Influence of sleep apnea severity on blood pressure variability of patients with hypertension

Obstructive sleep apnea in relation to beat-to-beat, reading-to-reading, and day-to-day blood pressure variability

We investigated blood pressure (BP) variability as assessed by beat-to-beat, reading-to-reading and day-to-day BP variability indices in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). In 786 hospitalized hypertensives (mean age, 53.2 years; 42.2% women), we performed 10-min beat-to-beat (n = 705), 24-h ambulatory (n = 779), and 7-day home BP (n = 445) measurements and the full overnight polysomnography. Mild, moderate and severe OSAHS were defined as an apnea-hypopnea index of 5-14, 15-29, and ≥ 30 events per hour, respectively. BP variability indices including variability independent of the mean (VIM), average real variability (ARV), and maximum-minimum difference (MMD), were compared across the OSAHS severity groups. In univariate analysis, beat-to-beat systolic VIM and MMD, reading-to-reading asleep systolic and diastolic ARV and MMD increased from patients without OSAHS, to patients with mild, moderate and severe OSAHS. This increasing trend for beat-to-beat systolic VIM and MMD remained statistically significant after adjustment for confounders (P ≤ 0.047). There was significant (P ≤ 0.039) interaction of the presence and severity of OSAHS with age and body mass index in relation to the beat-to-beat systolic VIM and MMD and with the presence of diabetes mellitus in relation to asleep systolic ARV. The association was stronger in younger (age < 50 years) and obese (body mass index ≥ 28 kg/m²) and diabetic patients. None of the day-to-day BP variability indices reached statistical significance (P ≥ 0.16). BP variability, in terms of beat-to-beat systolic VIM and MMD and asleep reading-to-reading asleep systolic ARV, were higher with the more severe OSAHS, especially in younger and obese and diabetic patients.

The association between the effective apnea-hypopnea index and blood pressure reduction efficacy following CPAP/oxygen treatment

BACKGROUND

The effect of sleep apnea treatment on reducing cardiovascular disease risk remains inconclusive. This study aims to assess if the effective apnea hypopnea index (eAHI), a measure of residual sleep apnea burden post-treatment, is a factor in determining blood pressure (BP) response to continuous positive airway pressure therapy. The eAHI integrates time on therapy, residual apnea, and % of sleep time untreated.

METHODS

A secondary analysis of the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study, a randomized, controlled, parallel group assessment of continuous positive airway pressure (CPAP), oxygen and sleep hygiene. The Delta-AHI (▲AHI) was defined as the difference between baseline AHI and effective AHI at 12 weeks. Logistic and linear regression models estimated the predictors for nocturnal systolic BP change following sleep apnea therapy.

RESULTS

One hundred and sixty-nine subjects with a mean age of 62.82 ± 6.99 years were included in the final analysis. Fifty subjects had ▲AHI ≤8/hour of sleep and 119 subjects were higher. After adjustment, baseline mean nighttime systolic blood pressure (OR 1.036, 95% CI 1.015-1.058, p: 0.001) and ▲AHI ≥8/hour (OR 2.406, 95% CI 1.116-5.185, p:0.025) were independent predictors for mean nighttime systolic blood pressure change >3 mm Hg. The higher effective AHI was negatively related with BNP (β: -2.564, SE: 1.167, p: 0.029) and positively related with troponin change (β: 0.703, SE: 0.256, p: 0.007).

CONCLUSION

The ▲AHI was an independent predictor of the blood pressure response to sleep apnea treatment.

REGISTER NUMBER

NCT01086800.

The association between sleep disturbances and blood pressure variability: a review of the literature

STUDY OBJECTIVES

Sleep disturbances are an underrecognized public health issue that results in various adverse outcomes and disturbed quality of life. Blood pressure variability (BPV) is an emerging entity in assessing cardiovascular disease risk and accumulating evidence suggests that BPV is closely associated with end-organ damage. This review aims to explore the association between sleep disturbances and BPV.

METHODS

A comprehensive systematic literature search was conducted electronically using Web of Science, Ovid MEDLINE, , and SCOPUS. The electronic search was restricted to relevant English-language studies published between 1985 and August 2020. Most studies were prospective cohorts in design. After applying eligibility criteria, 29 articles were included for synthesis.

