A pressure-time index' for assessing the severity of essential hypertension.

OBJECTIVE: A new derivative of 24 h ambulatory blood pressure monitoring (ABPM) is introduced and its association with left ventricular mass index (LVMI) in essential hypertension is examined. PATIENT: population One hundred and fifty-three previously untreated essential hypertension patients. METHODS: Patients underwent casual blood pressure (BP) readings, 24 h ABPM and left ventricular echocardiographic assessment The following 24 h awake and sleep ABP variables were calculated: mean systolic and diastolic BP, systolic and diastolic BP loads (percentage of systolic readings > 140/120 mmHg (day/ night) and diastolic readings > 90/80 mmHg (day/night)), standard deviation of systolic and diastolic ABP and nocturnal fall of systolic BP, as well as the integrated areas under the ABP curve. The area under the BP curve divided in horizontal slices was accurately modelled by a sigmoid curve. The parameters controlling the shape of the curve and in particular that regarding its 'slope' is hereafter called the 'pressure-time index'. RESULTS: 'Systolic pressure-time index 24 h' (SPTI24) is related to left ventricular mass index (multivariate analysis, P= 0.008). Using either partial correlation coefficients or a multivariate analysis, SPTI24 is related to left ventricular mass index, independently of age, casual blood pressure, mean systolic and diastolic ABP, systolic and diastolic BP loads, BP variability (standard deviation (SD), nocturnal fall of systolic BP) and integrated area under the curve (multivariate analysis, P= 0.004). CONCLUSIONS: In essential hypertension, the SPTI24 is related to LVMI independently of age, casual blood pressure, integrated area under the curve or any other derivative of 24 h ABPM, and might be used to assess the extent of hypertensive load.     

Out-of-office blood pressure in children and adolescents: disparate findings by using home or ambulatory monitoring

BACKGROUND: The validity of home blood pressure (HBP) measurements in children has not been evaluated, although in clinical practice such measurements are being used. This study compares HBP, with clinic (CBP) and daytime ambulatory blood pressure (ABP) in children and adolescents. METHODS: Fifty-five children and adolescents aged 6 to 18 years were evaluated with CBP (three visits), HBP (6 days), and daytime ABP. Mean age was 12.3 +/- 2.9 (SD) years, 33 boys. According to the Task Force CBP criteria, 26 were hypertensives, 6 had high-normal BP (hypertensive group), and 23 were normotensives (normotensive group). RESULTS: In the hypertensive group, CBP was 130.8 +/- 7.6/72.5 +/- 8.1 mm Hg (systolic/diastolic), HBP 118.9 +/- 6.3/73.7 +/- 6.7, and ABP 130.8 +/- 8.1/75.5 +/- 8.3. In the normotensive group, CBP was 112.8 +/- 8/63.1 +/- 6.3, HBP 106.7 +/- 8.4/67.2 +/- 5.2, and ABP 123.9 +/- 7.2/72 +/- 4.3. Strong correlations (P < .001) were observed between CBP-HBP (r = 0.73/0.57, systolic/diastolic), CBP-ABP (r = 0.59/0.49), and HBP-ABP (r = 0.72/0.66). In normotensive subjects, ABP was higher than both CBP and HBP for systolic and diastolic BP (P < .001). Furthermore, systolic HBP was lower than CBP (P < .01), whereas the opposite was true for diastolic BP (P < .05). In hypertensive subjects systolic HBP was lower than both CBP and ABP (P < .001), whereas CBP did not differ from ABP. For diastolic BP no differences were found among measurement methods. CONCLUSIONS: These data suggest that, in contrast to adults in whom HBP is close to the levels of daytime ABP, in children and adolescents HBP appears to be significantly lower than daytime ABP. Until more data become available, caution is needed in the interpretation of HBP in children and adolescents.     

