Early 24-hour blood pressure elevation in normotensive subjects with parental hypertension

Left ventricular mass and incident out-of-office hypertension in a general population

AIM

Findings regarding the association of left ventricular mass (LVM) and new-onset hypertension are based on blood pressure measured in the office. We sought to assess the value of LVM in predicting in-office and out-of-office incident hypertension in members of the general population enrolled in the Pressioni Monitorate E Loro Associazioni study.

METHODS

The study included participants with normal office (n = 792), home (n = 714) and 24-h (n = 825) ambulatory blood pressure (ABP) at baseline evaluation who had a readable echocardiogram at entry and at the end of follow-up. Each normotensive group was divided into quartiles of LVM indexed (LVMI) to height.

RESULTS

Over a follow-up of 148 months cumulative incidence of new office, home and 24-h ABP hypertension were 35.9, 30.7 and 36.1%, respectively. In fully adjusted models (including age, sex, BMI change during follow-up, baseline serum glucose, creatinine, total cholesterol office, home and 24-h SBP and DBP). higher LVMI values (i.e. the highest vs. the lowest quartile) were independently associated with an increased risk of home [odds ratio (OR) = 2.14, 95% confidence interval (CI) 1.21-3.77, P = 0.008] and 24-h ABP hypertension (OR = 1.70, 95% CI 1.05-2.76, P = 0.03). This was not the case for new-onset office hypertension (OR = 1.61, 95% CI 0.94-2.74, P = 0.07).

CONCLUSION

Our study provides the first evidence that in normotensive individuals the magnitude of LVMI is independently associated with the risk of incident out-of-office hypertension.

Homocysteine levels in normotensive children of hypertensive parents

OBJECTIVE

There are several studies showing an association between an increase in the plasma levels of homocysteine and the pathogenesis of hypertension. In this study, we assessed normotensive children of hypertensive adult parents to determine whether there is any change in homocysteine levels prior to the onset of hypertension.

METHODS

A total of 79 normotensive children of essential hypertensive parents who were followed-up at the cardiology department and 72 healthy children of normotensive parents who presented to the department of pediatrics at our clinic with complaints such as nonspecific chest pain and innocent murmur were included in the study. The participants' complete blood count and low-density lipoprotein, high-density lipoprotein, triglyceride, total cholesterol, folic acid, vitamin B12, and homocysteine levels were noted.

RESULTS

No statistically significant differences were noted between the two groups in terms of age, gender, height, weight, body mass index, or levels of fasting lipids, folic acid, and vitamin B12 (p>0.05). Although the mean systolic and diastolic blood pressures were within the normal limits in both groups, they were significantly higher in children with a family history of hypertension than in controls (p<0.05). Similarly, homocysteine levels of children with a family history of hypertension were significantly higher than those of controls (p<0.01).

CONCLUSION

Homocysteine levels of normotensive children of hypertensive parents are elevated before they develop hypertension. Homocysteine levels may be predictive of the subsequent development of hypertension in normotensive children of hypertensive parents.

Early diastolic functional abnormalities in normotensive offspring of Nigerian hypertensives

Background

Some studies have suggested that diastolic dysfunction precedes the clinical manifestation of hypertension. Whether changes in cardiac structure and function predate the clinical manifestation of hypertension later in life is now being investigated. The aim of this study was to assess the differences in cardiac structure and function between the offspring of hypertensive and normotensive parents.

Methods

Eighty normotensive offspring of hypertensive parents (OHyp) (41 females and 39 males) and 62 normotensive offspring of normotensive parents (ONorm) (31 males and 31 females) were recruited for echocardiography.

Results

The mean age was 25.0 (5.31) and 24.3 (3.60) years in the OHyp and ONorm participants, respectively (p = 0.369). Other baseline parameters were comparable between the two groups. Septal wall thickness in systole was higher in the OHyp than the ONorm subjects [1.3 (0.35) vs 1.1 (0.25), p = 0.0173]. Indexed left ventricular mass [28.1 (7.33) vs 27.5 (7.23), p = 0.631] and relative wall thickness [(0.3 (0.10) vs 0.3 (0.90), p = 0.280] were similar in the two groups. The offspring of hypertensives had lower deceleration time [149.9 (38.89) vs 169.0 (50.08) ms, p = 0.012], prolonged duration of pulmonary A reverse flow [113.5 (70.69) vs 81.7 (38.31) ms, p = 0.024], increased myocardial isovolumic relaxation time [173.4 (47.98) vs 156.1 (46.74) ms, p = 0.033] and a lower myocardial Em [0.2 (0.05) vs 0.3 (1.38), p = 0.037] and myocardial Em/Am ratio [1.6 (0.01) vs 2.1 (0.01), p = 0.019] than the offspring of normotensives.

Conclusion

This study showed that offspring of OHyp subjects had early diastolic functional abnormalities when compared with offspring of ONorm participants. Longitudinal studies are needed to determine the implications of this finding in this African population.

Echocardiographic and tissue Doppler imaging alterations associated with spontaneous canine systemic hypertension

BACKGROUND

Feline systemic arterial hypertension (SHT) is associated with a wide spectrum of left ventricular (LV) geometric patterns as well as diastolic, and to a lesser extent, systolic myocardial dysfunction. However, little is known about SHT-related cardiac changes in dogs.

HYPOTHESIS

SHT in dogs is responsible for morphological and functional cardiac alterations.

ANIMALS

Thirty dogs with spontaneous untreated SHT and 28 age- and body weight-matched healthy dogs as controls.

METHODS

Prospective observational study. Conventional echocardiography and 2-dimensional color tissue Doppler imaging were performed in SHT dogs by trained observers and compared with controls.

RESULTS

Forty-seven percent of SHT dogs (14/30) had diffuse concentric hypertrophy. None had left atrial dilatation and 10/30 (33%) had aortic insufficiency (AoI) associated with proximal aortic dilatation. Longitudinal diastolic left ventricular free wall (LVFW) motion was altered in all SHT dogs at the base (early to late diastolic wave ratio, E/A = 0.5 ± 0.1 versus 1.3 ± 0.3 for controls, P < .0001) and the apex (E/A = 1.6 ± 1.7 versus 3.9 ± 3.1, P < .05). Longitudinal motion of the interventricular septum at the base (E/A = 0.7 ± 0.4 versus 1.1 ± 0.1, P < .01) and radial LVFW motion in the subendocardium (E/A = 0.9 ± 0.5 versus 1.6 ± 0.3, P < .01) were also altered in dogs with SHT. Longitudinal LVFW systolic velocities and gradients were also significantly decreased (P < .05) in SHT dogs.

CONCLUSION AND CLINICAL IMPORTANCE

As in SHT in cats, SHT in dogs is associated with myocardial dysfunction independently of the presence of myocardial hypertrophy. However, unlike feline SHT, it results in a homogeneous LV geometric pattern with a relatively high prevalence of AoI.

