Impact of CPAP Therapy in Obstructive Sleep Apnea on Parameters of Nocturnal Pulse Wave Analysis
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|ClinicalTrials.gov Identifier: NCT01814462|
Recruitment Status : Recruiting
First Posted : March 20, 2013
Last Update Posted : January 6, 2017
|Condition or disease||Intervention/treatment||Phase|
|Obstructive Sleep Apnea||Device: 6 months CPAP||Not Applicable|
Obstructive sleep apnea (OSA) is characterized by repeated occurrence of apneas or reduced inspiratory air flow due to obstructions of the upper airways (hypopneas). These recurring events are accompanied by intermittent hypoxemia and sympathetic activation, leading to hemodynamic oscillations including relevant variations of pulse wave and blood pressure. Thus, OSA is associated with cardiovascular diseases and was identified as an independent risk factor for hypertension.
Direct effects of obstructive respiratory events (obstructive apneas and hypopneas) include changes of the peripheral pulse wave. The latter can easily be measured by finger plethysmography, e.g. by using established pulse oximeters. Certain pulse wave characteristics and their reaction towards obstructive respiratory events may provide information on cardiovascular function and thereby help in individual cardiovascular risk assessment.
Recently, Grote et al. published a concept for cardiovascular risk assessment based on pulse oximetry and pulse wave analysis ("ASI" - Grote et al. 2011, CHEST). The algorithm described herein is able to differentiate between high and low risk patients according to ESH/ESC risk classification (high risk = 4 and 5, low risk 1-3). To that end, oxygen saturation as measured by pulse oximetry, reductions in pulse wave amplitude, pulse rate accelerations, pulse propagation time and cardiorespiratory coupling are taken into account to calculate a quantitative total risk.
A successful OSA therapy applying positive airway pressure (e.g. CPAP) normalizes sleep-related breathing disturbances and thus counterbalances hemodynamic oscillations. This presumably results in reduced cardiovascular risk and should be detectable by measurable changes in pulse wave. This study aims to evaluate these effects by analyzing the single pulse wave parameters, which are part of the ASI algorithm. At the same time, established risk factors as well as the objective therapy outcome will be documented from the established sleep medicine viewpoint.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||300 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Primary Purpose:||Basic Science|
|Official Title:||Impact of CPAP Therapy in Obstructive Sleep Apnea on Parameters of Nocturnal Pulse Wave Analysis|
|Study Start Date :||March 2013|
|Estimated Primary Completion Date :||December 2017|
|Estimated Study Completion Date :||December 2017|
Experimental: 6 months CPAP
Application of continuous positive airway pressure (CPAP) therapy as established per routine clinical treatment. Home use of therapy for a period of 6 months.
Device: 6 months CPAP
- Change in pulse wave attenuation index [ Time Frame: 6 months ]The pulse wave attenuation index represents the number of decreases of the pulse wave amplitude >10% and <30% compared with baseline (a moving median value of 20 samples surrounding the observed sample). This number is given as attenuations per hour. The difference from baseline (without therapy) to 6 months (on CPAP therapy) is calculated.
- Change in mean pulse propagation time [ Time Frame: 6 months ]The pulse propagation time represents the time interval between the systolic and dicrotic notch of the pulse wave form. The mean pulse propagation time of a complete recording is documented. The difference from baseline (without therapy) to 6 months (on CPAP therapy) is calculated.
- Change in mean respiration-related pulse oscillation [ Time Frame: 6 months ]The respiration-related pulse oscillation is calculated by measuring the breathing-associated oscillation (respiratory sinus arrhythmia in the frequency band between 0.15 and 0.4 Hz) from the pulse rate signal in the time domain. The mean respiration-related pulse oscillation value of a complete recording is documented. The difference from baseline (without therapy) to 6 months (on CPAP therapy) is calculated.
- Change in pulse rate acceleration index [ Time Frame: 6 months ]The pulse rate acceleration index represents the number of pulse rate increases ≥10% from baseline (a moving median value of 20 samples surrounding the observed sample). This number is given as increases per hour. The difference from baseline (without therapy) to 6 months (on CPAP therapy) is calculated.
- Change in hypoxia index [ Time Frame: 6 months ]The hypoxia index represents the number of oxygen desaturation events per hour. A desaturation event is defined as a ≥2% drop of saturation of each sample compared with a 90 seconds time window of the upcoming SpO2 signal. The difference from baseline (without therapy) to 6 months (on CPAP therapy) is calculated.
- Change in ASI cardiovascular risk score [ Time Frame: 6 months ]The ASI algorithm described by Grote et al. (2011) combines several single parameters from pulse wave analysis to calculate an overall cardiovascular risk score. The difference from baseline (without therapy) to 6 months (on CPAP therapy) is calculated.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01814462
|Contact: Winfried J Randerath, Prof. Dr. med.||+49-212-63 60 firstname.lastname@example.org|
|Solingen, Germany, 42699|
|Contact: Marcel Treml, Dr. rer. nat. Marcel.Treml@klinik-bethanien.de|
|Principal Investigator: Winfried J Randerath, Prof. Dr. med.|
|Sub-Investigator: Christina Priegnitz, Dr. med.|