RESULTS

This review shows that sleep disturbances are linked to short-term, midterm, and long-term BPV. Restless legs syndrome, shift work, insomnia, short sleep, long sleep, obstructive sleep apnea, and sleep deprivation were all positively associated with systolic blood pressure or diastolic blood pressure fluctuations.

CONCLUSIONS

Given the prognostic implications of BPV and sleep disturbances on cardiovascular mortality, recognizing and treating both disorders is essential. More research is needed to examine the impact of sleep disorder treatment on BPV and cardiovascular mortality.

CITATION

Al Haddad N, Costanian C, Zibara V, et al. The association between sleep disturbances and blood pressure variability: a review of the literature. J Clin Sleep Med. 2023;19(8):1533-1544.

Pulse transit time-estimated blood pressure: a comparison of beat-to-beat and intermittent measurement

Pulse transit time (PTT), which refers to the travel time between two arterial sites within the same cardiac cycle, has been developed as a novel cuffless form of continuous blood pressure (BP) monitoring. The aim of this study was to investigate differences in BP parameters, including BP variability, between those assessed by beat-to-beat PTT-estimated BP (eBPBTB) and those assessed by intermittent PTT-estimated BP at fixed time intervals (eBPINT) in patients suspected of having sleep disordered breathing (SDB). In 330 patients with SDB (average age, 66.8 ± 11.9 years; 3% oxygen desaturation index [ODI], 21.0 ± 15.0/h) from 8 institutes, PTT-estimated BP was continuously recorded during the nighttime. The average systolic eBPBTB, maximum systolic and diastolic eBPBTB, standard deviation (SD) of systolic and diastolic eBPBTB, and coefficient variation (CV) of systolic and diastolic eBPBTB were higher than the respective values of eBPINT (all P < 0.05). Bland-Altman analysis showed a close agreement between eBPBTB and eBPINT in average systolic BP and SD and CV of systolic BP, while there were disagreements in both minimum and maximum values of eBPBTB and eBPINT in patients with high systolic BP (P < 0.05). Although systolic BP variability incrementally increased according to the tertiles of 3%ODI in both eBPBTB and eBPINT (all P < 0.05), there was no difference in this tendency between eBPBTB and eBPINT. In patients with suspected SDB, the difference between eBPBTB and eBPINT was minimal, and there were disagreements regarding both the minimum and maximum BP. However, there were agreements in regard to the index of BP variability between eBPBTB and eBPINT.

Sleep moderates the association between arterial stiffness and 24-hour blood pressure variability

BACKGROUND

Arterial stiffness and increased blood pressure variability (BPV) are important subclinical cardiovascular diseases (CVDs). Evidence is accumulating that poor sleep is associated with subclinical CVDs. The purpose of our study was to investigate how sleep was related to arterial stiffness and BPV. We also explored whether sleep moderated the association between arterial stiffness and BPV.

METHODS

We conducted a cross-sectional study including 78 healthy adults aged between 35 and 64 years. Variables of interest were: 1) objective seep characteristics, assessed with a wrist actigraphy for two consecutive nights; 2) arterial stiffness, measured by carotid-femoral pulse wave velocity (cfPWV); and 3) BPV, measured using an ambulatory blood pressure monitor over 24 h and estimated by average real variability.

RESULTS

Lower sleep efficiency was an independent predictor of higher cfPWV and higher systolic BPV, while longer wake after sleep onset (WASO) was an independent predictor of higher cfPWV only. In addition, cfPWV showed a positive relationship with systolic BPV, and this relationship was moderated by sleep efficiency and WASO, respectively. The relationship between cfPWV and systolic BPV became stronger among individuals who had a level of sleep efficiency lower than 84% and who had WASO higher than 67 min, respectively.

CONCLUSION

Our study showed that poor sleep not only directly linked with arterial stiffness and BPV but also moderated the relationship between these two subclinical CVDs. These findings suggest that improving sleep quality could be a target intervention to promote cardiovascular health in clinical practice.