Twenty-four hour ambulatory blood pressure in the population

Objectives. To establish a population-based 24-h ambulatory blood pressure (ABP) reference material with day/night mean BP calculated by standardized and true bedtimes.
Design. A cross-sectional study of 200 randomly selected subjects (20 men and 20 women in each 10-year age interval 20–70 years) in Linköping, Sweden.
Setting. University Hospital of Linköping, Sweden.
Results. Participation rate was 67%. Mean supine clinic BP (CBP) and 24-h-ABP values for the whole material were 123±13/79±8 mmHg and 120± 10/73±7 mmHg, respectively. White coat BP phenomenon increased with age (systolic CBP/ABP ratio versus age, r =0.35, P <0.0001). Seventeen participants had a night/day mean arterial blood pressure ratio >0.9 (non-dipper) when calculated from their own time-notations. If standardized day (06.00–23.00) and night (23.00–06.00) limits were used, 24 subjects were non-dippers. Of these, only eight were 'true'. 'True' non-dippers had a similar day-time mean arterial ABP as 'true' dippers (92.4±11 mmHg versus 91.9±13 mmHg, P = 0.92) while night-time BP was higher (89.9± 13 mmHg versus 74.1±7 mmHg, P <0.0001).
Conclusion. Population-based ABP reference values have been defined. We found 9% non-dippers and that standardized day/night-time limits may lead to misclassification. This could be due to gender- and age-differences in sleeping habits, which was also shown in this study. The frequency of white coat BP phenomenon increases with age.     

Effects of age on hypertensive status in patients with chronic kidney disease

OBJECTIVE: To evaluate effect of age on hypertensive status in chronic kidney disease (CKD). METHODS: We studied 459 prevalent CKD patients (stages 2-5, no dialysis), grouped by age (< 55, 55-64, 65-74, >or= 75 years), undergoing clinical blood pressure (CBP) and ambulatory blood pressure (ABP) measurement. RESULTS: Prevalence of diabetes, left ventricular hypertrophy and previous cardiovascular disease progressively increased with aging; glomerular filtration rate (GFR) and hemoglobin decreased. Achievement of CBP target decreased from 16% in patients < 55 years to 6% in those >or= 75 years (P = 0.023). ABP 24-h systolic rose while diastolic decreased, with a consequent pulse pressure increase from 45 +/- 8 to 65 +/- 14 mmHg (P < 0.0001). Age, proteinuria, diabetes, cardiovascular disease and anemia but not GFR predicted higher 24-h pulse pressure. CBP overestimated systolic/diastolic daytime ABP by 14 +/- 18/7 +/- 11 mmHg on average, a greater difference in older than younger groups (P < 0.005). Conversely, CBP night-time ABP difference did not vary among groups (24 +/- 20/16 +/- 11 mmHg). These age-dependent differences determined a rising prevalence of white-coat hypertension (from 19 to 40%, P = 0.001) and night/day ratio of at least 0.9 (from 43 to 66%, P = 0.0004). Age, diabetes, left ventricular hypertrophy and anemia but not GFR predicted nondipping status. Among the oldest patients, 13% had diastolic CBP below 70 mmHg, with 48% below the corresponding values of daytime (< 69 mmHg) or night-time ABP (< 60 mmHg). CONCLUSION: In CKD, prevalence of white-coat hypertension, nondipping status and potentially dangerous low diastolic ABP increases with aging. This suggests wider use of ABP monitoring in older patients and need for trials addressing identification of an age-specific blood pressure target.     

On-call workday cardiovascular response. A study of medical residents

OBJECTIVE: To compare 24 h blood pressure changes in medical residents when on call with those of a normal workday. DESIGN: Ambulatory blood pressure was recorded in 30 normotensive residents (14 men and 16 women) aged 27+/-2 years, during on-call workdays (24 h in the hospital) and then compared with values obtained during a normal 8 h workday. Ambulatory blood pressure was recorded every 15 min during the day (0700-2200 h) and every 20 min during the night (2200-0700 h). RESULTS: The normal workday 24 h ambulatory mean blood pressure rose from 85.0 mmHg to the on-call mean blood pressure of 88.9 mmHg (P < 0.001). During the daytime, ambulatory systolic and diastolic blood pressures rose by 4.6 mmHg (P < 0.001) and 2.7 mmHg (P < 0.001), respectively. During the night-time period, systolic and diastolic blood pressures rose by 5.4 mmHg (P < 0.01) and 4.6 mmHg (P < 0.01), respectively. The nocturnal systolic and diastolic blood pressure elevation was not related to gender, body mass index, waist: hip ratio, physical exercise or smoking habits. CONCLUSION: The on-call workday causes an elevation in mean 24 h blood pressure and only minimal changes in the 24 h blood pressure pattern.     

