 weeks therapy among three groups. Moreover, whether or not the sympathetic-parasympathetic nerve balance and the renin-angiotensin-aldosterone system are different in three groups would also be evaluated.

Primary outcomes

  1. awake systolic blood pressure(SBP)changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    as the mean systolic blood pressure measurements during a supine resting period of 1 0minute at awake state

  2. sleep systolic blood pressure(SBP)changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    as the average of systolic blood pressure values during sleep

  3. sympathetic-parasympathetic nerve balance changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    Studies using spectral analysis of R-R intervals have reported that the power spectrum contains both low-frequency(LF,0.04-0.15 Hz)and high-frequency peaks(HF,0.15-0.5Hz),HF power reflects parasympathetic activity,whereas LF power primarily reflects sympathetic activity with a parasympathetic component.The LF-to-HF ratio(LF/HF)is commonly regarded as an index of sympathovagal balance

  4. renin-angiotensin-aldosterone systemchanges

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    as the levels of plasma angiotension ⅰ( Ang I) and angiotension ⅱ( Ang ⅱ) before and after CPAP treatment

  5. AHI changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    the combined number of apnea and hypopnea episodes per hour of sleep

  6. TST90 changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    percentage of sleep time with oxygen saturation < 90%

  7. oxygen desaturation index（ODI） changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    oxygen desaturation index

  8. event-related systolic blood pressure elevation (△SBP) changes

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    as the gap between the peak value of postapneic SBP and lowest SBP during a obstructive respiratory event

  9. systolic blood pressure(SBP)index

    Time frame: change from Baseline Systolic Blood Pressure at 2 weeks

    as the number of △SBP>10mmHg per hour of sleep time.

  10. Desaturation rate

    Time frame: one night

    The rate of fall in SpO2 was counted as the change in the percentage of SpO2 per second during apnea

Sponsors and collaborators

Lead sponsor

Huai'an No.1 People's Hospital

Other

Collaborators

  • The First Affiliated Hospital with Nanjing Medical University

Registry information

Official study title

Huai'an First People's Hospital

Important dates

Study start
2018
Primary completion
2021
Study completion
2021
First posted
Aug 11, 2017
Registry last updated
Mar 29, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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