Circadian Blood Pressure Profile Research Articles

Effect of different hormone replacement therapy regimens on circadian blood pressure profile and active renin in postmenopausal women

Hormone replacement therapy (HRT) was considered as main prevention of cardiovascular disease (CVD) in postmenopausal women. Mechanisms of vasoprotective effect of this treatment are complex. However, recent data give rise to some uncertainties about HRT benefits and risks. Little is known about the effects of oral and transdermal HRT regimens on the renin-angiotensin-aldosterone system (RAS) and blood pressure (BP). This 3-month study comprised 28 menopausal women (age range 45-55 years) divided into two groups: Group 1: 12 normotensive women with natural occurrence of menopause receiving oral treatment with Climen® (Schering) containing estradiol valerate and cyproterone acetate; Group 2: 16 normotensive women with surgically induced menopause receiving transdermal application of Climara® (Schering) containing 17β-estradiol. There were no significant differences in office BP before and after treatment with Climara or Climen. However, ambulatory monitoring showed a significant fall in systolic BP (day-time, night-time and total 24-h) when estradiol alone was used. A similar trend towards lower values of systolic BP that was significant only for the night-time BP was observed after treatment with Climen. There were no significant changes in diastolic BP after both treatment regimens. Heart rate (day-time and 24-h) was significantly lower after transdermal estradiol treatment. There was no significant change in active renin after both treatment regimens. The present study showed that both treatment regimens resulted in lower ambulatory BP in normotensive postmenopausal women with more notable reduction in night-time BP. Increase in nocturnal dipping may account in part for the beneficial cardiovascular effects of HRT including decreased end-organ damage.

Growth hormone could have a role in essential hypertension. Its relationship with circadian blood pressure profile and insulin resistance

In the present study apolipoprotein-mediated free cholesterol (FC) efflux was studied in J774 macrophages having normal cholesterol levels using an experimental design in which efflux occurs in the absence of contributions from cholesteryl ester hydrolysis. The results show that cAMP induces both saturable apolipoprotein (apo) A-I-mediated FC efflux and saturable apo A-I cell-surface binding, suggesting a link between these processes. However, the EC50 for efflux was 5–7-fold lower than the Kd for binding in both control and cAMP-stimulated cells. This dissociation between apo A-I binding and FC efflux was also seen in cells treated for 1 h with probucol which completely blocked FC efflux without affecting apo A-I specific binding. Thus, cAMP-stimulated FC efflux involves probucol-sensitive processes distinct from apo A-I binding to its putative cell surface receptor. FC efflux was also dramatically stimulated in elicited mouse peritoneal macrophages, suggesting that cAMP-regulated apolipoprotein-mediated FC efflux may be important in cholesterol homeostasis in normal macrophages. The presence of a cAMP-inducible cell protein that interacts with lipid-free apo A-I was investigated by chemical cross-linking of 125I-apo A-I with J774 cell surface proteins which revealed a Mr 200 kDa component when the cells were treated with cAMP.

Effect of different hormone replacement therapy regimens on circadian blood pressure profile and active renin in postmenopausal women

Hormone replacement therapy (HRT) was considered as main prevention of cardiovascular disease (CVD) in postmenopausal women. Mechanisms of vasoprotective effect of this treatment are complex. However, recentdata give rise to some uncertainties about HRT benefits and risks. Little is known about the effects of oral and transdermal HRT regimens on the renin-angiotensin-aldosterone system (RAS) and blood pressure(BP). This 3-month study comprised 28 menopausal women (age range 45-55 years) divided into two groups: Group 1: 12 normotensive women with natural occurrence of menopause receiving oral treatment withClimen® (Schering) containing estradiol valerate and cyproterone acetate; Group 2: 16 normotensive women with surgically induced menopause receiving transdermal application of Climara® (Schering)containing 17β-estradiol. There were no significant differences in office BP before and after treatment with Climara or Climen. However, ambulatory monitoring showed a significant fall in systolicBP (day-time, night-time and total 24-h) when estradiol alone was used. A similar trend towards lower values of systolic BP that was significant only for the night-time BP was observed after treatment withClimen. There were no significant changes in diastolic BP after both treatment regimens. Heart rate (day-time and 24-h) was significantly lower after transdermal estradiol treatment. There was no significantchange in active renin after both treatment regimens. The present study showed that both treatment regimens resulted in lower ambulatory BP in normotensive postmenopausal women with more notable reductionin night-time BP. Increase in nocturnal dipping may account in part for the beneficial cardiovascular effects of HRT including decreased end-organ damage.

