Smoking as Cardiovascular Risk Factor in Low Cholesterol Population: The Hisayama Study

We investigated the relationship between sodium sensitivity and diurnal variation of blood pressure in outpatients with hypertension. Twenty hypertensives were maintained on both a regular sodium diet for a period of 2 weeks and a low salt (7 g/day) diet for a period of one or two weeks. Ambulatory blood pressure was recorded at thirty minute intervals for 24 hours by automatic device before and during low salt diet. Patients were classified by nocturnal fall in blood pressure. 14 patients were classified as sodium sensitive, whereas 6 were classified as non-sodium sensitive on the basis of a ≥ 0 in salt sensitive index caused by sodium restriction. Incidence of reversed dipper and non-dipper in systolic blood pressure was reduced by sodium restriction, however, dipper and extreme dipper were increased. In conclusion, the results of this study show that patients with high sodium sensitivity index have strong sodium sensitivity and non-dipper is not always changed by sodium restriction.     

Does sodium sensitivity affect nocturnal blood pressure variation in outpatients with hypertension?

We investigated the relationship between sodium sensitivity and diurnal variation of blood pressure in outpatients with hypertension. Twenty hypertensives were maintained on both a regular sodium diet for a period of 2 weeks and a low salt (7 g/day) diet for a period of one or two weeks. Ambulatory blood pressure was recorded at thirty minute intervals for 24 hours by automatic device before and during low salt diet. Patients were classified by nocturnal fall in blood pressure. 14 patients were classified as sodium sensitive, whereas 6 were classified as non-sodium sensitive on the basis of a > or = 0 in salt sensitive index caused by sodium restriction. Incidence of reversed dipper and non-dipper in systolic blood pressure was reduced by sodium restriction, however, dipper and extreme dipper were increased. In conclusion, the results of this study show that patients with high sodium sensitivity index have strong sodium sensitivity and non-dipper is not always changed by sodium restriction.     

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.     

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

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

The impact of dipper and non-dipper characteristics in the fluctuation of arterial blood pressure. A study of a population of 484 diabetic patients

Abnormal pattern of circadian blood pressure variations carries a high risk of cardiovascular complications. The aim of this study was to assess the frequency of abnormal blood pressure rhythm in diabetes and its consequences on micro and macrovascular complications. 484 diabetes mellitus patients were submitted to 24-h ambulatory blood pressure monitoring. They were divided into two groups according to the absence (non-dipper: group 1; n = 167) or presence (dipper: group 2; n = 317) of nocturnal BP reduction = 10% of daytime BP. Following data were collected and compared between these two groups: body mass index, glycated haemoglobin, urinary albumin excretion, research of retinopathy by fundoscopy, tests for presence of a macrovascular disease. There were no significant differences among the two groups in sex, body mass index, type and duration of diabetes and glycemic control. Clinical SBP and DBP did not differ from significant manner between non-dipper and dipper (140 +/- 18/81 +/- 1 versus 138 +/- 19/81 +/- 10 mmHg). Non-dipper 24-h SBP and 24-h DBP were higher than those of dipper (129 +/- 16/76 +/- 9 versus 122 +/- 15/73 +/- 8 mmHg; p < 0.001). Non-dipper were older than dipper (59.9 +/- 13 versus 55.8 +/- 15 years; p < 0.001) and there was more hypertensive patients in group 1 than in group 2 (50% versus 39%; p < 0.01). Macro- and microvascular diabetes complications were more common in non-dipper. In conclusion high blood pressure is frequently observed in diabetic patients. Its association with a diminished nocturnal BP fall could explain a higher risk of complications, especially retinopathy, nephropathy and cardiac events.     

Ambulatory blood pressure monitoring in doctors of various specialties

We compared parameters of 24-hour blood pressure (BP) monitoring during off duty free day and 24-hours on duty in male surgeons (n=76) and internists (n=53) aged 30 - 60 years. Arterial hypertension (AH) was diagnosed in 17.1 and 13.2% of surgeons and internists, respectively (p > 0.05). During on duty 24-hour BP monitoring surgeons without AH had higher nocturnal systolic and both nocturnal and diurnal diastolic BP than internists without AH. Moreover surgeons significantly more often had non-dipper type of systolic and diastolic BP (SBP and DBP) curve. In internists only mean nocturnal SBP differed between on and off duty days. Surgeons had higher levels of mean SBP and DBP, higher values of nocturnal indexes of time and SBP and DBP measurements. Percent of subjects with non-dipper 24-hour SBP and DBP rhythms during on duty day was higher among surgeons. Possibly high mortality and rate of vascular catastrophes in surgeons are to some extent related to the presence of stress induced cardiovascular phenomena described above.     