Increased left ventricular mass and diastolic dysfunction are associated with endothelial dysfunction in normotensive offspring of subjects with essential hypertension

OBJECTIVES

We aimed to investigate left ventricular (LV) morphology and function in normotensive offspring of subjects with essential hypertension (familial trait - FT), and to determine the association between LV mass and determinants of LV diastolic function and endothelium-dependent (NO-mediated) dilation of the brachial artery (BA).

MATERIALS AND METHODS

The study encompassed 76 volunteers of whom 44 were normotonics with FT aged 28-39 (mean 33) years and 32 age-matched controls without FT. LV mass and LV diastolic function was measured using conventional echocardiography and tissue Doppler imaging (TDI). LV diastolic filling properties were assessed and reported as the peak E/A wave ratio, and peak septal annular velocities (E(m) and E(m)/A(m) ratio) on TDI. Using high-resolution ultrasound, BA diameters at rest and during reactive hyperaemia (flow-mediated dilation--FMD) were measured.

RESULTS

In subjects with FT, the LV mass index was higher than in controls (92.14+/-24.02 vs 70.08+/-20.58); p<0.001). Offspring of hypertensive families had worse LV diastolic function than control subjects (lower E/A ratio, lower E(m) and E(m)/A(m) ratio; p<0.001). In subjects with FT, FMD was decreased compared with the controls (6.11+/-3.28% vs 10.20+/-2.07%; p<0.001). LV mass index and E(m)/A(m) ratio were associated with FMD (p<0.001).

CONCLUSIONS

In normotensive individuals with FT, LV morphological and functional changes were found. We demonstrated that an increase in LV mass and alterations in LV diastolic function are related to endothelial dysfunction.

Treatment of heart failure with preserved systolic function

Heart failure is a major public health problem. Heart failure with preserved systolic function (HF-PSF) is a common form, which is difficult to diagnose. Results of recent studies show that HF-PSF has a poor prognosis, with an annual survival rate similar to that of heart failure with left ventricular systolic dysfunction. Despite these findings, the therapeutic management of HF-PSF is not clearly defined. We will discuss in this review of the literature the current therapeutic management of HF-PSF, including the role of precipitating factors such as hypertension, myocardial ischaemia and supraventricular arrhythmias, and the main results of epidemiological registries and randomized controlled clinical trials in this disease. Only four large therapeutic trials have assessed the impact of different classes of drugs (digoxin, angiotensin II converting enzyme inhibitors, angiotensin II receptors type I blockers and beta-blockers) on morbidity and mortality in HF-PSF. Results of these trials are disappointing. Apart from the beta-blockers, the other three classes of drugs did not show benefit on the outcome of the disease. Moreover, the results of the beta-blocker trial are controversial as a mixed population of heart failure with and without preserved systolic function was studied. Finally, the current therapeutic management of patients with HF-PSF is still based on our pathophysiological knowledge: education, low salt diet, diuretics, slowing heart rate and controlling triggering factors. Other large randomized controlled multicenter trials, which may help us in the understanding of HF-PSP and its therapeutic management, are ongoing.

Evaluation of Insulin Resistance and Sodium Sensitivity in Normotensive Offspring of Hypertensive Individuals

BACKGROUND

Sodium sensitivity (SS) and insulin resistance (IR) might be a common link in the pathogenesis of essential hypertension. The aim of the present study is to investigate the relationship, if any, between SS and IR in a population with a family predisposition to develop hypertension.

METHODS

Twenty normotensive subjects aged 20 to 40 years with a family history of hypertension (1 or both parents hypertensive) and no other risk factor (group A) and 10 normotensive subjects aged 20 to 40 years without a family history of hypertension (group B) were enrolled. SS and IR were estimated using the euglycemic clamp technique and correlated in both groups. Blood pressure, mean blood pressure (MAP), and biochemical control were recorded.

RESULTS

The frequency of SS was equal in offspring of hypertensive subjects and the control group. Individuals with a family history of hypertension had a tendency to develop IR (45%) compared with the control group (20%). This group had a greater MAP at both salt-loading and salt-deprivation periods. Increased IR was associated with increased MAP. No significant relationship was found between SS and IR in either the entire sample or the subgroup of individuals with a family history of hypertension. Serum urea and total cholesterol levels were significantly greater in group A. Age, sex, and body mass index were not related to the presence of IR or SS in either group.

CONCLUSION

SS and IR do not relate in young normotensive adults or offspring of hypertensive parents. However, the latter may comprise a high-risk group, currently normotensive, who have an increased possibility to present or develop IR in early adolescent life. Moreover, the increased IR is related to the greater MAP in group A. Thus, they are subject to increased cardiovascular risk because of the subsequent disturbed glucose and lipid metabolism.

Left ventricular and carotid structure in untreated, uncomplicated essential hypertension: results from the Assessment Prognostic Risk Observational Survey (APROS)

The impact of hypertension on left ventricular (LV) and vascular structure and the relation of left ventricular hypertrophy (LVH) with vascular changes in untreated essential hypertensives has not been fully explored. This study investigated the prevalence of structural abnormalities of LV and carotid arteries and their determinants in a large population of untreated, uncomplicated essential hypertensive patients. The Assessment of Prognostic Risk Observational Survey was a multicentre (44 centres) prospective study including 1142 untreated hypertensives classified as low or medium cardiovascular risk on the basis of the routine diagnostic work-up recommended by the 1999 World Health Organization/International Society of Hypertension guidelines. All patients underwent ultrasound examinations of the heart and carotid arteries. LVH and carotid structural changes were diagnosed when: (1) LV mass index exceeded 125 g/m(2) in men and 110 g/m(2) in women; (2) there was at least one plaque (focal thickening>1.3 mm) in any segment of either carotid artery or a diffuse common carotid intima-media thickness (IMT) (average of IMT>/=0.8 mm) was present. Overall, 1074 patients (504 women, mean age 48.1+/-11.4 years) completed the study with ultrasonographic examinations of good technical quality. The prevalences of LVH and LV concentric remodelling in the total population were 26.8 and 10.7%, respectively. Eccentric hypertrophy was more prevalent than concentric hypertrophy (15.2 vs 11.6%). One or more carotid plaques or thickening were present in 27.4% of the patients. A stepwise increase in IM thickness occurred from the lowest values in patients with normal cardiac mass and geometry (0.68 mm) to intermediate in those with LV remodelling (0.76 mm) and eccentric LVH (0.81 mm) and to the highest level in patients with concentric LVH (0.87 mm). Patients with LV concentric remodelling and concentric LVH had a significantly greater relative carotid wall thickness than those with normal geometry and eccentric LVH (0.25 and 0.26 vs 0.18 and 0.19, respectively, P<0.01). According to a multivariate analysis age, blood glucose, systolic BP and pulse pressure were the main independent predictors of LVH, while age, systolic BP and total cholesterol were the variables with the greatest impact on IM thickening. To conclude, this study shows that: (1) altered patterns of LV structure and geometry and carotid structural changes occur in a large fraction of patients with untreated essential hypertension; (2) there is a significant association between carotid wall thickening and LVH; (3) the probability of LVH or carotid thickening is significantly greater in elderly, in patients with higher systolic BP and in patients with associated metabolic risk factors.

