Nycthemeral blood pressure monitoring in the diagnosis of borderline arterial hypertension in young adults

PURPOSE: Evaluating Blood Pressure Monitoring contribution at rest to the diagnosis and pathophysiology of borderline (BL) hypertension in the twenties. METHOD: a nycthemeral blood pressure recording each 15 minute has been performed during the 48 first hours of hospitalisation on two groups of white twenties males with a Dinamap: 143 Controls. Mean age: 21.1 +/- 2 yrs, mean height: 177 +/- 7 cm, mean weight: 71 +/- 11 kg; 104 BL hypertensive patients. Mean age: 21 +/- 2 yrs, mean height: 178 +/- 7 cm, mean weight: 78 +/- 12 kg. Mean BP recording levels are smaller than casual measurements in two groups: Controls (Casual BP: 125/71, BP recording on 24 hours: 117/60, day time: 121/63, nighttime: 110/54 mmHg). BL hypertensives (Casual BP: 144/83, BP recording on 24 h: 132/69, daytime: 137/73, nighttime: 121/60 mmHg). Nycthemeral BP variability measured by the standard deviation of mean pressure is not different in two groups for systolic variability, it significantly differs for diastolic variability (BL: 7.6/Controls: 5.5, p less than 0.01). Correlations between casual BP and diurnal records are stronger in controls than in BL patients showing a lower predictive value of clinical assessment in BL patients. Though the same heart rate at sleep, BP is significantly higher in BL than in controls. It probably means that factors different from sympathetic activity are involved in pathophysiology of borderline hypertension. The whole measurement study on 24 hours of two groups show an important overlap (the 65th percentile in BL systolic BP correspond with the 95th of controls, the 74th percentile in BL diastolic BP correspond with the 95th in controls). That make difficult the recording evaluation for a given patient.     

Ambulatory blood pressure monitoring and borderline hypertension.

Blood pressure fluctuates during daytime hours in response to changes in activities and to daily life stressors. Lifestyle factors may influence changes in blood pressure through a modulation of the sympathetic nervous system s activity, which is often elevated in subjects with borderline hypertension. In the HARVEST smoking, consumption of coffee, intake of alcohol, physical activity habits, and use of oral contraceptives influenced daytime blood pressure to a greater extent than did office blood pressure and had an effect on sympathetic tone (determined by measuring levels of urinary catecholamines). Subjects with borderline hypertension have a greater than normal risk of cardiovascular morbidity and mortality, but few data on the relation between ambulatory blood pressure and hypertensive complications during the early stage of hypertension are available. In the HARVEST the impact of ambulatory blood pressure on the walls of the left ventricle and on left ventricular mass in women was remarkable, whereas it was weak for men. The assessment of left ventricular systolic function confirmed that ejective performance in many young borderline hypertensive subjects is greater than normal. However, in 9.2% of the HARVEST participants left ventricular contractility evaluated by midwall measurement was found to be depressed. Although the prevalence of microalbuminuria (rate of excretion of urinary albumin > or = 30mg/24h) appeared to be low (6.1%), rate of excretion of albumin was highly statistically significantly correlated to 24h blood pressure. Ambulatory blood pressure monitoring is useful for identifying those borderline hypertensive subjects for whom antihypertensive treatment should be started.     

Ambulatory blood pressure in the young adult with hypertension history during childhood]