24-hour ambulatory blood-pressure effects of valsartan and hydrochlorothiazide combinations compared with amlodipine in hypertensive patients at increased cardiovascular risk: a VAST sub-study

BACKGROUND: There is a lack of data on the effects of angiotensin-receptor blocker and diuretic combinations on ambulatory blood pressure (ABP) in hypertensive patients with additional cardiovascular risk factors. METHODS: In a randomized, double-blind trial, the effects on 24-h ABP of the combination valsartan 160 mg od and hydrochlorothiazide 25 or 12.5 mg during 24 weeks of therapy were compared with the effects of amlodipine 10 mg monotherapy (group A10) in 474 stage-II hypertensive patients with additional cardiovascular risk factors. After a two-week single-blind placebo run-in period, patients were randomized to receive valsartan 160 mg od or amlodipine 5 mg od. At week 4, HCTZ 12.5 mg (group V160/HCTZ12.5) and 25 mg (group V160/HCTZ25) were added to the valsartan groups and in the A10 patients the amlodipine dose was force-titrated to 10 mg od. RESULTS: All three treatments reduced 24-h BP as well as night-time and daytime BP levels from baseline. Twenty-four hour systolic blood pressure (SBP) was reduced by 15.9+/-1.0 mmHg (least-squares mean change+/-SE), 19.3+/-1.0 mmHg and 16.1+/-1.1 mmHg in the V160/HCTZ12.5, V160/HCTZ25 and A10 groups, respectively and 24-h diastolic blood pressure (DBP) was reduced by 9.3+/-0.6 mmHg, 11.4+/-0.6 mmHg and 9.6+/-0.7 mmHg in the three groups. The differences between the V160/HCTZ25 group and the A10 group were significant (p<0.05) for the changes in 24-h systolic BP as well as for changes in daytime systolic BP and night-time diastolic BP. Control rates defined as ABPM < or =130/80 mmHg were: 48.4%, 60.8% and 50.9% in the V160/HCTZ12.5, V160/25 and A10 groups, respectively. The differences in control rates between the V160/HCTZ25 group and the other two treatment groups were significant at p<0.05. CONCLUSIONS: The fixed-dose combination of valsartan 160 mg+HCTZ 25 mg od is an attractive therapeutic option measured on the effects on 24-h ABPM, night-time and daytime BP reduction and control rates in hypertensive patients at additional cardiovascular risk.     

Morning blood pressure peak,QT intervals,and sympathetic activity in hypertensive patients

We investigated the relation between morning blood pressure (BP) variations, sympathetic activity, and QT intervals in 156 never-treated subjects with essential hypertension and different patterns of morning BP increase. The morning BP peak (MP) was defined as a rise in systolic BP >or=50 mm Hg and/or diastolic BP >or=22 mm Hg during early morning (6:00 to 10:00 AM) compared with mean BP during the night. Clinical characteristics of patients with morning BP peak (MP+, n= 69, morning systolic BP=+54+/-4, diastolic BP=+32+/-5 mm Hg) did not differ from patients without BP peak (MP-, n= 87, morning systolic BP=+24+/-5, diastolic BP=+19+/-3 mm Hg). The daytime (10:00 AM to 10:00 PM) and the nighttime (10:00 PM to 6:00 AM) BP profile did not differ between the two groups. During daytime and nighttime ECG monitoring, the corrected QT (QTc) interval, and QTc dispersion did not differ significantly between the two groups, whereas during the morning period the QT values were significantly broader in the MP+ group compared with the MP- group (P相似文献   