Radial artery compliance in response to mental stress in normotensive offspring of hypertensive parents

OBJECTIVES

Compared to normal subjects hypertensive patients have an increased radial artery isobaric distensibility, contrasting with a decrease in elasticity of large arteries and systemic compliance. To address the question whether elasticity is increased in response to long-standing elevated blood pressure or is present at an early stage of the disease, we compared normotensive offspring of hypertensive parents with control subjects. Furthermore, enhanced sympathetic response to mental stress was demonstrated in individuals predisposed to hypertension and might contribute to the elevation of blood pressure via a peripheral mechanism. Thus, an abnormal vasoconstrictive response of the radial artery to psychological stress was sought in these subjects.

DESIGN

The geometry and the elastic porperties of the radial artery were assessed in normotensive offspring of hypertensive and normotensiven parents at baseline and during mental stress.

METHODS

A high-precision echo-tracking ultrasound device was combined with photoplethysmography for continuous measurement of radial artery diameter and isobaric distensibility in 18 normotensive offspring of parents with essential hypertension and 18 control subjects under resting conditions and during a 3-minute mental stress test.

RESULTS

Baseline arterial distensibility and compliance were comparable in offspring of hypertensive and normotensive parents. During mental stress, blood pressure and heart rate increased similarly in both groups. Adrenergic activation did not alter the elastic properties of the radial artery in the individuals with a genetic predisposition to essential hypertension.

CONCLUSIONS

There was no alteration in elastic properties of the radial artery in normotensiven individuals at genetic risk to develop arterial hypertension. Furthermore, mental stress did not abnormally increase the vascular tone of this medium-sized muscular artery in these subjects as compared to controls. This indicates that functional and/or structural vascular alterations do not precede a distinct rise in blood pressure or abnormal blood pressure reactivity in subjects prone to develop essential hypertension.

Autonomic abnormalities demonstrable in young normotensive subjects who are children of hypertensive parents

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 +/- 11.7/78.5 +/- 8.6 mmHg, 137.3 +/- 12.3/74.4 +/- 7.9 mmHg, 68.5 +/- 8.4 bpm) compared to the FH- group (112.9 +/- 11.4/71.2 +/- 8.3 mmHg, 128.0 +/- 11. 8/66.5 +/- 7.4 mmHg, 62.1 +/- 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 +/- 104.5 pg/ml) than in the FH- group (169.1 +/- 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 +/- 0.3 vs 1.0 +/- 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group.

Cardiac and arterial target organ damage in adults with elevated ambulatory and normal office blood pressure

BACKGROUND

Ambulatory blood pressure may be higher or lower than clinic blood pressure. Attention has focused on "white coat hypertension" (normal ambulatory blood pressure elevated in the clinic). The converse phenomenon of high ambulatory blood pressure but normal office blood pressure-"white coat normotension"-has not been studied.

OBJECTIVE

To assess whether white coat normotension (awake ambulatory blood pressure > 134/90 mm Hg and clinic blood pressure < 140/90 mm Hg) is associated with target organ damage.

DESIGN

Cross-sectional observational study.

SETTING

University hospital hypertension center and participant work sites.

PATIENTS

295 clinically normotensive adults and 64 patients with sustained hypertension (elevated clinic and ambulatory blood pressure).

MEASUREMENTS

Target organ abnormalities were measured by echocardiography and arterial ultrasonography in 61 patients with white coat normotension, 234 with sustained normotension (normal clinic and ambulatory blood pressure), and 64 with sustained hypertension.

RESULTS

Patients with white coat normotension were older; had higher body mass indices, serum creatinine concentrations, and glucose levels; and a higher prevalence of current smokers. Left ventricular mass index and relative wall thickness were higher by 13 g/m2 (CI, 8 to 18 g/m2) and by 0.03 (CI, 0.01 to 0.04), respectively, in patients with white coat normotension compared with those who had sustained normotension. Patients with white coat normotension and those with sustained hypertension did not differ significantly for left ventricular mass index (4 g/m2 [CI, - 3 to 10 g/m2) or relative wall thickness (0.01 [CI, -0.01 to 0.03]). The prevalence of discrete atherosclerotic plaques was similar in patients with white coat normotension (17 of 61, or 28% [CI, 17% to 39%]) and those with sustained hypertension (17 of 64, or 27% [CI, 16% to 38%]), but the difference lost significance after adjustment for age.

CONCLUSIONS

White coat normotension is associated with left ventricular mass and carotid wall thickness similar to those in sustained hypertension. The association of white coat normotension with prognostically important target organ damage may partly explain the ability of high normal left ventricular mass and high normal clinic blood pressure to predict subsequent hypertension and cardiovascular events in patients with clinical normotension.

Determinants of left ventricular mass in a French male population

The aim of this analysis was to study the determinants of left ventricular mass evaluated by echocardiography. A total of 843 healthy men aged 47-61 years, who had a standard health check-up at the Centre d'Investigations Preventives et Cliniques (IPC Center), were included in the study. None of the subjects were being treated for cardiovascular disease at the time of their visit and each had a standard clinical and biological examination. The answers to a lifestyle questionnaire, weight at 20 years and family history were recorded. All subjects had an echocardiogram to evaluate left ventricular mass. Left ventricular mass values were adjusted for height using the ratio of left ventricular mass to height. Current body mass index, systolic and diastolic blood pressure, brachial circumference, triglycerides and a family history of sudden death were positively associated with this ratio (p < 0.01). Physical activity and tobacco consumption were associated with left ventricular mass. Body mass index at 20 years, variation of body mass index since that age, systolic blood pressure and family history of sudden death explain 21% of the ratio of left ventricular mass/height (body mass index at 20 years: 11.8%; variation of body mass index: 5.1%; systolic blood pressure: 2.3%; and family history of sudden death: 0.4%). The other factors explain only 1.4% of this variance and were not significantly associated with the ratio of left ventricular mass to height. Body mass index at 20 years was the strongest determinant of left ventricular mass, suggesting that left ventricular mass at middle age is in large measure determined much earlier in life. A family history of sudden death before the age of 60 years is also an important determinant of left ventricular mass, independent of obesity. These factors must be taken into account in order to prevent an increase in left ventricular mass.