The tendency of subjects to maintain their relative position within the distribution of blood pressure (BP) has been defined as "tracking". Regarding this phenomenon, the purpose of the study was to evaluate the interest of ambulatory BP monitoring (ABPM) in the assessment of arterial hypertension in young adults (YA) with childhood hypertension history (CHH). 52 subjects, 20.1 +/- 2.4 years old, 26 men, 26 women issued from a cohort of 150 children with high BP levels (greater than 97.5 th percentile) during their infancy (school check-up), were included in the study. An ABPM was performed with space-labs system 90202 from 8 a.m. to 6 p.m., measurements every 15 minutes (37.6 +/- 7.4 readings). Left ventricular mass index (LVMI) was determined with echocardiography, (Penn convention). Office BP, measured with mercury apparatus in lying and standing position, was respectively, 131.0 +/- 14.6/81.9 +/- 9.7 and 130.1 +/- 14/86.6 +/- 9.9. According to JNC 1988, this casual BP identified 40 normotensives (NT), 9 borderlines (BL) and 5 hypertensives (HT); 10 of them had a "high normal" diastolic BP (85-90 mmHg) ABP recordings of the study group were compared to day-time reference values of NT. Three subgroups are individualized: G1 NT, G2 HT, G3 BL. [table; see text] *p: less than 0.001; p: less than 0.01. Wall thickness (WTh) and LVMI were significantly higher in hypertensives (G2 + G3) than in normotensives (G1): [table; see text] There was a significant correlation between LVMI and mean systolic ABP (p less than 0.01: r = 0.44), but not with office SBP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Baroreflex control of muscle sympathetic nerve activity in borderline hypertension

Patients with borderline hypertension have exaggerated vascular responses to orthostatic stress produced by tilt or lower body negative pressure (LBNP). It has been suggested that 1) in the supine position, these patients have augmented activity of cardiopulmonary baroreceptors that exerts an increased restraint on sympathetic vasoconstrictor tone; 2) withdrawal of this augmented inhibitory baroreceptor activity during orthostatic stress elicits augmented reflex sympathetic vasoconstrictor outflow; and 3) augmented cardiopulmonary baroreceptor activity may be secondary to impaired arterial baroreflex mechanisms. To test these hypotheses, we recorded muscle sympathetic nerve activity from the peroneal nerve in seven borderline hypertensive subjects and seven age-, sex-, and weight-matched normotensive subjects during three levels of nonhypotensive LBNP and infusions of phenylephrine and nitroprusside. During LBNP, reductions of central venous pressure were similar in borderline hypertensive and normotensive subjects, and arterial pressure and heart rate values were unchanged. Increases of sympathetic nerve activity, however, were significantly greater in borderline hypertensive than in normotensive subjects at each level of LBNP, indicating an augmented gain of the cardiopulmonary baroreflex. To determine whether this augmentation is related to impairment of arterial baroreflexes, we measured changes of sympathetic nerve activity during increases and decreases of arterial pressure produced with infusions of intravenous phenylephrine and nitroprusside. Central venous pressure was held at control levels by LBNP during phenylephrine and saline infusion during nitroprusside. Changes of sympathetic nerve activity during alterations of arterial pressure were similar in borderline hypertensive and normotensive subjects. These data show that cardiopulmonary baroreflex control of SNA is augmented in borderline hypertensive subjects and that this augmentation does not result from an attenuation of the arterial baroreflex.     

临界性高血压患者冠状动脉血流储备功能的研究

目的 :了解无症状临界性高血压患者是否有冠状动脉功能异常。方法 :经食管超声心动描记术研究 2 0例正常人 (正常对照组 )及 17例无症状临界性高血压患者 (临界性高血压组 )的冠状动脉血流储备 (CFR)。以潘生丁静脉注射后和静息时舒张期的最大血流速度比率 (D/R PDV)和收缩期最大血流速度比率 (D/R PSV )作为CFR指标。结果 :1两组受检者静息时的 PDV无显著性差异〔(43± 10 ) m m/s∶ (46± 8) mm /s,P >0 .0 5〕;2静脉注射潘生丁后临界性高血压组的 D/R PDV、D/R PSV较正常对照组明显减少 ,两组之间有显著性差异 (D/RPDV:2 .2 5± 0 .36∶ 2 .86± 0 .42 ,D/R PSV:2 .0 0± 0 .2 6∶ 2 .5 6± 0 .41,P<0 .0 5 )。结论 :无症状临界性高血压患者 CFR能力降低。     

