Disturbed circadian blood pressure rhythm and C-reactive protein in essential hypertension

We investigated the effect of the diverse definition criteria of the dipping and non-dipping status on the assessed differences in inflammatory activation between dippers and non-dippers with essential hypertension. 269 consecutive subjects (188 males, aged 50+/-7 years) with untreated stage I-II essential hypertension underwent ambulatory blood pressure (BP) monitoring and high-sensitivity C-reactive protein (hs-CRP) level determination. The population was classified into dippers and non-dippers based on the three following different definitions: true non-dippers (TND): non-dippers (nocturnal fall of systolic and diastolic BP of <10% of the daytime values, n=95) and dippers (the remaining subjects, n=174); true dippers and true non-dippers (TD-TND): non-dippers (nocturnal fall of systolic and diastolic BP<10%, n=95) and dippers (nocturnal fall of systolic and diastolic BP> or =10%, n=75); systolic non-dippers (SND): non-dippers (nocturnal systolic BP fall of <10% of the daytime values, n=145) and dippers (the remaining subjects, n=124). Non-dippers compared to dippers in the TND, TD-TND and SND classification exhibited higher levels of log hs-CRP (by 0.11 mg l(-1), P=0.02; 0.13 mg l(-1), P=0.03 and 0.14 mg l(-1), P=0.02, respectively) and 24 h pulse pressure (PP) (by 4 mm Hg, P=0.006; by 5 mm Hg, P=0.003 and by 5 mm Hg, P<0.0001, respectively). Twenty-four hour PP and nocturnal systolic BP fall were independent predictors of log hs-CRP (P<0.05 for both) in multiple regression analysis. In conclusion, essential hypertensive non-dippers compared to dippers exhibit higher hs-CRP values, irrespective of the dipping status definition. Furthermore, ambulatory PP and nocturnal systolic BP fall interrelate and participate in the inflammatory processes that accompany non-dipping state.     

Absence of any significant effects of circadian blood pressure variations on carotid artery elastic properties in essential hypertensive subjects

We sought in this study to examine the effects of diurnal blood pressure variations upon common carotid artery (CCA) elasticity in selected subjects with uncomplicated moderate essential hypertension. Towards this end, 174 non-smoker subjects with stage I-II essential hypertension and without diabetes mellitus, left ventricular hypertrophy and carotid atherosclerosis, were classified as dippers and non-dippers according to the diurnal variation of >10% between mean daytime and night-time systolic and diastolic blood pressure (BP) in 24-h non-invasive ambulatory BP monitoring. CCA distensibility was derived by a combination of surface ultrasonographic data and simultaneous BP measurements at the brachial artery. The dippers and non-dippers were similar with respect to demographic characteristics. Non-dippers had significantly greater office systolic BP, 24-h systolic BP and ambulatory pulse pressure (PP) and significantly less (daytime-night-time) systolic and diastolic BP fall (by 16 mm Hg and 11 mm Hg respectively, P< 0.0001) compared to dippers. CCA distensibility was significantly reduced in non-dippers compared to dippers (by 0.89 dyne(-1)/cm(2/)10(-6), P < 0.05). Multiple linear regression analysis identified patient age and ambulatory PP as significant predictors of the CCA elasticity index. When patient age, 24-h systolic and diastolic BP were used as covariates in an analysis of covariance, the difference of CCA elasticity between dippers and non-dippers ceased to reach statistical significance. In contrast, when patient age, ambulatory PP, systolic (daytime-night-time) BP fall and diastolic (daytime-night-time) BP fall were used as covariates, the difference of CCA distensibility between dippers and non-dippers continued to be statistically significant. In conclusion, the excessive impairment of CCA elastic properties in non-dippers compared to dippers hypertensive seems to be ascribed to the increased of total 24-h haemodynamic load and not to the circadian pattern of BP. Journal of Human Hypertension (2000) 14, 813-818     

Electronic activity-monitor-derived sleeping and awake times and diurnal variation of blood pressure