Cardiovascular risk factors, angiotensin-converting enzyme gene I/D polymorphism, and left ventricular mass in systemic hypertension

We investigated the influence of major cardiovascular risk factors (smoking, hypercholesterolemia, diabetes mellitus) on the association between angiotensin-converting enzyme (ACE) gene insertion (I)/deletion (D) polymorphism and echocardiographic left ventricular mass in 225 patients with sustained hypertension, assessed by ambulatory blood pressure monitoring. When the study population was analyzed as a whole, the 3 ACE genotypes did not differ in left ventricular mass (II, 47 g/m2.7; ID, 49 g/m2.7; DD, 51 g/m2.7; p = NS). No difference was found in subjects (n = 135) in whom at least 1 major cardiovascular risk factor was present (II, 51 g/m2.7; ID, 51 g/m2.7; DD: 52 g/m2.7; p = NS). In contrast, in the absence of cardiovascular risk factors, DD subjects (n = 32) exhibited left ventricular mass index higher than non-DD (ID/II) subjects (n = 75; p <0.05). After controlling for age and sex, in the absence of cardiovascular risk factors, the risk of left ventricular hypertrophy was 3.8-fold higher in DD than in non-DD patients (odds ratio 3.8; 95% confidence interval 1.2 to 12.1, p <0.02). We conclude that in the present setting of patients with established sustained systemic hypertension, the absence of risk factors potentially affecting cardiovascular adaptation allows for the detection of a positive association between homozygosity for the D allele of the ACE gene and left ventricular hypertrophy.

The International Nifedipine GITS Study of Intervention as a Goal in Hypertension Treatment (INSIGHT) trial

Several trials have shown that antihypertensive drug treatment decreases cardiovascular morbidity and mortality rates. They have also shown, however, that the risk is not decreased to the level of nonhypertensive patients. Trials are therefore underway to determine whether the benefits achieved by older drugs, such as diuretics and beta blockers, can be enhanced by using newer classes of antihypertensive agents, such as calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor antagonists. Among these trials, the International Nifedipine GITS Study of Intervention as a Goal in Hypertension Treatment (INSIGHT) is of special interest because it is the first study to address, in a prospective fashion, the prognostic influence of antihypertensive treatment (nifedipine GITS vs a combined thiazide and potassium-sparing diuretic) in hypertensive patients with concomitant risk factors such as hypercholesterolemia, cigarette smoking, diabetes, and left ventricular hypertrophy. This article briefly describes the rationale and design of the INSIGHT trial and cites the substudies and the preliminary data available.

Increased blood pressure reactivity in children of borderline hypertensive fathers

OBJECTIVE

To evaluate the influence of heredity on blood pressure levels and reactivity in the offspring of borderline hypertensive and normotensive fathers.

PARTICIPANTS AND OUTCOME MEASURES

Borderline hypertensive and normotensive men having normotensive wives (n = 25 and 26) were identified in a population screening program. Their children aged above 12 years were invited to participate. Seventeen having a borderline hypertensive father (BHT+) and 19 with a normotensive father (NT+) were investigated. Clinical and 24 h ambulatory blood pressure was measured, as well as blood pressure reactivity to an arithmetic mental stress test.

RESULTS

The BHT+ group had a significantly higher clinical systolic blood pressure than the NT+ group (126 +/- 13 versus 115 +/- 7 mmHg, P< 0.01) but similar 24 h blood pressure levels. Systolic blood pressure variability (standard deviation of systolic blood pressure measurements each hour over 24 h) was significantly higher in the BHT+ group (18 +/- 4 versus 16 +/- 4 mmHg, P< 0.05). During mental stress test the BHT+ group had significantly higher increases in systolic and diastolic blood pressures at 4 min (NT+ 8% and 13% versus BHT+ 16% and 23% above baseline, P< 0.05) and significantly elevated DBP during the period after the stress test (NT+ 1% versus BHT+ 13% above baseline, P < 0.01).

CONCLUSION

Even a mild level of hypertensive heredity affects important markers of blood pressure regulation, such as blood pressure variability and reactivity to mental stress. This might have prognostic implications; it also points to the possible importance of these variables as early signs of a familial predisposition to hypertension.

Ambulatory systolic blood pressure is related to the deletion allele of the angiotensin I converting enzyme gene in young normotensives with parental history of hypertension

The aim of the present study was to evaluate the relationship between the angiotensin I converting enzyme (ACE) gene polymorphism and ambulatory blood pressure in young normotensive males with (n=45) and without (n=100) family history of hypertension. Twenty-four hour and daytime systolic blood pressure was significantly higher in subjects with a parental history of hypertension. Ambulatory blood pressure values did not differ significantly across ACE genotypes in subjects with negative family history of hypertension. In subjects with a parental history of hypertension, there was a significant positive association between the D allele of the ACE gene polymorphism and 24-h, daytime and nighttime systolic blood pressure. For twenty-four hour systolic blood pressure there was an average 9 mmHg difference between subjects with DD and II genotypes. The results indicate that in normotensive subjects with a genetic predisposition to hypertension, ambulatory systolic blood pressure is related to the D allele of the ACE gene.

Ambulatory-determined 24-hour blood pressure in mild hypertensives and in normotensives

Noninvasive ambulatory twenty-four-hour blood pressure (BP) monitoring was carried out in 30 normotensive subjects (16 women, 14 men), aged twenty-five to sixty years (mean thirty-eight) and in 29 mild essential hypertensive patients without target organ damage (14 women, 15 men), aged twenty-three to sixty-one years (mean thirty-nine). Hypertensive patients were not treated, and they discontinued any antihypertensive treatment at least four weeks before the study. During the daytime period (6 AM-10 PM) BP was monitored every fifteen minutes, and during the night (10 PM-6 AM), every thirty minutes. Obviously, mean twenty-four-hour systolic blood pressure (SBP) and diastolic blood pressure (DBP) were higher in hypertensive patients (P < 0.001). There was a persistent correlation in the group of mild hypertensives between successive BP hourly mean readings (r ranged from 0.61 to 0.93 for SBP and from 0.45 to 0.82 for DBP). In normotensive subjects these correlations failed in particular periods: 8 AM-9 AM, r = 0.30 for SBP and 0.45 for DBP; 1 PM-3 PM, r = 0.17-0.49 for SBP and 0.28-0.37 for DBP; 9 PM to midnight, r = 0.21-0.57 for SBP and 0.23-0.38 for DBP.

Cardiovascular characteristics in normotensive subjects with or without family history of hypertension

The aim of our study was to evaluate whether initial changes of cardiovascular structure and/or function can be detected in young normotensive subjects with (F+) and without (F-) family history of hypertension. Thirty-two subjects (19 F+, 10 males and 9 females, age range 17-32 years; 13 F-, 6 males and 7 females, age range 19-33 years) were studied. In each subject 24 hours ambulatory blood pressure monitoring, a M-mode, 2d guided and pulsed doppler echocardiogram and postischemic forearm strain gauge plethysmography were performed. The two groups of subjects did not differ for causal systolic and diastolic BP and 24 hours systolic and diastolic ambulatory monitored blood pressure. No differences in LV end-diastolic and end-systolic diameters, as well as in LV wall thickness, and in LV mass index were observed. Systolic functional parameters were also similar in the two groups. In F+ subjects peak early filling velocity was reduced in respect to F- (p < 0.01), peak late filling velocity integral was increased (p < 0.05) and the ratio of peak E/peak A integrals was decreased (p < 0.05). No difference was observed for postischemic forearm blood flow and minimal vascular resistance, taken as an index of arteriolar structural changes as well as intima-media thickness of carotid arteries. In conclusion in this study F+ and F- had similar BP values, LV mass and min VR; differences previously observed in LV mass between F+ and F- may have been due to the presence of different basal levels of BP; in F+ LV diastolic filling, although still in the normal range, shifted early toward the pattern of LV filling usually observed in hypertensive patients.