Circadian blood pressure variations in young and in older patients

Elevated blood pressure in the elderly is common despite they are normotensive. This "pseudo-hypertension" is probably a white-coat effect or depends on the increased arterial stiffness. Ambulant blood-pressure monitoring (by portable automated oscillometry) provides a reasonable accurate estimate of the blood pressure level throughout the day and better predicts cardiac end-organ damage. In normotensive elderly volunteers the systolic arterial pressure and the blood pressure amplitude was higher than in young normotensive subjects. The circadian profile of the two groups was comparable. Specific habits like an afternoon nap significantly influenced the blood pressure of the elderly. The blood pressure variability in geriatric hypertensives with antihypertensive therapy was smaller than in normotensive elderly controls. Any severe blood-pressure nadir at night was not registered in both groups. 24-hour ambulatory blood pressure monitoring is a careful method and should be used to determine the need and the effectiveness of antihypertensive treatment in the elderly.     

Evaluation of borderline arterial hypertension in young adults by ambulatory arterial pressure measurements

Casual measurements of blood pressure (BP) with a mercury manometer and ambulatory BP recordings with the Spacelabs apparatus at the rate of one measurement every 15 minutes during 24 hours were carried out in two groups of young male adults of the same age. One group consisted of 105 normotensive controls (age 21.2 +/- 1.5 years, weight 69 +/- 8 kg, height 177 +/- 8 cm, casual BP 129/75 mmHg). The other group comprised 104 subjects with borderline hypertension (BHT) as defined by the WHO criteria (age 21.2 +/- 1.6 years, weight 74 +/- 12 kg, height 177 +/- 7 cm, casual BP 148/83 mmHg). Mean levels of recorded BP in controls were: 24 hours 122/70 mmHg, active periods (9 a.m. to 8.30 p.m.) 128/74 mmHg, night 111/64 mmHg. The corresponding values in BHT subjects were: 24 hours 132/83 mmHg, active periods 137/79 mmHg, night 118/67 mmHg. There was no difference between mean casual BP measurements and mean BP recordings during periods of activity in controls, whereas BP recordings during periods of activity were lower in BHT subjects. Results of the two measurement methods showed important individual variations. BP variability (variation coefficient = VC) in BHT subjects was more pronounced in respect of systolic arterial pressure than in controls: Syst VC 24 h: Contr. 12 p. 100, BHT 13 p. 100, p less than 0.001; Diast VC 24 h: Contr. 17 p. 100, BHT 18 p. 100, p less than 0.05. In both populations there was no difference in VC between night and day.(ABSTRACT TRUNCATED AT 250 WORDS)     

Baroreflex sensitivity and the blood pressure response to beta-blockade

The objective of this analysis was to determine whether changes in baroreflex sensitivity (BRS) within 35 hypertensive patients (25 M, 10 F, mean age 47 years) treated with beta-blockade as monotherapy relate to reductions in ambulatory blood pressure (BP) or its variability. BP was recorded intra-arterially directly from the brachial artery before and during submaximal exercise. BRS was determined by the phenylephrine injection technique. MAP and its variability were determined for the awake period of 24-h BP monitoring. Subjects were randomised to one of atenolol, metoprolol, pindolol, or propranolol, and restudied after a mean of 5 months. Beta-blockade increased BRS in 24 patients and decreased BRS in 11. BRS increased from 6.53+/-4.94 to 9.40+/-8.62 ms/mm Hg (mean +/- s.d.) (P<0.01). Waking ambulatory MAP decreased from 125.8+/-15.8 to 106.4+/-16.2 mm Hg (P<0.0001), but its variability did not change. Higher BRS after chronic beta-blockade was associated with a decrease in waking ambulatory MAP (r = -0.55, P<0.001), but not with its variability (r = -0.08). Beta-blockade attenuated the pressor response to exercise, but there was a positive relationship between the effect of beta-blockade on BRS, and on the rise in systolic BP during bicycling (r = 0.63; P<0.001). Any dampening effect of beta-blockade on BP variability at rest in hypertensive patients with the greatest increase in BRS may be offset by increased pressor responses to physical activity such as exercise. Consequently, BP variability is unaffected, even though reductions in ambulatory BP during chronic beta-blockade are inversely related to changes in BRS. BP responses to beta-blockade may be a function of the action of this class of drugs on BRS. However, there is considerable variation, between subjects, in their effect on BRS. This may have implications for other conditions, such as dilated cardiomyopathy, or following myocardial infarction, in which improvement in BRS is one mechanism by which beta-adrenoceptor blockade could improve survival.     

