Night-time Blood Pressure Measurements Research Articles

Investigation of Antihypertensive Properties of Chios Mastic via Monitoring microRNA-21 Expression Levels in the Plasma of Well-Controlled Hypertensive Patients.

Hypertension is a chronic, multifactorial disease, leading to high cardiovascular morbidity and mortality globally. Despite the advantages of pharmaceutical treatments, natural products have gained scientific interest due to their emerging phytotherapeutic properties. Chios mastic is a natural Greek product, consisting of bioactive compounds which modify microRNAs' (small, expression-regulating molecules) expression. In this study, we investigated the antihypertensive properties of Chios mastic through the assessment of miR-21 levels. Herein, plasma samples of 57 individuals with hypertension, recruited for the purposes of the HYPER-MASTIC study, were analyzed. This was a clinical trial with Chios mastic supplements in which the patients were divided into groups receiving high and low mastic doses and placebo supplements, respectively. miR-21 was significantly upregulated in patients compared to normotensive individuals. Mean changes in miR-21 levels were statistically significant, after adjusting for sex and age, between the placebo and low-dose group and between the low- and high-dose group. Post-intervention miR-21 levels were positively associated with night-time systolic blood pressure, pulse pressure, and central systolic mean arterial pressure and negatively associated with night-time pulse wave velocity in the low-dose group. Our findings suggest a potential implication of miR-21 in the association of Chios mastic with night-time blood pressure measurements.

Contactless Blood Pressure Measurement Via Remote Photoplethysmography With Synthetic Data Generation Using Generative Adversarial Networks.

Remote photoplethysmography (rPPG) has been used to measure vital signs such as heart rate, heart rate variability, blood pressure (BP), and blood oxygen. Recent studies adopt features developed with photoplethysmography (PPG) to achieve contactless BP measurement via rPPG. These features can be classified into two groups: time or phase differences from multiple signals, or waveform feature analysis from a single signal. Here we devise a solution to extract the time difference information from the rPPG signal captured at 30 FPS. We also propose a deep learning model architecture to estimate BP from the extracted features. To prevent overfitting and compensate for the lack of data, we leverage a multi-model design and generate synthetic data. We also use subject information related to BP to assist in model learning. For real-world usage, the subject information is replaced with values estimated from face images, with performance that is still better than the state-of-the-art. To our best knowledge, the improvements can be achieved because of: 1) the model selection with estimated subject information, 2) replacing the estimated subject information with the real one, 3) the InfoGAN assistance training (synthetic data generation), and 4) the time difference features as model input. To evaluate the performance of the proposed method, we conduct a series of experiments, including dynamic BP measurement for many single subjects and nighttime BP measurement with infrared lighting. Our approach reduces the MAE from 15.49 to 8.78 mmHg for systolic blood pressure (SBP) and 10.56 to 6.16 mmHg for diastolic blood pressure(DBP) on a self-constructed rPPG dataset. On the Taipei Veterans General Hospital(TVGH) dataset for nighttime applications, the MAE is reduced from 21.58 to 11.12 mmHg for SBP and 9.74 to 7.59 mmHg for DBP, with improvement ratios of 48.47% and 22.07% respectively.

PS-C13-14: ARNI DECREASED NIGHTTIME BLOOD PRESSURE EVALUATED BY WRIST-TYPE NOCTURNAL MONITORING DEVICE IN A PATIENT WITH TREATMENT-RESISTANT HYPERTENSION AFTER RENAL DENERVATION