Ambulatory blood pressure monitoring: technique and application in the study of cardiac dysfunction and congestive heart failure.

Ambulatory blood pressure monitoring has become a widely used method of blood pressure and heart rate evaluation in the free-living subject. Recently, ambulatory monitoring has become covered by Medicare for the evaluation of "white-coat" hypertension. Although the technique provides only intermittent readings throughout the 24-hour period, average blood pressures obtained in this way correlate well with a variety of hypertensive disease processes and are also a better prognostic marker for future cardiovascular events than office blood pressure. Ambulatory blood pressure averages also correlate well with indices of diastolic dysfunction. In patients with congestive cardiac failure and systolic dysfunction, ambulatory monitoring suggests an impaired circadian blood pressure profile with high nocturnal blood pressure. Further research is needed on the relationship between ambulatory blood pressure and cardiac dysfunction, as well as the impact of observed circadian blood pressure changes on outcome. (c)2001 CHF, Inc.

Altered circadian blood pressure profile in patients with active acromegaly. Relationship with left ventricular mass and hormonal values.

To determine the relationships between the circadian blood pressure profile and left ventricular mass, hormonal pattern and insulin sensitivity indices in patients with active acromegaly, ambulatory 24-h blood pressure monitoring (ABPM) was recorded in 25 subjects (47.0 +/- 15.1 years, range 23-72). Serum growth hormone (GH) and insulin-like growth factor-1, fasting and mean plasma glucose and insulin during oral glucose tolerance test (OGTT), insulinogenic index, the sum of the plasma insulin levels and the homeostasis model insulin resistance index (Homa's index) were determined. Left ventricular mass index (LVMI) was calculated from two-dimensional guided M-mode echocardiogram. The prevalence of hypertension was 56% (n = 14) and 40% (n = 10) according to sphygmomanometric measurements and ABPM, respectively. Non-dipping profile was observed in six of 10 hypertensives and in six of 15 normotensives. Serum growth hormone, fasting glucose, the area under the serum insulin curve and LVMI were higher for acromegalics with non-dipping profile than for dippers (all of them, P < 0.05). In non-dippers daytime heart rate was higher than night time (P < 0.001). In conclusion, the main observations in the present study suggested that both normotensive and hypertensive acromegalics had a highly prevalent non-dipping profile with a preserved circadian pattern of heart rate, that was associated with higher levels of serum GH. The disturbance in nocturnal blood fall in normotensives was associated with a decreased insulin sensitivity. The role of GH in blood pressure circadian rhythm regulation in essential hypertension deserves further studies.

Hypertension after renal transplantation.

With current immunosuppression, elevated blood pressure is found in almost 90% of renal graft recipients. Major causes of this are impairment of renal function (secondary to chronic allograft nephropathy or less frequently recurrence of primary renal disease), the use of calcineurin inhibitors as immunosuppressants, uncontrolled renin secretion by the shrunken kidneys of the recipient, stenosing lesions of the transplant artery (or the upstream arteries of the recipient), polycythemia, and genetic predisposition to hypertension of the graft donor. Even minor degrees of blood pressure elevation have a significant impact on survival of the recipient and on graft survival, presumably by amplifying vascular injury to the graft. In this respect, elevation of systolic blood pressure and an abnormal circadian blood pressure profile are of particular relevance. In contrast to previous opinion, angiotensin converting enzyme inhibitors are indicated in treatment, but given the causal role of sodium retention and graft vasoconstriction, diuretics and calcium channel blockers remain mainstays of antihypertensive treatment in the renal allograft recipient.