BACKGROUND: Results of a number of studies have indicated that target-organ damage is more pronounced in non-dippers, those in whom the blood pressure falls by less than 10% with the onset of sleep, than it is in dippers with comparable clinic blood pressures. However, the standard use of arbitrarily defined daytime and night-time periods, rather than precise estimates of sleeping time and awake time, could limit the accuracy of estimates of diurnal variation of blood pressure and hence of dipping status. DESIGN AND METHODS: In this study of 102 consecutive patients undergoing ambulatory blood pressure monitoring we compared activity-derived estimates of sleeping and awake blood pressures using electronic activity monitoring and diary records with estimates determined using pre-defined day and night-time periods. The dipping/non-dipping status of each subject was assessed using these three different techniques for defining the awake/asleep time periods. RESULTS: The sleeping/awake times based on the activity monitor, diary and default data were 2356 h+/-55 min/0754 h+/-50 min, 2326 h+/-61 min/0722 h+/-72 min and 2300 h and 0700 h respectively. The percentage systolic/diastolic falls in blood pressure were 18+/-6/18+/-7% with six non-dippers (activity-monitor-derived data), 16+/-6/17+/-8% and 12 non-dippers (diary data) and 13+/-7/15+/-7% and 21 non-dippers (using the pre-set daytime and night-time periods). DISCUSSION: Results of this study demonstrate that the extent of the diurnal variation in blood pressure (and hence dipping status) can differ depending on the technique used to define periods of wakefulness and sleep.     

Seven-day (24-h) ambulatory blood pressure monitoring,self-reported depression and quality of life scores

OBJECTIVE: Effects of environmental conditions on blood pressure (BP) and heart rate (HR) variations as putative factors underlying the onset of vascular events. METHODS: BP and HR were monitored around the clock for 7 days on 54 residents from Urausu, Hokkaido, Japan. Daytime, night-time, and 24-h means served to identify dippers and non-dippers. Questionnaire-assessed depression and subjective quality of life were related to BP and HR by analyses of variance and linear regression. Statistical significance was at 5%. RESULTS: A circaseptan (about 7-day) component characterizes the 24-h mean and standard deviation (SD) of HR, and the daytime and day-night ratio of systolic BP. The SD of HR is higher on weekends and lower on Mondays and Thursdays. When awake, systolic BP is lowest on Sundays and the day-night ratio is optimal on weekends (Saturdays: 15.7 +/- 9.4%; Sundays: 14.0 +/- 13.2%). Depression was detected in 15 subjects, who had higher mean systolic and diastolic BP values (systolic BP: P = 0.028 Fridays, P = 0.021 Tuesdays; diastolic BP: P = 0.022 Mondays, P = 0.006 daytime Mondays) and a lower day-night ratio of diastolic BP (P = 0.012 Tuesdays, P = 0.005 Wednesdays, and P = 0.038 Thursdays). A depressive mood correlated positively with 24-h averages of systolic (P = 0.037) and diastolic (P = 0.030) BP. CONCLUSIONS: Depression (and subjective quality of life) can affect BP and HR variability. The results indicate the role that psychological factors may play in the pathogenesis of cardiovascular disease. Therapeutic implications are suggested for primary and secondary prevention.     

Diurnal variation of hemodynamic indices in non-dipper hypertensive patients.

The purpose of this study was to elucidate the underlying mechanisms of blunted nocturnal blood pressure reduction in non-dipper hypertensive patients. We studied the diurnal variations in systemic hemodynamic indices and baroreflex sensitivity. In 45 subjects with essential hypertension (24 men; mean age, 49+/-1 years), intra-arterial pressure was monitored telemetrically. Non-dippers were defined as those with a nocturnal reduction of systolic blood pressure of less than 10% of daytime systolic blood pressure. Stroke volume was determined using Wesseling's pulse contour method, calibrated with indocyanine green dilution. Baroreflex sensitivity was calculated as deltapulse interval/deltasystolic blood pressure on spontaneous variations. The mean values of the hemodynamic parameters were calculated every 30 min. Twenty-six subjects were classified as non-dippers. Daytime blood pressure was not significantly different between dippers (149+/-4/87+/-3 mmHg) and non-dippers (147+/-3/82+/-2 mmHg), while the nighttime blood pressure was significantly reduced in dippers (131+/-3/77+/-2 mmHg) but not in non-dippers (145+/-3/80+/-2 mmHg). Nocturnal decreases in both cardiac index and stroke index were smaller in non-dippers (-12.0+/-1.2% and 1.5+/-1.0%) than in dippers (-17.5+/-1.4% and -2.2+/-1.1%). Baroreflex sensitivity significantly increased at nighttime both in dippers (6.5+/-0.6 to 8.0+/-0.7 ms/mmHg) and in non-dippers (5.1+/-0.3 to 6.4+/-0.4 ms/mmHg). Neither daytime nor nighttime baroreflex sensitivity was significantly different between the groups. We conclude that the hemodynamics of non-dipper essential hypertension are characterized by an inadequate nocturnal decrease in cardiac index and stroke index, suggestive of relative volume expansion or malsuppressed sympathetic activity.     

