Nocturnal Blood Pressure Fluctuations Research Articles

O58 CONTINUOUS MEASUREMENT OF BLOOD PRESSURE DURING NIGHT - INSIGHTS INTO THE GENESIS OF THE NOCTURNAL BLOOD PRESSURE FLUCTUATIONS

Background and Objective: Nighttime blood pressure (BP) is a strongly predictive marker for overall cardiovascular risk. Traditional cuff-based BP measurements methods provide only discrete BP data. Short-term BP fluctuations are not detectable with such methods. Therefore, we applied two independent and continuously measuring methods with the aim to characterize systolic nocturnal blood pressure fluctuations (NBPF) related to sleep apnoea or periodic leg movements (PLM). Methods: BP fluctuations were analysed in patients with suspected sleep disturbances. The Portapres™ device (Penaz method) and a system based on the measurement of the pulse transit time (SOMNOscreen®) were used to measure the BP in addition to a polysomnography performed under the conditions of a clinical sleep laboratory. The calculation of the BP by the SOMNOscreen® was performed using a BP-pulse wave velocity (PWV) transfer function. Results: We saw BP fluctuations which occurred in connection with obstructive apnoeic events as well as in connection with PLM. Both methods recorded the same apnoea related NBPF. The amplitudes of these NBPF accounted for 24.7 mmHg and 22.8 mmHg (Portapres™ and SOMNOscreen®, respectively, 11 patients, number of events: n=695). PLM related PB fluctuations (in 5 of 11 patients, n=317) amounted to 18.4 mmHg (Portapres™ and 16.9 mmHg (SOMNOscreen®). Most of the patients did not show BP dipping when comparing awake with sleep time periods and they had a moderate to severe apnoea/hypopnoea index. Conclusions: The study demonstrates a strong relation between apnoeic events/PLM and NPBF. The NBPF were similarly detected by two different BP measuring methods suggesting that the more indirect method of BP determination using the PWV provides a reliable measurement of NBPF. The results suggest that OSA and PLM related NBPF strongly contribute to non- or reverse dipping of patients with these sleep disorders.

NOCTURNAL BLOOD PRESSURE FLUCTUATIONS IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA

Objective: Reverse dipping of nocturnal blood pressure (BP) is a sensitive predictor of cardiovascular morbidity and mortality. Nocturnal blood pressure fluctuations (NBPF) related to obstructive sleep apnea may be causative. Studies based on ambulatory blood pressure measurements (ABPM) can only provide mean BP values and long-term BP variability due to low frequent variability during the night. This limits the explanatory power of the method. Here, we apply non-invasive, continuously measuring methods to investigate NBPF in patients with obstructive sleep apnea syndrome (OSAS). Design and method: In a first study, we included 34 patients with suspected diagnosis of sleep apnea undergoing polysomnography. BP was estimated using pulse transit time (PTT, SOMNOscreenTM) as well as measured by Portapres®. In a second study, we included 97 patients with an apnea/hypopnea index greater than 30 (severe OSA). The systolic BP (SBP) was continuously determined using PTT (SOMNOscreenTM) during polysomnography. Results: In the first study, 11 patients with OSA were analyzed. Sleep apnea related SBP fluctuations >8mmHg measured by Portapres™ were included. Both, the PTT-based method and Portapres® detected the same apnea related SBP fluctuations during night. Bland Altman plot showed a mean difference <1mmHg between both methods, with limits of agreement of ±13.4 mmHg. Mean apnea related SBP fluctuations were between 28 and 29 mmHg for both methods. In the second study, we found, in addition to normal NBPFs, BP fluctuations arranged like steps in 48 patients. Thereby, the SBP decrease after the event did not reach the level before the apnea. This led to a continuous increase of the SBP baseline called “superposition” of BP. Further, this phenomenon resulted in extremely high SBP values in some of the patients. Conclusions: BP fluctuations induced by OSA may contribute to the non-dipping/reverse dipping phenomena in OSA patients. The continuously measuring methods used here offer detailed insight into patterns of BP fluctuations. This improves our understanding of BP control during night time and helps to identify patients with increased risk for cardiovascular events.

