Arterial distensibility and circadian blood pressure variability

OBJECTIVE: To analyse the relationships between arterial distensibility and blood pressure level and its circadian variability assessed by non-invasive ambulatory blood pressure monitoring. DESIGN: One hundred and six patients (69 men, 37 women; aged 20-72 years) without any cardiovascular complication or treatment underwent 24 h ambulatory blood pressure monitoring. Aortic distensibility was evaluated by carotid-femoral artery pulse-wave velocity measurements performed with a validated automatic device (Complior). RESULTS: The pulse-wave velocity correlated significantly with age (P < 0.001), systolic blood pressure (P < 0.01) and heart rate (P < 0.05). Subjects with higher pulse-wave velocities (above the median value) had higher ambulatory blood pressure and heart rate values, mainly during night-time, and present a smaller nocturnal fall both in systolic and in diastolic blood pressure than do those with lower pulse-wave velocities (below the median). The pulse-wave velocity was revealed to be an independent predictor of the nocturnal fall in systolic blood pressure (multiple r = 0.272, P < 0.02) whereas age and, to a lesser extent, mean 24 h diastolic blood pressure were independent predictors of the nocturnal fall in diastolic blood pressure (multiple r = 0.387, P < 0.001). CONCLUSION: Reductions in arterial distensibility are associated with increased blood pressure and heart rate levels whereas perturbations of the circadian blood pressure profile are associated with increased nocturnal values. The increased risk of end-organ damage and vascular events in the presence of higher nocturnal blood pressure values suggests that a study of arterial distensibility in the normal follow-up of hypertensive patients might be of benefit.     

Association of ambulatory arterial stiffness index and brachial pulse pressure is restricted to dippers

BACKGROUND: The ambulatory arterial stiffness index (AASI) is a new index that reflects the dynamic relation between diastolic and systolic blood pressure through the circadian blood pressure rhythm. It was the aim of this study to investigate the association between AASI, dipping status and pulse pressure as a classical indicator of arterial stiffness in normotensive and hypertensive subjects. METHODS: One hundred and twelve individuals were evaluated for a kidney donation to a relative at the University Hospital Essen, Germany. In this context routine 24-h ambulatory blood pressure measurements were performed. A nocturnal reduction in diastolic blood pressure of >10% was defined as 'dipping'. We determined the diurnal and nocturnal blood pressure and brachial pulse pressure values and computed AASI for each participant. RESULTS: AASI was a strong predictor for diastolic and systolic nocturnal blood pressure fall (r = -0.55 and -0.48, respectively; P < 0.001). Additionally, AASI predicted the status of 'dipping/nondipping'. 'Dippers' showed significantly lower AASI than 'nondippers' in both normotensive and hypertensive subjects. Dippers, but not nondippers, demonstrated an association between AASI and brachial pulse pressure. DISCUSSION: AASI is strongly correlated with nocturnal blood pressure fall and is increased in nondipping independent of blood pressure. The role of AASI as a potential marker for arterial stiffness depends, in this study, on the characterization of the dipping status.     

Diurnal blood pressure curve in children and adolescents

OBJECTIVE: To investigate the diurnal blood pressure curve in healthy normotensive children. Thirty-one children were re-examined after a median interval of 123 days in order to study the reproducibility of the diurnal profile. SUBJECTS: Twenty-four-hour ambulatory blood pressure monitoring and conventional blood pressure readings were obtained in 228 normotensive children, whose ages ranged from 6 to 16 years and of whom 116 were boys and 112 girls. RESULTS: The conventional blood pressure averaged 99+/-11/57+/-9 mmHg in boys and 98+/-12/56+/-9 mmHg in girls (means+/-SD); the corresponding 24 h pressures were 111+/-7/66+/-5 mmHg and 109+/-7/65+/-5 mmHg, respectively. Of the children, 83% had a significant diurnal blood pressure rhythm for systolic pressure and 89% for diastolic pressure. The nocturnal blood pressure fall was normally distributed, averaging 12.0+/-6.3 mmHg systolic and 14.2+/-5.9 mmHg diastolic. There was no evidence for a bimodal distribution. The amplitude of the diurnal blood pressure curve, determined by the Fourier approach, was positively skewed with a mean of 12.5+/-4.2 mmHg for systolic and 14.0+/-4.1 mmHg for diastolic blood pressure. The daily blood pressure maximum occurred at 1344+/-4 h 46 min for systolic and 1321+/-4 h 22 min for diastolic blood pressure. For systolic blood pressure the cumulative sum (cusum)-derived circadian alteration magnitude was 1.7+/-6.2 mmHg higher in boys than in girls, whereas the cusum plot height was also 7.3+/-27.0 mmHg x h higher in male subjects. The repeatability coefficient (2SD of the difference between paired recordings, expressed as a percentage of nearly maximal variation) was 80% for the conventional systolic pressure and 40% for the conventional diastolic blood pressure. The repeatability coefficients for the ambulatory blood pressure levels varied from 32 to 45% and for the parameters describing the diurnal blood pressure profile from 42 to 78%. CONCLUSION: A significant diurnal blood pressure rhythm is observed in most normotensive children and adolescents. There is no evidence for a bimodal distribution of the nocturnal blood pressure fall. The reproducibility of the parameters of the diurnal blood pressure curve tended to be less than that of the ambulatory blood pressure level. Thus, one 24 h recording is probably insufficient to characterize a child's diurnal blood pressure profile fully.     

