Prognostic value of ambulatory blood pressure : current evidence and clinical implications

Heritability of ambulatory and office blood pressure phenotypes in Swedish families

OBJECTIVE

The aim of this study was to estimate the heritability of 24-h ambulatory blood pressure and office blood pressure phenotypes in Swedish families.

METHODS

We measured ambulatory and office blood pressure in 260 siblings without antihypertensive treatment from 118 families. Blood pressure heritability was estimated using standard quantitative genetic variance component analysis implemented in the 'SOLAR' software package after adjustment for significant covariates.

RESULTS

Heritability values were significant for night-time systolic (37%), diastolic (32%) and mean (32%) ambulatory blood pressure (P < 0.05 for all). During daytime, systolic ambulatory blood pressure was significantly heritable (33%, P < 0.05). Twenty-four-hour systolic (30%) and diastolic (29%) ambulatory blood pressure also had significant values of heritability (P < 0.05). Pulse pressure ambulatory blood pressure was significantly heritable over 24 h (63%, P < 0.01), during daytime (53%, P < 0.01) and at night (34%, P < 0.05). None of the office blood pressure phenotypes had a significant heritability.

CONCLUSIONS

We conclude that ambulatory blood pressure, in particular at night, seems better than office blood pressure to capture the heritable part of blood pressure, suggesting that ambulatory blood pressure may be a more exact estimate of an individual's true blood pressure. Genetic studies using ambulatory blood pressure as the phenotype are likely to be more powerful than those using office blood pressure. The high heritability of pulse pressure ambulatory blood pressure indicates that variation in arterial stiffness in subjects free from antihypertensive medication is strongly affected by genetic factors.

Longitudinal studies on the effect of hypertension on circadian hemodynamic and autonomic rhythms in telemetered rats

This study dealt with the long-term effects of hypertension on circadian rhythms of hemodynamic and cardiovascular autonomic functions in radiotelemetered rats. Blood pressure (BP), heart rate (HR), spontaneous locomotor activity, and respiration.were monitored in spontaneously hypertensive rats (SHRs), a model of human hypertension, from 14 to 27 weeks of age and in Wistar-Kyoto rats (WKY) as controls. Cardiovascular autonomic changes were determined by time-domain analysis of the variability of BP (standard deviation of mean arterial pressure, SDMAP) and HR (standard deviation of R-R intervals, SDRR, and the root mean square of successive differences in R-R intervals, rMSSD). Compared with WKY rats, the 24-hr MAP and SDMAP were higher at week 14 in SHRs and showed stepwise increases over the study duration, suggesting progressive increases in vasomotor sympathetic activity in hypertensive rats. Also, higher SDRR, rMSSD, and activity and lower HR and respiration were demonstrated in SHRs. Normal circadian rhythms (higher dark-time values) of MAP, HR, SDMAP, and SDRR were evident in WKY rats at week 20 and continued thereafter. Compared with WKY rats, the circadian BP and HR patterns were abolished and inverted, respectively, in SHRs. Lower dark-time, compared with light-time, SDMAP values were observed in SHRs that were associated with temporal increases in HR variability indices. These findings demonstrate that hypertension elicits significant alterations in circadian autonomic and hemodynamic profiles. Further, the steady increases in BP, average level and oscillations, in SHRs may explain the reported progressive age-related vascular and cardiac hypertrophy in these rats.

Exercise blood pressure, cardiac structure, and diastolic function in young normotensive patients with polycystic kidney disease: a prehypertensive state

BACKGROUND

Increased left ventricular mass (LVM) and left ventricular hypertrophy have been found in early stages of autosomal dominant polycystic kidney disease (ADPKD). The mechanisms that lead to an increase in LVM in this population are unknown. The aim of this study is to evaluate blood pressure (BP) response to exercise and very early alterations in cardiac structure and diastolic function in young normotensive patients with ADPKD.

METHODS

Color Doppler echocardiography and exercise treadmill testing according to the Bruce protocol were performed in 18 young normotensive patients with ADPKD and 18 healthy subjects.