Administration-time-dependent effects of nifedipine-coat core “adalat-CR” on circadian blood pressure profile in patients with essential hypertension

Administration-time-dependent effects of nifedipine-coat core “adalat-CR” on circadian blood pressure profile in patients with essential hypertension

Body weight, 24-hour blood pressure profile and insulin resistance in lean and overweight hypertensives and normotensive controls

The aim of the study was to examine the relationship between body weight, circadian blood pressure profile, pulse pressure and insulin resistance. The participants were divided into a lean group with a BMI<26 and the overweight group with a BMI ≥26. Sixty-five overweight and 55 lean subjects (age 50.5±14.4 and 49.9±14.4 y, respectively) were included. Ninety five were hypertensives (SBP ≥140 mm Hg and/or DBP≥90 mm Hg on three office measurements). They were kept off antihypertensive agents for at least 3 weeks before the study and then assigned to 24-hour ambulatory blood pressure monitoring (ABPM) and a 2-hour oral glucose (75g)-tolerance test (OGTT). We determined fasting glucose, insulin, and after glucose ingestion. Insulin resistance was estimated by fasting insulin, fasting insulin/glucose ratio, the areas under the curve (AUC) of insulin and insulin/glucose ratio, the homeostasis model insulin resistance index (Homa's index) and the sum of plasma insulin levels 0,30,60, and 120min after the OGTT (ΣIRI). Overweight subjects presented higher waist: hip ratio (0.897±0.090 vs 0.843±0.075, P<.001), AUCInsulin (78.8±56.3 vs 54.5 ± 38.9μU/ml, P<.01), ΣIRI (269.4±197.3 vs 186.6±135.1μU/ml, P<.01), Homa's index (5.22±3.97 vs 3.06±3.21, P<.05), SBP load (% of 24-hour SBP>140 mm Hg) (62.8 ±24.9 vs 51.0±29.6 %, P<.01), and pulse pressure (64.9±13.3 vs 60.4±13.7 mm Hg, P<.01). Nondippers (n=41) compared with dippers presented higher pulse pressure (70.4 ± 12.8 vs 59.0±12.4 mm Hg, P<.001), waist: hip ratio (0.894 ±0.088 vs 0.860 ±0.086, P<.01), AUCInsulin (82.7±54.3 vs 52.4±39.2μU/ml, P<.01) and Homa's index (5.37±3.72 vs 3.12±3.17, P<.01). Correlations of blood pressure and insulin resistance indexes were no significant. BMI was positively related to AUCInsulin (r=0.358), ΣIRI (r=0.338) and Homa's index (r=0.262), all of them P<.01. In conclusion, these date indicate that among normotensive and hypertensive overweight subjects the prevalence of insulin resistance, SBP load and wide pulse pressure were higher than in lean subjects, and that insulin resistance may have some relationship with nondipper profile.

Ambulatory blood pressure in heart failure.

Ambulatory blood-pressure monitoring (ABPM) is accepted in the evaluation and management of hypertension. The use of ABPM in heart failure has received considerably less attention. Many patients with advanced heart failure experience disabling fatigue, orthostatic dizziness and symptoms of coronary and cerebrovascular insufficiency that may relate to periods of hypotension. These may be exacerbated by vasodilator drug therapy and may be difficult to evaluate by casual clinic recordings. ABPM in heart failure may help in the following: (i) evaluating time-dependent pharmacodynamic drug effects, such as peak and end-of-dose phenomena, tolerance and rebound; (ii) titrating ACE inhibitors and other drugs to highest-tolerated doses; and (iii) correlating circadian blood-pressure profiles with symptoms, quality of life, severity of heart failure, progression of ventricular and renal dysfunction, risks of stroke and myocardial infarction, and life expectancy. Devices for ABPM have been beset by problems of inaccuracy and unreliability. Standards for their manufacture and sale (including bench tests of accuracy against sphygmomanometry and intra-arterial recordings, and field tests of reliability) have been devised independently by several agencies, including the British Hypertension Society (BHS) and US Association for the Advancement of Medical Instrumentation (AAMI). A joint BHS/AAMI set of guidelines is in preparation. These guidelines emphasize the suitability of ABPM devices for hypertensive patients and those under general anesthesia, and may not be applicable to ambulant individuals with heart failure and blood pressures at or below the lower end of the evaluated ranges. Prospective studies of the accuracy and reliability of ABPM devices, their clinical utility and research potential should be undertaken in patients with heart failure before their informal and uncontrolled use in this population becomes widespread.