Sleep effects on ambulatory blood pressure measurements in pregnant women

The aim of this study was to investigate the effect of the definition of daytime and nighttime on ambulatory blood pressure (ABP) in pregnancy. To determine the prevalence of a <10% decrease in mean arterial pressure with sleep (nondipper) in pregnancy and the consistency of nondipper status throughout pregnancy. In a prospective, longitudinal study, 102 pregnant woman underwent 24-h ABP monitoring and recorded sleep patterns at < or = 14, 19 to 22, 27 to 30, 35 to 37 weeks' gestation and 5 to 9 weeks' postpartum. Nighttime was defined by arbitrary hours or actual periods of sleep. Ambulatory blood pressure measurements using the different definitions of nighttime were compared in the total cohort and individual women. Nondipper status of each woman was determined throughout pregnancy and postpartum. At 35 to 37 weeks' gestation, 19% of women napped during the day and 20% were awake during the night. Throughout pregnancy, mean day and night systolic and diastolic ABP measurements were similar whether daytime and nighttime were defined by arbitrary hours or by sleep periods. In individuals, the use of arbitrary hours (day 07:00 to 21:59, night 22:00 to 06:59) compared to sleep periods to define day and night resulted in differences in daytime systolic (SBP) and diastolic blood pressure (DBP) of up to 4 and 5 mm Hg, respectively. Similarly there were individual differences in nighttime SBP up to 10 mm Hg and DBP up to 11 mm Hg. A third of women were nondippers at least once during pregnancy, but only two women were consistent nondippers. The different definitions of day and night did not change group ABP measurements, but resulted in significant variation in ABP measurements in individual pregnant women. Nondippers were common and nondipper status frequently changed during pregnancy.     

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.     

Chronobiological analysis by ambulatory blood pressure monitoring of the hyperbaric and hypobaric indexes for evaluation of the antihypertensive effect of long-acting nifedipine.

BACKGROUND: It has been suggested that chronobiology can provide new insights into the evaluation and treatment of cardiovascular disease. In the present study the hyperbaric index (hyperBI) and hypobaric index (hypoBI) were compared with the mean blood pressure (BP) over 24 h to evaluate the antihypertensive effect of long-acting nifedipine on essential hypertension. METHODS AND RESULTS: Fourteen patients were treated with nifedipine CR (20-40 mg/day) for 6 months. Ambulatory BP monitoring was performed before and after treatment. The hyperBI (mmHg . h/day) was calculated as the integrated BP area above the conventional upper limit (140/90 mmHg for the daytime and 120/80 mmHg at night), and the hypoBI was calculated as the integrated BP area below the conventional lower limit (110/60 mmHg for the daytime and 100/50 mmHg at night). At baseline, both the systolic and diastolic 24-h hyperBI values closely correlated with the 24-h mean BP (r=0.994 and 0.935, p<0.0001). Treatment with nifedipine significantly lowered both the 24-h mean systolic and diastolic BP (143+/-14/89 +/-12 to 124+/-16/80+/-8 mmHg, p<0.001/p=0.001), as well as the casual BP (167+/-11/101 +/-8 to 140+/-13/86+/-10 mmHg, p<0.001/p<0.01). Reduction of both the systolic and diastolic hyperBI values was statistically significant over the 24-h period (274+/-266 to 90+/-155, p=0.009; 145+/-187 to 41+/-63, p=0.024), as well as during the daytime (200+/-181 to 66+/-116, p=0.014; 105+/-120 to 24+/-38, p=0.017) and at night (systolic, 74+/-106 to 24+/-52, p=0.021). The 24-h mean BP was normalized, but a small excess BP load persisted despite treatment. There was no significant increase of systolic hypoBI during the 24-h period (1+/-2 to 25+/-30, p=0.065), the daytime (0+/-0 to 14+/-38, p=0.20), or at night (1+/-3 to 11+/-19, p=0,052). Similar findings were obtained for diastolic hypoBI. CONCLUSIONS: Nifedipine CR improved the 24-h hyperBI and mean BP without causing excessive hypotension. These 2 parameters have a close relationship when assessment is done by 24-h BP monitoring. The hyperBI and hypoBI may assist in providing adequate antihypertensive therapy for individual patients by detecting an excessive BP load or hypotension, respectively.     