高血压患者血压节律与靶器官损害的相关性研究

目的 探讨高血压患者血压节律变化与心、脑、肾等靶器官损害的相关性。方法 应用无创性血压监测仪对84例高血压患者进行24小时动态血压监测,对比血压节律正常(勺型组)和异常(非勺型组)患者心、脑、肾靶器官损害程度。结果 非勺型组24小时平均收缩压和舒张压、白昼平均舒张压、夜间平均收缩压和舒张压、收缩压及舒张压负荷值较勺型组升高(P<0.01);左心室重量和重量指数显著增加(P<0.05,0.01),24小时平均动脉压与左心室重量指数呈显著相关性r=0.55,P<0.01;尿微量白蛋白阳性率明显增高(P<0.05);脑梗死发生率明显增加(P<0.05);组间在偶测平均收缩压和舒张压、白昼平均收缩压均无显著性差异(P>0.05)。结论 血压昼夜节律异常较节律正常的高血压患者有更显著的靶器官损害。     

Impaired diurnal blood pressure variation and all-cause mortality

BACKGROUND: Most healthy people exhibit a decrease in systolic blood pressure (SBP) at night. A drop of <10% from mean daytime values, "non-dipping," is associated with kidney disease and cardiovascular events. We hypothesized that non-dipping would predict all-cause mortality. METHODS: Consecutive patients referred for ambulatory blood pressure (BP) monitoring at the Cleveland Clinic between 1994 and 2004 were included. Mean daytime (6 AM-11 PM) and nighttime (11 PM-6 AM) SBP values were calculated. We examined diurnal BP variation as a continuous variable, ((Mean daytime SBP - Mean nighttime SBP)/(Mean daytime SBP)) x 100%, and also as a categorical variable, defining "non-dipping" as a nocturnal SBP drop of <10%; subjects who exhibited non-dipping were defined as "non-dippers" and the others as "dippers." All-cause mortality was ascertained from the Social Security Death Index. RESULTS: Of the 621 patients included in the study, 261 were dippers and 360 were non-dippers. Non-dippers were older (P < 0.0001), more likely to be non-white (P < 0.05), and had higher rates of smoking, diabetes, hypertension, coronary artery disease, congestive heart failure, and renal insufficiency (P < 0.01 for all). Over a mean follow-up of 6.3 years, 61 patients died, including 10 dippers (3.8%) and 51 non-dippers (14.2%). The unadjusted hazard ratio for death based upon a decrement in the dipping percentage from the 75th to 25th percentile was 2.22 (95% confidence interval 1.64-2.95; P < 0.0001). This was attenuated after adjustment for comorbid conditions, including mean 24-h SBP and renal function: adjusted hazard ratio 1.62 (1.14-2.24; P < 0.005). CONCLUSIONS: Blunted diurnal BP variation is a strong predictor of death, but this may be accounted for, in large part, by its association with other cardiovascular risk factors.     

Clinical trial of arotinolol in the treatment of hypertension: dippers vs. non-dippers.