Effects of lifestyle changes and metformin on salt sensitivity and nitric oxide metabolism in obese salt-sensitive Hispanics

Salt sensitivity is associated with obesity, and increased cardiovascular morbidity and mortality. We investigated whether treatment of obesity and its associated metabolic abnormalities corrects salt sensitivity and restores impaired nitric oxide (NO) metabolism characteristic of salt sensitivity. Twenty, otherwise, healthy obese salt-sensitive subjects completed a 12-month program of caloric restriction, aerobic exercise and metformin. Two salt sensitivity tests were performed, that is at baseline and end of program. Lifestyle-metformin treatment decreased weight (9.8+/-0.3 kg), body mass index (3.9+/-0.2 kg/m(2)), waist (11.5+/-0.5 cm), systolic blood pressure (SBP) (8.6+/-0.4 mm Hg), diastolic blood pressure (DBP) (5.5+/-0.4 mm Hg), triglyceride (40+/-5 mg/dl), fasting (8.3+/-1 microIU/ml) and post-load (20+/-4 microIU/ml) insulin levels, and salt sensitivity. Going from a high-sodium ( approximately 300 mmol) to a low-sodium diet ( approximately 30 mmol of sodium/day) lowered SBP/DBP by 14.7+/-1.7/7.4+/-0.9 mm Hg at baseline and by 8.6+/-1.9/3.2+/-1.2 mm Hg after treatment (P<0.001). More importantly, blood pressure (BP) sensitivity to customary levels of dietary salt ( approximately 150 mmol of sodium/day) was abolished by the lifestyle-metformin treatment. Differences in SBP/DBP between usual and low salt averaged 11+/-1/8+/-1 mm Hg before treatment, and 3+/-1/1+/-0.5 mm Hg after treatment (P<0.001). At baseline, NO-metabolite excretion was inhibited during high salt; this impairment was corrected by the lifestyle-metformin treatment. In conclusion, acquired correctable factors play an important role in the pathogenesis of salt sensitivity associated with obesity. Correction of salt sensitivity may account for the BP lowering induced by weight reduction. Restoration of the inability to increase or sustain NO production in response to high salt could account for the correction of salt sensitivity induced by the lifestyle-metformin treatment.     

The magnitude and duration of ambulatory blood pressure reduction following acute exercise.

The purpose of this study was to observe the magnitude and duration of the ambulatory blood pressure (BP) reduction following exercise and to identify the peak intervals of BP reduction throughout the 24-h diurnal period. Subjects were 25 normo- (N = 116.7/ 78.2+/-10.0/7.2 mm Hg) and 21 hypertensive (H = 140.8/96.9+/-13.9/9.6 mm Hg) adults. Twenty-four hour ambulatory blood pressures (SBP = systolic and DBP = diastolic) were recorded following exercise (E = 50 min @ 50% VO2 max) and during a non-exercise control day (C). The 24-h pressures were compared between the E and C days for (1) duration and magnitude of the BP reduction following exercise, and for (2) the time of day for the diurnal patterns to exhibit reductions in BP. No BP differences were found for N between E and C days. Significant reductions in BP were found for 24-h average SBP (decrease 6.8 mm Hg) and DBP (decrease 4.1 mm Hg), daytime (06.00-22.00 hrs) SBP (decrease 6.9 mm Hg) and DBP (decrease 3.3 mm Hg), and sleep (22.00-06.00) SBP (decrease 5.1 mm Hg) and DBP (decrease 4.4 mm Hg) for H subjects only. H also demonstrated an 11 h reduction in SBP (chi = decrease 8.3+/-2.2 mm Hg) and 4h reduction in DBP (chi = decrease 6.0+/-1.7 mm Hg) following exercise. For the diurnal variation, the peak interval of reduction in SBP (chi = 17.0+/-2.6 mm Hg) was for 11 h; from 11.00-21.00 hrs. For DBP, a significant reduction (chi = decrease 5.7+/-0.7 mm Hg) was found for 5 h; from 11.00-15.00 h. Thus, exercise reduces both systolic and diastolic BP for a significant length of time postexercise as well as reduces pressures during the time of day that typically exhibits higher diurnal pressures.     