Obstructive Sleep Apnea-Induced Neurogenic Nocturnal Hypertension: A Potential Role of Renal Denervation?

There is a bidirectional, causal relationship between obstructive sleep apnea (OSA) and hypertension. OSA-related hypertension is characterized by high rates of masked hypertension, elevated nighttime blood pressure, a nondipper pattern of nocturnal hypertension, and abnormal blood pressure variability. Hypoxia/hypercapnia-related sympathetic activation is a key pathophysiological mechanism linking the 2 conditions. Intermittent hypoxia also stimulates the renin-angiotensin-aldosterone system to promote hypertension development. The negative and additive cardiovascular effects of OSA and hypertension highlight the importance of effectively managing these conditions, especially when they coexist in the same patient. Continuous positive airway pressure is the gold standard therapy for OSA but its effects on blood pressure are relatively modest. Furthermore, this treatment did not reduce the cardiovascular event rate in nonsleepy patients with OSA in randomized controlled trials. Antihypertensive agents targeting sympathetic pathways or the renin-angiotensin-aldosterone system have theoretical potential in comorbid hypertension and OSA, but current evidence is limited and combination strategies are often required in drug resistant or refractory patients. The key role of sympathetic nervous system activation in the development of hypertension in OSA suggests potential for catheter-based renal sympathetic denervation. Although long-term, randomized controlled trials are needed, available data indicate sustained and relevant reductions in blood pressure in patients with hypertension and OSA after renal denervation, with the potential to also improve respiratory parameters. The combination of lifestyle interventions, optimal pharmacological therapy, continuous positive airway pressure therapy, and perhaps also renal denervation might improve cardiovascular risk in patients with OSA.

24-Hour Ambulatory Blood Pressure Variability in Children with Obstructive Sleep Apnea

OBJECTIVE

To evaluate blood pressure (BP) variability in 24-hour ambulatory BP monitoring in children with obstructive sleep apnea (OSA).

STUDY DESIGN

Case series study.

METHODS

Children aged 4 to 16 years with clinical symptoms were recruited in a tertiary medical center. Overnight polysomnography and 24-hour recordings of ambulatory BP were performed for each child. The severity of OSA was classified as primary snoring (apnea-hypopnea index [AHI] < 1), mild OSA (1 ≤ AHI < 5), moderate OSA (10 > AHI ≥ 5), and severe OSA (AHI ≥ 10). The standard deviation of mean BP was used as an indicator of BP variability.

RESULTS

A total of 550 children were included (mean age: 7.6 years; 70% were boys; 20% were obese). Compared with the children with primary snoring, children with severe OSA exhibited significantly higher nighttime systolic BP (108.0 vs. 100.5 mmHg, P < .001), nighttime diastolic BP (58.9 vs 55.6 mmHg, P = .002), nighttime mean arterial pressure (75.3 vs. 70.5 mmHg, P < .001), nighttime systolic BP load (40.5% vs. 25.0%, P < .001), nighttime diastolic BP load (25.3% vs. 12.9%, P < .001), and nighttime systolic BP variability (11.4 vs. 9.6, P = .001). Multiple linear regression analyses revealed an independent association between AHI and nighttime systolic BP variability (regression coefficient = 0.31, 95% CI = 0.06-0.56, P = .015) after adjustment for age, gender, adiposity, and hypertensive status.

CONCLUSIONS

OSA in children is associated with increased BP and BP variability.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:2126-2132, 2021.

Comparative effects of CPAP and mandibular advancement splint therapy on blood pressure variability in moderate to severe obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) is associated with increased blood pressure variability (BPV) and are risk factors for cardiovascular disease. We aimed to assess the comparative effects of two OSA therapies, continuous positive airway pressure (CPAP) and mandibular advancement splint (MAS), on BPV.

METHODS

This is a secondary analysis of data collected as part of a previously published randomised crossover trial of one month each of CPAP and MAS therapy. BPV was determined from 24-h-ambulatory blood pressure recordings in 92 patients with moderate to severe OSA at baseline and after one month of optimised treatment with each modality. BPV was assessed by three measures: Standard deviation of the mean (SD), Coefficient of variation (CoV), and the Average Real Variability (ARV) index.

