Awakenings change results of nighttime ambulatory blood pressure monitoring

[Multifunctional Monitoring: is it Possible to Simultaneously Evaluate Blood Pressure and Sleep-Disordered Breathing?]

Objective Carry out a comparative assessment of respiratory performance, based on multifunctional monitoring (MFM) and the recommended practice for complete polysomnography (PSG), and evaluate the effect of the blood pressure (BP) measurements in MFM on the quality of sleep.Materials and Methods At the first stage, 22 healthy volunteers (control group) underwent concomitant PSG and MFM, and 14 patients with suspected sleep-disordered breathing (SDB) underwent only PSG. At the second stage, concomitant PSG and MFM were performed in patients with confirmed SDB.Results In the control group, MFM detected a lower level of SpO2, a lower desaturation index (DI), and a higher apnea index (AI) than in the PSG group. However, the apnea-hypopnea index (AHI) was comparable in both groups. During concomitant PSG-MFM, the measurements of BP increased the number of micro-arousals only in the SDB group.Conclusion Results of the assessment of respiratory performance in MFM are comparable in both groups. The detected features of MFM indicators in the evaluation of the chest movements using rheopneumography, criteria different from that generally used for desaturation and hypoxemia, can lead to underestimation of desaturation and DI and underestimation of AI in the control group. The measurements of BP during sleep induced micro-arousals in the SDB group.

Continuous non-invasive determination of nocturnal blood pressure variation using photoplethysmographic pulse wave signals: comparison of pulse propagation time, pulse transit time and RR-interval

OBJECTIVE

Cardiovascular diseases are the leading cause of death, whereas nocturnal ambulatory blood pressure (BP) is the most potent predictor for cardiovascular risk. The volume clamp and pulse transit time (PTT) are common methods for continuous non-invasive BP measurement, but have drawbacks during unsupervised ambulatory use and undisturbed sleep. The pulse propagation time (PPT), defined as the time between pulse wave systolic peak and diastolic peak, provides valid information about the pressure pulse waveform. However, the use of PPT for nocturnal BP variation determination and whether such variation is affected by BP or heart rate (i.e. RR-interval or RRI) has not been investigated.

APPROACH

To assess whether the PPT method is suitable for ubiquitous nocturnal BP monitoring, we compared systolic blood pressure (SBP) estimates derived from PPT, PTT, and RRI signals with parallel recorded BP measurements. The RRI-derived SBP signals were used as a baseline for testing a potential heart rate dependency. This work provides an overview of BP measurements, presents the developed real-time signal analysis, and describes the performance assessment. The signal analysis was validated with data records from 42 subjects acquired from an ergometry and sleep laboratory in equal parts.

MAIN RESULTS

The algorithms applied to the ergometry laboratory database achieved a correlation coefficient between reference SBP and estimated SBP_PPT of 0.89 (p  <  0.001) with bias 0.1 mmHg and limits of agreement (LoA)  -29.8 to 30.0 mmHg, SBP_PTT of 0.97 (p  <  0.001) with bias 0.0 mmHg and LoA  -15.2 to 15.3 mmHg, and SBP_RRI of 0.96 (p  <  0.001) with bias 0.0 mmHg and LoA  -19.5 to 19.5 mmHg. For the sleep laboratory database, the correlation coefficient was 0.95 (p  <  0.001) with bias 0.2 mmHg and LoA  -18.3 to 18.8 mmHg for SBP_PPT, 0.88 (p  <  0.001) with bias 0.0 mmHg and LoA  -25.0 to 24.9 mmHg for SBP_PTT, and 0.88 (p  <  0.001) with bias of 0.1 mmHg and LoA  -23.6 to 23.7 mmHg for SBP_RRI. A heart rate dependency of PPT or PTT could not be found. The analysis of variance shows no significant differences between the reference SBP values and the estimated values for either the ergometry (F(3, 627)  =  2.27, p  =  0.08) or the sleep laboratory (F(3, 327)  =  2.28, p  =  0.08).

SIGNIFICANCE

In conclusion, the PPT method seems to be an interesting alternative for continuous determination of SBP during simplified cardiovascular monitoring and sleep screening compared to more expensive devices based on volume clamp or PTT methods.

The Effects of Ambulatory Blood Pressure Monitoring on Sleep Quality in Men and Women With Hypertension: Dipper vs. Nondipper and Race Differences

BACKGROUND

The nondipping circadian blood pressure (BP) profile is associated with both poor sleep quality and increased cardiovascular risk. The present study aimed to clarify the potential confounding effects of 24-hour ambulatory blood pressure monitoring (ABPM) used to characterize the circadian BP profile by assessing its impact on sleep quality.