Left ventricular function in patients with obstructive sleep apnoea syndrome before and after treatment with nasal continuous positive airway pressure

BACKGROUND: Previous studies have yielded disparate results regarding the effect of obstructive sleep apnoea (OSA) syndrome on left ventricular (LV) function. OBJECTIVES: In order to clarify this, we performed a prospective study investigating OSA patients with no history of systemic hypertension, coronary artery disease, myocardial, pericardial or valvular problems, asthma or chronic obstructive pulmonary disease before and after treatment with nasal continuous positive airway pressure (nCPAP). METHODS: Fifteen patients (3 women, 12 men) with an apnoea/hypopnoea index >15 (mean +/- SD = 52 +/- 21) were studied with complete polysomnography, ambulatory blood pressure monitoring, M-mode two-dimensional echocardiography and pulsed Doppler echocardiography in two phases, i.e. before and after 12-14 weeks of nCPAP therapy. We measured systolic and diastolic blood pressure (BP) separately in the daytime and night-time, isovolumic relaxation time (IVRT), the ratio of peak early filling velocity (E) to peak late velocity (A) diastolic transmitral flow (E/A), posterior wall thickness (PWT) and septal thickness (IVST). The shortening fraction (SF) was also calculated. Eleven overweight non-apnoeic normal subjects matched for age were used as the control group. RESULTS: Our results showed that the patient group exhibited, before treatment, LV diastolic, but not systolic, dysfunction compared with the normal group (IVRT = 94.3 +/- 11.6 ms, p < 0.05; E/A = 0.94 +/- 0.26, p < 0.02; SF = 39.9 +/- 4.1%, not significant (NS); IVST = 9.9 +/- 1.2 mm, NS; PWT = 8.3 +/- 1.2 mm, NS). Moreover, the patient group developed diastolic hypertension both in the daytime and night-time (BP/diastolic/daytime = 93.3 +/- 9.2 mm Hg, BP/diastolic/night-time = 90.3 +/- 10.7 mm Hg). After 12-14 weeks of nCPAP treatment (no change in body mass index), significant improvement in LV diastolic function and a drop in blood pressure were noticed (IVRT = 85.6 +/- 8.8 ms, p < 0.05; E/A = 1.07 +/- 0.3, p < 0.05; BP/diastolic/daytime = 86.3 +/- 5.5 mm Hg, p < 0.02; BP/diastolic/night-time = 83.9 +/- 8. 6 mm Hg, p < 0.05) in our patient group. CONCLUSIONS: We conclude that repetitive apnoeas/hypopnoeas are very important factors in the development of both LV diastolic dysfunction and diastolic systemic hypertension in patients with OSA syndrome. Treatment with nCPAP leads to significant improvement in both ventricular function and systemic hypertension.     

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.     

Relationship between Chemosensitivity, Obesity and Blood Pressure in Obstructive Sleep Apnoea

It has previously been documented that patients with obstructive sleep apnoea (OSA) have an abnormal blood pressure (pressor) response to acute hypoxia when awake. The relationship between hypoxic chemosensitivity and 24 h blood pressure in OSA is not known. Twenty-four hour ambulatory BP (ABP) was measured at 15 min intervals for 24 h using a non-invasive device (Oxford Medilog ABP or Spacelabs 90207 recorder) in 49 men (mean age 51 ± 9 years), with OSA. The BP response to acute hypoxia was measured either directly (radial arterial line) or indirectly (Finapress) during wakefulness. The pressor response to hypoxia (expressed as the slope of the regression line of mean BP on % fall in arterial oxygen saturation) was compared with the results of the ABP recording, sleep study data and clinical variables. A pressor response to acute hypoxia was present in all patients (mean 1.4 ± 1.1 mmHg/% δSaO₂, range 0.1-4.5). There was a relationship between the magnitude of the pressor response to hypoxia, severity of sleep apnoea (RDI and minimum SaO₂) and central obesity (waist measurement). In contrast, there was no relationship between BP response to hypoxia during wakefulness and 24-h BP. However, increasing obesity and severity of OSA were associated with loss of the normal fall in BP at night. We conclude that enhanced chemosensitivity is common in OSA but there is no demonstrable link between chemosensitivity and mean daytime or night-time ABP.     

