Diurnal Blood Pressure Variation Research Articles

Short-Term Changes in Weather and Space Weather Conditions and Emergency Ambulance Calls for Elevated Arterial Blood Pressure

Circadian rhythm influences the physiology of the cardiovascular system, inducing diurnal variation of blood pressure. We investigated the association between daily emergency ambulance calls (EACs) for elevated arterial blood pressure during the time intervals of 8:00–13:59, 14:00–21:59, and 22:00–7:59 and weekly fluctuations of air temperature (T), barometric pressure, relative humidity, wind speed, geomagnetic activity (GMA), and high-speed solar wind (HSSW). We used the Poisson regression to explore the association between the risk of EACs and weather variables, adjusting for seasonality and exposure to CO, PM10, and ozone. An increase of 10 °C when T > 1 °C on the day of the call was associated with a decrease in the risk of EACs during the time periods of 14:00–21:59 (RR (rate ratio) = 0.78; p < 0.001) and 22:00–7:59 (RR = 0.88; p = 0.35). During the time period of 8:00–13:59, the risk of EACs was positively associated with T above 1 °C with a lag of 5–7 days (RR = 1.18; p = 0.03). An elevated risk was associated during 8:00–13:59 with active-stormy GMA (RR = 1.22; p = 0.003); during 14:00–21:59 with very low GMA (RR = 1.07; p = 0.008) and HSSW (RR = 1.17; p = 0.014); and during 22:00–7:59 with HSSW occurring after active-stormy days (RR = 1.32; p = 0.019). The associations of environmental variables with the exacerbation of essential hypertension may be analyzed depending on the time of the event.

The relationship of age-adjusted Charlson comorbidity ındex and diurnal variation of blood pressure

ABSTRACTBackgrounds: Charlson Comorbidity index (CCI) is a scoring system to predict prognosis and mortality. It exhibits better utility when combined with age, age-adjusted Charlson Comorbidity Index (ACCI). The aim of this study was to evaluate the relationship between ACCI and diurnal variation of blood pressure parameters in hypertensive patients and normotensive patients.Methods: We enrolled 236 patients. All patients underwent a 24-h ambulatory blood pressure monitoring (ABPM) for evaluation of dipper or non-dipper pattern. We searched the correlation between ACCI and dipper or non-dipper pattern and other ABPM parameters. To further investigate the role of these parameters in predicting survival, a multivariate analysis using the Cox proportional hazard model was performed.Results: 167 patients were in the hypertensive group (87 patients in non-dipper status) and 69 patients were in the normotensive group (41 patients in non-dipper status) of all study patients. We found a significant difference and negative correlation between AACI and 24-h diastolic blood pressure (DBP), awake DBP, awake mean blood pressure (MBP) and 24-h MBP and awake systolic blood pressure(SBP). Night decrease ratio of blood pressure had also a negative correlation with ACCI (p = 0.003, r = −0.233). However, we found a relationship with non-dipper pattern and ACCI in the hypertensive patients (p = 0.050). In multivariate Cox analysis sleep MBP was found related to mortality like ACCI (p = 0.023, HR = 1.086, %95 CI 1.012–1.165)Conclusion: ACCI was statistically significantly higher in non-dipper hypertensive patients than dipper hypertensive patients while ACCI had a negative correlation with blood pressure. Sleep MBP may predict mortality.

Ambulatory blood pressure profiles in familial dysautonomia.