Determinants of blood pressure response to low-salt intake in a healthy adult population

Although the beneficial effects of lowering salt intake in hypertensive patients are widely appreciated, the impact of promoting dietary salt restriction for blood pressure (BP) reduction at the population level remains controversial. The authors used 24-hour ambulatory BP monitoring to characterize the determinants of systolic BP (SBP) response to low-salt intake in a large, relatively healthy Amish population. Patients received a high- and low-sodium diet for 6 days each, separated by a 6- to 14-day washout period. Variance component analysis was used to assess the association of several variables with SBP response to low-salt diet. Mean SBP was 0.7 ± 5.8 mm Hg and 1.3 ± 6.1 mm Hg lower on the low-salt compared with the high-salt diet during daytime (P=.008) and nighttime (P<.0001), respectively. SBP response to a low-salt diet was significantly associated with increasing age and pre-intervention SBP, in both daytime and nighttime, while the association with female sex and SBP response to cold pressor test (CPT) was significant only during nighttime. Our results suggest that salt reduction may have greater BP-lowering effects on women, older individuals, individuals with higher SBP, and individuals with higher SBP response to CPT.     

The circadian blood pressure rhythm in non-diabetic hemodialysis patients.

This study investigates the circadian blood pressure variation of non-diabetic chronic hemodialysis (HD) patients on both HD and non-HD days as well as the factors affecting diurnal BP variation. Forty-nine HD patients aged 61.8 +/- 12.9 years who were on daytime HD for 97 +/- 68 months were studied. No significant difference was found in every daytime and nighttime BP between the first (HD) and the second (non-HD) day. However, the ratio nighttime/daytime BP was significantly higher on the second day. Each BP diurnal variability pattern was classified as either Dipper (D: the ratio nighttime/daytime mean BP 0.8-0.9), non-dipper (0.9 < ND < 1.0), or inverted dipper (ID > 1.0). More than 75% of the cases were classified as ND (26 cases) or ID (11 cases). The ultrafiltration rate in D was significantly less than that in ND and ID. The difference of plasma renin activity between pre- and post-HD (dRen) was significantly higher in ID than in D and ND. The amount of dialysis (Kt/V) was found to be significantly correlated with nighttime BP fall. Ultrafiltration, dRen and Kt/V were independent factors for the abnormal BP diurnal variability. In conclusion, the decreased nocturnal BP fall seen in non-diabetic HD patients is associated with increased extracellular fluid even in the patients without overt overhydration, whereas relatively insufficient amount of dialysis (low Kt/V) may be another possible cause. The increased dRen observed only in ID patients may reflect occult cardiovascular damage or functional disturbances in aortic and carotid baroreflexes caused by arterial structural changes.     

Differences in exercise blood pressure response between dipper and non-dipper elderly patients with essential hypertension

We evaluated the circadian variation and exercise stress response patterns of blood pressure (BP) in elderly patients with essential hypertension. Ambulatory BP monitoring for 48 hours every 30 minutes, and treadmill exercise test using a Bruce protocol at PM 3 to 5 were performed in 49 untreated patients with hypertension. Mean daytime (awake), and night-time (sleeping) systolic BP (SBP) and diastolic BP (DBP) values were analyzed by reviewing the patients' diaries, and the nocturnal reduction rate (NRR) of SBP and DBP were calculated according to the following formula. NRR (%) = [(daytime mean-nighttime mean)/daytime mean] x 100. The patients were divided into two groups according to the presence (dipper, n = 25) or absence (non-dipper, n = 24) of a reduction in both SBP and DBP during the night by an average of more than 10% of the daytime BP. Mean values of SBP and DBP measured over 48 hours in the dipper and non-dipper groups were similar. Responses of SBP to dynamic exercise at 2 to 5 minutes in the non-dipper group were significantly smaller than those in the dipper group (p < 0.05). Non-dipper patients with hypertension responded to dynamic exercise stress with smaller increases in SBP than did those in the dipper group. The differences in BP responses to exercise may affect the circadian blood pressure profile in dipper and non-dipper elderly patients with essential hypertension.     