DAY-NIGHT VARIATION IN THE IN VITRO CONTRACTILITY OF AORTA AND MESENTERIC AND RENAL ARTERIES IN TRANSGENIC HYPERTENSIVE RATS*

TGR(mREN2)27 (TGR) rats develop severe hypertension and an inverted circadian blood pressure profile with peak blood pressure in the daytime rest phase. The present study investigated the in vitro responsiveness of different arteries of TGR rats during day and night. Twelve-week-old TGR rats and normotensive Sprague-Dawley (SPRD) controls, synchronized to 12h light, 12h dark (LD 12:12) (light 07:00 19:00), were killed at 09:00 (during rest) and 21:00 (during activity), and endothelium-dependent relaxation by acetylcholine and vascular contraction by angiotensin II were studied by measuring isometric force in ring segments of abdominal aorta and mesenteric and renal arteries. In SPRD rats, consistent day-night variation was found, with greater responses to angiotensin II during the daytime rest span. In TGR rats, biological time-dependent differences were found in the renal vasculature, but not in the aorta and mesenteric artery. Relaxation of SPRD rat aorta and mesenteric artery by acetylcholine was greater at 09:00, whereas in TGR rats, day-night variation was absent (mesenteric artery) or inverted (aorta). In conclusion, based on the study of two time points, daynight variation in vascular contractility of aorta and mesenteric artery is blunted in TGR rats, whereas renal artery segments showed an unchanged daynight pattern compared to SPRD controls. (Chronobiology International, 18(4), 665 681, 2001)

REDUCED BAROREFLEX SENSITIVITY AND BLUNTED ENDOGENOUS NITRIC OXIDE SYNTHESIS PRECEDE THE DEVELOPMENT OF HYPERTENSION IN TGR(mREN2)27 RATS

Transgenic TGR(mREN2)27 (TGR) rats are an animal model of fulminant hypertension characterized by an inverse circadian blood pressure profile. The present study addressed the contribution of nitric oxide (NO) synthesis and baroreflex function to hypertension and the inverse blood pressure pattern. NO synthesis was measured at four different times of day indirectly by excretion of NO metabolites (NOx: NO−2 and NO−3) in the urine of 5- and 11-week-old TGR and Sprague-Dawley (SPRD) controls. Blood pressure, heart rate, and motor activity were recorded in age-matched rats of both strains using an implantable telemetry system. Beat-to-beat recording of blood pressure and pulse interval was performed hourly in 6-week-old animals over 24h. From these data, baroreflex sensitivity (BRS) was calculated by linear regression of spontaneous fluctuations of blood pressure and corresponding changes of pulse interval. Baroreflex sensitivity was lower in prehypertensive TGR rats than in SPRD rats, and the reduction was restricted to the daily resting period. In both strains, NOx excretion showed circadian rhythmicity, with peak values during the activity period at night. Interestingly, excretion of NOx was reduced during the resting period in 5-week-old TGR rats prior to the development of hypertension. Impairment of NO synthesis and baroreflex function precede the development of hypertension in TGR rats. The reduction of both parameters was restricted to the resting period and, therefore, could be involved in the development of the inverse circadian blood pressure profile of TGR rats. (Chronobiology International, 18(2), 215–226, 2001)

Comparison of valsartan and irbesartan in the treatment of mild to moderate hypertension: a randomized, open-label, crossover study