NIGHT-TIME BLOOD PRESSURE AND BLOOD PRESSURE VARIABILITY IN HYPERTENSIVE PATIENTS WITH OR WITHOUT INSOMNIA. A PILOT STUDY

Objective: Recent studies found that insomnia is an independent risk factor for cardiovascular diseases, particularly arterial hypertension. Among the hypertensive population, insomnia could contribute to a worse blood pressure (BP) profile. In a sample of hypertensive patients, we compared those with and without insomnia with the aim of evaluating possible differences in BP, its variability, and breathing pattern. Design and method: We conducted a case-control study on patients with and without insomnia, based on the Insomnia Severity Index (ISI) questionnaire. Patients were recruited from the general practitioner's registry and were sent an invitation e-mail. All of them had long-lasting hypertension. One-hundred-and-fifty patients replied to the ISI questionnaire. Among them, twenty people with insomnia were selected (ISI greater than or equal to 15) and matched, based on their gender and age (±3 years), to 20 controls (with ISI lower than 15). All participants underwent night-time cardiorespiratory and 24-hour blood pressure monitoring by using a new cuff-less device that can estimate beat-to-beat BP (SomnoTouch-NIBP). Results: Comparing the two groups (insomnia vs. non-insomnia), no differences were observed in BP profile and all the respiratory indices, including the apnea-hypopnea index(AHI), the number of desaturations, and peripheral oxygen saturation (SpO2) values. Even the average BP and the indices of BP variability, such as the standard deviation (SD), the pressure coefficient of variation (CV), the BP dipping, and the nocturnal BP fluctuations (NBPF), were similar between the groups. Interestingly, to obtain the same average BP control, the insomnia group required a greater number of antihypertensive drugs (2,85 ± 0,88 vs. 1,95 ± 1,00 in the non-insomnia group; p<0.01). Conclusions: Patients with insomnia may need more antihypertensive medications to achieve the same average BP as patients without insomnia. Anyhow, they did not show, as expected, higher BP variability. How much beat-to-beat BP estimations are reliable compared to BP measurements by standard cuff-based devices is still under debate.

Influence of Photoplethysmogram Signal Quality on Pulse Arrival Time during Polysomnography.

Intervals of low-quality photoplethysmogram (PPG) signals might lead to significant inaccuracies in estimation of pulse arrival time (PAT) during polysomnography (PSG) studies. While PSG is considered to be a "gold standard" test for diagnosing obstructive sleep apnea (OSA), it also enables tracking apnea-related nocturnal blood pressure fluctuations correlated with PAT. Since the electrocardiogram (ECG) is recorded synchronously with the PPG during PSG, it makes sense to use the ECG signal for PPG signal-quality assessment. (1) Objective: to develop a PPG signal-quality assessment algorithm for robust PAT estimation, and investigate the influence of signal quality on PAT during various sleep stages and events such as OSA. (2) Approach: the proposed algorithm uses R and T waves from the ECG to determine approximate locations of PPG pulse onsets. The MESA database of 2055 PSG recordings was used for this study. (3) Results: the proportions of high-quality PPG were significantly lower in apnea-related oxygen desaturation (matched-pairs rc = 0.88 and rc = 0.97, compared to OSA and hypopnea, respectively, when p < 0.001) and arousal (rc = 0.93 and rc = 0.98, when p < 0.001) than in apnea events. The significantly large effect size of interquartile ranges of PAT distributions was between low- and high-quality PPG (p < 0.001, rc = 0.98), and regular and irregular pulse waves (p < 0.001, rc = 0.74), whereas a lower quality of the PPG signal was found to be associated with a higher interquartile range of PAT across all subjects. Suggested PPG signal quality-based PAT evaluation reduced deviations (e.g., rc = 0.97, rc = 0.97, rc = 0.99 in hypopnea, oxygen desaturation, and arousal stages, respectively, when p < 0.001) and allowed obtaining statistically larger differences between different sleep stages and events. (4) Significance: the implemented algorithm has the potential to increase the robustness of PAT estimation in PSG studies related to nocturnal blood pressure monitoring.