METHODS

Participants were 121 middle-aged men and women with untreated hypertension (age = 46 ± 8 years; 43% women; 45% African-American). Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index. Wrist actigraphy was used to measure sleep quality objectively as sleep efficiency (SE) and total sleep time (TST) on 7 consecutive non-ABPM days (baseline) and 3 subsequent 24-hour ABPM days.

RESULTS

Average ambulatory BP was 137.2 ± 10.8/84.3 ± 8.5 mm Hg during the day and 119.6 ± 12.4/69.5 ± 9.8 mm Hg at night. Using the criterion of <10% dip in systolic BP (SBP) to define nondippers, there were 40 nondippers (SBP dip = 7.3 ± 2.6%) and 81 dippers (SBP dip = 15.5 ± 3.4%). There was no effect of time on SE or TST over non-ABPM and ABPM days, suggesting that ABPM does not adversely affect sleep quality. Sleep quality was generally poorer (lower SE) in nondippers compared with dippers (P = 0.033), but differences were independent of whether or not participants were undergoing 24-hour ABPM. African-American race (P = 0.002) was also associated with lower SE.

CONCLUSION

Sleep quality generally appears to be poor in men and women with untreated hypertension and especially among African-Americans. Importantly, for both dippers and nondippers, we found no evidence that ABPM had an adverse effect on sleep quality.

The association between home vs. ambulatory night-time blood pressure and end-organ damage in the general population

OBJECTIVE

The aim of this study was to test the agreement between night-time home and night-time ambulatory blood pressure (BP) and to compare their associations with hypertensive end-organ damage for the first time in the general population.

METHODS

A population sample of 248 participants underwent measurements for night-time home BP (three measurements on two nights with a timer-equipped home device), night-time ambulatory BP, pulse wave velocity (PWV), carotid intima-media thickness (IMT) and echocardiographic left ventricular mass index (LVMI).

RESULTS

No significant or systematic differences were observed between mean night-time ambulatory and home BPs (systolic/diastolic difference: 0.7 ± 7.6/0.2 ± 6.0 mmHg, P = 0.16/0.64). All night-time home and ambulatory BPs were positively correlated with PWV, IMT and LVMI (P < 0.01 for all). No significant differences in Pearson's correlations between end-organ damage and night-time home or ambulatory BP were observed (P ≥ 0.11 for all comparisons using Dunn and Clark's Z), except for a slightly stronger correlation between PWV and ambulatory SBP than for home SBP (r = 0.57 vs. 0.50, P = 0.03). The adjusted R of all multivariable-adjusted models for PWV, IMT or LVMI that included night-time home or ambulatory SBP/DBP were within 2/1%.

CONCLUSION

Our study demonstrates that night-time home and ambulatory measurements produce similar BP values that have comparable associations with end-organ damage in the general population even when a clinically feasible measurement protocol is used for measuring night-time home BP. In the future, night-time home BP measurement may offer a feasible and easily accessible alternative to ambulatory monitoring for the measurement of night-time BP.

A Population-Based Assessment of 24-Hour Ocular Perfusion Pressure Among Patients With Primary Open Angle Glaucoma: The Handan Eye Study

PURPOSE

To compare the 24-hour ocular perfusion pressure (OPP) among patients with primary open angle glaucoma (POAG) and those with suspected POAG identified in a population-based study in China.

METHODS

Forty-seven patients with POAG and 35 with suspected POAG attended the 24-hour OPP study. Intraocular pressure (IOP) and blood pressure (BP) were measured at 2, 6, and 10 AM and 2, 6, and 10 PM. Subjects were not taking any medications to lower IOP, which was measured with Goldmann applanation in an upright sitting position. Blood pressure was measured in a supine position using a digital automatic BP monitor (OMRON, model HEM-907). Mean arterial pressure was calculated as diastolic BP + 1[Fraction Slash]3 × (systolic BP - diastolic BP). Mean OPP (MOPP) was defined as 2[Fraction Slash]3 × mean arterial pressure - IOP, systolic OPP (SOPP) was defined as 2[Fraction Slash]3 × systolic BP - IOP, and diastolic OPP (DOPP) was defined as 2[Fraction Slash]3 × diastolic BP - IOP.