Assessment of blood pressure control in hypertensive stroke survivors: an ambulatory blood pressure monitoring study

BACKGROUND: We compared the sensitivity of office blood pressure and ambulatory blood pressure monitoring recordings in evaluating the effectiveness of antihypertensive treatment and identified factors related to inadequate blood pressure control among hypertensive stroke survivors. METHODS: Office blood pressure and ambulatory blood pressure monitoring measurements were performed at 120+/-30 days after ictus in 187 first-ever consecutive hypertensive stroke survivors who were receiving blood pressure-lowering medications according to international guidelines. Handicap was assessed by the modified Rankin Scale. Blood pressure was regarded as controlled if office and daytime ambulatory systolic and diastolic blood pressure values were <140/90 and <135/85 mmHg, respectively. Patients were subclassified according to the degree of their nocturnal systolic blood pressure fall [(mean daytime values-mean night-time values)100/mean daytime values] as dippers (>or=10%), nondippers (>or=0% and <10%) and reverse dippers (<0%). RESULTS: Effective blood pressure control was documented in significantly (P<0.001) fewer patients using ambulatory blood pressure monitoring (32.1%) than those using office recordings (43.3%), whereas in 16% of the study population a masked lack of per-treatment blood pressure control (elevated ambulatory blood pressure in the presence of normal office blood pressure levels) was identified. The distribution of dipping patterns differed significantly (P=0.01) between controlled hypertensive individuals (normal office and ambulatory measurements) and patients with isolated ambulatory hypertension (dippers: 31.3 vs. 10.0%; nondippers:56.9 vs. 53.3%; reverse dippers: 11.8 vs. 36.7%). Logistic regression analysis revealed diabetes mellitus and functional independency (modified Rankin Scale score<2) as independent predictors of inadequate blood pressure control. CONCLUSION: Ambulatory blood pressure monitoring detects a substantial number of treated hypertensive stroke survivors with a masked lack of per-treatment blood pressure control, who present a higher prevalence of abnormal circadian blood pressure patterns (reverse dipping). Diabetes mellitus and poststroke functional independency are the main factors contributing to inadequate blood pressure control.     

Lack of effect of percutaneous transluminal renal angioplasty on nocturnal hypotension in renovascular hypertensive patients

OBJECTIVE: To investigate whether nocturnal blood pressure fall is blunted in renovascular hypertension and can therefore be used as a diagnostic criterion for this condition. METHODS: In 14 renovascular hypertensive patients (age 43.8+/-2.1 years, mean+/-SEM, clinic blood pressure 173.6+/-3.7 mmHg systolic and 109.0+/-2.0 mmHg diastolic) and in 14 age- and blood pressure-matched essential hypertensive controls 24 h ambulatory blood pressure was measured after washout from drug treatment, during angiotensin converting enzyme inhibitor treatment and, in renovascular hypertension, also after percutaneous transluminal renal angioplasty. RESULTS: The 24 h average systolic and diastolic blood pressures were 146.4+/-5.7 and 97.5+/-3.6 mmHg in renovascular and 144.3+/-1.2 and 98.0+/-2.2 mmHg in essential hypertensive patients. The angiotensin converting enzyme inhibitor treatment reduced 24 h average systolic and diastolic blood pressures by 8.5% and 9.7% in the renovascular and by 8.3% and 10.8% in the essential hypertensive group. Greater systolic and diastolic blood pressure reductions (-18.2% and -18.1%) were observed in renovascular hypertensive patients after percutaneous transluminal renal angioplasty. Blood pressure fell by about 10% during the night and the fall was similar in renovascular and in essential hypertensive patients. In the former group, nocturnal hypotension was similar after washout, during angiotensin converting enzyme inhibitor treatment and after percutaneous transluminal renal angioplasty. Similar results were obtained for nocturnal bradycardia. CONCLUSIONS: Nocturnal blood pressure fall is equally manifest in renovascular and essential hypertension. The removal of the renal artery stenosis and blood pressure normalization do not enhance this phenomenon. Nocturnal hypotension seems therefore to be unaffected by renovascular hypertension.     