Evaluation of the activity of the autonomic nervous system in "dipper" and "non dipper" essential hypertensives. Gender differences]

OBJECTIVES: 1) To compare the autonomic nervous system activity parameters obtained from a photoplethysmographic recording in dipper and non dipper hypertensive. 2) To look for an interaction between dipper/non dipper status and gender. METHODS: Prospective study involving 245 untreated hypertensives (51 +/- 13 years, 146 men, 99 women). All of the patients underwent a 24-hour ambulatory blood pressure measurement (ABPM) as well as an echocardiography for left ventricular mass index determination (LVMI) and a photoplethysmographic recording of blood pressure (BP). Nondippers were defined as those whose nocturnal decrease in systolic BP (SBP) and/or diastolic BP (DBP) was < 10% of daytime BP. Spectral powers were obtained from the photoplethysmographic recording using a fast Fourier transform over the low frequency band (LF) and the high frequency band (HF). Baroreflex sensitivity (BRS) was evaluated by the sequences method. RESULTS: Of the 245 patients, 159 were dippers (98 men, 61 women) and 86 were non dippers (48 men and 38 women). Clinic BP was significantly higher in non dippers than in dippers (168/101 vs 161/98 mmHg; p < 0.01 for SBP and p < 0.05 for DBP) whereas daytime ABPM and LVMI were not different, whatever the gender. LF spectral powers were significantly lower in non dippers than in dippers for SBP (respectively 25 +/- 11% vs 30 +/- 13%; p < 0.01) for DBP (respectively 35 +/- 14% vs 41 +/- 15%; p < 0.01) and for HR (respectively 34 +/- 15% vs 38 +/- 15%; p = 0.03). They showed a positive correlation with the nocturnal SBP fall (r = 0.21, p < 0.001 for SBP and DBP spectral powers, r = 0.19; p < 0.005 for HR spectral power) and with the nocturnal DBP fall, too (r = 0.19; p < 0.005 for SBP spectral power, r = 0.20; p < 0.002 for DBP spectral power, r = 0.19; p < 0.005 for HR spectral power). HF spectral powers tended to be higher in non dippers than in dippers but in a non significative way. BRS was roughly the same in dippers and non dippers (7.5 +/- 2.7 vs 7.0 +/- 3.1 ms/mmHg, NS). The interaction between non dipper/dipper status and sex was non significant whatever the LF spectral power. CONCLUSIONS: 1) The greater the nocturnal BP fall, the higher the sympathetic activity indexes. 2) This relationship was found both in males and females.     

Nighttime blood pressure and nocturnal dipping are associated with daytime urinary sodium excretion in African subjects

Blood pressure (BP) follows a circadian rhythm, with 10% to 15% lower values during nighttime than during daytime. The absence of a nocturnal BP decrease (dipping) is associated with target organ damage, but the determinants of dipping are poorly understood. We assessed whether the nighttime BP and the dipping are associated with the circadian pattern of sodium excretion. Ambulatory BP and daytime and nighttime urinary electrolyte excretion were measured simultaneously in 325 individuals of African descent from 73 families. When divided into sex-specific tertiles of day:night ratios of urinary sodium excretion rate, subjects in tertile 1 (with the lowest ratio) were 6.5 years older and had a 9.8-mm Hg higher nighttime systolic BP (SBP) and a 23% lower SBP dipping (expressed in percentage of day value) compared with subjects in tertile 3 (P for trend <0.01). After adjustment for age, the SBP difference across tertiles decreased to 5.4 mm Hg (P=0.002), and the SBP dipping difference decreased to 17% (P=0.05). A similar trend across tertiles was found with diastolic BP. In multivariate analyses, daytime urinary sodium and potassium concentrations were independently associated with nighttime SBP and SBP dipping (P<0.05 for each). These data, based on a large number of subjects, suggest that the capacity to excrete sodium during daytime is a significant determinant of nocturnal BP and dipping. This observation may help us to understand the pathophysiology and clinical consequences of nighttime BP and to develop therapeutic strategies to normalize the dipping profile in hypertensive patients.     

