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

Huai'an First People's Hospital

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.

Study Overview

• Status: Completed
• Conditions: Hypertension Secondary
• Intervention / Treatment: Other: continuous positive airway pressure

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 78

Contacts and Locations

Study Locations

• China
  • Jiangsu
    • Huai'an, Jiangsu, China, 223300
      • Department Of Respiratory Medicine,Huai'an First People's Hospital,Nanjing Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

1. age between 18 to 70 yrs;
2. newly diagnosed OSAS without treatment;

Description

Inclusion Criteria:

1. BP≤180/110mmHg,but≥140/90mmHg
2. 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.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Group l; SBP index was less than 30% of AHI	Other: continuous positive airway pressure; 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.
Group 2; SBP index was less than 60% but more than 30%	Other: continuous positive airway pressure; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
awake systolic blood pressure(SBP)changes	as the mean systolic blood pressure measurements during a supine resting period of 1 0minute at awake state	change from Baseline Systolic Blood Pressure at 2 weeks
sleep systolic blood pressure(SBP)changes	as the average of systolic blood pressure values during sleep	change from Baseline Systolic Blood Pressure at 2 weeks
sympathetic-parasympathetic nerve balance changes	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	change from Baseline Systolic Blood Pressure at 2 weeks
renin-angiotensin-aldosterone systemchanges	as the levels of plasma angiotension ⅰ( Ang I) and angiotension ⅱ( Ang ⅱ) before and after CPAP treatment	change from Baseline Systolic Blood Pressure at 2 weeks
AHI changes	the combined number of apnea and hypopnea episodes per hour of sleep	change from Baseline Systolic Blood Pressure at 2 weeks
TST90 changes	percentage of sleep time with oxygen saturation < 90%	change from Baseline Systolic Blood Pressure at 2 weeks
oxygen desaturation index（ODI） changes	oxygen desaturation index	change from Baseline Systolic Blood Pressure at 2 weeks
event-related systolic blood pressure elevation (△SBP) changes	as the gap between the peak value of postapneic SBP and lowest SBP during a obstructive respiratory event	change from Baseline Systolic Blood Pressure at 2 weeks
systolic blood pressure(SBP)index	as the number of △SBP>10mmHg per hour of sleep time.	change from Baseline Systolic Blood Pressure at 2 weeks
Desaturation rate	The rate of fall in SpO2 was counted as the change in the percentage of SpO2 per second during apnea	one night

Collaborators and Investigators

• Sponsor: Huai'an No.1 People's Hospital
• Collaborators: The First Affiliated Hospital with Nanjing Medical University
• Investigators: Study Director: Zili Meng, Master, Department Of Respiratory Medicine,Huai'an First People's Hospital,Nanjing Medical University

Publications and helpful links

General Publications

• Wang N, Meng Z, Ding N, Chen W, Zhang X, Huang M, Xu J. Oxygen desaturation rate as a novel intermittent hypoxemia parameter in severe obstructive sleep apnea is strongly associated with hypertension. J Clin Sleep Med. 2020 Jul 15;16(7):1055-1062. doi: 10.5664/jcsm.8396.

Study record dates

Study Major Dates

• Study Start (Actual): April 3, 2018
• Primary Completion (Actual): December 30, 2021
• Study Completion (Actual): December 30, 2021

Study Registration Dates

• First Submitted: August 5, 2017
• First Submitted That Met QC Criteria: August 9, 2017
• First Posted (Actual): August 11, 2017

Study Record Updates

• Last Update Posted (Actual): March 29, 2022
• Last Update Submitted That Met QC Criteria: March 28, 2022
• Last Verified: August 1, 2021

More Information

Terms related to this study

• Keywords: hypertension; continuous positive airway pressure; oxygen desaturation; blood pressure fluctuation; intermittent hypixa
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: Huaian First People's Hospital

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No