Ambulatory blood pressure monitoring in elderly patients with isolated systolic hypertension.

OBJECTIVES: This study compared clinic and ambulatory blood pressure measurement and the reproducibility of these measurements in older patients with isolated systolic hypertension (ISH). PATIENTS: Eighty-seven patients aged greater than or equal to 60 years with ISH on clinic measurement were followed in the placebo run-in phase of the Syst-Eur trial. METHODS: Clinic blood pressure was defined as the mean of two blood pressure readings on each of three clinic visits (six readings in total). Ambulatory blood pressure was measured over 24 h using non-invasive ambulatory blood pressure monitors. RESULTS: Daytime ambulatory systolic pressure was, on average, 21 mmHg lower than the clinic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. In the 42 patients who had repeat measurements, clinic blood pressure levels nad the amplitude of the diurnal blood pressure profile (fitted by Fourier analysis) were equally reproducible. However, both were less reproducible than ambulatory blood pressure levels. The repeatability coefficients, expressed as per cent of near maximum variation (four times the standard deviation of a given measurement), were 52% and 45% for the clinic systolic and diastolic pressures, 56% and 42% for the amplitude of the diurnal profile, and 29% and 26% for mean 24-h pressures. CONCLUSIONS: In older patients with ISH, clinic and ambulatory systolic blood pressure measurements may differ largely: the prognostic significance of this difference remains to be elucidated. Furthermore, in these patients the level of pressure is more reproducible by daytime ambulatory blood pressure measurement than by clinic measurement.     

Association of clinic and ambulatory blood pressure with vascular damage in the elderly: the EPICARDIAN study

OBJECTIVES: In middle-aged adults, vascular damage correlates better with ambulatory than with clinic blood pressure. This study aimed to determine whether vascular damage evaluated by carotid ultrasonography in the elderly is also more closely related to ambulatory than to clinic blood pressure, and which blood pressure variables are better associated with vascular damage. METHODS: Cross-sectional study of 292 randomly selected >65 years old participants who underwent 24-h noninvasive ambulatory blood pressure monitoring. Blood pressure variables analyzed were (a) clinic blood pressure: systolic and diastolic blood pressure, pulse pressure; (b) ambulatory blood pressure monitoring: mean values of systolic and diastolic blood pressure, systolic and diastolic blood pressure load, pulse pressure, as well as variability, evaluated within 24 h, diurnal and nocturnal periods; and day-night blood pressure difference. A clinical history, physical examination, carotid ultrasonography and laboratory tests were performed. To estimate the relationship between blood pressure and vascular damage, univariate and multivariate analyses were performed. RESULTS: Mean age: 73+/-6 years, 45% men, 76.7% hypertensive patients. In the simple regression analysis, the best significant correlations (P<0.05) were common carotid intima-media thickness with 24-h and nocturnal pulse pressure (r=0.32), and common carotid diameter with 24-h systolic blood pressure load (r=0.47). In the multivariate analysis, the significant associations (P<0.05) were (a) linear regression: nocturnal pulse pressure with common carotid intima-media thickness, and diurnal pulse pressure as well as 24-h systolic blood pressure load with common carotid diameter; (b) logistic regression, adjusted odds ratio: nocturnal pulse pressure and nocturnal diastolic blood pressure load with the presence of carotid atherosclerotic plaques 1.03 and 0.98, respectively. CONCLUSIONS: In the elderly, ambulatory blood pressure monitoring is better associated with carotid damage than clinic blood pressure. Systolic blood pressure variables are the best associated, blood pressure load and pulse pressure being better associated with carotid damage than the mean levels of ambulatory blood pressure.     