Ambulatory blood pressure and neuroendocrine control after diet-assisted gastric restrictive surgery

BACKGROUND: Long-term weight control after conventional diet is disappointing but may be improved when diet is assisted by gastric restrictive surgery (GRS). OBJECTIVE: To determine the effects of GRS on ambulatory blood pressure (ABP) and neuroendocrine BP control in 28 morbidly obese subjects. METHODS: A BP and heart rate were recorded every 10 min for 25 h before and 4 months after GRS. Effects of marked reductions in body weight on the renin-angiotensinaldosterone system, on plasma insulin and on sympathetic activity were also determined. RESULTS: Body mass index decreased from 43 +/- 1 to 34 +/- 1 kg/m2 and systolic (S) BP decreased by 7 +/- 2 mmHg during daytime (P=0.01) and by 8 +/- 3 mmHg during the night (P=0.02). Pulse pressure, a marker of reduced arterial compliance, decreased by 5 +/- 1 mmHg throughout the 24 h period (P < 0.001). Diastolic BP remained unchanged. Heart rate decreased more during the night (-13 +/- 2 bpm, P<0.0001) than during daytime (-5 +/- 2 bpm, P=0.03). Reductions in SBP were largest in subjects with highest initial BP values (r = -0.63, P<0.001) but were unrelated to weight loss. GRS decreased fasting glycaemia, plasma insulin, plasma C peptide and 24 h urine sodium (n=20) and noradrenaline (n=19) excretion (P<0.01). CONCLUSIONS: Diet-assisted GRS favourably affects neuroendocrine BP control in obese patients. Reductions in sodium intake, insulin levels and sympathetic tone combined with possible improvements in arterial compliance induce persistent 24 h reductions in SBP and pulse BP. Reductions in BP are largest in subjects with highest initial BP values and are unrelated to the amount of weight loss, thereby emphasizing the importance of even moderate reductions in weight on BP control.     

Reproducibility of blood pressure variability, white-coat effect and dipping pattern in untreated, uncomplicated and newly diagnosed essential hypertension

OBJECTIVE: To investigate the reproducibility of blood pressure (BP) variability, white-coat effect (WCE) and nocturnal dipping pattern in untreated patients with uncomplicated essential hypertension using 24-hour ambulatory BP monitoring (ABPM). METHODS: Seventy-five newly diagnosed, untreated essential hypertensive subjects (54 men, 21 women 47.6 +/- 9.3 years) were recruited for the study based on conventional measured BP from a total of 180 patients referred for ABPM. Of these, 65 patients underwent repeated ABPM after 4 weeks observation without treatment. Reproducibility of BP, nocturnal dipping pattern, WCE and BP variability were assessed using different methods. RESULTS: The average 24-hour BP (140.8 +/- 11.9/91.8 +/- 6.4 vs. 140.5 +/- 14.5/90.7 +/- 7.6 mmHg, ns) or PP (49.6 +/- 10.8 vs. 49.8 +/- 9.8 mmHg, ns) did not change, nor did daytime BP or PP. The WCE diminished significantly during the observation period (reduction in SBP WCE delta8.2 +/- 12.5 mmHg, p < 0.0001, in DBP WCE, delta3.3 +/- 9.2 mmHg, p = 0.008 and in PP WCE delta4.8 +/- 11.2 mmHg, p = 0.002). Variability in SBP, DBP and PP decreased consistently and significantly during the observation period. The nocturnal dipping pattern was unchanged in 82% of the patients. In 12% non-dipping pattern was converted to dipping pattern after repeated measurement. CONCLUSION: Average ABPs are highly reproducible in patients with uncomplicated essential hypertension of limited duration. Similarly, nocturnal dipping pattern reproduced satisfactorily. These measures have important clinical applicability. The white-coat effect as well as variability are greatly attenuated during repeated measurements, and these measures may thus be of less utility in clinical practice.     

Treatment of non-dipper hypertension with bedtime administration of valsartan

BACKGROUND: Previous results have indicated that valsartan administration at bedtime, as opposed to upon wakening, may improve the diurnal: nocturnal ratio of blood pressure without loss in 24-h coverage and efficacy. OBJECTIVES: To investigate the administration time-dependent antihypertensive efficacy of valsartan in non-dipper patients. METHODS: We studied 148 non-dipper patients with grade 1-2 essential hypertension, aged 53.0+/-12.6 years, who were randomly assigned to receive valsartan (160 mg/day) as a monotherapy either on awakening or at bedtime. Blood pressure was measured every 20 min during the day and every 30 min at night for 48 consecutive hours before and after 3 months of treatment. Physical activity was simultaneously monitored every minute by wrist actigraphy to accurately calculate the diurnal and nocturnal means of blood pressure on a per subject basis. RESULTS: The significant blood pressure reduction after 3 months of valsartan (P<0.001) was similar for both treatment times (13.1 and 8.5 mmHg reduction in the 24-h mean of systolic and diastolic blood pressure with morning administration; 14.7 and 10.3 mmHg with bedtime administration; P>0.126 for treatment-time effect). The diurnal: nocturnal ratio of blood pressure was significantly increased only when valsartan was administered before bedtime, which resulted in 75% of the patients in this group reverting to dippers, a significant increase in the percentage of patients with controlled blood pressure over 24 h, and a reduction in urinary albumin excretion. CONCLUSIONS: In non-dipper hypertensive patients, dosing time with valsartan should be chosen at bedtime, for improved efficacy during the nocturnal resting hours, as well as the potential associated reduction in cardiovascular risk.     