RESULTS

Neither CPAP nor MAS therapy improved BPV, with no difference between treatments. BPV did not change in hypertensive OSA patients, however, there was a reduction in ARV of diastolic blood pressure in the effectively treated compared to ineffectively treated CPAP patients, Δ ARV 24-h-DBP (mmHg), -0.72 ± 2.14, 0.34 ± 1.52, P = 0.02, respectively. There was no difference between effective versus ineffective MAS treatment, Δ ARV 24-h-DBP (mmHg), -0.04 ± 2.4, 0.02 ± 1.9, P = 1.00, respectively.

CONCLUSIONS

One month of optimised CPAP or MAS therapy did not improve short term BPV in patients with moderate to severe OSA. The subgroup of patients on effective CPAP showed some improvement in BPV with CPAP but not MAS. Further work on the effect of OSA therapy on BPV following long-term therapy is needed.

Association of Circadian Rhythm of Blood Pressure and Cerebral Small Vessel Disease in Community-Based Elderly Population

BACKGROUND

Although it is accepted that the etiology of cerebral small vessel disease (CSVD) is associated with cardiovascular risk factors, the association between CSVD and the circadian rhythm of blood pressure (BP) is unclear. We aimed to determine if such an association existed in the elderly population.

METHOD

White matter hyperintensities (WMHs), lacunes, microbleeds, nocturnal dipping pattern (NDP), and morning surge in systolic blood pressure (SBP) were assessed in 2,091 participants ≥60 years of age.

RESULTS

During an average of 63 months of follow-up, WMH and the WMH-to-intracranial volume ratio were significantly increased in extreme dippers, nondippers, and reverse dippers than those in dippers (p < .001). For new-incident Fazekas scale ≥2, the hazard ratios were 1.77 (95% confidence interval [CI], 1.09-2.86) for extreme dippers, 2.20 (95% CI, 1.48-3.28) for nondippers, and 2.43 (95% CI, 1.59-3.70) for reverse dippers compared with dippers, and 1.04 (95% CI, 0.81-1.35) for higher morning surge compared with lower morning surge. Nondippers and reverse dippers were associated with higher risks of new-incident lacunes and microbleeds than dippers (p < .05). Higher morning surge was associated with a higher risk of new-incident microbleeds than lower morning surge (p < .05).

CONCLUSION

NDPs in SBP played an important role in CSVD, and the morning surge in SBP was associated with cerebral microbleeds in community-based elderly population beyond the average SBP level.

Inducers of post-apneic blood pressure fluctuation monitored by pulse transfer time measurement in obstructive sleep apnea varied with syndrome severity

PURPOSE

This study investigated the properties of blood pressure (BP) fluctuation and sympathovagal imbalance with the severity of OSAS.

METHODS

Nocturnal BP was continuously monitored by polysomnography for mild (n = 33), moderate (n = 34), and severe (n = 37) OSAS patients. Apnea-related systolic BP elevation (△SBP) indicated the amplitude of BP fluctuation. The SBP index, number of △SBP > 10 mmHg/h of sleep, indicated the frequency of significant BP fluctuations. The low frequency/high frequency (LF/HF) ratios indicated heart rate variability and sympathovagal imbalance.

RESULTS

△SBP and the SBP index were the highest in severe OSAS (12.9 ± 2.3 mmHg and 33.7 ± 14.7/h), followed by moderate OSAS (9.5 ± 2.6 mmHg and 7.1 ± 4.4/h), and mild OSAS (8.3 ± 1.6 mmHg and 3.4 ± 2.1/h). The LF/HF ratios in severe OSAS were significantly higher than that in moderate and mild OSAS. In mild OSAS, arousal played a more important role in BP fluctuation. In moderate OSAS, the oxygen desaturation index (ODI) and the SBP index were correlated. The difference in △SBP induced by hypoxia or by arousal was not significant. In severe OSAS, the apnea-hypopnea index (AHI) and LF/HF ratio were correlated with the SBP index, and △SBP was larger with hypoxia than arousal.

CONCLUSIONS

BP fluctuation and sympathovagal imbalance were both related to obstructive sleep apnea severity. The influence of arousal and hypoxia on BP fluctuation varied with OSAS severity.