To compare the effects of an alpha, beta blocker, arotinolol, in the treatment of essential hypertension between patients with a dipper and those with a non-dipper profile by means of 24-h ambulatory blood pressure monitoring (ABPM), a multicenter single blind parallel trial was carried out in five clinical centers. After a one-week single blind placebo run-in period, the patients underwent ABPM if their clinic diastolic blood pressure (DBP) ranged from 90-109 mmHg and their clinic systolic blood pressure (SBP) was <180 mmHg. They were divided into two groups according to the absence (non-dipper group, 24 cases) or presence (dipper group, 23 cases) of nocturnal BP reduction > or =10% of daytime BP. ABPM was measured again at the end of the active treatment phase. All patients were given Arotinolol 10-20 mg twice daily for 4 weeks. Twenty four-hour systolic and diastolic average BPs (MSBP, MDBP), 24-h systolic and diastolic blood pressure load (LS BP, LDBP), daytime systolic and diastolic average BPs (dMSBP, dMDBP), daytime systolic and diastolic blood pressure load (dLSBP, dLDBP), nighttime systolic and diastolic average BPs (nMSBP, nMDBP) and nighttime systolic and diastolic blood pressure load (nLSBP, nLDBP) were calculated. Arotinolol was effective in 78.2% of dippers and 54.2% of non-dippers, but the difference in effectiveness between these groups was not statistically significant. After treatment, SBP and DBP-including 24-h, daytime and nighttime systolic and diastolic BPs- were significantly reduced in both groups. During the daytime period, the systolic and diastolic blood pressures were significantly reduced in both dippers and non-dippers, while nighttime systolic and diastolic blood pressures were significantly reduced only in the non-dipper group. No significant changes were found in the dipper group over this period. In conclusion, Arotinolol, which can be dosed twice daily, is an effective antihypertensive agent which effectively lowers blood pressure during the day while reducing nighttime blood pressure more in non-dippers than in dippers, without excessive lowering blood pressure in the latter.     

Use of a mild sedative helps to identify true non-dippers by ABPM: a study in patients with diabetes mellitus and hypertension

BACKGROUND: The interplay between the continuity or quality of sleep and diurnal variation in blood pressure has not been directly examined before. We examined the influence of a mild, non-hypotensive sedative on nocturnal dipping. DESIGN: This was a randomized, single-blind study. SETTING: The study took place in an out-patient clinic in an academic hospital. INTERVENTION: Zolpidem 10 mg or placebo was given randomly for the first or second night, and ambulatory blood pressure monitoring was instigated for 48 h. PATIENTS: The population under study comprised 96 male patients with type 2 diabetes mellitus and hypertension (mean age 54 +/- 6 years, mean blood pressure 158/94 +/- 9/6 mmHg). MAIN OUTCOME MEASURE: Nocturnal dipping (nocturnal blood pressure >/= 10% lower than daytime pressure) was found in 71% of the patients taking the sedative compared with 27% of those on placebo (P=0.001). RESULTS: On placebo, non-dippers and dippers had similar profiles of cardiovascular risk parameters. In contrast, non-dippers taking zolpidem had significantly higher values for most cardiovascular risk parameters compared with dippers: higher systolic blood pressure, higher low-density lipoproteins, lower high-density lipoproteins, higher serum creatinine, a higher urinary albumin:creatinine ratio, higher serum insulin and insulin resistance. CONCLUSION: The use of a mild sedative during ambulatory blood pressure monitoring may help to identify the patients with a very high cardiovascular risk. These are the patients with a blunted nocturnal hypotension despite sedation.     

Changes of nocturnal blood pressure dipping status in hypertensives by nighttime dosing of alpha-adrenergic blocker, doxazosin : results from the HALT study

Abnormal nocturnal blood pressure (BP) dipping status may be partly determined by nocturnal sympathetic activity. We studied the effect of nighttime dosing of an alpha(1)-adrenergic blocker, doxazosin, on the BP dipping status of 118 hypertensives, all of whom underwent 24-hour ambulatory BP monitoring before and after treatment. The mean nighttime/daytime ratio of systolic BP was increased (0.91 after therapy versus 0.89 at baseline, P<0.05). The patients were initially divided into 4 groups on the basis of their dipping status at the baseline assessment: 18 (15%) were extreme dippers, with a nighttime systolic BP fall of at least 20% of daytime BP; 46 (39%) were dippers (fall between 10% and 20%); 48 (41%) were nondippers (fall between 0% and 10%); and 6 (5%) were risers (nocturnal increase of systolic BP). A shift in dipping status toward less nocturnal BP dipping was observed after doxazosin therapy (P<0.05). Dipping status was determined by nighttime more than by daytime BP, and this was not explained by differences in the number of daytime and nighttime readings. The effects of doxazosin on the mean nocturnal systolic BP changes were an increase of 4.3 mm Hg in extreme dippers and decreases of 0.7 mm Hg in dippers, 12 mm Hg in nondippers, and 18 mm Hg in risers; the reduction was only significant in the latter 2 groups (both P<0.01). To estimate the effects of regression to the mean on the changes in dipping status, we also defined dipping status with the average of the BPs before and after doxazosin and found no difference in the degree of nighttime BP reduction among each group. The reduction of daytime BP was now significantly greater in the subgroups with less dipping: 6. 4 mm Hg for extreme dippers and 16 mm Hg for risers (P<0.05). In conclusion, nighttime dosing with doxazosin markedly affects the nocturnal BP dipping status of hypertensives, but the apparently greater reduction in nighttime pressure in nondippers and risers may be, at least partly, due to the effect of regression to the mean. The most important determinants of the effect of doxazosin were the absolute BP levels, both day and night, rather than dipping status per se.     