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

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

Is the nocturnal fall in blood pressure reduced in essential hypertensive patients with metabolic syndrome?

OBJECTIVE: The aim of this study was to examine whether an impaired reduction in nocturnal blood pressure (BP), defined on the basis of two periods of ambulatory BP monitoring (ABPM), is present in hypertensive patients with metabolic syndrome, as defined by the NCEP criteria. METHODS: 460 grade 1 and 2 untreated essential hypertensives (mean age 45.9 +/- 11.9 years) referred for the first time to our outpatient hospital clinic underwent the following procedures: 1) medical history and physical examination; 2) repeated clinic BP measurements; 3) routine examinations; 4) ABPM over two 24-hour periods within 4 weeks. Metabolic syndrome was defined as at least three of the following alterations: increased waist circumference, increased triglycerides, decreased HDL-cholesterol, increased BP, or high fasting glucose. Nocturnal dipping was defined as a night-time reduction in average SBP and DBP >10% compared to average daytime values. RESULTS: The 135 patients with metabolic syndrome (group I) were similar for age, gender and known duration of hypertension to the 325 patients without it (group II). There were no significant differences between the two groups in average 48-hour, daytime, night-time SBP/DBP values and the percentage nocturnal SBP and DBP decrease (-17.7 / -15.7 vs. -18.4 / -16.2, p = ns). A reproducible nocturnal dipping (decrease in BP >10% from mean daytime in both ABPM periods) and non-dipping profile (decrease in BP < or =10% in both ABPM periods) was found in 74 (54.8%) and 29 (21.4%) in group I and in 169 (52.1%) and 73 (22.4%) in group II, respectively (p = ns); 32 patients (23.7%) in group I and 83 patients (25.5%) in group II had a variable dipping profile (p = ns). CONCLUSIONS: This study shows that no significant difference exists in nocturnal BP patterns, assessed by two ABPMs, in untreated essential hypertensive patients with metabolic syndrome compared to those without it.     

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.     

Moderate sodium restriction enhances the pressor response to hyperlipidemia in obese,hypertensive patients

The effect of dietary sodium restriction on insulin, lipids, and blood pressure has been controversial. Evidence suggests that adverse short-term effects in response to very low-salt diets do not persist long-term with modest sodium restriction. In this study, the effects of modest dietary sodium restriction (60 and 120 mmol sodium) were measured for 3 weeks in 12 lean normotensives and 10 obese hypertensives. Blood pressure, plasma lipids, and the pressor response to an infusion of Intralipid and heparin were obtained. In contrast to previous reports concerning very low-salt diets, obese hypertensives did not manifest a pressor response or an adverse lipid effect with moderate salt restriction. Obese hypertensives were not more salt-sensitive than lean normotensives and did not manifest a different hemodynamic response to 4-hour infusion of Intralipid and heparin while on the 120-mmol/day salt diet. During the 60-mmol/day salt diet, however, plasma triglycerides increased more in obese than in lean volunteers during the Intralipid and heparin infusion (398+/-38 vs. 264+/-18 mg/dL; p<0.05), and there were greater increases in mean blood pressure (12+/-2 vs. 7+/-2 mm Hg; p<0.05) and systemic vascular resistance (111+/-38 vs. 225+/-44 dyne.sec.cm-5) as well as a larger decrease in small artery compliance (22.5+/-0.6 vs. 20.4+/-0.6 mL/mm Hg x 100; p<0.05). These data suggest that modest dietary sodium restriction in obese hypertensives does not adversely affect baseline blood pressure or lipids, but it does magnify their adverse lipid and hemodynamic response to fat loading.