Temporal blood pressure patterns in children

Circadian rhythms of BP are established early in life. The ABPM coupled with an objective measure of activity is a powerful tool for the management of hypertension and is a sensitive tool for the dissection of the determinants of hypertension. The challenge for pediatricians in the future includes such important goals as establishing normal values for the circadian assessment of BP for a growing child, coupling of BP determinations with activity, using the ABPM to better understand BP tracking, studying the rhythms of families using the ABPM, educating the medical and lay communities of the importance of rhythmic phenomena, studying longitudinally patients with varying forms of hypertension, using the ABPM to test and optimize antihypertensive medications, and determining the proper diagnosis of hypertension in children based on end-organ damage rather than surrogate measures.

Evaluation of arterial compliance in humans

Compliance is a measure of the elastic properties of arterial vessels and is a function of blood pressure. In recent years new techniques have been developed which allow to measure arterial compliance non invasively and continuously over the range of existing blood pressure values. It has been thus possible to investigate the alterations of arterial compliance in a variety of diseases and to address the physiological factors involved in arterial compliance modulation. This article will focus on the new data available on these issues.

Plasma angiotensin II, predisposition to hypertension, and left ventricular size in healthy young adults

BACKGROUND

We studied the correlates of left ventricular mass (LVM) in 84 healthy young adults aged 16 to 24 years from the general population. Subjects were selected according to predisposition to hypertension into four groups with either high or low personal blood pressures and either high or low parental blood pressures.

METHODS AND RESULTS

LVM was measured by echocardiography, and measurements of blood pressure, heart rate, body dimensions, and plasma concentrations of components of the renin-angiotensin system were made under resting conditions. LVM was similar in individuals predisposed to hypertension (high personal and parental blood pressures) and those with contrasting predisposition (low personal and parental pressures). Regression analysis of the combined groups showed that LVM correlated closely with body size, particularly lean body mass (r=.69, P<.0001) and systolic (r=.35, P<.0001) but not diastolic blood pressure. Plasma angiotensin II (r=.39, P<.0001), renin (r=.302, P<.01), and angiotensin-converting enzyme (r=.22, P<.05) showed significant correlation with LVM. Multiple regression analysis revealed that plasma angiotensin II was the most important component of the renin-angiotensin system and that its effect was independent of systolic blood pressure and body size.

CONCLUSIONS

These findings provide evidence in humans that angiotensin II exerts a direct on myocardial size. This association may have important implications for the complications and treatment of left ventricular hypertrophy.

Increased activation of sympathetic nervous system and endothelin by mental stress in normotensive offspring of hypertensive parents

BACKGROUND

The pathogenesis of essential hypertension is still uncertain, but genetic factors and the sympathetic nervous system are likely to be involved. Sympathetic nerve activity and hormonal circulatory control mechanisms, however, are affected by blood pressure itself. Hence, early functional changes are best investigated in normotensive subjects at risk to develop hypertension, such as normotensive offspring of hypertensive parents.

METHODS AND RESULTS

Muscle sympathetic nerve activity (MSA) was measured in the peroneal nerve of 10 normotensive offspring of parents with essential hypertension and 8 offspring of normotensive parents. Measurements were performed under resting conditions, during a 10-minute period of hypoxia (12.5% O2/87.5% N2) and during a 3-minute mental stress test. The tests were separated by a 30-minute resting period. Plasma samples for determination of norepinephrine and endothelin were collected before and after the tests. Baseline values of MSA were comparable in offspring of hypertensive and normotensive parents. During hypoxia, MSA, heart rate, and norepinephrine and endothelin plasma levels increased in offspring of hypertensive and normotensive parents to a comparable degree, whereas no significant changes in blood pressure and plasma norepinephrine levels were observed in either group. During mental stress, MSA and plasma norepinephrine and endothelin increased only in offspring of hypertensive parents (P < .001 to .01). In parallel, blood pressure increased significantly only in offspring of hypertensive parents (P < .001 to .05) but heart rate increased in both groups (P < .001 to .05).

CONCLUSIONS

The activity of the sympathetic nervous system and plasma norepinephrine and endothelin levels are increased during mental stress only in offspring of hypertensive parents, whereas the response to hypoxia was similar in offspring of hypertensive and normotensive parents, suggesting a genetically determined abnormal regulation of the sympathetic nervous system to certain stressful stimuli in offspring of hypertensive parents. This may play a role in the pathogenesis of essential hypertension.

Urinary dopamine and noradrenaline outputs during oral salt loading in healthy Chinese subjects with a family history of hypertension

1. Increased salt sensitivity has been reported in first-degree relatives of hypertensive patients. To determine if the enhanced effect of oral salt intake on blood pressure in such individuals is related to abnormal renal dopamine (DA) or sympathetic nervous system responses, we studied the effects of two different sodium intakes (20 mmol/day followed by 220 mmol/day each given for 5 days) on mean arterial pressure (MAP) and urinary excretion of sodium, free DA and noradrenaline (NA) in seven normotensive Chinese subjects with a family history of hypertension. We compared these results with those we have reported previously for normotensive subjects without a family history of hypertension. 2. There was a seven- to ten-fold increase in sodium excretion (P < 0.02). MAP increased from 80.1 +/- 2.5 to 83.1 +/- 2.1 mmHg (P < 0.05). A 23% increase in urine DA (P < 0.02) was seen on day 1. From day 2 to day 5, the increase in urine DA (12-15%) became attenuated and reached statistical significance only on days 2 and 5. There was no significant change in urinary NA output. 3. As in healthy Chinese subjects without a family history of hypertension, those with a family history showed an early but unsustained rise in urine DA during oral sodium loading. Such an increase was rather small compared to the increase in urine sodium, suggesting that renal DA only contributes partly to the natriuretic response. Unlike those with no family history, subjects with a family history showed an increase in blood pressure after oral salt loading, possibly because of inadequate suppression of sympathetic nervous system activity.

Relationship of cardiovascular risk factors to echocardiographic left ventricular mass in healthy young black and white adult men and women. The CARDIA study. Coronary Artery Risk Development in Young Adults

BACKGROUND

The objective of this study was to describe the distribution of echo left ventricular (LV) mass and its association with demographic and cardiovascular risk factors in a large race- and sex-balanced cohort of young adults. Recent epidemiological data have suggested that M-mode echocardiographically determined LV hypertrophy is an independent predictor of mortality and morbidity from coronary heart disease (CHD) in older adults. Echocardiographic LV mass has been associated in middle-aged and older adults with multiple factors including age, arterial blood pressure, body mass, and sex. However, there are few data describing the distribution of echo LV mass among black and white young adult men and women and relating LV mass to cardiovascular disease risk factors within race-sex subgroups.