RESULTS

After adjustment for age, sex, and IOP, the maximum, mean, and minimum SOPP, DOPP, and MOPP were statistically significantly lower in subjects with POAG than in those with suspected POAG (P < 0.05). The minimum MOPP, SOPP, and DOPP occurred from 10 AM to 2 PM in approximately 60% of eyes with POAG and between 20% and 30% of minimum MOPP, SOPP, and DOPP occurred around 10 PM.

CONCLUSIONS

Systolic OPP, DOPP, and MOPP were consistently lower in eyes with POAG than in those with suspected POAG, providing further evidence that OPP plays a role in the development of glaucoma.

A randomized, controlled pilot trial of hormone therapy for menopausal insomnia

Insomnia is a frequent climacteric symptom. This pilot, double-blind, randomized placebo-controlled trial compared estradiol associated with trimegestone or placebo in 12 women with perimenopausal insomnia. The Pittsburgh Sleep Quality Index (PSQI) was administered, and polysomnography was performed at baseline and after 28 days. Sleep efficiency and median score of the PSQI improved significantly in the hormone therapy group (HT) (p=0.041 and p=0.027, respectively) and not in placebo group. Perimenopausal insomnia improved after short-term HT.

Repeating administration of Epworth Sleepiness Scale is clinically useful

PURPOSE

We aimed to verify whether it is clinically useful to repeat the Epworth Sleepiness Scale (ESS) in individuals with suspected sleep-disordered breathing (SDB).

METHODS

In this cross-sectional, prospective study, results of the repeated administration of the ESS were analyzed. In 929 consecutive patients, ESS was obtained as usual in the laboratory routine, immediately before the sleep study (ESS1) and was repeated in the morning, after the polysomnography (ESS2). ROC curve, classical psychometry, and item response theory (IRT) Rasch analysis were used to assess measurement properties of ESS.

RESULTS

The ESS1 score was (mean ± SD), 11 ± 5.1, and the ESS2, 13 ± 4.7 (p < 0.001). Change in ESS score is explained in multivariate analysis by age, but not by gender, educational level, change in Stanford Sleepiness Scale, symptoms of sleep disorder, or polysomnography results. Accuracy of an ESS score >10 to predict apnea-hypopnea index ≥5 increased from 56% (ESS1) to 72% (ESS2). IRT psychometric properties (unidimensionality, invariance, local independence) were maintained in ESS2.

CONCLUSIONS

Repeating the administration of the Epworth Sleepiness Scale in a clinical setting increases its score and diagnostic accuracy and correlation with SDB variables, without changing the psychometric properties of the scale. This experiment indicates the clinical usefulness of repeating the ESS. The scale can be repeated at a negligible cost, before dismissing individual patients on the basis of a low ESS score, discontinuing a potentially lifesaving diagnostic and therapeutic process.

Light sleep and sleep time misperception - relationship to alpha-delta sleep

OBJECTIVE

We investigated the association of alpha-delta sleep (A-DS) with: (1) perception of light sleep and (2) discrepancy between subjective and objective sleep duration.

METHODS

We analyzed data from 5764 individuals who underwent polysomnography (PSG) and replied questions about quantity and quality of sleep, including sleep depth. The difference between objectively recorded sleep time and subjectively estimated sleep time was calculated. Alpha-delta sleep (A-DS) was visually scored in a scale from 1 to 4, based on the density and overnight duration of alpha activity and confirmed using spectral array of the electroencephalographic activity.

RESULTS

A-DS scores 1-4 occurred in, respectively, 37.9%; 31.3%; 20.5%; and 6.2% of the cases. ANOVA showed significant difference of light sleep sensation (p<0.001) and sleep time underestimation (p<0.001) among the four A-DS categories. Regression to explain both light sleep and sleep time underestimation, controlling for confounders, confirmed A-DS as a significant regressor.

CONCLUSIONS

This study of a large prospective sample provides evidence for the association of alpha-delta sleep with subjective sensation of light sleep and with sleep time underestimation.

SIGNIFICANCE

Alpha-delta sleep may be a marker of the physiological disorder underlying light sleep and sleep state misperception.

Nocturnal blood pressure profiles among normotensive, controlled hypertensive and refractory hypertensive subjects

BACKGROUND

Nocturnal blood pressure abnormalities are independently associated with an increased risk of death and cardiovascular disease. It is unclear, however, whether they are related to the presence or severity of hypertension.