TRIAL REGISTRATION

NCT02876471.

Systemic hypertension in obstructive sleep apnea

There is consistent epidemiological evidence that sleep disordered breathing and systemic arterial hypertension are deeply associated, being linked through a bidirectional complex interaction among multiple mechanisms including autonomic nervous system alterations, inflammation, hormonal and hemodynamic components, sleep alterations. However there are several unanswered questions not only from a pathophysiological perspective, but also regarding the effects of obstructive sleep apnea (OSA) treatment on arterial blood pressure values. At present, while many studies have supported the possibility to obtain at least a small blood pressure reduction with OSA treatment, in particular in hypertensive patients, large trials have not clearly confirmed a significant anti-hypertensive effect, nor a beneficial effect of this intervention on cardiovascular endpoints including cardiovascular mortality. Aim of the present review article is to address the relationship between OSA and hypertension in the light of the latest evidence in the field. Moreover we will discuss research topics which need to be investigated in the future, in order to better clarify still pending issues with the aim of obtaining an early diagnosis, a more suitable phenotyping including comorbidities, and better strategies to improve patients' compliance and adherence to treatment.

A review of the associations between obstructive sleep apnea and hypertensive disorders of pregnancy and possible mechanisms of disease

Obesity is prevalent among pregnant women in the United States; 15-20% of obese pregnant women have obstructive sleep apnea. The prevalence of obstructive sleep apnea increases along with body mass index, age and in the presence of other co-morbidities. Untreated obstructive sleep apnea in women is associated with a range of cardiovascular, pulmonary and metabolic co-morbidities; recent studies suggest that women with obstructive sleep apnea in pregnancy may be at significantly greater risk of entering pregnancy with chronic hypertension and/or of developing hypertensive disorders of pregnancy: gestational hypertension; preeclampsia; or eclampsia. This has serious public health implications; hypertensive disorders of pregnancy are a major cause of maternal and neonatal morbidity and mortality and are associated with a greater lifetime risk for cardiovascular disease. The mechanisms that associated obstructive sleep apnea with hypertensive disorders of pregnancy have not been defined, but several pathways are scientifically plausible. In this review, we will present a comprehensive literature review of the following: the associations between obstructive sleep apnea and hypertensive disorders of pregnancy; the proposed mechanisms that may connect obstructive sleep apnea and hypertensive disorders of pregnancy; and the effectiveness of treatment at mitigating these adverse outcomes.

Severity of OSAS, CPAP and cardiovascular events: A follow-up study

BACKGROUND

Previous studies suggested obstructive sleep apnoea syndrome (OSAS) as a major risk factor for incident cardiovascular events. However, the relationship between OSAS severity, the use of continuous positive airway pressure (CPAP) treatment and the development of cardiovascular disease is still matter of debate.

STUDY OBJECTIVES

The aim was to test the association between OSAS and cardiovascular events in patients with concomitant cardio-metabolic diseases and the potential impact of CPAP therapy on cardiovascular outcomes.

METHODS

Prospective observational cohort study of consecutive outpatients with suspected metabolic disorders who had complete clinical and biochemical workup including polysomnography because of heavy snoring and possible OSAS. The primary endpoint was a composite of major adverse cardiovascular and cerebrovascular events (MACCE).

RESULTS

Median follow-up was 81.3 months, including 434 patients (2701.2 person/years); 83 had a primary snoring, 84 had mild, 93 moderate and 174 severe OSAS, respectively. The incidence of MACCE was 0.8% per year (95% confidence interval [CI] 0.2-2.1) in primary snorers and 2.1% per year (95% CI 1.5-2.8) for those with OSAS. A positive association was observed between event-free survival and OSAS severity (log-rank test; P = .041). A multivariable Cox regression analysis showed obesity (HR = 8.011, 95% CI 1.071-59.922, P = .043), moderate OSAS (vs non-OSAS HR = 3.853, 95% CI 1.069-13.879, P = .039) and severe OSAS (vs non-OSAS HR = 3.540, 95% CI 1.026-12.217, P = .045) as predictors of MACCE. No significant association was observed between CPAP treatment and MACCE (log-rank test; P = .227).