RESULTS

LVM index was greater and isovolumic relaxation time (IVRT) was longer in patients with ADPKD than controls (93.3 +/- 21.4 versus 77.5 +/- 18.6 g/m2; P = 0.02; 100 +/- 20.2 versus 80 +/- 9.7 milliseconds; P = 0.001, respectively). Exercise capacity in metabolic equivalents was similar in both groups. Systolic BP response during exercise and recovery were similar in both groups. Diastolic BP decreased during exercise, but the magnitude of decrease was lower in patients with ADPKD than controls (P = 0.01). During recovery, patients with ADPKD showed a greater sustained diastolic BP than controls (P = 0.02). Patients with ADPKD with an exaggerated systolic BP response had a greater LVM index than those with a normal response (112.1 +/- 10.4 versus 84 +/- 19.2 g/m2; P = 0.001). Multivariate regression analysis showed that exercise systolic BP and diastolic BP were independent predictors of LVM index and IVRT, respectively.

CONCLUSION

Young normotensive patients with ADPKD showed increased LVM index and prolonged IVRT, which are related to exercise BP response. Exaggerated diastolic BP response during exercise suggests an impaired capacity for exercise-induced vasodilatation and may indicate a greater risk for the development of future hypertension.

Latin American consensus on diabetes mellitus and hypertension

Diabetes mellitus and hypertension, responsible of a major burden of cardiovascular complications, are increasing their incidence in Latin America in similar proportions to the rest of the world. The metabolic syndrome, a strong predictor of both diabetes and hypertension deserves more attention from the primary care physicians. Evidence based and updated guidelines on detection, prevention and treatment of diabetes and hypertension, issued by local experts, are willing to inform and translate these recommendations to the clinical practice of physicians assisting these patients throughout Latin America.

Job characteristics, occupational status, and ambulatory cardiovascular activity in women

BACKGROUND

Prior research concerning the effects of occupational status and work stress on ambulatory blood pressure (AmBP) has seldom included women, and available results are equivocal. Moreover, the concurrent effects of occupational status and job characteristics have rarely been investigated. Some research is consistent with the idea that stressful job characteristics are especially detrimental to health in low-status workers, creating a cumulative physiological burden.

PURPOSE

To examine the independent and joint effects of occupational status and perceived demands, control, and social support at work on AmBP and heart rate (HR) in women.

METHODS

One hundred eight women (M age = 41.07 years) wore an AmBP monitor for 2 days and completed a self-report assessment of job control, demands, and support (i.e., Karesek et al.'s Job Content Questionnaire).

RESULTS

After controlling for numerous potential confounds, occupational status and job characteristics accounted for 18% and 22% of the inter-individual variability in ambulatory systolic blood pressure (SBP) and HR, respectively. Occupational status independently predicted ambulatory cardiovascular activity and interacted with job characteristics, particularly in relation to SBP.

CONCLUSIONS

Inasmuch as ambulatory SBP and HR predict future cardiovascular morbidity and mortality, women with both lower status occupations and stressful job circumstances could be at disproportionately high cardiovascular risk.

Twenty-four-hour ambulatory blood pressure profiles in liver transplant recipients

Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has proven to have better reproducibility than office blood pressure (BP) and is increasingly used for the study of hypertension in children and adolescents. The aim of our study was to assess 24-h BP profiles and to compare the results of office BP measurements with ABPM in stable liver transplant recipients transplanted before the age of 18 yr. ABPM was performed in 29 patients (nine males, 20 females), aged 3.9-24.8 yr (median 10.8 yr). The investigation was conducted 1.1-11.5 yr (median 5.1 yr) following transplantation. ABPM confirmed hypertension in one out of three office hypertensive patients. Seven patients (24%), whose office BP recordings were within the normotensive range, were reclassified as hypertensive. Non-dippers (n = 17), arbitrarily defined as patients with less than 10% nocturnal fall in BP, were similarly distributed among patients with ambulatory normotension and ambulatory hypertension (chi(2), p = 0.79). In addition, non-dippers showed a negative correlation between 24-h total urinary albumin excretion and both systolic and diastolic nocturnal decline in BP (Rho = -0.48, p < 0.05 and Rho = -0.86, p < 0.01, respectively). Our study found office BP readings to be poorly representative of 24-h BP profile. Larger studies are needed to confirm our observations as well as to determine whether routine BP measurements in the follow-up of paediatric liver transplant recipients should be based solely on office BP.