Background: Differences in the pharmacokinetic and pharmacodynamic variables of angiotensin II receptor blockers (ARBs) have been cited as potentially important causes of differential clinical efficacy with respect to the magnitude and duration of the antihypertensive response. Objective: The goal of this study was to compare the antihypertensive efficacy of valsartan versus irbesartan using 24-hour ambulatory blood pressure monitoring (ABPM) in the treatment of mild to moderate hypertension. Methods: After a 2-week placebo washout period, outpatients of both sexes aged 31 to 60 years with mild to moderate hypertension were randomly assigned to treatment with irbesartan 150 mg or valsartan 80 mg, both administered once daily, for 4 weeks. After another 2-week placebo washout period, patients were switched to the alternate regimen for an additional 4 weeks. Patients were assessed at the end of each placebo and active treatment period. At each visit, casual blood pressure (BP) and heart rate were measured and 24-hour ABPM was performed using a portable, noninvasive, fully automatic recorder. Recordings were excluded from analysis when >10% of all readings or >1 reading per hour was missing or incorrect. Trough/peak ratio was assessed in each treatment group, and the smoothness index was determined to quantify the homogeneity of the antihypertensive effect over 24 hours. Results: Forty patients (20 men and 20 women; mean age, 51 ± 7 years) were included in the study. One patient withdrew after randomization (lost at follow-up); the results are given for 39 patients. Both valsartan and irbesartan significantly lowered 24-hour, daytime, and nighttime BP values ( P < 0.001 vs placebo) without affecting the normal BP circadian profile. No significant differences in efficacy were found between the 2 drugs. Mean values for 24-hour, daytime, and nighttime heart rate, as well as the 24-hour heart rate profile, were not significantly affected by either drug. Both drugs had a trough/peak ratio >50% (valsartan, 0.65 ± 0.72 for systolic BP [SBP] and 0.62 ± 0.55 for diastolic BP [DBP]; irbesartan, 0.57 ± 0.58 for SBP and 0.69 ± 0.54 for DBP) and a similar smoothness index (valsartan, 1.26 ± 0.31 for SBP and 1.41 ± 0.17 for DBP; irbesartan, 1.32 ± 0.43 for SBP and 1.52 ± 0.43 for DBP), which suggests that their antihypertensive effect was homogeneous throughout the 24-hour period and lasted to the end of the dosing interval. Casual BP results confirmed that valsartan and irbesartan were equally effective in reducing SBP and DBP values. Conclusions: Valsartan and irbesartan are 2 ARBs with different pharmacologic properties. Valsartan is more selective for angiotensin type 1 receptors than is irbesartan; irbesartan has a longer half-life and demonstrates insurmountable antagonism. These distinct pharmacologic properties did not appear to result in different effects on the magnitude and duration of antihypertensive efficacy.

Circadian rhythm of blood pressure in renal disease.

Ambulatory blood pressure (BP) measurement has added a new dimension to the evaluation of abnormal BP in patients with various stages of renal disease. Although there is not complete consensus concerning the definition of normal values, a high prevalence of an abnormal circadian BP profile is noted in patients with essential hypertension with renal involvement (ie, microalbuminuria), in diabetic patients (particularly those with microalbuminuria or overt proteinuria), and in patients with primary chronic renal disease. Studies in diabetic patients point to an important role of both hypervolemia and disturbed autonomic innervation in the genesis of an abnormal circadian BP profile. In both patients with diabetic renal disease and patients with nondiabetic renal disease, retrospective studies suggest that an abnormal nocturnal decline in BP is associated with more rapid progression independent of 24-hour mean arterial pressure. The abnormal circadian BP profile persists in dialyzed patients, is ameliorated by long and frequent dialysis sessions, but is not completely normalized after successful renal transplantation.

Experimental heart failure in rats: effects on cardiovascular circadian rhythms and on myocardial beta-adrenergic signaling.