CONCLUSIONS

Our findings support the role of moderate/severe OSAS as a risk factor for incident MACCE. CPAP treatment was not associated with a lower rate of MACCE.

Obstructive sleep apnea increases systolic and diastolic blood pressure variability in hypertensive patients

OBJECTIVE

Obstructive sleep apnea (OSA) has been identified as the most common secondary contributing factor for the development and worsening of hypertension. However, the underlying relationships between blood pressure variability (BPV) and OSA are still not very clear. Therefore, we investigated the influences of OSA on BPV in hypertensive patients and explored the potential pathophysiologic mechanisms.

PARTICIPANTS AND METHODS

Ambulatory blood pressure (BP) monitoring was carried out and polysomnography was performed to detect sleep apnea. A total of 86 hypertensive individuals were divided into patients without OSA (n=43) and patients with severe OSA (n=43). Systolic and diastolic BPV were obtained by calculating the SD, coefficient of variation, and average real variability during day-time, night-time, and over 24 h. The relationship between OSA and BPV was assessed after adjustment for potential confounding variables (age, sex, BMI, neck circumference, heart rate, and snoring history).

RESULTS

Compared with participants without OSA, nocturnal systolic BPV and 24-h systolic BP average real variability from OSA participants were obviously increased (P<0.05), but there were no statistically significant differences in day-time and 24-h systolic BP SD and coefficient of variation (P>0.05). Compared with participants without OSA, 24-h diastolic BPV and day-time diastolic BP SD from OSA participants were markedly increased (P<0.05), but nocturnal indices showed no significant differences between the two groups.

CONCLUSION

OSA mainly increases night-time systolic and 24-h diastolic BPV in hypertensive patients. This may provide a plausible explanation for OSA remaining a major risk determinant for cardiovascular diseases.

Nocturnal blood pressure fluctuation and associated influential factors in severe obstructive sleep apnea patients with hypertension

PURPOSE

Obstructive sleep apnea syndrome (OSAS) can induce dramatic blood pressure (BP) fluctuations during sleep and it can be associated with hypertension. We investigated the properties and associated influential factors of BP fluctuation in severe OSAS with and without hypertension.

METHODS

Two hundred one severe OSAS subjects were divided into hypertensive and normotensive groups. BP was continuously monitored via measurement of pulse transmit time (PTT). The value of apnea-related systolic BP elevation (ΔSBP) was used to reflect the amplitude of BP fluctuation, and the SBP index (the number of ΔSBP > 10 mmHg per hour of sleep time) was used to stand for the frequency of significant BP fluctuations.

RESULTS

Compared with the normotensive group, △SBP and SBP index were higher in the hypertensive group (13.8 ± 4.4 mmHg vs 10.9 ± 3.1 mmHg; 44.8 ± 21.3 events/h vs 26.8 ± 15.8 events/h, all p < 0.001). Multiple regression analysis showed that percentage of sleep time with oxygen saturation < 90% (TST90) and SBP index correlated more with mean level of awakeness and sleep SBP than with apnea-hypopnea index (AHI). Analysis of all apnea events demonstrated that △SBP and the frequency of BP fluctuations were more remarkable following hypoxia than following arousal; △SBP correlated more with oxygen desaturation degree (r = 0.388, p < 0.01) and minimal SpO₂ (r = 0.392, p < 0.01) than with apnea length and desaturation duration.

CONCLUSIONS

In severe OSAS, nocturnal and awake BP levels are associated more with the nocturnal hypoxic duration and BP fluctuation than with AHI. Nocturnal BP fluctuation can be induced by both hypoxia and arousal, and especially by hypoxia.

TRIAL REGISTRATION

NCT02876471.