Can improved software facilitate the wider use of ambulatory blood pressure measurement in clinical practice?

BACKGROUND

24-h ambulatory blood pressure measurement (ABPM) is now recognized as being indispensable in the diagnosis and management of hypertension. The technique must, therefore, be made available in primary care, but in doing so it must be recognized that unfamiliarity with the technique may lead to misinterpretation of data.

OBJECTIVE

To facilitate the wider application of ABPM, especially in primary care, we examined the features that would facilitate the development of a standardized user-friendly software program for the presentation, analysis and interpretation of data.

METHODS AND RESULTS

The following features were considered essential to any software program for ABPM: standardized plots of 24-h profiles; computer interpretation of ABPM data and patterns; a user-friendly one-page report, flexible statistical analysis, and the facility to group data and to export data for audit and research analysis. The dabl ABPM program incorporating these features was introduced into the Blood Pressure Unit, Beaumont Hospital in 2000 and has been used in over 15 000 ABPM recordings. The program is now being used widely in general practice and specialized centres.

CONCLUSIONS

It is feasible to design a software program to provide a standardized plotting format for ABPM, a basic analysis of data for day-to-day clinical work, or elaborate analyses for research, and an interpretative report to assist diagnosis and to provide an educational process for doctors and nurses not familiar with the technique.

Reproducibility of nocturnal blood pressure fall in early phases of untreated essential hypertension: a prospective observational study

A number of studies have shown that a smaller than normal nocturnal blood pressure (BP) decrease is associated with cardiovascular disease. However, no large prospective studies have examined the reliability of nocturnal dipping within individuals. The aim of our study was to investigate the short-term variability of nocturnal BP fall in a large cohort of patients with recently diagnosed essential hypertension. In all, 414 uncomplicated never treated hypertensive patients referred to our outpatient hypertension hospital clinic (mean age 46+/-12 years; 257 M, 157 F) prospectively underwent: (1). repeated clinic BP measurements; (2). routine examinations recommended by WHO/ISH guidelines; and (3). ambulatory BP monitoring (ABPM) twice within a 4-week period. Dipping pattern was defined as a reduction in the average systolic and diastolic BP at night greater than 10% compared to average daytime values. Overall, 311 patients (75.1%) showed no change in their diurnal variations in BP. Of the 278 patients who had a dipping pattern on the first ABPM, 219 (78.7%) confirmed this type of profile on the second ABPM, while 59 (21.3%) showed a nondipping pattern. Among 37 dipper patients with >20% of nocturnal systolic BP decrease (extreme dippers), only 16 (43.2%) had this marked fall in BP on the second ABPM. Of the 136 patients who had a nondipping pattern on the first ABPM, 92 (67.6%) confirmed their initial profile on the second ABPM, while 44 (32.4%) did not. Patients with reproducible nondipping profile were older (48+/-12 years) than those with reproducible dipping profile (44+/-12 years, P<0.05). These findings indicate that: (1). short-term reproducibility of nocturnal fall in BP in untreated middle-aged hypertensives is rather limited: overall, one-fourth of patients changed their initial dipping patterns when they were studied again after a few weeks; (2). this was particularly true for extreme dipping and nondipping patterns; (3). abnormalities in nocturnal BP fall, assessed by a single ABPM, cannot be taken as independent predictors of increased cardiovascular risk.