Angiotensin receptor-neprilysin inhibitor (ARNI), Sacubitril/Valsartan has been reported to decrease nighttime blood pressure (BP). Moreover, Sacubitril/Valsartan is expected to be useful in treatment resistant hypertension because neprilysin inhibition offers an additional effect to reducing BP levels. In this case report, we observed decreasing nighttime BP by changing from angiotensin-1 receptor blocker (ARB) and hydrochlorothiazide (HCTZ) to Sacubitril/Valsartan in a patient with sustained resistant hypertension despite he had been conducted the procedure of renal denervation. Additionally, we evaluated nighttime BP by newly developed wrist-type nocturnal BP monitoring device, Nightview (Omron HEM9601T, Omron health care, Kyoto, Japan). A 46 year old Asian male, who had underwent renal denervation 8-years ago, suffered for treatment-resistant hypertension despite of administration of multiple antihypertensive medications including combination agent of ARB/HCTZ, Ca-channel antagonist, beta-blocker, alpha-blocker, and mineralocorticoid receptor antagonist. His average of usual daytime (morning and evening) home BP level was 155/85 mmHg. We performed a 7-day consecutive nighttime BP measurement using wrist-type BP monitoring device, which also revealed nocturnal hypertension, 125/65 mmHg. To decrease his daytime or nighttime BP levels, we initiated administration of sacubitril/valsartan 400 mg instead of combination agent of ARB/hydrochlorothiazide (Candesartan 8 mg and Hydrochlorothiazide 6.25 mg). Then, we performed nighttime BP measurements using wrist-type device again, which revealed decreasing nighttime BP to 119/61 mmHg just after initiating Sacubitril/Valsartan instead of combination agent of ARB/HCTZ. His usual daytime home BP also decreased to 140/80 mmHg. Additionally, NT-pro BNP also decreased from 87 to 55 pg/mL. From these observations in this case report, ARNI is expected to improve BP control, especially nighttime BP level, in patients with uncontrolled treatment-resistant hypertension despite multiple drug and denervation therapy. ARNI may be also expected to prevent heart failure in resistant hypertension.

Comparison of nighttime measurement schedules using a wrist-type nocturnal home blood pressure monitoring device.

We investigated the optimal nighttime home blood pressure (BP) measurement schedule for wrist BP monitoring. Fifty hypertensive patients (mean age 68.9 ± 11.3 years) self‐measured their nighttime BP hourly using a wrist‐type nocturnal home BP monitoring device at home on two consecutive nights. Using the average 7.2 ± 1.5 measurements per night, we compared the clock‐based index (average of three measurements at 2:00, 3:00, and 4:00 a.m.) and the bedtime‐based index (average of three measurements at 2, 3, and 4 h after bedtime). The clock‐based average was significantly higher than the bedtime‐based average for both systolic BP (2.7 ± 8.2 mmHg, P = .002) and diastolic BP (1.9 ± 5.1 mmHg, P < .001). Compared to the average of all measurements throughout a night (the same definition of ambulatory BP monitoring, ie, from the time point of going to bed to awakening), the clock‐based average was comparable (systolic/diastolic BP: −0.5 ± 5.5/−0.2 ± 3.7), whereas the bedtime‐based average was significantly lower (−3.3 ± 5.0/−2.1 ± 3.6). Thus, the repeated measurement of wrist‐measured nighttime BP at three clock‐based time points per night provided reliable values. Further prospective studies of larger populations are required to confirm the optimal nighttime BP measurement schedule for wrist BP monitoring for the prediction of cardiovascular events.

The Role of Nocturnal Blood Pressure and Sleep Quality in Hypertension Management.

The accurate measurement, prediction and treatment of high blood pressure (BP) are essential to the management of hypertension and the prevention of its associated cardiovascular (CV) risks. However, even if BP is optimally controlled during the day, nocturnal high blood pressure may still increase the risk of CV events. The pattern of circadian rhythm of BP can be evaluated by ambulatory BP monitoring (ABPM). Night-time ABPM is more closely associated with fatal and nonfatal CV events than daytime ambulatory BP. However, the use of ABPM is limited by low availability and the fact that it can cause sleep disturbance, therefore may not provide realistic nocturnal measurements. Home blood pressure monitoring (HBPM) offers an inexpensive alternative to ABPM, is preferred by patients and provides a more realistic assessment of BP during an individual’s daily life. However, until recently, HBPM did not offer the possibility to measure nocturnal (sleep time) BP. The development and validation of new BP devices, such as the NightView (OMRON Healthcare, HEM9601T-E3) HBPM device, could overcome these limitations, offering the possibility of daytime and night-time BP measurements with minimal sleep disturbance.