Influence of blood pressure profile on erythropoietin levels in diabetics

The purpose of this study was to investigate the relationships between 24-h BP profil and erythropoietin level in diabetics. PATIENTS AND METHODS: This study included 58 patients (26 women and 32 men, mean age: 58.7 +/- 14.6 yrs, diabetes duration: 16 +/- 11.2 yrs). Patients were divided by 24 hrs ABPM into 2 groups, one in which night-time pressures dipped by more than 10% (dippers, n = 16) and the other in which pressures dipped by less than 10% (non-dippers, n = 42) when compared to daytime pressures. Haemoglobin (Hb) and erythropoietin (EPO) levels where compared between diabetics and a control group (n = 110) and between dippers and non-dippers. RESULTS: Hb concentration of diabetics was significantly lower than those of control subjects (13.5 +/- 1.5 vs 14.5 +/- 1 g/dL; p < 0.0001) but EPO levels did not differ from significant manner between these two groups. EPO concentrations were lower in dippers than in control subjects (13.7 +/- 5.4 vs 17.9 +/- 5 mU/mL; p < 0.01), but there was not significant difference in Hb levels. Non-dippers had a Hb level lower than dippers (13.1 +/- 1.5 vs 14.6 +/- 1.1 g/dL, p < 0.0001), but EPO concentrations did not differ from significant manner. Hb was correlated with between daytime and night-time BP difference (SBP: r = 0.262; p < 0.05 and DBP: r = 0.396; p < 0.002). Hb was negatively correlated with albumin excretion rate (r = -0.335, p < 0.01) and with creatinine level (r = -0.419: p < 0.001). CONCLUSION: These data indicated that EPO production could be impaired in diabetics with abnormal diurnal BP variation. Nephropathy and cardiac autonomic dysfunction could explain these results.     

The relationship between nighttime dipping in blood pressure and cerebral hemodynamics in nonstroke patients

Inadequate dipping in nighttime blood pressure (BP) is associated with cerebrovascular disease. The authors aimed to determine whether inadequate nocturnal dipping was associated with abnormalities in cerebrovascular hemodynamics in individuals without stroke. Participants in this study underwent 24-hour ambulatory BP monitoring followed by morning transcranial Doppler measurements of blood flow velocities (BFVs) in the middle cerebral artery during supine rest, head-up tilt, hypocapnia, and hypercapnia. Nighttime BP decline by <10% was considered nondipping. Of the 102 nonstroke participants (mean age, 53.6 years), 35 (34%) were dippers. Although nondippers had similar BFV and cerebrovascular resistance (CVR) while supine, they had a lower BFV (P=.04) and greater CVR (P=.02) during head-up tilt compared with dippers. Moreover, greater nighttime dipping in both systolic BP (P=.006) and diastolic BP (P=.03) were associated with higher daytime BFV and lower CVR (P=.01 for systolic BP; P=.02 for diastolic BP). Inadequate nocturnal BP dipping is associated with lower daytime cerebral blood flow, especially during head-up tilt.     

Target organ damage and non-dipping pattern defined by two sessions of ambulatory blood pressure monitoring in recently diagnosed essential hypertensive patients