Ambulatory blood pressure monitoring in patients with hyperthyroidism before and after control of thyroid function

BACKGROUND AND OBJECTIVE: Thyroid hormones have pronounced effects on the cardiovascular system. Thyrotoxicosis affects blood pressure (BP), modifying both diastolic (DBP) and systolic (SBP) pressures. There are no studies examining BP with ambulatory blood pressure monitoring (ABPM) in hyperthyroidism before and after control of thyroid function. Our aims were (1) to analyse ABPM in a group of normotensive hyperthyroid patients before and after normalizing circulating thyroid hormones and (2) to compare these results with those obtained in a group of euthyroid subjects. PATIENTS AND MEASUREMENTS: We studied 20 normotensive hyperthyroid subjects [18 women; age (mean +/- SEM) 49.0 +/- 3.0 years] and 15 healthy subjects. Patients were evaluated by ABPM over 24 h, at diagnosis and after therapy (n = 18). RESULTS: The average 24-h, daytime and night-time SBP was significantly greater in hyperthyroid patients than in controls with no significant differences in DBP. Circadian BP rhythm, estimated by the difference between mean values of SBP, DBP and mean BP during daytime and night-time, was unchanged. The average 24-h and daytime SBP significantly decreased after normalizing thyroid function in the 18 hyperthyroid evaluated patients. Daytime SBP and DBP were higher than night-time values both before and after control of thyroid function. However, no differences in circadian BP rhythm were observed. CONCLUSIONS: Normotensive hyperthyroid patients exhibit higher ambulatory SBP throughout 24 h than normotensive euthyroid subjects. Control of hyperthyroidism decreases ambulatory SBP values. Mean nocturnal fall in BP is comparable in normotensive hyperthyroid patients and control subjects.     

Nurse-recorded and ambulatory blood pressure predicts treatment-induced reduction of left ventricular hypertrophy equally well in hypertension: results from the Swedish irbesartan left ventricular hypertrophy investigation versus atenolol (SILVHIA) study

OBJECTIVE : To compare the relationships of treatment-induced reductions of left ventricular hypertrophy to the changes in clinic and ambulatory blood pressure (BP). DESIGN : Double-blind and randomized treatment with irbesartan or atenolol for 48 weeks. PATIENTS : Patients with hypertension and left ventricular hypertrophy (n = 66) with a seated diastolic BP 90-115 mmHg (average of three measurements one minute apart by nurses). MAIN OUTCOME MEASURES : Registrations of echocardiographic left ventricular (LV) mass. Clinic and ambulatory BP. RESULTS : In the total material, nurse-measured BP was reduced by 23 +/- 15/16 +/- 7.7 mmHg and 24-h ambulatory BP fell 20 +/- 15/14 +/- 8.5 mmHg by treatment. The correlation between the change in nurse-measured BP and LV mass index (LVMI) induced by treatment was r = 0.35, P = 0.004 for systolic BP and r = 0.26, P = 0.03 for diastolic BP. Corresponding values for 24-h ambulatory BP were r = 0.29, P = 0.02 and r = 0.35, P = 0.004, respectively, with similar correlations for day- and night-time ambulatory BP. The nurse-recorded BP was slightly higher than ambulatory BP (systolic clinic - systolic 24-h ambulatory BP = 5 mmHg). Using 130/80 mmHg as a cut-off value for normal 24-h ambulatory BP, eight subjects had normal diastolic or systolic ambulatory BP, or both. Interestingly, these patients also experienced LVMI regression following treatment (low/normal ABP, -13 +/- 21 g/m2; remaining patients, -18 +/- 22 g/m2, P > 0.5). CONCLUSIONS : In patients with hypertension and left ventricular hypertrophy, ambulatory BP is not superior to carefully standardized nurse-recorded seated BP in terms of associations with treatment-induced changes in LV mass.     