Association of Office and Ambulatory Blood Pressure With Mortality and Cardiovascular Outcomes

Blood pressure (BP) is a known risk factor for overall mortality and cardiovascular (CV)-specific fatal and nonfatal outcomes. It is uncertain which BP index is most strongly associated with these outcomes. To evaluate the association of BP indexes with death and a composite CV event. Longitudinal population-based cohort study of 11 135 adults from Europe, Asia, and South America with baseline observations collected from May 1988 to May 2010 (last follow-ups, August 2006-October 2016). Blood pressure measured by an observer or an automated office machine; measured for 24 hours, during the day or the night; and the dipping ratio (nighttime divided by daytime readings). Multivariable-adjusted hazard ratios (HRs) expressed the risk of death or a CV event associated with BP increments of 20/10 mm Hg. Cardiovascular events included CV mortality combined with nonfatal coronary events, heart failure, and stroke. Improvement in model performance was assessed by the change in the area under the curve (AUC). Among 11 135 participants (median age, 54.7 years, 49.3% women), 2836 participants died (18.5 per 1000 person-years) and 2049 (13.4 per 1000 person-years) experienced a CV event over a median of 13.8 years of follow-up. Both end points were significantly associated with all single systolic BP indexes (P < .001). For nighttime systolic BP level, the HR for total mortality was 1.23 (95% CI, 1.17-1.28) and for CV events, 1.36 (95% CI, 1.30-1.43). For the 24-hour systolic BP level, the HR for total mortality was 1.22 (95% CI, 1.16-1.28) and for CV events, 1.45 (95% CI, 1.37-1.54). With adjustment for any of the other systolic BP indexes, the associations of nighttime and 24-hour systolic BP with the primary outcomes remained statistically significant (HRs ranging from 1.17 [95% CI, 1.10-1.25] to 1.87 [95% CI, 1.62-2.16]). Base models that included single systolic BP indexes yielded an AUC of 0.83 for mortality and 0.84 for the CV outcomes. Adding 24-hour or nighttime systolic BP to base models that included other BP indexes resulted in incremental improvements in the AUC of 0.0013 to 0.0027 for mortality and 0.0031 to 0.0075 for the composite CV outcome. Adding any systolic BP index to models already including nighttime or 24-hour systolic BP did not significantly improve model performance. These findings were consistent for diastolic BP. In this population-based cohort study, higher 24-hour and nighttime blood pressure measurements were significantly associated with greater risks of death and a composite CV outcome, even after adjusting for other office-based or ambulatory blood pressure measurements. Thus, 24-hour and nighttime blood pressure may be considered optimal measurements for estimating CV risk, although statistically, model improvement compared with other blood pressure indexes was small.

Usefulness of ambulatory blood pressure monitoring in chronic kidney disease: The moroccan experience.