OBJECTIVE : To evaluate in a selected population of patients with a recent diagnosis of hypertension whether a reduced nocturnal fall in blood pressure, confirmed by two 24 h ambulatory blood pressure monitoring (ABPM) sessions is associated with more prominent target organ damage (TOD). METHODS : The study was structured in two phases: in the first, 141 consecutive, recently diagnosed, never-treated essential hypertensives underwent 24 h ABPM twice within 3 weeks; in the second phase, 118 of these patients showing reproducible dipping or non-dipping patterns underwent the following procedures: (1) routine blood chemistry, (2) 24 h urinary collection for microalbuminuria, (3) amydriatic photography of ocular fundi, (4) echocardiography and (5) carotid ultrasonography. RESULTS : The 92 patients with (>10%) night-time fall in systolic blood pressure (SBP) and diastolic blood pressure (DBP) (dippers) in both monitoring sessions were similar for age, gender, body surface area, smoking habit, clinic BP, 24 h and 48 h BP to the 26 patients with a < or = 10% nocturnal fall (non-dippers) in both sessions. The prevalence of left ventricular hypertrophy (LVH) (defined by two criteria: (1) LV mass index > or = 125 g/m2 in both genders; (2) LV mass index > or = 120 and 100 g/m2 in men and women, respectively) and that of carotid intima-media (IM) thickening (IM thickness > or = 0.8 mm) were significantly higher in non-dippers than in dippers (23 versus 5%, P < 0.01; 50 versus 22%, P < 0.05; and 38 versus 18%, P < 0.05, respectively). There were no differences among the two groups in the prevalence of retinal changes and microalbuminuria. The strength of the association of LV mass index with night-time BP was slightly but significantly greater than that with daytime BP. CONCLUSIONS : This study suggests that a blunted reduction in nocturnal BP, persisting over time, may play a pivotal role in the development of some expressions of TOD, such as LVH and IM thickening, during the early phase of essential hypertension, despite similar clinic BP, 24 h and 48 h BP levels observed in non-dippers and dippers.     

Studies on diurnal blood pressure variation in kidney diseases associated with excessive salt and water retention.

Salt and water retention, a cardinal feature of nephrotic syndrome, was suggested to be an important factor leading to reduced diurnal blood pressure (BP) variation in renoparenchymal disease. Twenty-four hour BP (SpaceLabs SL 90207), 24-h urine excretion of catecholamines, plasma renin activity and plasma aldosterone concentration were therefore determined in 10 nephrotic patients with normal serum creatinine levels (group A, serum creatinine 1.0+/-0.2 mg/dl), in 10 nephrotic patients with increased serum creatinine levels (group B, serum creatinine 2.4+/-0.9 mg/dl) and in 20 controls matched in respect of age and BP. To study the direct influence of fluid volume overload, diurnal BP variation was determined before and after volume depletion by ultrafiltration in 10 patients with end-stage renal failure. Diurnal BP variation was characterised by the difference of mean BP during daytime (10 pm to 8 am) and night-time (8 am to 10 pm). In group A, the systolic and diastolic day-night difference was not changed when compared with the controls (NS). In contrast, in group B the day-night difference was significantly lower than in the controls (P < 0.01). Twenty-four hour urine catecholamine excretion and plasma aldosterone were comparable between the study groups. Plasma renin activity, however, was significantly increased in group A (P < 0.05). Nocturnal BP drop was not related to plasma renin activity in the nephrotic patients. The blunted diurnal blood pressure variation in end-stage renal failure was not influenced by ultrafiltration. The study demonstrates that the blunted diurnal BP variation in kidney disease is unaffected by marked changes in total exchangeable sodium and fluid volume, but is sensitive to changes in glomerular filtration rate.     

Reproducibility of nocturnal blood pressure fall in early phases of untreated essential hypertension: a prospective observational study

A number of studies have shown that a smaller than normal nocturnal blood pressure (BP) decrease is associated with cardiovascular disease. However, no large prospective studies have examined the reliability of nocturnal dipping within individuals. The aim of our study was to investigate the short-term variability of nocturnal BP fall in a large cohort of patients with recently diagnosed essential hypertension. In all, 414 uncomplicated never treated hypertensive patients referred to our outpatient hypertension hospital clinic (mean age 46+/-12 years; 257 M, 157 F) prospectively underwent: (1). repeated clinic BP measurements; (2). routine examinations recommended by WHO/ISH guidelines; and (3). ambulatory BP monitoring (ABPM) twice within a 4-week period. Dipping pattern was defined as a reduction in the average systolic and diastolic BP at night greater than 10% compared to average daytime values. Overall, 311 patients (75.1%) showed no change in their diurnal variations in BP. Of the 278 patients who had a dipping pattern on the first ABPM, 219 (78.7%) confirmed this type of profile on the second ABPM, while 59 (21.3%) showed a nondipping pattern. Among 37 dipper patients with >20% of nocturnal systolic BP decrease (extreme dippers), only 16 (43.2%) had this marked fall in BP on the second ABPM. Of the 136 patients who had a nondipping pattern on the first ABPM, 92 (67.6%) confirmed their initial profile on the second ABPM, while 44 (32.4%) did not. Patients with reproducible nondipping profile were older (48+/-12 years) than those with reproducible dipping profile (44+/-12 years, P<0.05). These findings indicate that: (1). short-term reproducibility of nocturnal fall in BP in untreated middle-aged hypertensives is rather limited: overall, one-fourth of patients changed their initial dipping patterns when they were studied again after a few weeks; (2). this was particularly true for extreme dipping and nondipping patterns; (3). abnormalities in nocturnal BP fall, assessed by a single ABPM, cannot be taken as independent predictors of increased cardiovascular risk.     