Effects of Continuous Positive Airway Pressure Therapy on Nocturnal Blood Pressure Fluctuation Patterns in Patients with Obstructive Sleep Apnea.

This retrospective study was designed to evaluate the effects of continuous positive airway pressure (CPAP) therapy, a well-established treatment for obstructive sleep apnea (OSA), on nocturnal blood pressure fluctuations (NBPFs) during rapid eye movement (REM) and non-REM sleep, and to evaluate the NBPF patterns in patients with OSA. We included 34 patients with moderate-to-severe OSA who underwent polysomnography using pulse transit time before and at 3–6 months after CPAP therapy. Nocturnal BP and NBPF frequency in REM and non-REM sleep were investigated, as well as NBPF pattern changes after receiving CPAP therapy. CPAP therapy resulted in significant reductions in the apnea–hypopnea index (AHI), arousal index, nocturnal systolic and diastolic BP, and NBPF frequency in REM and non-REM sleep (all p < 0.01). A higher AHI before CPAP resulted in lower nocturnal systolic BP (r = 0.40, p = 0.019) and NBPFs (r = 0.51, p = 0.002) after CPAP. However, 58.8% of patients showed no change in NBPF patterns with CPAP therapy. CPAP therapy significantly improved almost all sleep-related parameters, nocturnal BP, and NBPF frequency in REM and non-REM sleep periods, but NBPF patterns showed various changes post-CPAP therapy. These results suggest that factors other than OSA influence changes in NBPF patterns.

The effect of APAP and CPAP treatment on the nocturnal blood pressure fluctuation in OSA with hypertension patients

The effect of APAP and CPAP treatment on the nocturnal blood pressure fluctuation in OSA with hypertension patients

Nocturnal Blood Pressure Fluctuations in Patients with Rapid Eye Movement-Related Obstructive Sleep Apnea.

Rapid eye movement-related obstructive sleep apnea (REM-related OSA) is a polysomnographic phenotype. Nocturnal blood pressure (BP) fluctuations remain unclear in patients with REM-related OSA. We studied 27 patients with REM-related OSA, categorized as having REM-apnea-hypopnea index (REM-AHI) ≥ 5/h, REM-AHI/non-REM-AHI ≥ 2, and non-REM-AHI < 15/h. Beat-to-beat systolic BP (SBP) variability and nocturnal SBP fluctuation patterns using pulse transit time (PTT) were investigated. The maximum increase and average nocturnal SBP were significantly higher in males than in females (p = 0.003 and p = 0.008, respectively). The rate of non-dipping patterns in nocturnal SBP fluctuations was 63% in all patients (males, 70%; females, 50%). Epworth Sleepiness Scale (ESS) and Self-rating Depression Scale (SDS) scores in females were higher than those in males (8.4 ± 6.1 vs. 13.4 ± 5.4 points, p = 0.04; 43.8 ± 7.9 vs. 52 ± 11.6 points, p = 0.04, respectively). A high proportion of patients with REM-related OSA had a non-dipping pattern. Using PPT, we observed that in patients with REM-related OSA, SBP variability was greater in males. Despite clinical symptoms being slightly more severe in females, nocturnal SBP fluctuations should be considered in male patients with REM-related OSA.

Nocturnal blood pressure and nocturnal blood pressure fluctuations: the effect of short-term CPAP therapy and their association with the severity of obstructive sleep apnea.