Blood-pressure variability in patients with obstructive sleep apnea: current perspectives

Obstructive sleep apnea (OSA) is often associated with hypertension and other cardiovascular diseases. Blood pressure (BP) variability is part of the assessment of cardiovascular risk. In OSA, BP variability has been studied mainly as very short-term (beat-by-beat) and short-term (24-hour BP profile) variability. BP measured on consecutive heartbeats has been demonstrated to be highly variable, due to repeated peaks during sleep, so that an accurate assessment of nocturnal BP levels in OSA may require peculiar methodologies. In 24-hour recordings, BP frequently features a "nondipping" profile, ie, <10% fall from day to night, which may increase cardiovascular risk and occurrence of major cardiovascular events in the nocturnal hours. Also, BP tends to show a large "morning BP surge", a still controversial negative prognostic sign. Increased very short-term BP variability, high morning BP, and nondipping BP profile appear related to the severity of OSA. Treatment of OSA slightly reduces mean 24-hour BP levels and nocturnal beat-by-beat BP variability by abolishing nocturnal BP peaks. In some patients OSA treatment turns a nondipping into a dipping BP profile. Treatment of arterial hypertension in OSA usually requires both antihypertensive pharmacological therapy and treatment of apnea. Addressing BP variability could help improve the management of OSA and reduce cardiovascular risk. Possibly, drug administration at an appropriate time would ensure a dipping-BP profile.

Influences of obstructive sleep apnea on blood pressure variability might not be limited only nocturnally in middle-aged hypertensive males

PURPOSE

In this cross-sectional study, we analyzed the potential association between sleep measures and blood pressure variability.

METHODS

Ninety-three middle-aged hypertensive males, who underwent polysomnography and 24-h ambulatory blood pressure monitoring, were enrolled. Blood pressure variability was assessed by blood pressure standard deviation. Obstructive sleep apnea (apnea hypopnea index ≥ 15) was diagnosed in 52 (55.91%) patients. Mean body mass index and age were 27.77 ± 3.11 kg/m² and 44.05 ± 8.07 years, respectively.

RESULTS

Hypertensive males with obstructive sleep apnea showed significantly higher 24-h, diurnal, and nocturnal diastolic blood pressure variability, compared to those without obstructive sleep apnea. While total cohort was further divided into two groups using the median of oxygen desaturation index, another indicator for severity of OSA, significant differences were also observed in 24-h, diurnal, and nocturnal diastolic blood pressure variability between two groups with higher and lower oxygen desaturation index. While subjects were also divided into two groups via the mean of sleep stage 1, hypertensive males with sleep stage 1 ≥ 8.1% showed significantly higher diurnal diastolic blood pressure variability than those with sleep stage 1 < 8.1%. Apnea hypopnea index was independently associated with 24-h and nocturnal diastolic blood pressure variability; oxygen desaturation index of 3% with 24-h diastolic, diurnal, and nocturnal diastolic blood pressure; and sleep stage 1 was with 24-h and with diurnal diastolic blood pressure variability in all study subjects.

CONCLUSION

Effects of obstructive sleep apnea on blood pressure variability may not be limited nocturnally.

Twenty-four hour Blood Pressure in Obese Patients with Moderate-to-Severe Obstructive Sleep Apnea

BACKGROUND

Obesity, systemic arterial hypertension (SAH) and obstructive sleep apnea (OSA) are closely related. Up to 70% of patients with OSA may be asymptomatic, and there is evidence that these patients have cardiovascular disease, especially nocturnal SAH.

OBJECTIVES

The aim of this study was to evaluate 24-hour blood pressure circadian variation in asymptomatic, obese individuals with moderate-to-severe OSA and compare it with that in individuals with mild OSA or without OSA.

METHODS

Eighty-six obese subjects aged between 30 and 55 years (BMI 30-39 kg/m2), with casual blood pressure < 140/90 mmHg and without comorbidities were recruited. Eighty-one patients underwent clinical and anthropometric assessment, ambulatory blood pressure monitoring (ABPM), and Watch-PAT. Participants were divided into two groups, based on the apnea-hypopnea index (AHI): group 1, with AHI < 15 events/hour, and group 2 with AHI ≥ 15 events/hour.