Among patients with chronic kidney disease (CKD), hypertension (HTN) is very common and widely recognized to accelerate the progression of CKD and increase the risk for cardiovascular events. Accumulated data indicate that ambulatory blood pressure monitoring (ABPM) is better in detecting HTN than office blood pressure (BP) measurement. The goal of this study is to describe the ABPM characteristics in a group of CKD and hypertensive patients. A transversal study was conducted over a period of six months, to evaluate the ABPM patterns among a group of hypertensive patients with CKD (Group 1) and compared the data with a control group (Group 2). ABPM was performed with measurement rate every 15 min during daytime and 30 min at night. Nondipping BP patterns were defined as the absence of fall in nocturnal systolic and diastolic BP >10% of daytime values. Masked HTN was defined as controlled office BP (<140/90 mm Hg) with an elevated overall average BP by 24-h ABPM (>125/75 mm Hg), and white-coat HTN was defined as association of elevated BP readings (>140/90 mm Hg) in a clinical setting and normal 24-h average BP levels (<130/80 mm Hg). Fifty patients were included in each group. HTN was much longer in duration among hypertensive patients with CKD and frequently associated with obesity, dyslipidemia, and diabetes (64% vs. 39.60%). Positive proteinuria was present in 82% of CKD patients with HTN. CKD patients with HTN received more antihypertensive drugs than Group 2 patients. HTN was much more uncontrolled among CKD patients (60% vs. 24%), more serious with higher daytime and nighttime SBP, and loss of physiologic dipping during nighttime BP measurement (80%). Out-of-office BP monitoring by ABPM may improve the assessment and the successful management of HTN in patients with CKD. Standardized definitions for the diagnosis of masked and white-coat HTN would facilitate research.

Different Relevance of Peripheral, Central or Nighttime Blood Pressure Measurements in the Prediction of Chronic Kidney Disease Progression in Patients with Mild or No-Proteinuria

Background/Aims: Arterial hypertension is one of the leading factors aggravating the course of chronic kidney disease (CKD). It seems that the novel parameters used in the assessment of the blood pressure (BP) load (i.e. central blood pressure, nighttime blood pressure) may be more precise in predicting the cardiovascular risk and the progression of CKD in comparison with the traditional peripheral blood pressure measurements in the office conditions. The aim of the study was to assess the impact of the central, or nighttime blood pressure on the progression of CKD in patients with mild or no-proteinuria (autosomal, dominant polycystic kidney disease or IgA nephropathy). Methods: In each of the enrolled 46 patients with CKD stage 3 or 4, serum creatinine concentration was assessed, eGFR (MDRD) was calculated, also central blood pressure and pulse wave velocity (PWV) was assessed and the 24-hour ambulatory blood pressure monitoring (ABPM) was conducted at the beginning of the study and then repeated after one-year observation period. Results: During the observation period mean eGFR decreased from 44.1 (33.2-50.6) mL/min to 36.7 (29.7-46.3) mL/min. No significant differences were observed in the peripheral blood pressure or central blood pressure parameters. After one-year observation period the values of diastolic blood pressure dipping during the night significantly decreased from 16 (13-19) mmHg to 12 (10-15) mmHg; p< 0.05. The values of systolic dipping during the night or the mean BP values recorded in ABPM did not change significantly. Additionally, no significant differences in the PWV values were found. In the multivariate regression model the change of serum creatinine concentration was explained by the initial diastolic dipping values. Conclusion: 1. In patients with CKD stages 3 or 4 and mild or no- proteinuria, peripheral and central blood pressure did not change significantly during a one-year observation period despite the significant decline of eGFR and seems not to participate in the CKD progression. 2. Reduced magnitude of the diastolic dipping, which reflects the increase of diastolic blood pressure load during the nighttime, may play an important role in the pathogenesis of deterioration of kidney function in these patients.

Effect of Olmesartan-Based Therapies on Therapeutic Indicators Obtained Through Out-of-Office Blood Pressure.

Ambulatory blood pressure (BP) correlates more significantly with hypertension-associated cardiovascular mortality and morbidity than BP obtained in the doctor’s office. Assessing ambulatory BP, either through 24-h monitoring or through protocolized self-measurement at home, is essential in diagnosing and monitoring patients with hypertension. Several ambulatory BP-derived indicators are related with cardiovascular prognosis. These include 24-h, daytime and nighttime BP measurements, BP measurements obtained through home self-measurement, dipping status, morning surge, and BP variability. The objective of this article was to review the effect of olmesartan-based antihypertensive therapy on the main risk variables obtained when assessing ambulatory BP.Electronic supplementary materialThe online version of this article (doi:10.1007/s40119-015-0042-2) contains supplementary material, which is available to authorized users.