We determined the relationship of cardiovascular risk factors, cardiovascular diseases, nocturnal blood pressure (NBP), and NBP fluctuations (NBPFs) with the severity of obstructive sleep apnea (OSA). We also investigated the effect of short-term continuous positive airway pressure therapy on NBP parameters. This retrospective study included 548 patients from our cardiac clinic with suspected OSA. Patients underwent polysomnography and continuous NBP measurement using the pulse transit time. According to their apnea-hypopnea index (AHI), patients were subclassified as controls (AHI < 5 events/h), mild (AHI 5 to < 15 events/h), moderate (AHI 15 to < 30 events/h), and severe OSA (AHI ≥ 30 events/h); 294 patients received continuous positive airway pressure therapy. Analysis of covariance showed that NBP and the frequency of NBPFs were the highest in severe followed by moderate and mild OSA (all P < .001). Multivariable regression analysis revealed a significant association of NBPFs with AHI, body mass index, systolic NBP, and lowest SpO2. The severity of OSA is also associated with the frequency of obesity, hypertension, diabetes mellitus, atrial fibrillation, heart failure (all P < .001), and coronary artery disease (P = .035). Short-term continuous positive airway pressure decreased the frequency of NBPFs in all OSA groups and the systolic NBP in severe and moderate but not in mild OSA. The severity of OSA is associated with an increase in NBP and NBPFs. Continuous positive airway pressure reduces NBP parameters already after the first night. In addition to BP, the diagnosis and therapy of NBPFs should be considered in patients with OSA. Registry: German Clinical Trials Register; Name: Nocturnal blood pressure and nocturnal blood pressure fluctuations associated with the severity of obstructive sleep apnea; URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00024087; Identifier: DRKS00024087. Picard F, Panagiotidou P, Tammen A-B, et al. Nocturnal blood pressure and nocturnal blood pressure fluctuations: the effect of short-term CPAP therapy and their association with the severity of obstructive sleep apnea. J Clin Sleep Med. 2022;18(2):361-371.

Associations between nocturnal continuous blood pressure fluctuations and the characteristics of oxygen desaturation in patients with obstructive sleep apnea: a pilot study

BackgroundPatients with obstructive sleep apnea (OSA) frequently experience apnea-related oxygen desaturation events (ODE) accompanied by striking blood pressure (BP) fluctuations during sleep. We aimed to investigate the effects of characteristics of ODE on nocturnal BP fluctuations in OSA patients. Methods and resultsA total of 6199 ODE were obtained from 30 patients with who underwent overnight portable monitoring and beat-to-beat BP monitoring simultaneously. The associations between nocturnal BP parameters and the characteristics of ODE were studied. The mean value of systolic BP (SBP) monitored during ODE was higher than the non-hypoxia SBP value (122.0 ± 15.9 vs. 120.4 ± 15.1 mmHg, P = 0.001) and nighttime SBP value (122.0 ± 15.9 vs. 120.8 ± 15.0 mmHg, P = 0.002). SBP variability (SBPV) during ODE was higher than the values not during ODE (14.0 ± 2.8 vs. 13.2 ± 2.6 mmHg, P = 0.043) and nighttime SBPV (14.0 ± 2.8 vs. 12.9 ± 2.3 mmHg, P < 0.001). Hypoxia SBP index, defined as the percentage of SBP surge (△SBP) ≥10 mmHg to all △SBP during ODE, increased with greater respiratory event index (P = 0.01). Both the coefficient of variation for SBP values of an ODE (SBPV′) and event-related SBP elevation (△SBP′) increased with raised amplitude of ODE (P < 0.001 for SBPV′ and P < 0.001 for △SBP′). Similar results were observed when the duration of events was analyzed (P < 0.001 for SBPV′ and P < 0.001 for △SBP′). ConclusionBP related to ODE may be the main component of increased BP during sleep in OSA patients. In addition to the frequency of respiratory events, the amplitude and duration of ODE may have a role in nocturnal BP fluctuations in OSA patients.