RESULTS

Compared with group 1, group 2 had higher neck circumference and waist-hip circumference (40.5 ± 3.2 cm vs. 38.0 ± 3.7 cm, p = 0.002, and 0.94 ± 0.05 vs. 0.89 ± 0.05, p = 0.001, respectively), higher systolic and diastolic blood pressure measured by the 24-h ABPM (122 ± 6 vs 118 ± 8 mmHg, p = 0.014, and 78 ± 6 vs 73 ± 7 mmHg, p = 0.008, respectively), and higher nocturnal diastolic pressure load (44,6 ± 25,9% vs 31,3 ± 27,3%, p = 0,041). Moreover, there was a positive correlation between nocturnal diastolic blood pressure and AHI (r = 0.43, p < 0.05).

CONCLUSIONS

Asymptomatic obese subjects with moderate-to-severe OSA have higher systolic and diastolic blood pressure at 24 hours compared with those with absent / mild OSA, despite normal casual blood pressure between the groups. These results indicate that ABPM may be useful in the evaluation of asymptomatic obese patients with moderate-to-severe OSA.

An update on cardiovascular effects of obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome is an important health problem which may cause or worsen systemic diseases. Chronic intermittent hypoxia during repetitive airflow cessations may cause endothelial dysfunction. Sleep apnoea is also shown to be associated with hypercoagulability which may be due to decreased nitric oxide levels and impaired vasodilatation. Endothelial dysfunction, increased systemic inflammation, sympathetic nervous system activation, increased oxidative stress and dysglycaemia may all contribute to cardiovascular processes such as hypertension, arrhythmia, stroke, heart failure and coronary artery disease in patients with obstructive sleep apnoea. Treatment approaches in patients with obstructive sleep apnoea mainly focus on maintaining upper airway patency either with positive airway pressure devices or upper airway appliances. Strategies involving positive airway pressure therapy are associated with decreased morbidity and mortality. Obstructive sleep apnoea should be suspected as an underlying mechanism in patients with cardiovascular disease and warrants appropriate treatment.

Obstructive Sleep Apnea as Possible Causal Factor for Visit-to-Visit Blood Pressure Variability

BACKGROUND

Recent studies have shown that visit-to-visit blood pressure variability (BPV) is an independent risk factor for cardiovascular disease. However, it has not been clarified whether obstructive sleep apnea (OSA) is associated with visit-to-visit BPV.

METHODS AND RESULTS

The 56 subjects with OSA and 26 control subjects without OSA were examined. Office BP was measured on 5 separate consecutive occasions prior to a polysomnography examination. The visit-to-visit BPV was expressed as the standard deviation and the coefficient of variation of the 5 systolic BP measurements. In subjects with an apnea-hypopnea index (AHI) of more than 20 episodes per hour, the visit-to-visit BPV was also measured after the start of continuous positive airway pressure (CPAP) therapy. Overall, the AHI positively correlated with the standard deviation and the coefficient of variation of systolic BP. In a multivariate analysis, the plasma noradrenaline level and the AHI were independently and positively correlated with the standard deviation and the coefficient of variation of the systolic BP. Among the patients who underwent CPAP therapy, good adherence with CPAP therapy significantly reduced the visit-to-visit BPV.

CONCLUSIONS

OSA is associated with abnormal visit-to-visit BPV and sympathetic activation seems to be related in some way. (Circ J 2016; 80: 1787-1794).

Nocturnal systolic blood pressure is increased in restless legs syndrome

Purpose

Restless legs syndrome (RLS) is a frequent sensorimotor disorder characterized by an urge to move the legs, with symptoms appearing during the night and disturbing nocturnal sleep. There is a growing body of evidence that RLS correlates with an increased risk of cardiovascular diseases and hypertension. The aim of this study was to test the hypothesis that patients with RLS have higher blood pressure (BP) during the night than people without RLS.

Methods

We have analyzed polysomnographic (PSG) recordings of 30 patients with RLS and 27 subjects without the sleep disorder. During PSG, beat-to-beat BP measurement was performed.

Results

Patients with RLS have higher nocturnal and sleep-time systolic blood pressure compared to controls (124.4 vs. 116.5 mmHg, p < 0.05; 123.5 vs. 116.1 mmHg, p < 0.05). There was no noticeable dip in the values of nocturnal systolic pressure of patients with RLS.

Conclusions

Our results support the hypothesis that RLS and hypertension are linked. Thus, we believe patients with RLS require close observation with regard to cardiovascular risk factors.