Asleep home blood pressure monitoring in obstructive sleep apnea

Obstructive sleep apnea (OSA) is known to be related to nocturnal blood pressure (BP) and nondipping hypertension. This pilot study evaluated night-time BP assessed using a home monitor in patients with OSA. Patients referred to a sleep clinic were subjected to polysomnography, clinic BP measurements, and home BP monitoring using a device that allows daytime (3 days, two duplicate readings per day) and automated night-time BP measurement (3 nights, three readings per night). Thirty-nine patients were included [72% men, mean age 48.7±10.8 years, clinic BP 131.2±19.6/84.1±11.9 mmHg, apnea-hypopnea index (AHI): 35.2±25.7]. All BP measurements were significantly correlated with the polysomnography indices. There was a consistent trend toward stronger correlations of the night-time diastolic home BP with the AHI (r=0.56), the duration of desaturation (0.53), and the maximum (-0.57) and minimum (-0.48) arterial oxygen saturation (all P<0.001). In stepwise multivariate analysis (independent variables age, sex, body weight, smoking status, and BP parameters), the AHI was associated independently with weight and night-time diastolic home BP (R=0.53). In patients with OSA, the assessment of night-time BP using a home monitor appears to be feasible and related to the severity of OSA. Given the wide availability of home BP monitoring in clinical practice, this method appears to be useful in the evaluation of BP in patients with OSA.

Prognostic Role of Ambulatory Blood Pressure Measurement in Patients With Nondialysis Chronic Kidney Disease

Ambulatory blood pressure (BP) measurement allows a better risk stratification in essential hypertension compared with office blood pressure measurement, but its prognostic role in nondialysis chronic kidney disease has been poorly investigated. The prognostic role of daytime and nighttime systolic BP (SBP) and diastolic BP (DBP) in comparison with office measurements was evaluated in 436 consecutive patients with chronic kidney disease. Primary end points were time to renal death (end-stage renal disease or death) and time to fatal and nonfatal cardiovascular events. Quintiles of BP were used to classify patients. The mean (SD) age of the patients was 65.1(13.6) years, and the glomerular filtration rate was 42.9(19.7) mL/min/1.73 m(2); 41.7% of the participants were women, 36.5% had diabetes, and 30.5% had cardiovascular disease. Office-measured SBP/DBP values were 146(19)/82(12) mm Hg; daytime SBP/DBP was 131 (17)/75 (11) mm Hg, and nighttime SBP/DBP was 122(20)/66(10) mm Hg. During follow-up (median, 4.2 years), 155 and 103 patients reached the renal and cardiovascular end points, respectively. Compared with a daytime SBP of 126 to 135 mm Hg, patients with an SBP of 136 to 146 mm Hg and those with an SBP higher than 146 mm Hg had an increased adjusted risk of the cardiovascular end point (hazard ratio [HR], 2.23; 95% confidence interval [CI], 1.13-4.41 and 3.07; 1.54-6.09) and renal death (1.72; 1.02-2.89 and 1.85; 1.11-3.08). Nighttime SBPs of 125 to 137 mm Hg and higher than 137 mm Hg also increased the risk of the cardiovascular end point (HR, 2.52; 95% CI, 1.11-5.71 and 4.00; 1.77-9.02) and renal end point (1.87; 1.03-3.43 and 2.54; 1.41-4.57) with respect to the reference SBP value of 106-114 mm Hg. Office measurement of BP did not predict the risk of the renal or cardiovascular end point. Patients who were nondippers and those who were reverse dippers had a greater risk of both end points. In chronic kidney disease, ambulatory BP measurement and, in particular, nighttime BP measurement, allows more accurate prediction of renal and cardiovascular risk; office measurement of BP does not predict any outcome.