METHODS AND RESULTS

CARDIA (Coronary Artery Risk Development in Young Adults) is a multicenter study of young adults, including approximately equal proportions of black and white men and women aged 23 to 35 years at the time of echo examination (1990 through 1991). Two-dimensionally guided M-mode echocardiograms were attempted in 4243 participants with recordings deemed acceptable for calculation of LV mass, that is, of at least fair quality score, obtained in 3840 (90.5% of the 1990-1991 cohort). M-mode LV mass was calculated from the formula of Devereux and Reicheck, adapted for use with measurements made according to the American Society of Echocardiography Standards. LV mass was greater in men than in women and greater in blacks than in whites (P < .001) (mean +/- SD): black men, 176 +/- 42 g; white men, 169 +/- 40 g; black women, 135 +/- 38 g; and white women, 125 +/- 33 g. In all race-sex groups, LV mass was positively correlated (P < .0001) in bivariate analyses with body weight, subcapular skinfold thickness, height, and systolic blood pressure. In multivariate analyses, LV mass remained independently and positively related to body weight and systolic blood pressure and, when body weight was not considered, with subcapular skinfold thickness and height. In addition, the multivariate models allowed us to infer a direct relation between LV mass and both fatness and lean body mass. Weaker positive associations were noted of LV mass with pulse pressure in white participants and with physical activity in men. After adjustment for subscapular skinfold thickness, height, systolic and diastolic blood pressures, alcohol consumption, pulmonary function, smoking history, physical activity, total serum cholesterol, and family history of hypertension, LV mass remained higher in men than in women (P < .0001), in black men (167 +/- 43 g) than in white men (156 +/- 50 g, P < .0001), and in black women (142 +/- 49 g) than in white women (137 +/- 43 g, P < .002).

CONCLUSIONS

In the healthy young adults of the CARDIA cohort, LV mass was highly correlated with body weight, subscapular skinfold thickness, height, and systolic blood pressure across race and sex subgroups. Furthermore, after adjustment for anthropometric, blood pressure, and other covariates, LV mass remained higher in men than in women and in blacks than in whites. Longitudinal studies are necessary to delineate the possible roles of these factors in the genesis of LV hypertrophy.

Comparison of casual blood pressure and twenty-four-hour ambulatory blood pressure in high school students

OBJECTIVE

To perform ambulatory blood pressure monitoring (ABPM) in high school students and to compare the 24-hour values with casual blood pressure (BP).

METHODS

Ambulatory BP monitoring was carried out in 190 high school students, 15 or 16 years of age, with elevated casual BP during the first examination at school for hypertension; 66 had elevated casual BP at both the first and the second examinations (group H1), and 124 students were normotensive at the second examination (group H2). Sixty-two students who were consistently normotensive served as control subjects (group N). Average BPs for the 24-hour period, the awake period (10 AM to 10 PM), and the sleeping period (1 AM to 6 AM) were calculated.

RESULTS

Average BP for each period was significantly higher in group H1 than in group N. Average BP in group H2 for these periods was intermediate between those of group H1 and of group N. The casual BP had a significant positive correlation with the average BP during the awake period (r = 0.55, p < 0.01 for systolic BP; r = 0.37, p < 0.01 for diastolic BP). In most subjects the casual BP readings were higher than BP during ABPM.

CONCLUSIONS

Casual BP measurements correlated with 24-hour BP, but they tended to be higher than the measurements obtained during 24-hour ABPM.

Molecular basis of human hypertension: the role of angiotensin

On the basis of recent advances in molecular biology and statistical genetics, it has become possible to search for chromosome regions that contain genes predisposing to hypertension and to directly link specific mutations on candidate genes to hypertension. As the human genome has been extensively mapped, highly informative, polymorphic markers are available, which can be used to detect genes in their proximity with 'hypertensinogenic' alleles. Some of these markers have been shown to be tightly linked to the genes of the renin-angiotensin system. Furthermore, the coding and regulatory regions of the genes encoding for renin, ACE, angiotensinogen and the AT1 receptor have been partially characterized. This provides a basis for further definition of specific polymorphisms within these genes that are of functional importance and that can be used to examine their contribution to the inheritance of primary hypertension. The first studies of these links have already emerged and have been reviewed in this article. Several problems arise in performing such linkage studies in human primary hypertension, however. It is difficult to define the genetic background of heterogeneous, multigenetic and multifactorial diseases such as human hypertension. Extensive studies of population genetics, including the analysis of large numbers of generations and controlled breeding experiments, cannot be performed, for obvious reasons. Blood pressure is not a convenient study trait, because it exhibits great intraindividual variance and also because of the relatively low reliability of just a few indirect measurements obtained under loosely controlled environmental conditions. Twenty-four-hour ambulatory blood pressure measurements may improve such investigations in the near future. Ravogli et al (1990) reported that the 24-hour ambulatory systolic blood pressure is higher in normotensive subjects of hypertensive parents than in normotensive subjects of normotensive parents--a finding that had not been previously reported using the conventional method of measurement. Hypertension as a trait per se is also problematic: its classification (above 140/90 mmHg) is purely artefactual, and its aetiology is highly heterogeneous. Thus, we have to keep in mind that even strong gene effects, if present in only a small subgroup of hypertensives, may not be detected in these studies. Attempts are being made to strengthen the analysis by characterizing physiologically distinct subgroups. In addition, the investigation of intermediate phenotypes, such as plasma parameters, which are more reliable and less subject to variations, may be helpful.(ABSTRACT TRUNCATED AT 400 WORDS)

Test-retest reliability of 24-hour ambulatory blood pressures

The test-retest reliability of 24-hour ambulatory blood pressures (ABP) was examined using correlational analyses as well as idiographic and nomothetic time-series regression analyses. Thirty normotensives (equal males and females) underwent ABP monitoring on three occasions, each of which was separated by a week. When analyzing the data, various postural positions, activities, and locations were controlled for in order to differentially assess the effects of these variables independently. Correlational analyses found the overall test-retest reliability of the ABPs to be quite good (SBP r = .84-.88, DBP r = .83-.86, HR r = .91-.95). Correlations examined within specific postural positions, activities, and locations were also significant. The time-series regression analyses used confirmed the reproducibility of the ABPs, with no greater than 20% of the subjects showing significant changes in ABPs over the three monitoring periods. Gender effects were also examined. In general, males had significantly higher systolic ABPs overall, although there was no influence of gender in terms of the test-retest reliability of the ABPs.

Hypertension in children

Early identification of children at risk for hypertension, proper evaluation, and appropriate management is important to prevent the serious long-term complications associated with the condition. This article defines primary and secondary hypertension in children, describes accurate blood pressure measurement techniques in children, presents the evaluation of a child with hypertension, and discusses therapy and prevention.