Blood pressure and heart rate variability in elderly hypertensive patients

In elderly hypertensive patients (HP) blood pressure (BP) and heart rate (HR) control and variability seem to be affected by a reduced baroreceptor sensitivity, or autonomic dysfunction, and concomitant cardiovascular diseases. Therefore, the aim of present study was to investigate the circadian profiles and variability of BP and HR, by means of a 24-hour ambulatory BP monitoring, in a group of 22 elderly HP compared with those of a group of 24 middle aged patients with essential hypertension. Many differences in BP and HR profile and variability were observed in elderly HP when compared to those of middle aged HP, such as significantly lower diurnal diastolic BP values, lower nocturnal BP fall, lower diurnal HR but with a greater diurnal variability. Conversely, in middle aged HP a significantly greater diurnal systolic BP variability was observed, and a significant correlation was found between hourly diastolic BP and hourly HR values, while in elderly HP this correlation was not detectable. The changes in BP and HR profile and variability observed in elderly HP may play a role as risk factors for cardiovascular complications and indicate a dysfunction of autonomic and nonautonomic factors in BP control.     

Diurnal blood pressure variations and silent cerebrovascular damage in elderly patients with hypertension.

OBJECTIVE: To examine the effect of diurnal blood pressure changes upon cerebrovascular damage in elderly patients with hypertension. DESIGN: Fifty-four asymptomatic hypertensive and 34 normotensive elderly subjects underwent both 24-h non-invasive ambulatory blood pressure monitoring and brain magnetic resonance imaging. METHODS. Diurnal variation was defined as a difference of greater than or equal to 10 mmHg between mean awake and asleep systolic blood pressure. Hypertensives were thus classified as dippers or non-dippers. Low intense foci (lacunae) and advanced periventricular hyperintensity were identified as silent cerebrovascular damage. RESULTS: In the hypertensive group, lacunae were correlated more closely with mean asleep systolic blood pressure than with mean awake systolic blood pressure. Age, awake blood pressure, predicted whole blood viscosity, lipid profiles or quantity of sleep did not differ between the hypertensive dippers or non-dippers. The non-dippers, however, showed significantly higher grades of cerebrovascular damage as well as cardiac hypertrophy by electrocardiography than the dippers, whose results were similar to those of normotensives in this regard. CONCLUSIONS: An absent or lower nocturnal blood pressure fall in elderly hypertensives is associated with silent cerebrovascular damage. In contrast, the presence of a nocturnal fall could prevent the development of hypertensive vascular damage.     

Comparison between office and ambulatory blood pressure in young and elderly subjects with isolated systolic hypertension

BACKGROUND: It has been claimed that isolated systolic hypertension (ISH) in the elderly is not a sustained condition but a short-lasting increase in office systolic blood pressure magnified by arterial stiffness. DESIGN: Office and ambulatory blood pressures werecompared at baseline and after 3 months of observation of young and elderly subjects with ISH. METHODS: The study was carried out in 39 young (mean age 27.1+/-9.8 years) and 37 elderly patients (mean age 72.5+/-5.7 years). Office blood pressure was defined as the mean of six readings. All subjects underwent two non-invasive 24 h blood pressure monitorings performed 3 months apart and echocardiography (n = 50). RESULTS: The difference between office and mean 24 h systolic/diastolic blood pressure was 27.9/8.2 mmHg in the young and 18.9/6.9 mmHg in the elderly patients (P < 0.01 for systolic blood pressure). Twenty-four-hour (P < 0.001), daytime (P = 0.001) and night-time (P < 0.001) systolic blood pressures were higher in the elderly and the difference between daytime and night-time systolic blood pressure was greater in the young (P < 0.05). Office and ambulatory heart rates were significantly higher in the young subjects. The elderly patients showed a greater left ventricular wall thickness ( P = 0.005 for posterior wall; P < 0.005 for septum), relative wall thickness (P = 0.01) and left ventricular mass index (P = 0.001) and impaired left ventricular filling rate ( P = 0.05), whereas systolic performance and stroke volume were no different in the two groups. Due to the higher heart rate, cardiac output was greater in the young (P = 0.03). CONCLUSION: These data show that larger differences between office and ambulatory systolic blood pressure are not unique to elderly patients with ISH. Increased ambulatory blood pressure levels and a decreased nocturnal blood pressure fall were associated with left ventricular structural and functional abnormalities in the elderly subjects.     