Familial dysautonomia (FD) is a rare genetic disease that involves extreme blood pressure fluctuations secondary to afferent baroreflex failure. The diurnal blood pressure profile, including the average, variability, and day-night difference, may have implications for long-term end organ damage. The purpose of this study was to describe the circadian pattern of blood pressure in the FD population and relationships with renal and pulmonary function, use of medications, and overall disability. We analyzed 24-h ambulatory blood pressure monitoring recordings in 22 patients with FD. Information about medications, disease severity, renal function (estimated glomerular filtration, eGFR), pulmonary function (forced expiratory volume in 1s, FEV1) and an index of blood pressure variability (standard deviation of systolic pressure) were analyzed. The mean (±SEM) 24-h blood pressure was 115±5.6/72±2.0mmHg. The diurnal blood pressure variability was high (daytime systolic pressure standard deviation 22.4±1.5mmHg, nighttime 17.2±1.6), with a high frequency of a non-dipping pattern (16 patients, 73%). eGFR, use of medications, FEV1, and disability scores were unrelated to the degree of blood pressure variability or to dipping status. This FD cohort had normal average 24-h blood pressure, fluctuating blood pressure, and a high frequency of non-dippers. Although there was evidence of renal dysfunction based on eGFR and proteinuria, the ABPM profile was unrelated to the measures of end organ dysfunction or to reported disability.

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.

Association between day-by-day and ambulatory blood pressure variability in type 2 diabetes patients

It remains unclear whether ambulatory blood pressure variability (BPV) contributes toward day-by-day BPV, despite the fact that not only day-by-day but also ambulatory BPV is reported to be a risk factor for type 2 diabetes patients. This study aimed to determine the association between day-by-day BPV and ambulatory BPV, which is especially distinguished between diurnal and nocturnal BPV, in type 2 diabetes patients. Day-by-day and ambulatory BPV were assessed in 30 type 2 diabetes patients (aged 54±15 years; 87% men; glycated hemoglobin: 9.1±1.9%) in inpatient settings. Day-by-day systolic BPV was correlated significantly with diurnal systolic BPV (r=0.426, P=0.019), but not nocturnal systolic BPV (r=0.175, P=0.354). Multiple regression analysis showed that diurnal systolic BPV and diurnal mean systolic blood pressure were associated independently with day-by-day systolic BPV. With respect to type 2 diabetes, these findings suggest that day-by-day BPV is reflected in diurnal BPV rather than nocturnal BPV.

Improvement of Diurnal Blood Pressure Variation by Azilsartan.

BackgroundAzilsartan is an angiotensin II receptor blocker with a potent antihypertensive effect.MethodsIn a multicenter, prospective, open-label study, 265 patients with poor blood pressure control despite treatment with other angiotensin II receptor blockers were switched to 20 mg/day of azilsartan (patients on standard dosages) or 40 mg/day of azilsartan (patients on high dosages).ResultsBlood pressure was 149/83 mm Hg before switching and was significantly reduced from 1 month after switching until final assessment (132/76 mm Hg, P < 0.001). The pulse rate was 72/min before switching and increased significantly from 3 months after switching until final assessment (74/min, P < 0.005). A significant decrease of home morning systolic and diastolic pressure was observed from 1 and 3 months, respectively. Home morning blood pressure was 143/82 mm Hg before switching and 130/76 mm Hg at final assessment (P < 0.01). The morning-evening difference of systolic blood pressure decreased from 14.6 to 6.6 mm Hg after switching (P = 0.09). The estimated glomerular filtration rate was significantly decreased at 3, 6, and 12 months after switching, and serum uric acid was significantly increased at 12 months. No serious adverse events occurred.ConclusionAzilsartan significantly reduced the blood pressure and decreased diurnal variation in patients responding poorly to other angiotensin II receptor blockers.

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

In this cross-sectional study, we analyzed the potential association between sleep measures and blood pressure variability. 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±3.11kg/m2 and 44.05±8.07years, respectively. 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. Effects of obstructive sleep apnea on blood pressure variability may not be limited nocturnally.

31 Influence of Night Shift Clinical Rotation Towards Diurnal Variation of Blood Pressure of The Clinical Clerks Compared with Preclinical Students

31 Influence of Night Shift Clinical Rotation Towards Diurnal Variation of Blood Pressure of The Clinical Clerks Compared with Preclinical Students

Abstract P486: Effects of Isometric Leg Training on Ambulatory Blood Pressure and Morning Blood Pressure Surge in Young Normotensive Men and Women