Carotid baroreflex function in young men with borderline blood pressure elevation.

Carotid baroreflex function was assessed in 10 normotensive young men and 20 age-matched subjects with borderline hypertension (successive blood pressures above and below 140/90 mm Hg) by measuring sinus node responses to brief neck suction. Subjects with borderline hypertension were divided into two equal groups according to their average systolic arterial pressures. Baroreflex responses were reset to function at higher pressure levels than normal in subjects with mild borderline hypertension, but reflex sensitivity was normal. Responses were also reset in subjects with more severe borderline hypertension, but reflex was subnormal. The results suggest that a gradation of baroreflex responsiveness exists among patients classified as having borderline hypertension: Subnormal responsiveness was found in those subjects whose resting average systolic arterial pressure was greater than or equal to 140 mm Hg.     

Pathogenesis of borderline arterial hypertension in young persons

A total of 1000 students were screened, and borderline arterial, hypertension (BAH) was found in 152 of those. The investigation of microcirculation (by conjunctive biomicroscopy), central hemodynamics and physical stress tolerance showed increased minute blood volume in the absence of adequate arteriole dilatation to be the primary factor in BAH pathogenesis. Physical stress tolerance was similar in BAH and normotensive subjects. BAH subjects showed a specific pattern of cardiovascular response to muscular work.     

Role of ambulatory blood pressure monitoring in the assessment and prognosis of patients with borderline hypertension

The role of ambulatory blood pressure (ABP) monitoring in the assessment of mild/borderline hypertension (BHT) is unclear. The aim of this study was to test the hypothesis that measurement of ABP in borderline hypertensives differentiates patients with true mild hypertension from those with isolated clinic hypertension (raised office BP but normal ABP) and that a raised ABP identifies a subgroup who are more likely to progress to and require treatment over 1 year. Consecutive untreated patients with BHT (n = 127, 44 +/- 13 years, 45% male) were divided into two groups according to awake ABP: Group 1 (normal ABP < or = 136/86, n = 48), and Group 2 (abnormal ABP > 136/86, n = 79). Left ventricular mass index (LVMI) was greater (116 +/- 30 vs 101 +/- 25 g/m2, p < 0.01) and the proportion of patients with an increased LVMI was significantly higher (34% vs 17%, p = 0.05) in Group 2. During 1 year of follow-up, significantly more patients in Group 2 (34%) required antihypertensive treatment compared with Group 1 (8%, p = 0.01). ABP monitoring usefully discriminates between patients with true BHT and those with isolated clinic hypertension. An elevated awake ABP on initial assessment is associated with a higher LVMI and a greater likelihood of progression to moderate hypertension requiring pharmacological treatment.     

Exercise response in young women with borderline hypertension

We compared the response to dynamic exercise in 157 females (mean age 19 +/- 3 years) with borderline hypertension (BH) to findings in 105 normotensive controls. Near-maximal physical working capacity was 90 +/- 17 W in females with BH and 71 +/- 23 W for the controls (p less than 0.001). Mean heart rate, systolic and diastolic blood pressure, and pulse pressure levels both at rest and at exercise were significantly higher in BH patients (p less than 0.001 for all). Mean change between rest and exercise for all the above parameters was not significantly different among BH patients compared with controls. Nonspecific ST-T changes at rest (p less than 0.001) and exercise (p less than 0.005) were more common and mean corrected QT interval was significantly longer (p less than 0.001) in BH patients. The parallel exercise response that we found in BH and normotensives would not appear to substantiate the view that ergometry is particularly useful as a modality for diagnosing hypertension in young females.     