24-h Ambulatory Blood Pressure Monitoring in Healthy Young Adult Anglo,Hispanic, and African-American Subjects

The purpose of this study was to compare office and 24-h ambulatory blood pressure (ABP) values for adolescent and young adult males and females of Anglo, Hispanic, and African-American descent. One hundred and eighteen healthy subjects (62 females, 56 males) participated, with an ethnic distribution of 50 Anglo, 32 Hispanic, and 36 African-American subjects. All subjects came to the clinic for height, weight, sitting blood pressure (BP), and to begin 24-h ABP monitoring using the SpaceLabs model 90207 automatic noninvasive monitor. The monitor recorded readings every 0.5 h from 06:00 to 22:00 and every hour at night from 22:00 to 06:00.Office systolic and diastolic BP values were higher for all males compared to all females. Mean 24-h, nighttime, and daytime systolic ABP values were also significantly higher for males compared to females. The 24-h mean and daytime systolic ABP values were significantly different by ethnic groups. The African-American subjects always had the highest readings. Mean 24-h diastolic ABP was also significantly different by ethnic groups, with the African-American subjects being higher than the Anglos or the Hispanics. Diastolic ABP (24-h mean, daytime, and nighttime) values (for all subjects combined) increased gradually and varied significantly with age.This study provides preliminary normative data about ABP in an understudied population (ie, teenagers and young adults of different ethnic backgrounds). It also shows that higher blood pressures are present among males and among subjects of African-American descent in the teenage and young adult population.     

Physical activity, dipping and haemodynamics

OBJECTIVE: To determine the effect of physical activity on diurnal blood pressure (BP) and haemodynamic variation. METHODS: Ambulatory measurements were performed during 24 h in 36 subjects (18 hypertensive, 13 male), aged 49.7 +/- 13.5 years. BP was recorded in the brachial artery. Physical activity and posture were measured with five acceleration sensors. RESULTS: Of the subjects 50% were dippers (nocturnal decrease in systolic or diastolic BP >/= 10%). Dippers and non-dippers had similar daytime BP, daytime, night-time, and day-night difference in physical activity, subjective sleep quality, and nocturnal cardiac output decrease (14.9 +/- 9.6 and 16.0 +/- 5.9%). In non-dippers vascular resistance increased from day to night by 9.7 +/- 8.3%, while it remained unchanged (-1.0 +/- 13.9%) in dippers. Day-night changes in heart rate and cardiac output were correlated with day-night changes in physical activity (r = 0.39 and 0.43), whereas day-night changes in systolic BP were correlated with night-time activity (r = -0.34). By selection of the active (i.e. walking) and inactive (i.e. not walking) periods during the day, we showed that physical activity has a large potential effect on dipping status and diurnal haemodynamic variation underlying BP variation. Depending on the BP taken (systolic or diastolic, respectively) the proportion of dippers increased to 81% or decreased to 25% if only the walking period was considered, whereas it decreased to 36% or increased to 53% if only the non-walking period was considered. CONCLUSIONS: Non-dippers differ from dippers by an increase of vascular resistance during the night. The degree of physical activity normally encountered during ambulatory monitoring has little influence on the diurnal BP profile or dipping status, but significantly influences underlying haemodynamics. Related to the different effects of posture and activity on systolic and diastolic BP, dipping classification may vary with the BP index taken.     

Effect of dietary patterns on ambulatory blood pressure : results from the Dietary Approaches to Stop Hypertension (DASH) Trial. DASH Collaborative Research Group.

We measured ambulatory blood pressure (ABP) in 354 participants in the Dietary Approaches to Stop Hypertension (DASH) Trial to determine the effect of dietary treatment on ABP (24-hour, day and night) and to assess participants' acceptance of and compliance with the ABP monitoring (ABPM) technique. After a 3-week run-in period on a control "typical" American diet, subjects (diastolic blood pressure [BP], 80 to 95 mm Hg; systolic BP, <160 mm Hg; mean age, 45 years) were randomly assigned to 1 of 3 diets for an 8-week intervention period: a continuation of the control diet; a diet rich in fruits and vegetables; and a "combination" diet that emphasized fruits, vegetables, and low-fat dairy products. We measured ABP at the end of the run-in and intervention periods. Both the fruit/vegetable and combination diets lowered 24-hour ABP significantly compared with the control diet (P<0. 0001 for systolic and diastolic pressures on both diets: control diet, -0.2/+0.1 mm Hg; fruit/vegetable diet, -3.2/-1.9 mm Hg; combination diet, -4.6/-2. 6 mm Hg). The combination diet lowered pressure during both day and night. Hypertensive subjects had a significantly greater response than normotensives to the combination diet (24-hour ABP, -10.1/-5.5 versus -2.3/-1.6 mm Hg, respectively). After correction for the control diet responses, the magnitude of BP lowering was not significantly different whether measured by ABPM or random-zero sphygmomanometry. Participant acceptance of ABPM was excellent: only 1 participant refused to wear the ABP monitor, and 7 subjects (2%) provided incomplete recordings. These results demonstrate that the DASH combination diet provides significant round-the-clock reduction in BP, especially in hypertensive participants.     