Introduction: Cardiovascular disease (CVD) is a major cause of death globally with hypertension reported to be a leading modifiable risk factor. Ambulatory blood pressure (BP), in particular diurnal BP variability, is considered to be associated with CVD risk. In addition, the morning BP surge (MBPS) is thought to be associated with increased stroke risk and to be a destabilizing factor for atherosclerotic plaque. Isometric resistance training (IRT) is an effective method of lowering BP and has been recommended by the American Heart Association as an alternative treatment for reducing BP. To date, few studies have investigated the effects of IRT on ambulatory BP and particularly the morning surge in BP. Therefore, the purpose of this study was to determine whether (i) IRT causes reductions in ambulatory BP and the MBPS, in young normotensives and (ii) there are any sex differences in these changes. Methods: Ambulatory BP was measured prior to, and after, 10 weeks of bilateral leg IRT using an isokinetic dynamometer (4 x 2 minute contractions at 20% MVC, with 2 minute rest periods on 3 days per week). Twenty normotensive individuals (10 men, age=21 ± 4 years; 10 women, age=23 ± 5 years) were recruited. A two-way repeated measures ANOVA was used to assess the within and between groups ambulatory (mean 24-h, daytime, night time and diurnal variation) BP and MBPS. MBPS was calculated as: mean systolic BP 2 hours after waking minus the lowest sleeping 1 hour mean systolic BP. Results: There were significant reductions in 24-h ambulatory (4 ± 2 mmHg, p=0.0001; 4 ± 2 mmHg, p=0.0001) systolic BP in both men and women following IRT. This comprised significant reductions in day time (5 ± 5 mmHg, p=0.019; 5 ± 4 mmHg, p=0.002) but not night time (1 ± 5 mmHg, p=0.75; 1 ± 3 mmHg, p=0.3) systolic BP. Additionally, there were significant reductions in the MBPS (6 ± 8 mmHg, p=0.044; 6 ± 7 mmHg, p=0.019). There were no significant differences between men and women in these changes (p&gt;0.05). Conclusion: These results support previous research showing that IRT is effective in lowering ambulatory BP. Furthermore, the significant reductions in the MBPS offer the potential for clinically meaningful CVD and stroke risk reduction, provided these effects can be demonstrated in those who are at risk.

Reversal of nocturnal non-dipping of blood pressure after Levothyroxine therapy in patients with subclinical hypothyroidism

AimsTo study the loss of diurnal variation in blood pressure in normotensive patients with Subclinical/overt hypothyroidism and effect of Levothyroxine (L-T4) treatment. Materials and methodsIn this interventional study Eighty patients between 17- 50 years with newly detected OH and SCH (74 women and 6 men) and nine euthyroid subjects (all men) with blood pressure <140/90 were recruited. All patients underwent 24h ambulatory blood pressure monitoring (ABPM) using ABPM machine before and after treatment with L-T4. Diurnal index (DI), Percent time elevation (PTE), Hyperbaric impact (HBI) were studied pre and post L-T4 treatment. ResultsOf the 89 subjects (22 SCH, 58 OH and 9 controls), 7 of the SCH and 30 of OH subjects reported back in follow up after L-T4 supplementation for evaluation. DI, HBI and PTE when compared at baseline between different groups (SCH- OH, SCH- control, OH- control) were insignificant. After L-T4 supplementation DI, HBI and PTE varied significantly with p value 0.007, 0.003 and 0.003 respectively between SCH- OH only. Post L-T4 analysis in SCH group was statistically insignificant (p-value 0.102) but a trend toward improvement in DI was noted (baseline and post treatment DI mean 7.00 and 13.00 respectively). ConclusionLoss of nocturnal dipping was found in patients with OH and SCH which was restored after L-T4 therapy only in patients with SCH and not with OH. Treatmentof SCH patients with high cardiovascular risk may be beneficial in this setting and can be a new indication for LT4 therapy in SCH.

Effects of the glucagon-like peptide-1 receptor agonist liraglutide on 24-h ambulatory blood pressure in patients with type 2 diabetes and stable coronary artery disease: a randomized, double-blind, placebo-controlled, crossover study.