Plasma homocysteine concentration and blood pressure in young adult African Americans

BackgroundAn association of plasma homocysteine concentration ([Hcy]) with cardiovascular events has been described, but the role of [Hcy] in the early phase of cardiovascular disease is uncertain. The purpose of this study was to determine whether [Hcy] is related to blood pressure (BP) or other risk factors in African Americans, a population at high risk for cardiovascular disease.MethodsThis cross-sectional study was conducted on a sample of premenopausal African American women (N = 119) and men (N = 56), 30 to 40 years of age. Each subject was classified as normotensive or hypertensive. Fasting blood samples were obtained for serum lipids, insulin, glucose, Hcy, folate, and B-12, followed by an oral glucose tolerance test.ResultsMean [Hcy] was higher in hypertensives compared to normotensives, but the difference was statistically significant only in women (10.5 ± 5.3 v 8.2 ± 2.3; P < .01). In women, the simple correlation analysis revealed a statistically significant relationship of [Hcy] with systolic BP (r = 0.22, P = .02) and diastolic BP (r = 0.240, P = .01). However, after adjusting for age and body mass index (BMI), the correlations were attenuated and no longer significant. There was a significant inverse relationship of [Hcy] with plasma folate (r = −0.35, P < .001) and B-12 (r = −0.29, P < .01) in women.ConclusionsAlthough the simple correlation coefficient suggests a significant relationship of [Hcy] with BP in women, this relationship was no longer statistically significant after adjustment for age and BMI. The significant inverse relationship of plasma folate and B-12 with [Hcy] suggest that diet factors may affect the crude [Hcy]–BP relationship identified in this sample.     

The hemodynamics in young patients with borderline hypertension

Hemodynamics in supine position were studied echocardiographically in 56 young patients with borderline hypertension and 56 age-matched normotensive subjects. In hypertensive patients, the cardiac index (CI) did not increase, but the total peripheral resistance (TPR) increased significantly (p less than 0.005). The hypertensive patients were classified into 2 groups, according to the level of the CI. In patients in group A ("normal" CI), the CI, heart rate and the mean circumferential fiber shortening velocity (mVCF) were normal, but the TPR was increased significantly. In patients in group B ("high" CI), the CI, heart rate and the mVCF increased significantly (hyperkinetic state), but the TPR was normal. Plasma renin activity (PRA) was significantly higher in patients in group B than the normal subjects, but the level of PRA in patients in group A was normal. These findings support the hypothesis that sympathetic nervous activity increases in patients in group B, but not in those in group A. Therefore, this study provides evidence that the TPR is abnormal in patients with borderline hypertension, and an impaired neurogenic activity seems to be important in the early stage of hypertension, as in borderline hypertension associated with a hyperkinetic circulatory state (group B).     

Twenty-four hour automatic recording of blood pressure and cardiac rhythm in patients with borderline hypertension

The aim of the study was to evaluate the usefulness of 24-hour automatic recording of blood pressure and cardiac rhythm in patients with borderline hypertension. The study was performed in 50 patients aged 38.8 +/- 13.1 using the Del Mar Avionics device. Mean time of recordings was 21.3 hours, and the mean number of blood pressure measurements per one patient was 52.4. Great fluctuations of systolic blood pressure (from 92.1 +/- 12.6 to 191 +/- 37.0 mm Hg) and diastolic one (from 57.3 +/- 11.4 to 118.9 +/- 13.8 mm Hg) were observed. Mean systolic blood pressure (125.6 +/- 10.6 mm Hg) was significantly lower than the mean value of last three ambulatory measurements (141.9 +/- 9.8; p less than 0.001). Also mean diastolic pressure was lower than that obtained in the out patient clinic (84.7 +/- 9.7 vs 91.9 +/- 3.2 mm Hg; p less than 0.001). Mean heart rate during the day was 86.2 +/- 10.7 and at night 69.7 +/- 10.5 beats per minute. Ventricular and/or supraventricular cardiac arrhythmias were observed in 14 (28%) of examined patients. Results of the study indicate, that 24-hour automatic blood pressure recording is the valuable method, affording possibilities for more precise estimation of blood pressure and its 24-hour fluctuations in patients with borderline hypertension.     