Patients with chronic heart failure frequently show blunted circadian blood pressure profiles. The mechanisms involved in the loss of physiological day-night variation are still unclear, but a continuously active sympathetic nervous system could play a role. The present study evaluated long-term consequences of rat heart failure on cardiovascular circadian patterns in vivo, and on density and function of cardiac beta-adrenoceptor subtypes in vitro, as a marker of cardiac adrenergic drive. Heart failure in rats was induced by coronary artery ligation leading to infarct sizes of >30% of left ventricular circumference. Blood pressure and heart rate were monitored for 10 weeks after infarction using radiotelemetry. Density and function of cardiac beta(1) and beta(2)-adrenoceptors were measured by radioligand binding and adenylyl cyclase stimulation. During the activity period at night blood pressure and heart rate were lower in rats with heart failure than in sham controls, leading to reduced night-day variation in the heart failure group. Depression of circadian rhythmicity in blood pressure was found over the whole study period, while that in heart rate occurred with a lag-time of several weeks. In failing left ventricles beta-adrenoceptors showed reduced high affinity agonist binding, a shift in the beta(1):beta(2) ratio towards the beta(2)-subtype, and decreased beta(1)-adrenergic stimulation of adenylyl cyclase. In right ventricles no differences were found between failing and control rats. The blunted nocturnal increase in blood pressure and heart rate as well as beta(1)-adrenergic desensitization were correlated with the severity of left ventricular dysfunction. Heart failure in rats leads to disturbed circadian patterns in blood pressure and heart rate, and to desensitization of cardiac beta(1)-adrenoceptors, indicating chronic sympathetic overactivity.

Altered circadian blood pressure profile in patients with active acromegaly. relationship with left ventricular mass and hormonal values

Altered circadian blood pressure profile in patients with active acromegaly. relationship with left ventricular mass and hormonal values

Poor sleep quality among hypertensive patients may cause a nondipper circadian blood pressure profile

Poor sleep quality among hypertensive patients may cause a nondipper circadian blood pressure profile

The relationship of electronically monitored physical activity to blood pressure, heart rate, and the circadian blood pressure profile

We studied how closely changes in electronically monitored physical activity are reflected in changes in blood pressure and heart rate in a group of untreated hypertensive subjects. Thirty-nine hypertensive patients (office blood pressure > 140/90 mm Hg) of mean age 57 ± 10 years (mean ± SD) wore an ambulatory blood pressure monitor and a wrist actigraph simultaneously. Both average and peak activity for 5 min before each valid blood pressure reading were determined, as was average activity for awake and sleep periods, determined by patient kept diaries. For the overall group, awake and 24-h activities were inversely correlated to age (n = 39, r = −0.42; P = 0.01 and n = 39, r = −0.38; P = 0.01, respectively). No correlation was found between group awake activity and group-average blood pressure or heart rate. For individual patients, there was marked variation in the degree of correlation between awake activity measures (both peak and average) and blood pressure and heart rate. The strongest positive correlation was between activity levels and the heart rate-pressure product. Nondipper profile hypertensives had higher sleep activity than dipper hypertensives (44 ± 28 units/min v 25 ± 20 units/min, df = 37, t = 2.12; P = 0.04), but awake activity levels were similar. The higher sleep activity remained after adjustment for age. These findings indicate that the relationship between actigraphic activity and hemodynamic parameters is highly variable and that the rate-pressure product is the strongest correlate of short-term activity. Furthermore, hypertensives with the nondipper profile have higher sleep activity than dipper hypertensives. These findings stress the need for further study into the role of day-to-day activity in determining ambulatory blood pressure and heart rate variability.

CIRCADIAN RHYTHMS IN THE RENIN-ANGIOTENSIN SYSTEM AND ADRENAL STEROIDS MAY CONTRIBUTE TO THE INVERSE BLOOD PRESSURE RHYTHM IN HYPERTENSIVE TGR(mREN-2)27 RATS