American College of Sports Medicine position stand. Exercise and hypertension

Hypertension (HTN), one of the most common medical disorders, is associated with an increased incidence of all-cause and cardiovascular disease (CVD) mortality. Lifestyle modifications are advocated for the prevention, treatment, and control of HTN, with exercise being an integral component. Exercise programs that primarily involve endurance activities prevent the development of HTN and lower blood pressure (BP) in adults with normal BP and those with HTN. The BP lowering effects of exercise are most pronounced in people with HTN who engage in endurance exercise with BP decreasing approximately 5-7 mm HG after an isolated exercise session (acute) or following exercise training (chronic). Moreover, BP is reduced for up to 22 h after an endurance exercise bout (e.g.postexercise hypotension), with greatest decreases among those with highest baseline BP. The proposed mechanisms for the BP lowering effects of exercise include neurohumoral, vascular, and structural adaptations. Decreases in catecholamines and total peripheral resistance, improved insulin sensitivity, and alterations in vasodilators and vasoconstrictors are some of the postulated explanations for the antihypertensive effects of exercise. Emerging data suggest genetic links to the BP reductions associated with acute and chronic exercise. Nonetheless, definitive conclusions regarding the mechanisms for the BP reductions following endurance exercise cannot be made at this time. Individuals with controlled HTN and no CVD or renal complications may participated in an exercise program or competitive athletics, but should be evaluated, treated and monitored closely. Preliminary peak or symptom-limited exercise testing may be warranted, especially for men over 45 and women over 55 yr planning a vigorous exercise program (i.e. > or = 60% VO2R, oxygen uptake reserve). In the interim, while formal evaluation and management are taking place, it is reasonable for the majority of patients to begin moderate intensity exercise (40-<60% VO2R) such as walking. When pharmacological therapy is indicated in physically active people it should be, ideally: a) lower BP at rest and during exertion; b) decrease total peripheral resistance; and, c) not adversely affect exercise capacity. For these reasons, angiotensin converting enzyme (ACE) inhibitors (or angiotensin II receptor blockers in case of ACE inhibitor intolerance) and calcium channel blockers are currently the drugs of choice for recreational exercisers and athletes who have HTN. Exercise remains a cornerstone therapy for the primary prevention, treatment, and control of HTN. The optimal training frequency, intensity, time, and type (FITT) need to be better defined to optimize the BP lowering capacities of exercise, particularly in children, women, older adults, and certain ethnic groups. based upon the current evidence, the following exercise prescription is recommended for those with high BP: Frequency: on most, preferably all, days of the week. Intensity: moderate-intensity (40-<60% VO2R). Time: > or = 30 min of continuous or accumulated physical activity per day. Type: primarily endurance physical activity supplemented by resistance exercise.

Office blood pressure underestimates ambulatory blood pressure in peripheral arterial disease in comparison to healthy controls

Patients with peripheral arterial disease (PAD) constitute a subgroup of high-risk hypertensives, but controlled studies on 24-h blood pressure (BP) and diurnal variation of BP are lacking. This study was performed in order to test the hypothesis that office BP (OBP) may underestimate 24-h BP in PAD patients in comparison to a matched control group. In all, 98 male patients (mean age 68 years) with a history of intermittent claudication and an ankle/brachial index less than 0.9, and 94 controls matched for age but without PAD or ischaemic heart disease performed 24-h recordings of ambulatory BP. A total of 59 patients had a history of hypertension and 69 were on treatment with BP-lowering drugs as compared to 17 and 23 of the control subjects, respectively. Office as well as 24-h systolic BP (SBP) were higher in patients as compared to controls (151 +/- 22 vs 140 +/- 20 mmHg, P < 0.001 and 142 +/- 14 vs 133 +/- 15 mmHg, P < 0.001, respectively), but did not differ with regard to diastolic BP. In an analysis of covariance with the continuous factors age, office SBP and the categorical factor antihypertensive treatment, 24-h SBP was higher in PAD patients compared to controls (P < 0.05). The difference between office and night SBP was lower in PAD patients with antihypertensive treatment compared to controls (P = 0.01). In conclusion, Male patients with PAD had higher systolic but not diastolic BP than age-matched control subjects. In PAD patients, 24-h SBP was higher than expected from OBP compared to controls. Night SBP was higher only in patients with antihypertensive treatment. In PAD patients, especially when on antihypertensive treatment, the severity of hypertension may be underestimated when based on OBP only.