Data on the echocardiogram, pressure profile during exertion, and ambulatory blood pressure measurements in borderline arterial hypertension

Comparative study is performed between echocardiographic measurements (TM), exercise test blood pressure profile (ETP) and ambulatory blood pressure load (BPL) in 26 borderline hypertensive subjects (19 males, 7 females). An abnormal ETP is found for 15 subjects (57 p. 100), an abnormal BPL for 10 subjects (38 p. 100). The diastolic interventricular septum thickness (IVS) and the diastolic posterior wall thickness (PWT) are abnormal (greater than 11 mm) for 6 and 3 subjects. Patient with pathologic ETP or/and BPL have greater IVS and PWT than other subjects (p less than 0,001). A good correlation is found between individual activity systolic blood pressure or 24 hours systolic blood pressure means values and PWT, IVS or left ventricular mass. These 3 examinations lead to a better assessment of cardiovascular strain and allow a better diagnosis and therapeutic approach in borderline hypertensive patients.     

Diurnal variations of cardiac rhythm,arterial pressure,and urinary catecholamines in borderline and established essential hypertension

Ambulatory continuous ECG and arterial pressure (BP) were recorded simultaneously (Delmar Avionics Pressurometer II) for 24 hours in 13 age-matched normotensive subjects, 11 patients with borderline hypertension (HBP), and in 10 patients with uncomplicated established essential HBP. Urinary concentrations of epinephrine, norepinephrine, and dopamine were simultaneously collected over four successive 4-hour periods and one 8-hour period. Prevalence and total number of ventricular and supraventricular ectopic beats was low and not affected by arterial BP. Twenty-four-hour heart rate (HR) and 4-hourly excretion of epinephrine, norepinephrine, and dopamine were comparable between normotensive and HBP persons and no correlation between urinary catecholamines and arterial BP (systolic, diastolic, or mean), HR, or prevalence of ectopic beats was found in any of the three groups or in the total study population. We conclude that HBP patients without ECG evidence of left ventricular hypertrophy do not have a higher prevalence of supraventricular or ventricular ectopic beats. Urinary catecholamines are not related to circadian fluctuations or variability in arterial BP, HR, or prevalence of ectopic beats.     

Air jet noise exposure rapidly increases blood pressure in young borderline hypertensive rats.

The present study tested the hypothesis that air jet noise exposure elicits sympathetically-mediated increases in the blood pressure of weaning-aged borderline hypertensive rats (BHR). BHR were the F1 offspring of spontaneously hypertensive female rats and male Wistar-Kyoto rats. Beginning at weaning (4 weeks of age), restrained BHR were exposed to air jet noise (30-120 s pulses of 120 dB) for 2 h/day, 5 days per week. Controls were restrained but did not receive air jet noise exposure. After only 1 week of air jet exposure, the systolic blood pressure (SBP) levels of the noise-exposed rats were increased significantly above those of restrained controls. Measures of mean arterial pressure (MAP) made in the home cage after 2 weeks of noise exposure confirmed the increased SBP. Ten weeks of air jet noise exposure increased MAP compared with restrained controls (144 +/- 4 versus 128 +/- 4 mmHg), with both SBP and diastolic blood pressure (DBP) being significantly increased. Baroreceptor sensitivity, assessed by bradycardic responses to graded doses of phenylephrine (0.5, 1, 2 and 4 micrograms/kg, intravenously), did not differ from restrained controls after 10 weeks of noise exposure. Autonomic (largely sympathetic) influence on home-cage blood pressure, inferred from ganglion blockade with chlorisondamine, also did not differ between groups after 10 weeks of stress. After maximal vasodilation with hydralazine, the DBP of air jet noise-exposed rats was somewhat higher than restrained controls (62 +/- 5 versus 49 +/- 3 mmHg; P = 0.08), suggesting that structural changes may have contributed to the increased MAP in air jet noise-exposed rats.(ABSTRACT TRUNCATED AT 250 WORDS)