Reproducibility of dipping/nondipping pattern in untreated essential hypertensive patients: impact of sex and age

OBJECTIVE: We aimed to evaluate the intrasubject short-term reproducibility of nocturnal blood pressure patterns (dipping/nondipping) in essential hypertensive patients in relation to age (<50 and > or =50 years) and sex. METHODS: A total of 619 never-treated essential grade 1 and 2 hypertensive patients (383 men, 236 women) underwent the following procedures: (1) repeated clinic blood pressure measurements, (2) routine examinations, (3) ambulatory blood pressure monitoring over two 24-h periods within 4 weeks. Dipping pattern was defined as a 10%, or more, reduction in average systolic blood pressure/ diastolic blood pressure at night compared to daytime values. RESULTS: Of the 407 patients showing a dipping pattern during the first ambulatory blood pressure monitoring period, 329 (80.1%) had the same pattern during the second ambulatory blood pressure monitoring recording. Of the 212 patients with a nondipping pattern during the first ambulatory blood pressure monitoring period, 140 (65.9%) confirmed the same pattern during the second ambulatory blood pressure monitoring period. Overall, 149 patients (24.1%) changed their initial nocturnal pattern at the second ambulatory blood pressure monitoring recording, without significant age and sex-related differences. Lower reproducibility rates of the nondipping as compared to the dipping pattern were found in the whole population as well as in men regardless of age and in younger but not in older women. CONCLUSIONS: These findings indicate that nocturnal blood pressure patterns have a limited short-term reproducibility in the whole study population as well as in different age and sex subgroups. As variability of nocturnal blood pressure patterns is not predicted by easy available clinical data, such as sex and age, a reliable classification of patients according to circadian blood pressure patterns should be obtained by repeating ambulatory blood pressure monitoring.     

Ambulatory blood pressure predicts end-organ damage only in subjects with reproducible recordings. HARVEST Study Investigators. Hypertension and Ambulatory Recording Venetia Study.

OBJECTIVE: To determine whether the prediction of target-organ damage varies according to the reproducibility of 24 h blood pressure. SETTING: Seventeen hypertension clinics in northeast Italy. MAIN OUTCOME MEASURES: Correlations of left ventricular mass index and albumin excretion rate with 24 h and office blood pressures in relation to tertiles of ambulatory blood pressure reproducibility. PATIENTS AND METHODS: In 716 consecutive, stage I, hypertensives enrolled in the Hypertension and Ambulatory Recording Venetia Study (HARVEST), ambulatory blood pressure monitoring was performed twice, 3 months apart In all subjects, the albumin excretion rate was measured by radioimmunoassay, and in 567, the left ventricular mass index was assessed by echocardiography. RESULTS: The subjects were divided into tertiles of ambulatory blood pressure consistency (between-monitoring differences, regardless of the sign). In the tertile of subjects with good reproducibility, correlation coefficients of systolic and diastolic ambulatory blood pressure with left ventricular mass and urinary albumin excretion were significant and higher than those of office blood pressure. In contrast, in the two tertiles with poorer reproducibility, the coefficients were barely or not significant for both pressures. The advantage of ambulatory blood pressure over office blood pressure in predicting target-organ damage was no longer present for systolic blood pressure differences greater than 3.8 mmHg and diastolic blood pressure differences greater than 3.1 mmHg. CONCLUSIONS: These data indicate that ambulatory blood pressure is a better predictor of left ventricular mass and urinary albumin excretion than office blood pressure, but only in subjects with good pressure reproducibility. Therefore, the assessment of hypertensive patients should be based on duplicate blood pressure monitorings. Recordings with 24 h systolic and diastolic blood pressure differences greater than 4 and 3 mmHg, respectively, should be considered with caution.     