Impact of Volume Status on Blood Pressure and Left Ventricle Structure in Patients Undergoing Chronic Hemodialysis

In this study, we aimed to examine the impact of volume status on blood pressure (BP) and on left ventricular mass index (LVMI) in chronic hemodialysis (HD) patients. This study enrolled 74 patients (F/M: 36/38, mean age 53.5 ± 15.3 years, mean HD time 41.5 ± 41 months) that were on HD treatment for at least 3 months. Demographics, biochemical tests, hemogram and C-reactive protein levels, mean interdialytic weight gain (IDWG), mean percentage of ultrafiltration (UF), and intradialytic complications such as hypotension and cramps were determined. Mean values of predialysis and postdialysis BP measurements were recorded a month before echocardiographic examination. On the day after a midweek dialysis session, 24 h ambulatory BP monitoring (ABPM) and echocardiographic examination were made concurrently. The patients were classified into two groups according to volume status: normovolemic (group 1; 14F/24M, mean age 50 ± 16.7 years, mean dialysis time 47.7 ± 47.7 months) and hypervolemic (group 2; 15F/21M, mean age 57.3 ± 12.7 years, mean dialysis time 34.9 ± 32 months). HD duration, IDWG, UF, and interdialytic complication rates were similar between the two groups (p < 0.05). Eleven patients (28.9%) of group 1 and 8 patients (22.2%) of group 2 showed dipper (p = 0.50). Valvular damage was more common in group 2 (p = 0.002). Whereas 33 patients (91.7%) had left ventricular hypertrophy (LVH) in group 2, 21 patients of the group 1 (55.3%) had LVH (p < 0.001). Although LVMI showed a significant positive correlation with cardiothoracic index, predialysis and postdialysis BP, IDWG, UF, daytime and nighttime BP measurements of 24 h ABPM, a significant negative correlation was seen with Kt/V urea and serum albumin levels. In conclusion, increased IDWG and UF and elevated BP are independent predictors of LVH for HD patients. Increased volume status leads to IDWG and elevated BP and eventually causes severe LVMI increases.

Arterial stiffness and dipper/nondipper blood pressure status in women with preeclampsia

The aim of this study was to investigate the clinical relevance of dipper status in women with preeclampsia by comparing arterial stiffness index (SI) values, and dipper and nondipper status. A total of 60 pregnant women in their third trimester were enrolled in the study. SI values were measured using a digital photoplethysmographic method (Pulse Trace System, Micro Medical Ltd., Gillingham, Kent, UK). Twenty-four-hour ambulatory blood pressure was measured by a SpaceLabs 90217 oscillometric device (SpaceLabs Inc., Redmond, WA, USA). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP) were recorded. Those preeclamptic women whose mean nighttime blood pressure measurements were at least 10% lower compared with mean daytime measurements were classified as dipper status, and those with a decrease of less than 10% were classified as nondipper status. Seventeen women were preeclamptic with a dipper status, 13 women had nondipper status preeclampsia, and 30 women were normotensive. SI values were significantly higher in preeclamptic women compared with normotensive women (8.8+/-1.2 m/s vs. 5.9+/-0.8 m/s, P<0.001), but SI values of preeclamptic women with dipper status and preeclamptic women with nondipper status did not differ significantly from each other (P=0.485). There was no significant difference in SI values between the dipper and nondipper preeclamptic groups. These results indicate that dipper and nondipper measurements may not be suitable for clinical follow-up of preeclamptic women.

Monitorização ambulatorial da pressão arterial e diabete melito tipo 2

Hypertension is one of the main risk factors for the onset and progression of chronic complications in type 2 diabetes mellitus (DM). Ambulatory blood pressure (BP) monitoring (ABPM) provides a better correlation with target organ lesions than BP obtained in the office. Furthermore, it allows the evaluation of distinct BP parameters such as the 24-h, daytime and nighttime systolic and diastolic BP means, BP loads and the absence of nocturnal drop of BP, as well as the identification of white-coat and masked hypertension. DM patients have higher daytime and nighttime BP means than non-DM patients. In addition, one third of normotensive type 2 DM patients have masked hypertension, which is associated with an increase in albuminuria and in left ventricle wall thickness. On the other hand, the prevalence and effect of white-coat hypertension in type 2 DM patients have not yet been properly evaluated. The absence of nocturnal drop of BP does not add information to the 24 h, daytime or nighttime BP measurements, but the nighttime BP means seem to be relevant in DM retinopathy. In conclusion, BP determination by ABPM allows better patient risk stratification for the development of DM chronic complications and is an essential instrument for effective BP control in these patients.