The glucagon-like peptide-1 receptor agonist liraglutide has been shown to reduce blood pressure (BP) in clinical trials using office BP measurements. However, the effects of liraglutide on 24-h BP and on the diurnal variation in BP have not been explored sufficiently. Forty-one patients with type 2 diabetes and stable coronary artery disease were randomized to receive liraglutide or placebo to a backbone therapy of metformin in this double-blind, placebo-controlled 12 along with 12 weeks crossover study. Ambulatory blood pressure monitoring (ABPM) was performed at the start and end of each intervention. Twenty-four individuals completed all 24-h BP measurements. Liraglutide, when compared with placebo, did not induce any significant changes in mean 24-h SBP [difference +1.8 mmHg (95% confidence interval, 95% CI: -4.33 to 7.93)] or DBP [+4.2 mmHg (-0.74 to 9.17)]. Twenty-four-hour BP profiles revealed a trend for increase in evening SBP and DBP [+9.2 mmHg (95% CI: 1.1-17.2) and +9.7 mmHg (95% CI: 3.9-15.5), respectively]. Mean heart rate significantly increased after liraglutide [+7.6 bpm (95% CI: 2.56-12.62)]. Liraglutide did not affect the BP variability or the nocturnal BP dipping. We could not demonstrate any BP-lowering effect of liraglutide when using 24-h ABPM. Liraglutide exhibited diurnal variation in the effect on BP without affecting the BP variability or nocturnal BP dipping.

Nocturnal Dipping of Blood Pressure in Renal Transplant Recipients

Background: There is a marked diurnal variation in blood pressure (BP). Compared with daytime values, BP in most subjects is considerably lower during the night and a ‘non-dipping BP profile’ is usually defined as a nocturnal SBP fall of less than 10%. Association between non-dipper pattern of circadian rhythm of BP and impaired renal capacity was observed in some studies. A circadian non-dipping pattern is often found in renal transplant recipients, and is related to poor allograft function. Materials and Method: In this analytic-cross sectional study, 24 hours ambulatory blood pressure monitoring (ABPM) was performed in 100 renal post-transplant patients, aged >18 years old, with the serum creatinine level <2 mg/dl after one month of transplant. According to the nocturnal reduction of systolic blood pressure (SBP), dipper (SBP ≥ 10%), non-dipper (0 < SBP < 10%) and reverse dipper (SBP nocturnal rise) pattern were defined. Result: Of 100 participants of this study, 56 patients (56%) were male, and 44 patients (44%) were female. Mean age of participants was 43.34 ± 2.442 years overall, 44.27 ± 2.974 years in males and 42.16 ± 4.074 years in females. Non-dipper pattern was found in 58 patients (58%), revers dipper pattern in 35 patients (35%) and dipper pattern was found only in 7 patients (7%). The nocturnal reduction of systolic blood pressure pattern in participants regarding the gender was not significant (p = 0.794). Mean age of patients with non-dipper pattern was significantly lesser than patients with revers dipper pattern (p = 0.009), but mean age of patients with dipper pattern was not significantly different from patients with non-dipper or revers dipper pattern (p = 0.368, p = 0.605). There was no significant correlation between dipper or non-dipper or revers dipper pattern with immunosuppressive drugs(cyclosporine, tacrolimus and non calcineurin inhibitors), duration of dialysis before transplant, and the time past transplant (p = 0.194, p = 0.252, and p = 0.392, respectively). Conclusion: The revers dipper pattern was seen more frequently in older patients than younger, and there was no significant correlation between dipper or non-dipper or revers dipper pattern with immunosuppressive drugs, duration of dialysis before transplant, and the time past transplant. Urology Research Center, Guilan University of Medical Sciences.

Management of Hypertension in Patients with Chronic Kidney Disease.

Hypertension is the leading factor in the global burden of disease. It is the predominant modifiable risk factor for stroke, heart disease, and kidney failure. Chronic kidney disease (CKD) is both a common cause and sequel of uncontrolled hypertension. The pathophysiology of CKD-associated hypertension is complex and multi-factorial. This paper reviews the key pathogenic mechanisms of CKD-associated hypertension, the importance of standardized blood pressure (BP) measurement in establishing the diagnosis and management plus the significance of ambulatory BP monitoring for assessment of diurnal BP variation commonly seen in CKD. The optimal BP target in CKD remains a matter of discussion despite recent clinical trials. Medical therapy can be difficult and challenging. In addition to lifestyle modification and dietary salt restriction, treatment may need to be individualized based on co-morbidities. Combination of antihypertensive drugs, including appropriate diuretic choice and dose, is of great significance in hypertension management in CKD.