The reproducibility of dipping status: beyond the cutoff points

A limited reproducibility has been ascribed to 24-h ambulatory blood pressure monitoring, especially in relation to the dipper and nondipper phenomena. This study examined the reproducibility of 24-h ambulatory blood pressure monitoring in three recordings of pressure at intervals of 8-15 days in 101 study participants (73% treated hypertensive patients) residing in the city of Recife, Pernambuco, Brazil. SpaceLabs 90207 monitors were used, and the minimum number of valid measurements was 80. No significant differences were found between the mean systolic and diastolic pressures, between the second and third recordings when the normotensive and hypertensive patients were assessed jointly (P=0.44). Likewise, no significant differences were present when the normotensive patients were analyzed separately (P=0.96). In the hypertensive group, a significant difference existed between only the first and second ambulatory blood pressure readings (135.1 vs. 132.9 mmHg, respectively; P=0.0005). Regarding declines in pressure during sleep, no significant differences occurred when continuous percentage values were considered (P=0.27). The values obtained from 24-h ambulatory blood pressure monitoring are reproducible when tested at intervals of 8-15 days. Small differences, when significantly present, always involved the first ambulatory blood pressure monitoring. The reproducibility of the dipper and nondipper patterns is of greater complexity because it considers cutoff points rather than continuous ones to characterize these states.     

The spectrum of circadian blood pressure changes in type I diabetic patients

BACKGROUND: The objective of the present study was to characterize the spectrum of circadian blood pressure changes in type I diabetes at different stages of nephropathy by using two monitorings in each patient in order to avoid intra-individual variability. PATIENTS AND METHODS: A total of 80 type I diabetic subjects and the same number of age, sex and awake mean blood pressure (BP)-matched controls were included. According to urinary albumin excretion, there were 57 normoalbuminurics, 15 persistent microalbuminurics and eight proteinurics. Two 24 h ambulatory blood pressure monitorings were performed at the same urinary albumin excretion stage in absence of antihypertensive treatment for each diabetic subject and for their respective control. Blood pressure and heart rate averages during 24 h, awake, sleep, and day: night ratio were calculated. RESULTS: Seven of the eight proteinuric subjects were hypertensives, whereas hypertension was absent in the normoalbuminuric and microalbuminuric groups. The intraindividual reproducibility in diabetics showed repeatability coefficients for the 24 h systolic and diastolic pressure of 33 and 42%, respectively. This reproducibility for the day: night ratio was generally worse, 57% for systolic and 59% for diastolic. A progressive increment in the mean ambulatory BP was observed across the three groups of diabetics and the differences in BP observed were most evident during the night-time period. Though no differences in the 24 h circadian pattern were present between the normoalbuminurics and their controls, nocturnal differences were observed, not only in microalbuminurics for systolic BP (P < 0.05), but also in proteinurics for both systolic BP (P < 0.01) as well as diastolic BP (P < 0.05). No differences were observed in heart rate among the diabetic groups. The non-dipping pattern in the two monitorings was observed in 80, 58, 18 and 10% of the proteinurics, microalbuminurics, normoalbuminurics and control groups, respectively. CONCLUSIONS: Persistent abnormal circadian variability seems to be an early and frequent characteristic of type I diabetics with an increased urinary albumin excretion. Although present in some normalbuminuric subjects, the frequency of this abnormality increases as the incipient nephropathy progresses. By the time proteinuria is established, nearly all subjects present the abnormal pattern.     

Is HOMA index a predictor of nocturnal nondipping in hypertensives with newly diagnosed type 2 diabetes mellitus?

OBJECTIVE: Insulin resistance is involved in glucose intolerance, type 2 diabetes mellitus and hypertension. We aimed to analyze relationship between insulin resistance and nocturnal nondipping. METHODS: Patients underwent physical and biochemical evaluation, clinic and ambulatory blood pressure measurements. The homeostasis model assessment (HOMA) index was calculated. RESULTS: Ninety-six essential hypertensive patients, of whom 42 were dippers, with newly diagnosed type 2 diabetes mellitus were included. Nighttime average heart rate and mean arterial pressure of nondippers were higher than dippers (P<0.0001 and 0.001). Nondippers had higher fasting plasma glucose, serum insulin levels and HOMA indices than dipper patients (P=0.006, <0.0001 and <0.0001). Ten dippers and 36 nondippers were insulin resistant (P<0.0001). Clinic (r=+0.22, P=0.031), daytime average (r=+0.27, P=0.007), nighttime average (r=+0.33, P=0.001), 24-h average systolic (r=+0.25, P=0.015) and nighttime average diastolic blood pressures (r=+0.31, P=0.002) were positively correlated with homeostasis model assessment index. Nighttime mean arterial pressure and heart rates (daytime, nighttime, 24-h average) showed positive correlation with homeostasis model assessment index. In multivariate analysis, high homeostasis model assessment index was associated with increased nondipping risk (odds ratio: 1.85, confidence interval: 1.24-2.76, P=0.003). After adjustment of several factors, average nighttime systolic (P<0.0001), diastolic (P<0.0001) and 24-h diastolic blood pressure (P=0.029) and heart rate (P=0.001) measurements of insulin resistant patients were higher than nonresistant patients. CONCLUSIONS: Insulin resistance is related with diurnal blood pressure variation. The HOMA index may be a predictor of nocturnal nondipping in patients with essential hypertension and newly diagnosed type 2 diabetes mellitus.     