Blood pressure variability and its implications for antihypertensive therapy

Although it is clear that antihypertensive treatment is beneficial in reducing stroke morbidity and mortality, the results of the major outcome studies show less impact on coronary heart disease. Studies utilizing 24-h blood pressure (BP) monitoring show a positive association between target organ damage and the level of 24-h BP, and with variability in BP, which is an independent determinant of target organ damage. Current understanding of the pathogenesis and pathophysiology of coronary heart disease suggests that optimal antihypertensive treatment should ensure the following: effective 24-h BP control, smooth antihypertensive effect with reduced variability; attenuation of the early morning surge in BP; maintenance of the normal circadian pattern of BP; effective therapeutic coverage in the face of suboptimal compliance; and lack of reflex activation of the sympathetic nervous system. On the basis of our current understanding, this optimum is most likely to be achieved by the use of antihypertensive agents with a long duration of action.

The Bergen Blood Pressure Study: prehypertensive changes in cardiac structure and function in offspring of hypertensive families

Cardiac morphology and function were determined by echocardiography in normotensive offspring of 23 hypertensive and 22 normotensive families. The family histories of hypertension or normotension were based on 27 years' observation of parental blood pressure. Pulsed Doppler and M-mode echocardiography were performed in standard views. Out of the total 109 offspring, 94 participated in the present study (age (mean +/- SD) 36 +/- 7 years). Left ventricular posterior wall thickness was higher in offspring of hypertensive than normotensive families (10.1 +/- 1.7 vs. 9.3 +/- 1.5 mm; p < 0.05). Offspring of hypertensive families had lower transmitral early/late peak flow velocities (p < 0.001) and higher transmitral late peak flow velocities (p < 0.001) than offspring of normotensive families, but the differences between groups became inconsistent after adjustment for confounding variables (including left ventricular structural parameters). On the other hand, the family history of hypertension was consistently associated with increased transmitral early peak flow velocity and increased transmitral acceleration and deceleration slopes p < 0.05), a pattern suggesting increased left ventricular stiffness. Increased posterior wall thickness and diastolic functional changes may indicate cardiac hypertrophy and decreased left ventricular compliance and precede the development of hypertension in offspring of hypertensive families.

Campodimele study: blood pressure and heart rate pattern in clinically healthy elderly subjects

Noninvasive ambulatory blood pressure (BP) monitoring is a developing method in clinical practice. Its interpretation needs reference standards stratified by age and gender. This study addresses ambulatory BP monitoring in elderly people with the purpose of quantifying the discrete and periodic variability of BP pattern over a 24-h period. The ABPM was performed in 92 clinically healthy subjects (45 men and 47 women) ranging in age from 76 to 102 years. The results refer to the time-qualified mean values with their dispersion, to the circadian rhythm with its parameters, and to the daily baric impact (BI) with its variability. The conclusion is drawn that BP preserves its nychtohemeral variability and circadian rhythmicity despite old age. The daily BP mean level and BI in older people in good health are comparable with those of young subjects, suggesting that humans surviving into old age are characterized by a eugenic control of their pressure regimen.

The relationship between 24-hour ambulatory blood pressures and laboratory measures of cardiovascular reactivity

The relationship between 24-hour ambulatory blood pressures (ABP) and blood pressures (BP) obtained during laboratory stressors was examined. Thirty normotensives (equal males and females) underwent ABP monitoring on three occasions separated by a week. They also underwent a laboratory assessment which included standard stressors (i.e., mental arithmetic, cold pressor, orthostatic response, treadmill exercise). Correlational analyses found laboratory pressures to be significantly correlated with ambulatory pressures, with laboratory baseline BPs showing higher correlations to the ambulatory BPs than the BPs obtained during laboratory stressors. In addition, gender effects were examined. In the correlational analyses between ABPs and laboratory BPs, males and females did not differ significantly in the strength of the correlations. In terms of absolute values, males were found to have significantly higher SBP during ambulatory monitoring, random-zero recordings, calibration readings, and during baselines of the laboratory assessment. There were no gender effects for these measures with respect to diastolic blood pressure or heart rate. There were also no gender effects on reactivity to laboratory stressors as measured by change scores. Exploratory analyses found no significant effect of history of familial hypertension on either the ABPs or the laboratory pressures.

The Bergen Blood Pressure Study: inappropriately low levels of circulating atrial natriuretic peptide in offspring of hypertensive families

Plasma atrial natriuretic peptide (ANP), plasma and 24-h urine catecholamines, plasma renin activity (PRA), and serum aldosterone were studied in offspring of hypertensive and normotensive families [n = 82; age 37 +/- 7 years (mean +/- SD)]. Despite higher age, higher blood pressure, and higher urine excretion of catecholamines--all of which are factors associated with increased ANP levels--the mean basal plasma ANP concentration tended to be lower in offspring of hypertensive than normotensive families. The same pattern was found in all age-tertiles, and the between-group difference was statistically significant in subjects aged 34-39 years (p < 0.01). Also, the family history of hypertension was associated with low ANP levels after covariate adjustment (p < 0.05). The 24-h urine excretion of epinephrine and norepinephrine tended to be higher in offspring of hypertensive than normotensive families while the morning venous plasma levels were similar. The ratio between venous plasma ANP and norepinephrine was lower in offspring of hypertensive than normotensive families (p < 0.05). PRA, serum aldosterone level, and 24-h urine excretion of dopamine did not differ significantly between groups. Inappropriately low basal plasma ANP concentrations and low plasma ANP/norepinephrine ratios may be related to the development of essential hypertension in offspring of hypertensive families.

Clinical uses of ambulatory blood pressure monitoring

Traditional office measurements of blood pressure are commonly used to initiate and monitor therapy for hypertension, but these measurements are limited in their ability to provide information from the patient's normal work or play environment and do not include data from the overnight period when the patient is asleep. Thus, much potentially important information is lost. The ambulatory blood pressure monitor offers the attractive advantage of providing multiple blood pressure measurements from a subject's normal environment during his normal activities, thereby revealing important patterns of blood pressure in health and in illness. Further, the results of ambulatory monitoring have an excellent correlation with end-organ damage and these data can be obtained in a very short time period. This review will discuss the chronobiology of blood pressure, the clinical uses of the ambulatory blood pressure monitor in health and in disease, including the patterns of blood pressure identified, correlation with end-organ damage and its uses in clinical trials of antihypertensive medications; the experience in children with this technology will also be discussed.