24 HOUR BLOOD PRESSURE PROFILE IN YOUNG AND MIDDLE-AGED PATIENTS WITH RETINAL VEIN OCCLUSION

Background. Absence of nocturnal decrease (non-dipper) or an extreme decrease of blood pressure (BP) (overdipper) may be a sign of vascular dysregulation. Non-dipper pattern is associated with increased risk of strokes and cardiovascular events. Over-dipper pattern increases the risk of non-arteritic anterior ischemic neuropathy and glaucoma progression. Daily BP profile in young and middle-aged adults with retinal vein occlusion (RVO) has not been previously examined. The target organ damage is determined by BP dynamics, regional microcirculation and associated perfusion pressure decrease, which verifies the relevance of our study. Objective. To evaluate the diurnal BP variation, the prevalence of arterial hypertension (HTN) and its character, ocular blood flow in RVO in young and middle-aged adults. Design and methods. The study included 30 patients with RVO. In all patients, routine ophthalmic examination was performed, as well as an additional ocular blood flow assessment (ophthalmoplethysmography, ophthalmorheography, ophthalmosphygmography, and fluorescein angiography). 24‑hour blood pressure monitoring (BPM) was performed to estimate systemic hemodynamics. Results. Statistically significant differences between eyes were noted in visual acuity (p = 0,001) and retinal thickness in macular area (p &lt; 0,001). Patients with HTN showed lower visual acuity (р = 0,04), ocular blood flow parameters (p &lt; 0,05) and retinal mean sensitivity (RMS) (р = 0,02) according to automated static perimetry. Fluorescein angiography showed zones of peripheral retinal ischemia with a mean area of 103 mm 2 (from 0 to 250 mm 2 ). 8 patients had masked HTN according to ambulatory BPM. Depending on the night decrease of BP 13 patients had an extreme decrease of BP (over-dipper), 12 had non-dipper pattern and 5 had dipper pattern. No relation between evaluated parameters was found. However, non-dippers showed a tendency towards lower hemodynamic and automated static perimetry parameters. Conclusions. The prevalence of HTN was 57%, while 47% demonstrated masked HTN. Lower ocular blood flow parameters and RMS according to automated static perimetry were associated with HTN. Vascular dysregulation is considered as a possible cause of RVO in young and middle-aged adults. Its manifestation is the equal frequency of non-dipper and over-dipper patterns. Ambulatory BPM in patients with RVO can be recommended for the detection of HTN, BP profiles, and indirectly, for the evaluation of ocular perfusion pressure, risk stratification and the selection of adequate and individualized antihypertensive therapy to reduce the risk of developing and progressing cardiovascular diseases and mortality.

Lifestyle patterns and the prevalence of hypertension among the teachers of Kashmir University (Age 35 to 60 years)

Background : Lifestyle factors are critical determinants of blood pressure levels. With urbanisation and increasing prosperity, prevalence of hypertension is on rise, about 60 per cent population of Kashmir is hypertensive and lifestyle is an important risk factor for it. Hypertension thus, becomes an increasingly important clinical problem. Objectives : To study the prevalence of high blood pressure among the teachers of Kashmir University (age group 35+), to observe the relationship between the different parameters of lifestyle and hypertension. Methods : 106 participants (age 35+ to 60 years) from Kashmir University undertaken for the study were examined using both questionnaires as well as monitored twice a day (before and after work) for their blood pressures to check the diurnal variations. This study was a casecontrol study. The analysis of the data was done using t-test, χ 2 -test, p-value, and odd ratios, respectively. Results : The prevalence was 31 per cent and more in males. A strong relationship was found between workload and diurnal variations in blood pressure (p-value <0.01). Physical inactivity, skipping of meals, type of the salt was found to have a direct relationship in the development of hypertension (p-value < 0.05). However other parameters like high socio-economic status, stress, waistline obesity, high body mass index (BMI), sleeping patterns, work hours, smoking, and intake of fat, salt and dietary patterns were important risk factors which could be the contributors in the development of hypertension. Conclusion : It was thus concluded that a healthy lifestyle helps in preventing hypertension. And lifestyle modifications like physical activity, reduction of weight, reducing dietary sodium, stress free life and a good diet can surely help in maintain controlled blood pressure.