Metabolic syndrome score and ambulatory blood pressure in untreated essential hypertension

BACKGROUND: The relationship between metabolic syndrome components, as defined by the Adult Treatment Panel III report, and ambulatory blood pressure in hypertensive patients has not been investigated to date. OBJECTIVE: To explore the relation between metabolic syndrome components ambulatory blood pressure levels and blood pressure day/night variations in a large population of never-treated essential hypertensive patients. METHODS: This investigation included 519 patients with uncomplicated grade 1 and 2 hypertension (mean age 45+11 years) who were attending a hypertension hospital outpatient clinic. They underwent the following procedures: (1) repeated clinic blood pressure measurements; (2) blood sampling for routine chemistry examinations; and (3) ambulatory blood pressure monitoring over two 24-h periods within 4 weeks. Because, by selection, all participants fulfilled one of the Adult Treatment Panel III criteria, the additional four criteria, abdominal obesity, hypertriglyceridemia, low HDL cholesterol and high blood fasting glucose, were specifically searched for. Patients were stratified according to the absence (group I) or the presence of one (group II), two (group III), three or four (group IV) components of the metabolic syndrome. Nocturnal dipping was defined as a night-time reduction in average systolic and diastolic blood pressure >10% compared to average daytime values. Each participant was classified according to the consistency of the dipping or nondipping status in the first and second ambulatory blood pressure measurement periods as follows: reproducible dipper (DD: decrease in blood pressure >10% in both ambulatory blood pressure measurement periods), reproducible nondipper (ND-ND: decrease in blood pressure <10% in both ambulatory blood pressure measurement periods) and variable dipper (VD: i.e dipper in one and nondipper in the other ambulatory blood pressure measurement period). RESULTS: In the whole population mean clinic and 48-h ambulatory blood pressures were 146/96 and 136/87 mmHg, respectively. In all, 197 patients (38%) had no metabolic syndrome components other than high blood pressure, 171 (33%) had one, 109 (21%) had two and 42 (8%) had three or four components. The four groups did not differ in age, clinic blood pressure, average 48-h, daytime, night-time systolic and diastolic blood pressure, and percentages of nocturnal fall in systolic and diastolic blood pressure. Furthermore, the distribution of three different ambulatory blood pressure patterns (DD, ND-ND and VD) was similar in the four groups: I=54.6%, 23.0%, 22.4%; II=51.1%, 21.7%, 27.2%; III=51.9%, 23.6%, 24.5%; and IV=52.7%, 27.2%, 25.1%, respectively. CONCLUSIONS: Our findings indicate that no significant relationship exists between the extent of metabolic alterations and ambulatory blood pressure levels or circadian variations in blood pressure in uncomplicated essential hypertensive patients.     

Diurnal variation of pulmonary artery pressure in chronic heart failure

Variation in pulmonary artery pressure has important consequences for the interpretation of isolated pressure measurements in patients with chronic heart failure. To investigate the nature of diurnal variation in pulmonary artery pressure in chronic heart failure, eight angina-free men (aged 50-72 years) with treated chronic heart failure caused by ischaemic heart disease underwent continuous ambulatory pulmonary artery pressure recording by a transducer tipped catheter. The mean (1 SD) daytime pulmonary artery pressure was 29.6 (5.0) mm Hg systolic and 13.7 (5.6) mm Hg diastolic. The mean change in pressure from day to night was +5.1 (3.2) mm Hg systolic and +3.8 (1.7) mm Hg diastolic; and the mean change from standing to lying +9.3 (2.3) mm Hg systolic and +6.4 (2.1) mm Hg diastolic. In six of the eight patients there was considerable rise in pulmonary artery pressure at night, but in the two patients with the most severe symptoms there was no nocturnal rise. In patients with chronic heart failure, nocturnal pulmonary artery pressure is not determined by postural change alone. But interpretation of isolated pulmonary artery pressure measurements must take the posture of the patient into account.     