QT interval prolongation in association with impaired circadian variation of blood pressure and heart rate in adolescents with Type 1 diabetes.

AIMS: The aim of our study was to assess diurnal blood pressure (BP) and heart rate variability and their possible relationship to the duration of the QT interval in adolescents with Type 1 diabetes. METHODS: In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/- sd) age of 17.3 (+/- 4.1) years and a mean (+/- sd) diabetes duration of 8.5 (+/- 3.3) years, 24-h ambulatory BP was recorded. In addition, 24-h heart rate (HR) monitoring was performed and QT and corrected QT (QTc) intervals were estimated as indices of autonomic function. The patients were divided into two groups according to the absence of a decrease (non-dippers) or the presence of a decrease (dippers) in nocturnal diastolic BP (DBP). RESULTS: In comparison with the dippers, the non-dippers showed reduced mean 24-h HR (79.6 vs. 84.0 beats/min, P = 0.05) and reduced mean daytime HR (81.3 vs. 86.0 beats/min, P = 0.05). The QT interval was prolonged in the non-dippers (366.3 vs. 347.5 ms, P = 0.015), and end systolic (28.7 vs. 25.9 mm, P = 0.004) and end diastolic left ventricular diameters (47.8 vs. 45.5 mm, P = 0.037) were greater. In stepwise multiple regression, HR variables were the most important factors affecting DBP ratio or the duration of the QT interval. CONCLUSIONS: In conclusion, normotensive diabetic adolescents with impaired nocturnal BP reduction also have impaired autonomic function tests, in association with prolonged QT interval and increased left ventricular diameters. These findings suggest that diabetic adolescents who have the 'non-dipper' phenomenon may need close follow-up for the possible development of vascular complications, such as cardiac arrhythmias and left-ventricular hypertrophy.     

Risers and Extreme‐Dippers of Nocturnal Blood Pressure in Hypertension: Antihypertensive Strategy for Nocturnal Blood Pressure

There is increasing evidence that disruption of diurnal blood pressure (BP) variation is a risk factor for hypertensive target organ damage and cardiovascular events. Especially, the risers (extreme non‐dippers), who exhibit a nocturnal BP increase compared with daytime BP, have the worst cardiovascular prognosis, both for stroke and cardiac events. On the other hand, extreme‐dippers (with marked nocturnal BP falls) are at risk for non‐fatal ischemic stroke and silent myocardial ischemia, particularly extreme‐dippers complicated with atherosclerotic arterial stenosis and excessive BP reduction due to antihypertensive medication. Extreme‐dipping status of nocturnal BP is closely associated with excessive morning BP surge and orthostatic hypertension. Hypertensive patients who have these conditions and exhibit marked BP variations are likely to have silent cerebral infarct and to be at high‐risk with regard to future stroke. Individualized antihypertensive medication targeting disrupted diurnal BP variation might thus be beneficial for such high‐risk hypertensive patients.     