Awakenings change results of nighttime ambulatory blood pressure monitoring

Investigate the effect of distinguishing nighttime and sleep on nocturnal blood pressure results in ambulatory blood pressure monitoring. We recruited 36 patients, 29 men, with suspected obstructive sleep apnea/hypopnea syndrome attending a sleep clinic for diagnostic polysomnography and who agreed to wear a Spacelabs 90207 ambulatory blood pressure monitor during polysomnography. Their mean age was 45+/-11 years; body mass index (BMI), 30.8+/-5.4 kg/m; apnea-hypopnea index, 35+/-29 AH/h; 13 had a history of hypertension. A microphone attached to the ambulatory blood pressure monitor recorded its sounds in the polygraph and allowed us to classify each ambulatory blood pressure monitoring measurement as being made in electrographically-determined wake (e-wake) or sleep state (e-sleep). Patients were asleep during (mean+/-SD) 61+/-24% (range 0-100%) of the 14+/-1 nighttime blood pressure measurements. Systolic and diastolic ambulatory blood pressure monitoring readings were significantly higher during e-wake (121+/-12/73+/-9 mmHg) than during total nighttime (119+/-11/70+/-8 mmHg) and e-sleep (116+/-13/68+/-9 mmHg). On the basis of nighttime measurements, 22 patients (61%) had nocturnal hypertension. On the basis of measurements made during e-sleep, nocturnal hypertension was diagnosed in 12 patients (33%; chi2=5.54; P=0.018). A multiple linear regression model showed that the percentage of measurements made in e-sleep was the only variable that significantly explained the difference between nighttime and e-sleep blood pressure figures, when controlling for sex, age, BMI, apnea-hypopnea index, and lowest SaO2. During ambulatory blood pressure monitoring, nighttime blood pressure readings are higher than during e-sleep and this changes dipping and nocturnal hypertension classification.

24-h blood pressure monitoring in normal tension glaucoma: night-time blood pressure variability

Systemic arterial hypotension, hypertension and altered ocular blood flow are known risk factors in glaucoma. In this study, 24-h ambulatory blood pressure monitoring was performed in patients with normal tension glaucoma (NTG) and controls to evaluate blood pressure variability. In all, 51 patients with NTG and 28 age-matched controls were included in this prospective study. A 24-h ambulatory blood pressure monitoring (SpaceLabs Medical Inc., Redmond, USA) was performed and systolic, diastolic and mean arterial blood pressures were measured every 30 min during daytime (0800-2000) and night time (0000-0600). To evaluate blood pressure variability a variability index was defined as the s.d. of blood pressure measurements. Night-time blood pressure depression ('dip') was calculated (in percent of the daytime blood pressures). Patients with NTG exhibited higher night-time diastolic (P = 0.01) and mean arterial blood pressure values (P = 0.02) compared to controls, whereas systolic blood pressure data were not significantly different. The variability indices of night-time systolic, diastolic and mean arterial blood pressure measurements were significantly increased in patients with NTG compared to controls (P < 0.05). The night-time blood pressure depression of systolic (P = 0.47), diastolic (P = 0.11) and mean arterial blood pressures (P = 0.28) was not significantly different between patients with NTG and controls. In conclusion, patients with NTG showed increased variability of night-time blood pressure measurements compared to controls. Increased fluctuation of blood pressure may lead to ocular perfusion pressure fluctuation and may cause ischaemic episodes at the optic nerve head.