Effects of Continuous Positive Airway Pressure Titration on Nocturnal Blood Pressure Fluctuation in Severe Sleep Apnea Patients with Hypertension

Effects of Continuous Positive Airway Pressure Titration on Nocturnal Blood Pressure Fluctuation in Severe Sleep Apnea Patients with Hypertension

A12854 Severity of obstructive sleep apnoea is not associated with nocturnal blood pressure fluctuation in elderly hypertensive patients receiving amlodipine

Objectives: Obstructive sleep apnoea (OSA) is associated with increased variability in nocturnal blood pressure (BP). Calcium channel blockers (CCBs) are superior to other classes of antihypertensives in decreasing BP variability. We investigated whether OSA severity is associated with nocturnal BP variability in elderly hypertensive patients treated with amlodipine. Methods: We measured systolic and diastolic BP and pulse rate (PR) automatically during sleep at an interval of an hour once a week using an electronic sphygmomanometer in twenty-three hypertensive patients (≥65 years) receiving amlodipine. We calculated the coefficient of variation (CV) in data from 4 consecutive measurements. All patients underwent a home-based portable sleep study. Results: There were no differences in the average and CV of BP and the average PR between patients without OSA or with mild OSA and those with moderate to severe OSA as categorized by the respiratory disturbance index (RDI) and 3% oxygen desaturation index (ODI). The CV of PR in patients with moderate to severe OSA was lower than those of patients without OSA or with mild OSA categorized by 3% ODI. BMI was correlated with RDI and 3% ODI (r = 0.58 and 0.50, respectively). RDI and 3% ODI were not correlated with the CV of BP. The CV of PR was positively correlated with both RDI and 3% ODI (r = 0.42 and 0.45, respectively). Conclusion: The severity of OSA was associated with PR variability but not BP variability in older patients receiving CCB. Our results suggest the need for future studies to determine whether CCBs can suppress the influence of OSA on BP fluctuation during sleep.

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

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. 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 > 10mmHg per hour of sleep time) was used to stand for the frequency of significant BP fluctuations. Compared with the normotensive group, △SBP and SBP index were higher in the hypertensive group (13.8 ± 4.4mmHg vs 10.9 ± 3.1mmHg; 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. 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. NCT02876471.

Circadian blood pressure profile and comparison with clinic blood pressure in patients with essential hypertension on treatment; experience from a Teaching Hospital in Sri Lanka

Background and Objectives: Ambulatory blood pressure monitoring (ABPM) is more reflective of an individual’s Blood Pressure (BP) profile and its control, eliminating several confounding and contributory factors. The present study was intended to look at the circadian pattern of BP variation, the prognostication of patients with nocturnal BP fluctuations and to compare the clinic BP measurements over ambulatory readings in patients with essential hypertension, who are on treatment. Methods: A Prospective study was conducted at Teaching Hospital Kandy from August 2015 to October 2015 with recruitment of 100 patients who met the inclusion criteria. It included patients who were above 18 years with stage I to III hypertension with normal renal functions and having no previous history of coronary or cerebro-vascular events. All patients underwent electrocardiograms, 2D echocardiography assessment, manual BP as well as 24-hour ABPM. Results: There were 100 subjects with female preponderance and mean age of 61 ± 9 years. One third had uncontrolled BP according to office BP readings whereas 60% had uncontrolled BP according to ABPM. The agreement between the office BP and ABPM in diagnosing control or uncontrolled BP was low (58%, Kappa = 0.23). Significant statistical difference (p Conclusion: ABPM is more reflective of an individual’s naive BP pattern and its response to treatment. It captures the different types of diurnal variation of BP thus guiding the physician to treat the patient optimally. Moreover, its non-invasive and portable nature allows it to be used with ease and will gather more widespread recognition and acceptance as a more reliable diagnostic and prognostic tool in the future.