The transgenic TGR(mREN-2)27 rat is not only characterized by fulminant hypertension, but also by a disturbance in circadian blood pressure regulation, resulting in inverse circadian blood pressure profiles. The reasons for these alterations are not very well understood at present. We therefore investigated the circadian rhythms in several hormones participating in blood pressure regulation. From TGR and Sprague-Dawley (SPRD) control rats synchronized to 12h light and 12h dark (LD 12:12) blood was collected at different circadian times (07, 11, 15, 19, 23, 03, and 07 again, 5 rats per strain and time). The activities of plasma renin and converting enzyme, as well as plasma concentrations of corticosterone and aldosterone, were determined by radioimmunoassay (RIA). SPRD rats showed significant circadian rhythms in all variables except plasma renin activity, with maxima occurring during the day. TGR rats showed significant circadian rhythmicity in plasma renin activity and corticosterone and daily variation in aldosterone; angiotensin-converting enzyme (ACE) activity did not reach statistical significance. In TGR rats, 24h means in plasma renin activity and aldosterone were approximately sevenfold and fourfold higher, respectively, than in SPRD rats. Peak concentrations in corticosterone around 15h were more than two times higher in TGR rats than in SPRD rats, whereas no differences were observed during the night. It is concluded that, in TGR rats, the overall increase in plasma renin activity and aldosterone may contribute to the elevated blood pressure. The comparatively high levels in corticosterone and plasma renin activity during daytime may be involved in the inverse circadian blood pressure profiles in the transgenic animals. (Chronobiology International, 17(5), 645–658, 2000)

A classification of circadian blood pressure profiles using a cumulative chi-squared technique

Non-invasive ambulatory blood pressure monitoring has been used to assess circadian rhythms in blood pressure in a qualitative fashion. However, there are no established methods for assessing circadian changes in blood pressure in a quantitative fashion. In this study, we developed a quantitative method to evaluate the circadian rhythm based on profile analysis and a cumulative chisquare technique. This method was used to analyse the circadian blood pressure variations in 100 normotensive volunteers and 127 hypertensive patients. Three blood pressure profiles were identified for the normotensive group, while four were identified for the hypertensive group. Furthermore, there was a relationship between the discriminate blood pressure profiles and the severity of hypertension. We conclude that profile analysis of 24-h ambulatory blood pressure monitoring may be used to stratify patients with regard to the risk of complications of hypertension.

Circadian blood pressure during the early course of type 1 diabetes. Analysis of 1,011 ambulatory blood pressure recordings in 354 adolescents and young adults.

Little information is available on the early course of hypertension in type 1 diabetes. The aim of our study, therefore, was to document circadian blood pressure profiles in patients with a diabetes duration of up to 20 years and relate daytime and nighttime blood pressure to duration of diabetes, BMI, insulin therapy, and HbA1c. Ambulatory profiles of 24-h blood pressure were recorded in 354 pediatric patients with type 1 diabetes (age 14.6 +/- 4.2 years, duration of diabetes 5.6 +/- 5.0 years, follow-up for up to 9 years). A total of 1,011 profiles were available for analysis from patients not receiving antihypertensive medication. Although daytime mean systolic pressure was significantly elevated in diabetic subjects (+3.1 mmHg; P < 0.0001), daytime diastolic pressure was not different from from the height- and sex-adjusted normal range (+0.1 mmHg, NS). In contrast, both systolic and diastolic nighttime values were clearly elevated (+7.2 and +4.2 mmHg; P < 0.0001), and nocturnal dipping was reduced (P < 0.0001). Systolic blood pressure was related to overweight in all patients, while diastolic blood pressure was related to metabolic control in young adults. Blood pressure variability was significantly lower in girls compared with boys (P < 0.01). During follow-up, no increase of blood pressure was noted; however, diastolic nocturnal dipping decreased significantly (P < 0.03). Mean daytime blood pressure was significantly related to office blood pressure (r = +0.54 for systolic and r = +0.40 for diastolic pressure); however, hypertension was confirmed by ambulatory blood pressure measurement in only 32% of patients with elevated office blood pressure. During the early course of type 1 diabetes, daytime blood pressure is higher compared with that of healthy control subjects. The elevation of nocturnal values is even more pronounced and nocturnal dipping is reduced. The frequency of white-coat hypertension is high among adolescents with diabetes, and ambulatory blood pressure monitoring avoids unnecessary antihypertensive treatment.