Cardiovascular reactivity, coronary risk factors, and sympathetic activity in young men

We have previously demonstrated that awareness of high blood pressure may increase blood pressure, plasma catecholamine levels, and stress responses. In the present study, three groups of 19-year-old men, all unaware of their blood pressure status, were selected from the first (group-1, 62 +/- 2 mm Hg, [mean +/- SEM], n = 15), 50th (group-50, 90 +/- 4 mm Hg, n = 15), and 99th (group-99, 123 +/- 5 mm Hg, n = 14) percentiles in causal mean blood pressure at a screening. They were studied (blinded examiners) with intra-arterial blood pressure recordings and multiple measurements of arterial plasma epinephrine and norepinephrine during a mental arithmetic challenge and cold pressor test. Despite high mean blood pressure at the screening, group-99 did not differ from group-50 either in intra-arterial mean blood pressure after 30 minutes of supine rest (89 +/- 3 versus 86 +/- 2 mm Hg) or in serum lipids and resting plasma epinephrine and norepinephrine. However, in group-99 resting plasma epinephrine showed a positive hyperbolic relation to resting diastolic blood pressure (r = .73, P = .004) and a negative hyperbolic relation to the ratio of high-density lipoprotein cholesterol to total cholesterol (r = -.75, P = .002). None of these correlations were present in the two other groups. Furthermore, the three groups differed in heart rate responses (P < .0005) and systolic (P < .0005) and diastolic (P < .05) blood pressure responses to mental arithmetic challenge, group-99 being hyperreactive compared with the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory blood pressure monitoring in hypertension

Ambulatory blood pressure monitoring generates a greater interest among investigators and clinicians because of its potential to 1) study the mechanisms involved in cardiovascular control in daily life (particularly if monitoring is performed on a beat-to-beat basis) and 2) improve the diagnosis of hypertension, the estimate of the patient's risk and the assessment of the efficacy of antihypertensive treatment. This paper will discuss the evidence pros and cons the latter indications of this approach. It will be shown that 24 hour blood pressure values correlate more closely than clinic blood pressure with various measures of the end organ damage of hypertension, suggesting that it may reflect better than traditional blood pressure measurements the cardiovascular consequences of this condition. Wider use of ambulatory blood pressure monitoring in the medical practice, however, must await a more clear demonstration of its prognostic importance, by longitudinal studies based on cardiovascular morbidity and mortality or on surrogate end points with undisputable clinical significance (e.g. left ventricular hypertrophy). It must also await clear definition of ambulatory blood pressure normality based on population studies. Until then ambulatory blood pressure monitoring should be employed to resolve special problems, e.g. identification of white coat hypertension and false non response to treatment.

Role of preclinical cardiovascular disease in the evolution from risk factor exposure to development of morbid events

Conventional risk factors (especially high arterial pressure, elevated cholesterol and glucose levels, and cigarette smoking) are useful predictors of morbid atherosclerotic and hypertensive events, and their control variably reduces the incidence of events. However, both the ability to predict risk and the ability to reduce it by modification of established risk factors are limited. These limitations occur in part because the progression from risk factor exposure to morbid events depends on the variable likelihood that individuals exposed to the same risk factors will progress through two stages: the development of asymptomatic or "preclinical" anatomic and functional cardiovascular disease in response to standard risk factors and other variables, and the precipitation of morbid events by progression of preclinical disease or by the action of additional "triggering" mechanisms in the presence of preclinical disease. Advances in diagnostic methodology now make possible accurate noninvasive detection in many asymptomatic individuals of preclinical disease such as left ventricular hypertrophy, carotid atherosclerosis, and renal dysfunction. Progress in elucidating stimuli to left ventricular hypertrophy and systemic atherosclerosis suggests that focusing research separately on these two stages of disease evolution is a fruitful strategy. The closer relation of measures of preclinical disease than risk factors with the subsequent risk of complications indicates that their detection improves clinical risk stratification. However, critical testing of whether clinical outcome is improved or treatment cost is lowered by basing antihypertensive or antihyperlipidemic treatment decisions in part on the presence of preclinical cardiovascular disease is needed before this strategy is adopted on a widespread scale.

The Bergen Blood Pressure Study: ambulatory blood pressure in subjects with an accurately defined family history of hypertension or normotension

24-hour ambulatory blood pressure (BP) was monitored by non-invasive methods in 42 offspring of hypertensive families (age [mean (SD1)] 40(7) years) and 38 offspring of normotensive families (age 33(6) years). The family history was defined according to parental BP data from two surveys conducted 27 years apart. Casual BP was 137(17)/84(12) mmHg in offspring of hypertensive families and 117(9)/69(6) mmHg in offspring of normotensive families (difference: p < 0.001). Average 24-h BP was 123(10)/74(6) mmHg and 113(8)/65(5) mmHg, respectively (difference: p < 0.001). The systolic and diastolic BP difference of approximately 10 mmHg was observed between the groups throughout the monitoring period. Hypertension--defined according to a recent meta-analysis as an average 24-h BP > or = 139/87 mmHg--was found in 6 offspring of hypertensive families and in no offspring of normotensive families (p < 0.05). The 24-h systolic and diastolic BP load--the percentage of readings above 140/90 mmHg (day-time) and 120/80 mmHg (night-time)--was higher in offspring of hypertensive than normotensive families (27%/17% vs. 7%4%; p < 0.001). After adjustment for intrafamilial covariation, age, and other possibly confounding variables, the differences between the groups remained. The present findings suggest that BP in subjects with a family history of hypertension is elevated on a permanent basis, and not only when it is measured in the doctor's office.

Anger inhibition and family history as modulators of cardiovascular responses to mental stress in adolescent boys

Sixty boys aged 12-16 took part in an experiment in which physiological and subjective measures were obtained at rest and in response to mental arithmetic and mirror drawing tasks. Blood pressure was recorded from biological parents, and subjects were subsequently categorized as being at high family risk for cardiovascular disease if either parent had a history of coronary heart disease or hypertension, or a resting blood pressure > or = 140/85 mmHg. Twenty boys were classified as high family risk and forty as low risk. A significant interaction between family risk and a disposition towards anger inhibition was observed, with the greatest systolic blood pressure responses to tasks being recorded in high risk boys who reported high levels of anger inhibition. This effect was maintained after controlling for initial blood pressure level, age and body mass. The cardiac baroreceptor reflex was inhibited during tasks, and was lower in high than low family risk subjects. The results suggest that the tendency to inhibit anger expression interacts with familial factors in determining reactivity patterns that may be indicative of raised risk of future cardiovascular disease.

Ambulatory blood pressure measurements in children and young adults selected by high and low casual blood pressure levels and parental history of hypertension: the Bogalusa Heart Study

Ambulatory blood pressure measurements were obtained in 57 children and young adults selected by prior high or low casual blood pressure levels and parental history of hypertension. Considerable variation in blood pressure levels occurred over 24 hours, with generally higher levels occurring in those so selected. Parental history had a small influence on higher levels, although statistical significance was not shown. Persons with higher blood pressure levels did not reach levels as low during sleep, especially with regard to the systolic measurement, and a greater variability was noted in those selected for higher levels. Although differentiation of persons with high and low blood pressure levels can be obtained by noting average levels persisting above a cut point, for example, 140/85, in growing children an arbitrary 90th percentile based on age, height, and weight may be more appropriate. Ambulatory monitoring showed that young persons, selected by casual measurements as having high blood pressure, have a greater percentage of high levels persisting over a 24-hour period, comprising a greater blood pressure load. These observations also showed that even two series of casual measurements may misclassify a person as having hypertension. Ambulatory blood pressure monitoring will enhance understanding of the early natural history of hypertension and allow improved prevention of the disease.