Diurnal variation of pulmonary artery pressure in chronic heart failure.

Variation in pulmonary artery pressure has important consequences for the interpretation of isolated pressure measurements in patients with chronic heart failure. To investigate the nature of diurnal variation in pulmonary artery pressure in chronic heart failure, eight angina-free men (aged 50-72 years) with treated chronic heart failure caused by ischaemic heart disease underwent continuous ambulatory pulmonary artery pressure recording by a transducer tipped catheter. The mean (1 SD) daytime pulmonary artery pressure was 29.6 (5.0) mm Hg systolic and 13.7 (5.6) mm Hg diastolic. The mean change in pressure from day to night was +5.1 (3.2) mm Hg systolic and +3.8 (1.7) mm Hg diastolic; and the mean change from standing to lying +9.3 (2.3) mm Hg systolic and +6.4 (2.1) mm Hg diastolic. In six of the eight patients there was considerable rise in pulmonary artery pressure at night, but in the two patients with the most severe symptoms there was no nocturnal rise. In patients with chronic heart failure, nocturnal pulmonary artery pressure is not determined by postural change alone. But interpretation of isolated pulmonary artery pressure measurements must take the posture of the patient into account.     

Home blood pressure measurement: reproducibility and relationship with left ventricular mass.

OBJECTIVE: To evaluate the reproducibility and relationship with left ventricular mass index of home blood pressure in comparison with ambulatory and office blood pressures. METHODS: We measured home, ambulatory and office blood pressures of 84 previously untreated hypertensive patients, aged 60-74 years, from primary care, at baseline and after 12 weeks, without active intervention in between. Left ventricular mass index was determined echocardiographically during week 12. RESULTS: Decreases in systolic and diastolic blood pressures were found after 12 weeks for mean home and office blood pressures (P<0.05), but not for mean ambulatory blood pressure. The coefficients of reproducibility for systolic and diastolic ambulatory blood pressures were 26.4 and 16.0, respectively. Correlation coefficients for correlation of left ventricular mass index to ambulatory blood pressure (0.51 and 0.36) were higher than the correlation coefficients for home (0.31 and 0. 16) and office (0.32 and 0.21) blood pressures, for systolic and diastolic values, respectively. However, we could find no statistically significant difference among the correlation coefficients for all three types of measurements. CONCLUSIONS: Home blood pressure was considerably less reproducible than ambulatory blood pressure and no different from office blood pressure in this respect. The relationship with left ventricular mass index appeared to be stronger for ambulatory than it was for home and office blood pressures, although not statistically significant so.     

Reproducibility of postexercise ambulatory blood pressure in Stage I hypertension

The accuracy and reproducibility of ambulatory blood pressure monitoring used in intervention and treatment studies is essential to assure the desired health outcomes. The reproducibility of ambulatory variables in pharmacological studies has been reported, however, the reproducibility of ambulatory blood pressure variables associated with exercise has not been reported. Thus, the purpose of this study was to investigate the reproducibility of the postexercise ambulatory blood pressure in Stage I hypertensive adults. It was hypothesized that the reproducibility of the ambulatory blood pressure variables would not be different following two corresponding exercise and control treatments. A total of 18 Stage I hypertensive adults (142.1+/-3.15/91.6+/-1.80 mmHg) performed four randomized, 24 h AmBP monitoring sessions: two following a 50 min treadmill walk (50% VO(2) peak) and two on control days. Variables measured were: (1) average systolic and diastolic pressures for 24 h, daytime (06:00-22:00 h) and night time (22:00-06:00 h) and (2) systolic and diastolic load for the same time periods. Both a nonsignificant paired t-test and an excellent intraclass correlation were used to define reproducibility of the variables between the 1st and 2nd exercise trials and between the 1st and 2nd control trials. Reproducibility was found for all the control variables except for nighttime diastolic load. Reproducibility was found for all the systolic and diastolic exercise variables. Ambulatory blood pressure measurements, including average systolic and diastolic blood pressures and systolic and diastolic loads for 24 h, daytime and night time periods are reproducible following exercise.