Nocturnal blood pressure fluctuations measured by using pulse transit time in patients with severe obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is related to arterial hypertension. In the present study, we test the hypothesis that patients with severe OSAS have excessive apnea induced blood pressure (BP). We investigated 97 patients with an apnea/hypopnea index (AHI) greater than 30. Systolic BP (SBP) was continuously determined by using the pulse transit time (PTT). Apnea/hypopnea induced nocturnal BP fluctuations (NBPFs) were detected and showed phenomena of continuous increases of the SBP baseline. Such periods of SBP baseline elevations ≥ 10mmHg were called superposition. Respiratory and cardiac parameters were obtained from the polysomnographic investigation. Eighty-four periods of superposition were detected in 48 patients. They occurred mainly during REM sleep (76%). Apnea duration was increased and the time in respiration was reduced in periods of superposition compared to non-superposition periods. In superposition periods mean oxygen saturation (SpO2) and the minimal SpO2 were lower, desaturations were more pronounced, and the mean heart rate (HR) was increased. The maximum SBP during superposition was significantly increased (204±32 vs.171±28mmHg). The clinic BP was higher in patients with superposition (SBP 149.2±17.5 vs. 140±19.1, DBP 91.5±11.5 vs. 86.3±11.8). The study reveals that patients with severe OSAS can have periods of BP superposition during night with extremely high SBP and very low oxygen saturation, which may add to a high risk for cardiovascular events during the night.

Nocturnal blood pressure fluctuations: Superposition phenomena in patients with obstructive sleep apnea syndrome – Risk factor for nocturnal cardiovascular events?

Nocturnal blood pressure fluctuations: Superposition phenomena in patients with obstructive sleep apnea syndrome – Risk factor for nocturnal cardiovascular events?

Nocturnal blood pressure changes in patients with restless legs syndrome

To assess heart rate (HR) and blood pressure (BP) changes associated with periodic leg movements during sleep (PLMS) with or without EEG signs of arousal in subjects with primary restless legs syndrome (RLS). Ten patients with RLS (4 women, aged 47.3 +/- 13.5 years) underwent one night of polysomnography along with noninvasive beat-to-beat BP monitoring. Ten PLMS with microarousals (PLMS-MA) and 10 PLMS without microarousals (PLMS-noMA) were analyzed in each subject. Systolic and diastolic BP (SBP, DBP) were measured within a 25-beat temporal window comprising 10 beats before and 15 beats after onset of each movement. PLMS-related BP changes were assessed by repeated measures one-way analysis of variance. BP changes associated with PLMS-MA and PLMS-noMA were compared by paired t-tests. Pearson correlation coefficients were used to assess the relationship between cardiovascular changes and clinical and polysomnographic variables. BP increased significantly in association with all PLMS (on average, SBP 22 mm Hg, DBP 11 mm Hg). BP changes associated with PLMS-MA were greater vs those associated with PLMS-noMA (p < 0.05). SBP and DBP changes increased with age and the duration of illness. Periodic leg movements-related repetitive nocturnal blood pressure fluctuations could contribute to the risk of cardiovascular diseases in patients with restless legs syndrome, especially in the elderly.

Nocturnal sleep and blood pressure in essential hypertension.

Blood pressure and sleep-wakefulness patterns were monitored in the sleep laboratory over four consecutive nights in six patients with mild hypertension and six age- and sex-matched controls. In both hypertensives and normals, blood pressure levels decreased during sleep compared with presleep levels by 16.6 and 8.4%, respectively; levels for hypertensives, however, remained significantly above those for the normals. The nocturnal drop in blood pressure for both groups appeared to be related primarily to the general state of sleep rather than to any specific sleep stage. Nocturnal patterns of sleep stages and sleep cycling were almost identical for the two groups. Nocturnal blood pressure fluctuation was correlated positively with the distribution of nocturnal wakefulness in hypertensives but not in normotensives. This suggests that with hypertension there is some diminution of the dampening effect of sleep itself upon blood pressure which normally carries over into periods of nocturnal wakefulness. This alteration in patients with mild hypertension may reflect a decrease in the sensitivity of the baroreceptor reflex or some other pathophysiological process.