White coat effect and white coat hypertension in community pharmacy practice

OBJECTIVE: The aim of the present study was to investigate whether a white coat effect (WCE) can be observed and quantified in community pharmacy practice. METHODS: In five community pharmacies of Basel, Switzerland, clients asking for blood pressure (BP) measurement were recruited to participate in a free of charge study. Blood pressure was measured in four different settings: pharmacy (using mercury sphygmomanometers), outpatient clinic (measurement by a nurse using mercury sphygmomanometers), self-measurement at home (using automated wrist devices) and daytime ambulatory BP (ABP) monitoring (using SpaceLabs 90207 monitors). WCE was defined as the difference between pharmacy or outpatient and daytime ABP. RESULTS: A total of 50 subjects completed all measurements (42% male, mean age 53.7 years+/-14.0). Blood pressure values of the different settings: (means in mmHg+/-SD, systolic; diastolic): pharmacy BP 129+/-19; 82+/-10, outpatient clinic BP 127+/-15; 82+/-10, home BP 119+/-15; 73+/-9, daytime ABP 124+/-10; 79+/-8. Pharmacy BP was significantly higher (P=0.03 systolic; P=0.02 diastolic) compared with daytime ABP and differences among subjects with antihypertensive medication (n=22) were even more significant (P<0.01). Individual differences were found between pharmacy BP and daytime ABP: +4.6+/-14.8; +2.9+/-8.3. Outpatient BP was significantly higher compared with daytime ABP in diastolic (P=0.04) but not in systolic values. Individual differences between outpatient BP and daytime ABP were +2.5+/-13.1; +2.8+/-9.2. 'Clinically important WCE' (>or=20 mmHg systolic or >or=10 mmHg diastolic) was observed in 24% of all subjects in the pharmacy and in 20% in the outpatient clinic. CONCLUSIONS: Our findings show that WCE and white coat hypertension exist in community pharmacy practice and are similar to the effects in an outpatient clinic.     

Impaired urinary flow rate during the day: a new factor possibly involved in hypertension and in the lack of nocturnal dipping

Previous studies suggest that a low urinary flow rate may reduce the capacity of the kidney to excrete sodium and could thus favour hypertension. In the present study, we evaluated the relationships between urinary flow rate (V) during day (D) and night (N), blood pressure (BP), and the day-night BP difference (delta in % of day BP) in 65 diabetic patients (glycosuria < 90 mmol/24 h) (35 F and 30 M, age 59 +/- 2 y) hospitalized for a 24 h urine collection and mean ambulatory blood pressure recording (AMBP). Urine was collected as two separate samples during D (8:00 am to 10:00 pm) and N (10:00 pm to 8:00 am). V, sodium excretion (NaEx) and mean systolic and diastolic BP (SBP and DBP, respectively) were calculated for the two periods. Patients were a posteriori classified according to the D/N ratio of V, and the mean values of 3 tertiles (T1, T2, T3, n = 22, 22, and 21 subjects) were calculated and compared by ANOVA (see table; *: p < 0.05; **: p < 0.01; ***: p < 0.001). [table: see text] Although total 24 h urine volume was similar in the three tertiles (1,670, 1,927 and 2,007 mL, NS), the fraction of urine excreted during D and N differed widely, with parallel differences in NaEx. With lower V during the day, BP tended to be higher and the fall in nocturnal BP to be reduced. CONCLUSIONS: This study shows the advantages of separate day and night urine collections in relation with AMBP. For a similar total diuresis, some subjects exhibit a too low urine flow rate and too low NaEx during the day, and a compensatory rise during the night. This low diurnal diuresis is associated with a higher blood pressure and a lower nocturnal fall (= nocturnal pressure diuresis). The factors responsible for a too low diuresis during the day need further investigation.