Circadian rhythm of blood pressure and the renin-angiotensin system in the kidney.

Activation of the intrarenal renin-angiotensin system (RAS) has a critical role in the pathophysiology of the circadian rhythm of blood pressure (BP) and renal injury, independent of circulating RAS. Although it is clear that the circulating RAS has a circadian rhythm, reports of a circadian rhythm in tissue-specific RAS are limited. Clinical studies evaluating intrarenal RAS activity by urinary angiotensinogen (AGT) levels have indicated that urinary AGT levels were equally low during both the daytime and nighttime in individuals without chronic kidney disease (CKD) and that urinary AGT levels were higher during the daytime than at nighttime in patients with CKD. Moreover, urinary AGT levels of the night-to-day (N/D) ratio of urinary AGT were positively correlated with the levels of N/D of urinary protein, albumin excretion and BP. In addition, animal studies have demonstrated that the expression of intrarenal RAS components, such as AGT, angiotensin II (AngII) and AngII type 1 receptor proteins, increased and peaked at the same time as BP and urinary protein excretion during the resting phase, and the amplitude of the oscillations of these proteins was augmented in a chronic progressive nephritis animal compared with a control. Thus, the circadian rhythm of intrarenal RAS activation may lead to renal damage and hypertension, which both are associated with diurnal variations in BP. It is possible that augmented glomerular permeability increases AGT excretion levels into the tubular lumen and that circadian fluctuation of glomerular permeability influences the circadian rhythm of the intrarenal RAS.

Characterizing the Severity of Autonomic Cardiovascular Dysfunction after Spinal Cord Injury Using a Novel 24 Hour Ambulatory Blood Pressure Analysis Software.

Cardiovascular disease is one of the leading causes of morbidity and mortality in the spinal cord injury (SCI) population. SCI may disrupt autonomic cardiovascular homeostasis, which can lead to persistent hypotension, irregular diurnal rhythmicity, and the development of autonomic dysreflexia (AD). There is currently no software available to perform automated detection and evaluation of cardiovascular autonomic dysfunction(s) such as those generated from 24 h ambulatory blood pressure monitoring (ABPM) recordings in the clinical setting. The objective of this study is to compare the efficacy of a novel 24 h ABPM Autonomic Dysfunction Detection Software against manual detection and to use the software to demonstrate the relationships between level of injury and the degree of autonomic cardiovascular impairment in a large cohort of individuals with SCI. A total of 46 individuals with cervical (group 1, n = 37) or high thoracic (group 2, n = 9) SCI participated in the study. Outcome measures included the frequency and severity of AD, frequency of hypotensive events, and diurnal variations in blood pressure and heart rate. There was good agreement between the software and manual detection of AD events (Bland-Altman limits of agreement = ±1.458 events). Cervical SCI presented with more frequent (p = 0.0043) and severe AD (p = 0.0343) than did high thoracic SCI. Cervical SCI exhibited higher systolic and diastolic blood pressure during the night and lower heart rate during the day than high thoracic SCI. In conclusion, our ABPM AD Detection Software was equally as effective in detecting the frequency and severity of AD and hypotensive events as manual detection, suggesting that this software can be used in the clinical setting to expedite ABPM analyses.