Ambulatory blood pressure monitoring in haemodialysis and continuous ambulatory peritoneal dialysis (CAPD) patients

The aim of this study was to compare the results of the 44-h ambulatory blood pressure monitoring (ABPM) data between haemodialysis (HDp) and CAPD patients and to investigate the relation of circadian rhythm in blood pressure (BP) with development of left ventricular hypertrophy. Twenty-two HDp (11 male, 11 female, mean age: 50 +/- 17 years) and 24 CAPDp (11 male, 13 female, mean age: 47 +/- 15 years) were included. Echocardiographic measurements and ABPM were performed in all study groups. ABPM of the first and second days were analysed separately and compared with CAPDp. Left ventricular hypertrophy was detected in 17 of the 22 HDp (77%) and 17 of the 24 CAPDp (71%). There was no significant differences between HD and CAPDp in respect to 44-h, daytime and night-time systolic and diastolic BP values. Although the course of BP in CAPDp was stable during the 44-h period, systolic and diastolic BP levels on the second day were significantly higher than those of on the first day in HDp (P < 0.001 for both). Daytime systolic and diastolic BP levels on the first day in HD group were recorded lower than those of the CAPD group. On the second day, night-time BP readings (both systolic and diastolic BP) were measured significantly higher in the HD group compared with the CAPD group. Twenty-one of the 24 (88%) CAPD patients were dippers, whereas only four of the 22 (18%) HDp were dippers (P < 0.001). Dipper patients had significantly lower left ventricular mass index (LVMI) than non-dipper patients (131 +/- 29 g/m(2) vs 153 +/- 40 g/m(2), P = 0.03). In 44-h ABPM, there were no differences in daytime and night-time systolic and diastolic blood pressures between HD and CAPD patients. Non-dipper patients had increased LVMI as compared with dipper patients. Abnormalities in circadian rhythm of the blood pressure might be one of the implicated factors for development of left ventricular hypertrophy.     

Racial differences in nocturnal dipping status in diabetic kidney disease: Results from the STOP‐DKD (Simultaneous Risk Factor Control Using Telehealth to Slow Progression of Diabetic Kidney Disease) study

While racial variation in ambulatory blood pressure (BP) is known, patterns of diurnal dipping in the context of diabetic kidney disease have not been well defined. The authors sought to determine the association of race with nocturnal dipping status among participants with diabetic kidney disease enrolled in the STOP‐DKD (Simultaneous Risk Factor Control Using Telehealth to Slow Progression of Diabetic Kidney Disease) trial. The primary outcome was nocturnal dipping—percent decrease in average systolic BP from wake to sleep—with categories defined as reverse dippers (decrease <0%), nondippers (0%–<10%), and dippers (≥10%). Twenty‐four‐hour ambulatory BP monitoring was completed by 108 participants (54% were nondippers, 24% were dippers, and 22% were reverse dippers). In adjusted models, the common odds of reverse dippers vs nondippers/dippers and reverse dippers/nondippers vs dippers was 2.6 (95% confidence interval, 1.2–5.8) times higher in blacks than in whites. Without ambulatory BP monitoring data, interventions that target BP in black patients may be unable to improve outcomes in this high‐risk group.     

Diurnal variation of blood pressure; reproducibility and association with left ventricular hypertrophy in hemodialysis patients

OBJECTIVE: The objective of this paper is to describe the pattern of diurnal blood pressure (BP) change in hemodialysis patients, determine the association of the non-dipping pattern of diurnal BP with left ventricular mass index (LVMI), and to determine if the nocturnal profile of BP is reproducible when repeated over time. METHODS: In a cross-sectional study, ambulatory blood pressure monitoring (ABPM) was performed over a midweek 44-h period and echocardiography was performed on the interdialytic day. Patients with a night/day systolic and diastolic BP ratio on both days >0.9 were defined as non-dippers. Ambulatory blood pressure monitoring was repeated at 6 and 12 months follow-up. RESULTS: Of the 59 patients, 88% were African-American, and 48% were non-dippers. Mean LVMI was significantly higher in the non-dipper (68.3+/-25 g/height) compared to the dipper patients (55.6+/-16, P<0.05). Mean nocturnal systolic BP (r=0.35) and the night/day systolic BP ratio (r=0.39) had a higher correlation with M-mode LVMI than pre-dialysis (r=0.32). After adjustment for 44-h mean SBP, night/day systolic BP ratio remained independently associated with LVMI (beta coefficient 147.62, P=0.004). Of 12 patients who had a non-dipper profile at baseline, 11 (92%) demonstrated the same profile after 6 months and 1 year of follow-up. CONCLUSION: Many hemodialysis patients demonstrate a non-dipper profile; the degree of decline in nocturnal BP is independently associated with LVMI even after adjustment for mean BP. Patients who are identified as non-dippers consistently reproduce the same profile over time.