OBJECTIVES

To determine and compare the prevalence of sleep pattern disturbances in normotensive (NT) and hypertensive patients.

METHODS

The present cross-sectional study assessed the nocturnal blood pressure profiles from 24 h ambulatory blood pressure monitoring of refractory hypertensive (RH) (n=26), controlled hypertensive (CH) (n=52) and NT (n=52) subjects who were matched for age, sex and body mass index. Results are expressed as mean +/- SD or proportion, as appropriate.

RESULTS

During sleep, the percentage fall in mean arterial pressure was 15.1+/-6.1% in the NT group, 11.5+/-7.0% in the CH group and 7.7+/-7.7% in the RH group (P<0.0001). The corresponding proportions of nondipping were 25.0%, 42.3% and 61.5%, respectively (P=0.006), and those of nocturnal hypertension were 9.6%, 23.1% and 84.6%, respectively (P<0.0001). All pairwise comparisons of nocturnal blood pressure fall were significant. The proportion of subjects in the RH group who experienced a rise in nocturnal blood pressure (19.2%) was significantly greater than the proportions in the NT and CH groups (P=0.001), as was the proportion of subjects with nocturnal hypertension (P<0.0001). There was less extreme dipping in RH, although the difference was not statistically significant (P=0.08).

CONCLUSIONS

A significantly higher prevalence of nondipping, nocturnal hypertension and nocturnal blood pressure rising in RH was demonstrated. These sleep disturbances or independently, their cause, may account for the difficulties in attaining blood pressure control.

Can nocturnal hypertension predict cardiovascular risk?

Nocturnal hypertension and non-dipping of blood pressure during sleep are distinct entities that often occur together and are regarded as important harbingers of poor cardiovascular prognosis. This review addresses several aspects related to these blood pressure abnormalities including definitions, diagnostic limitations, pathogenesis and associated patient profiles, prognostic significance, and therapeutic strategies. Taken together, persistent nocturnal hypertension and non-dipping blood pressure pattern, perhaps secondary to abnormal renal sodium handling and/or altered nocturnal sympathovagal balance, are strongly associated with deaths, cardiovascular events, and progressive loss of renal function, independent of daytime and 24-hour blood pressure. Several pharmacological and non-pharmacological approaches may restore nocturnal blood pressure and circadian blood pressure rhythm to normal; however, whether this translates to a clinically meaningful reduction in unfavorable cardiovascular and renal consequences remains to be seen.

The price of obstructive sleep apnea-hypopnea: hypertension and other ill effects

This review addresses the cardiovascular, cerebrovascular, and metabolic consequences that accompany obstructive sleep apnea-hypopnea (OSAH) in conjunction with the mechanistic pathways implicated in mediating these effects. Particular emphasis is placed on the association with hypertension (HTN). Varying levels of evidence support a role of OSAH in perpetuating sustained HTN, nocturnal HTN, and difficult to control HTN as well as in contributing to the occurrences of nondipping of blood pressure (BP) and increased BP variability. In this context, the emergence of matched designs, adjusted analyses, meta-analyses as well as longitudinal and interventional studies strengthens causal inferences drawn from older observational studies, which suffered from such limitations as confounding.

Hall M, Strollo PJ, Owens JF, Buysse DJ, Lee L, Reis SE. Blood pressure dipping and sleep disturbance in African-American and Caucasian men and women

BACKGROUND

Elevated night time/daytime blood pressure (BP) ratios are associated with cardiovascular morbidity and mortality. We evaluated the associations between sleep/awake BP ratios and sleep disturbances.

METHODS

Sleep disturbances were assessed by in-home actigraphy and diary measures for nine nights, and polysomnography (PSG) for two nights; ambulatory BP was measured for at least 48 h. Participants were 186 middle-aged African-American and Caucasian men and women who were free from prevalent myocardial infarction, stroke, history of interventional cardiology procedures, diabetes, and diagnosed apnea or other sleep disorders.

RESULTS

Results showed that the greater the sleep/wake ratios of BP, the more fragmented the sleep, the greater the proportion in stage 1 (light) sleep and the smaller the proportion in rapid eye movement (REM) sleep, and the greater the number of arousals from sleep. These results were independent of age, race, gender, Framingham Risk status, cardiovascular medications, body mass index, and apnea/hypopnea index. Indicators of psychosocial stress were not greater among those with higher sleep/wake BP ratios.

CONCLUSIONS

Findings are consistent with the hypothesis that elevated night time/daytime pressure may be a consequence of poor sleep.