Assessment of arterial wall stiffness by 24-hour blood pressure monitoring

Arterial wall stiffness is an early marker of cardiovascular diseases. The gold standard for assessment of the stiffness of large vessels is presently pulse wave velocity (PWV). Work is in progress on the study of the reference values of PWV in people of different genders and ages. 24-hour blood pressure (BP) monitoring is not only a procedure that can estimate diurnal BP variability, but also monitor the indicators of vascular wall stiffness in a number of cases over a 24-hour period. The given review highlights the pathophysiology of arterial stiffness, methods for its assessment, and the aspects of use in therapeutic practice.

Therapeutic effect and its mechanism of antioxidant taurine plus metoprolol on elderly spontaneously hypertensive rats

Objective To investigate the protective effects of antioxidant taurine plus metoprolol on the blood pressure(BP)and blood vessel function of elderly spontaneously hypertensive rats(SHR). Methods SHRs were divided into three groups(6 rats, each): metoprolol group(100 mg·kg-1·d-1, intragastric administration); taurine group(200 mg·kg-1·d-1, intraperitoneal injection); taurine plus metoprolol group(metoprolol 100 mg·kg-1·d-1, intragastric administration + taurine 200 mg·kg-1·d-1, intraperitoneal injection). The control group[6 Wistar-Kyoto(WKY)rats]was treated with the same volume of sterile normal saline on the same schedule in intragastric administration and intraperitoneal injection.Blood pressure variability(BPV), diurnal variation of BP, the level of glutathion peroxidase(GSH-Px), malonaldehyde(MDA)and the aorta GSTM1 enzyme expression were evaluated before and 14 days after treatment. Results The serum GSH-Px activities were higher in metoprolol group〔(2 759.8±117.6)kU/L〕, taurine group〔(2 848.0±280.2)kU/L〕and taurine plus metoprolol group〔(3 052.8±283.7)kU/L〕than in control group〔(2 368.0±60.4)kU/L〕(all P<0.05). Fourteen days after treatment, MDA level was significantly lower in taurine group〔(9.5±0.7)ng/L, P<0.01〕than in control group〔(13.7±1.5)ng/L〕. However, there was no statistical difference in MDA level between metoprolol group/taurine plus metoprolol group and control group.Forty weeks after treatment with taurine, GSTM1 protein expression was increased, but it had no statistical difference. Conclusions The combined antioxidant taurine and metoprolol can effectively decrease BPV of elderly SHRs, in which the antioxidant effect might be associated with elevated GSTM1 protein expression. Key words: Hypertension; Antioxidants; Adrenergic beta-antagonists

Determinants of day\u2013night difference in blood pressure, a comparison with determinants of daytime and night-time blood pressure

Blunted day–night difference in blood pressure (BP) is an independent cardiovascular risk factor, although there is limited information on determinants of diurnal variation in BP. We investigated determinants of day–night difference in systolic (SBP) and diastolic (DBP) BP and how these compared with determinants of daytime and night-time SBP and DBP. We analysed the association of mean daytime, mean night-time and mean day–night difference (defined as (mean daytime−mean night-time)/mean daytime) in SBP and DBP with clinical, lifestyle and biochemical parameters from 1562 adult individuals (mean age 38.6) from 509 nuclear families recruited in the GRAPHIC Study. We estimated the heritability of the various BP phenotypes. In multivariate analysis, there were significant associations of age, sex, markers of adiposity (body mass index and waist–hip ratio), plasma lipids (total and low-density lipoprotein cholesterol and triglycerides), serum uric acid, alcohol intake and current smoking status on daytime or night-time SBP and/or DBP. Of these, only age (P=4.7 × 10−5), total cholesterol (P=0.002), plasma triglycerides (P=0.006) and current smoking (P=3.8 × 10−9) associated with day–night difference in SBP, and age (P=0.001), plasma triglyceride (P=2.2 × 10−5) and current smoking (3.8 × 10−4) associated with day–night difference in DBP. 24-h, daytime and night-time SBP and DBP showed substantial heritability (ranging from 18–43%). In contrast day–night difference in SBP showed a lower heritability (13%) while heritability of day–night difference in DBP was not significant. These data suggest that specific clinical, lifestyle and biochemical factors contribute to inter-individual variation in daytime, night-time and day–night differences in SBP and DBP. Variation in day–night differences in BP is largely non-genetic.