Established vascular effects of continuous positive airway pressure therapy in patients with obstructive sleep apnoea-an update

Effect of Maternal Obstructive Sleep Apnea-Hypopnea on 24-Hour Blood Pressure, Nocturnal Blood Pressure Dipping and Arterial Stiffness in Hypertensive Disorders of Pregnancy

Rationale: Maternal obstructive sleep apnea-hypopnea (OSAH) is associated with hypertensive disorders of pregnancy (HDP). Attenuation of the normal nocturnal blood pressure (BP) decline (non-dipping) is associated with adverse pregnancy outcomes. OSAH is associated with nocturnal non-dipping in the general population, but this has not been studied in pregnancy. We therefore analyzed baseline data from an ongoing RCT (NCT03309826) assessing the impact of OSAH treatment on HDP outcomes, to evaluate the relationship of OSAH to 24-h BP profile, in particular nocturnal BP dipping, and measures of arterial stiffness.

Methods: Women with a singleton pregnancy and HDP underwent level II polysomnography. Patients with OSAH (apnea-hypopnea index (AHI) ≥ 5 events/h) then underwent 24-h ambulatory BP monitoring and arterial stiffness measurements (applanation tonometry, SphygmoCor). Positive dipping was defined as nocturnal systolic blood pressure (SBP) dip ≥ 10%. The relationships between measures of OSAH severity, measures of BP and arterial stiffness were evaluated using linear regression analyses.

Results: We studied 51 HDP participants (36.5 ± 4.9 years, BMI 36.9 ± 8.6 kg/m²) with OSAH with mean AHI 27.7 ± 26.4 events/h at 25.0 ± 4.9 weeks’ gestation. We found no significant relationships between AHI or other OSA severity measures and mean 24-h BP values, although BP was generally well-controlled. Most women were SBP non-dippers (78.4%). AHI showed a significant inverse correlation with % SBP dipping following adjustment for age, BMI, parity, gestational age, and BP medications (β = −0.11, p = 0.02). Significant inverse correlations were also observed between AHI and DBP (β = −0.16, p = 0.01) and MAP (β = −0.13, p = 0.02) % dipping. Oxygen desaturation index and sleep time below SaO₂ 90% were also inversely correlated with % dipping. Moreover, a significant positive correlation was observed between carotid-femoral pulse wave velocity (cfPWV) and REM AHI (β = 0.02, p = 0.04) in unadjusted but not adjusted analysis.

Conclusion: Blood pressure non-dipping was observed in a majority of women with HDP and OSAH. There were significant inverse relationships between OSAH severity measures and nocturnal % dipping. Increased arterial stiffness was associated with increasing severity of OSAH during REM sleep in unadjusted although not adjusted analysis. These findings suggest that OSAH may represent a therapeutic target to improve BP profile and vascular risk in HDP.

The impact of continuous positive airway pressure on cardiac arrhythmias in patients with sleep apnea

Background

Obstructive sleep apnea (OSA) can lead to cardiac complications: brady and tachyarrhythmias and sudden cardiac death. Continuous positive airway pressure (CPAP) is the gold standard for the treatment of OSA. The present study aims to demonstrate the efficiency of CPAP in the treatment of cardiac arrhythmias in patients with OSA. The study also recorded the frequency of arrhythmias in patients with untreated OSA and assessed the association between the severity of OSA and the occurrence of arrhythmias.

Materials and Methods

This is a prospective cohort study. Ninety-three patients with OSA were included, aged 60 (58-64) years, with female/male sex ratio of 1:4. They were subjected simultaneously to home respiratory polygraphy examination and Holter electrocardiogram monitoring, in two different stages: at diagnosis and at the 3-month checkup after CPAP treatment. The presence of supraventricular and ventricular arrythmias was noted. Respiratory parameter values were also recorded.

Results

Statistically significant decrease in the occurrence of supraventricular (P < 0.001) and ventricular extrasystoles (P < 0.001), atrial fibrillation (AF) (P = 0.03), nonsustained ventricular tachycardia (NSVT) (P = 0.03), and sinus pauses (P < 0.001) was observed 3 months after treatment with CPAP, compared with baseline. The apnea-hypopnea index (AHI) was correlated with the ventricular extrasystoles (r = 0.273; P = 0.008). The ejection fraction of the left ventricle was inversely correlated with the episodes of NSVT (r = -0.425; P < 0.001). AF was associated with the longest apnea (r = 0.215; P = 0.04). Cardiac activity pauses were correlated with AHI (r = 0.320; P = 0.002), longest apnea (r = 0.345; P = 0.01), and oxygen desaturation index (r = 0.325; P = 0.04).

Conclusion

The prevalence of cardiac arrhythmias in patients with OSA was reduced after 3 months of CPAP therapy. Cardiac arrhythmias were correlated with the severity of OSA.

Use of CPAP to reduce arterial stiffness in moderate-to-severe obstructive sleep apnoea, without excessive daytime sleepiness (STIFFSLEEP): an observational cohort study protocol

INTRODUCTION

Sleepiness is a cardinal symptom in obstructive sleep apnoea (OSA) but most patients have unspecific symptoms. Arterial stiffness, evaluated by pulse wave velocity (PWV), is related to atherosclerosis and cardiovascular (CV) risk. Arterial stiffness was reported to be higher in patients with OSA, improving after treatment with continuous positive airway pressure (CPAP). This study aims to assess whether the same effect occurs in patients with OSA and without sleepiness.

METHODS AND ANALYSIS

This observational study assesses the CV effect of CPAP therapy on a cohort of patients with moderate-to-severe OSA; the effect on the subcohorts of sleepy and non-sleepy patients will be compared. A systematic and consecutive sample of patients advised CPAP therapy will be recruited from a single outpatient sleep clinic (Centro Hospitalar de Lisboa Central-CHLC, Portugal). Eligible patients are male, younger than 65 years, with confirmed moderate-to-severe OSA and apnoea-hypopnea index (AHI) above 15/hour. Other sleep disorders, diabetes or any CV disease other than hypertension are exclusion criteria. Clinical evaluation at baseline includes Epworth Sleepiness Scale (ESS), and sleepiness is defined as ESS above 10. OSA will be confirmed by polygraphic study (cardiorespiratory, level 3). Participants are advised to undertake an assessment of carotid-femoral PWV (cf-PWV) and 24 hours evaluation of ambulatory blood pressure monitoring (ABPM), at baseline and after 4 months of CPAP therapy. Compliance and effectiveness of CPAP will be assessed. The main outcome is the variation of cf-PWV over time.

ETHICS AND DISSEMINATION

This protocol was approved by the Ethics Committees of CHLC (reference number 84/2012) and NOVA Medical School (number36/2014/CEFCM), Lisbon. Informed, written consent will be obtained. Its results will be presented at conferences and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02273089; Pre-results.