Administration of tibolone decreases 24h heart rate but not blood pressure of post-menopausal women

OBJECTIVE

Elevation of blood pressure and heart rate increase the risk of cardiovascular disease. Administration of estrogens does not affect heart rate but may decrease 24 h blood pressure. In this study, we tested the effect of the estro-progestogenic compound tibolone.

METHODS

Thirty healthy, post-menopausal women were randomized to receive placebo (n = 15) or tibolone, at the commonly prescribed dose of 2.5 mg per day (n = 15). Before and after 6 months of treatment, in each woman blood pressure and heart rate were monitored every 30 min for 41 h by an ambulatory device. Valuable readings were those collected from 8:00 a.m. of the second day to 8:00 a.m. of third day. Analyses were performed of 24 h, day-time (7:00 a.m.-11:00 p.m.) and night-time (11:00 p.m.-7:00 a.m.) values. Day to night difference was also calculated.

RESULTS

Placebo did not modify 24h, day-time, and night-time blood pressure or heart rate values. Day-night differences were also not affected by placebo. Similarly to placebo, tibolone administration did not modify any of the blood pressure parameters taken into consideration. By contrast, a significant decline of 24 h heart rate (73.2 +/- 2.3 beats/min versus 69.3 +/- 1.7 beats/min; P < 0.0008) was observed. The effect was significant both at day (76.6 +/- 2.4 beats/min versus 72.1 +/- 1.9 beats/min; P < 0.0001) and night (65.8 +/ 2.6 beats/min versus 62.4 +/- 1.9 beats/min; P < 0.05). Day-night blood pressure and heart rate differences were not affected by tibolone.

CONCLUSIONS

In post-menopausal women, administration of tibolone does not influence 24 h blood pressure but reduces heart rate.

Reproducibility of intra-arterial ambulatory blood pressure

OBJECTIVE

To examine the effects of physical activity, body posture and sleep quality on the reproducibility of continuous ambulatory blood pressure monitoring.

METHODS

Measurements were performed in 35 subjects (18 hypertensive, 11 male), mean +/- standard deviation age 49 +/- 13 years. Blood pressure (BP) was measured in the brachial artery, and beat-to-beat values of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure and heart rate (HR) were computed. Physical activity and posture were continuously measured with five accelerometers. Subjective quality of sleep was assessed with a questionnaire. Reproducibility was expressed as an intraclass correlation coefficient and as the standard deviation of the within-subject differences.

RESULTS

Posture and activity significantly influenced BP and HR. From lying to sitting, the SBP, DBP and HR increased 6 mmHg, 8 mmHg and 8 beats/min, respectively. From sitting to standing these respective increases were 4 mmHg, 2 mmHg and 13 beats/min. A further rise in activity (from standing to moving generally or walking) increased the SBP by 7 mmHg and the HR by 7 beats/min, and decreased the DBP by 8 mmHg. For daytime SBP, DBP and HR, the intraclass correlation coefficient (standard deviation of the within-subject differences) values were 0.93 (7.2 mmHg), 0.94 (3.8 mmHg) and 0.90 (4.1 beats/min). For night-time these respective values were 0.98 (4.4 mmHg), 0.97 (2.5 mmHg) and 0.96 (2.2 beats/min). Correction for physical activity level and posture hardly improved the reproducibility of daytime BP and HR. Reproducibility of night-time BP and HR was not improved by correction for physical activity, supine position or self-reported sleep quality.

CONCLUSIONS

Within-subject differences between ambulatory BP recordings cannot be explained by differences in physical activity and body posture.

Clinical prediction of normotension in borderline hypertensive men ??? a 10 year study

OBJECTIVE

To investigate 24-h ambulatory blood pressure measurements (ABPM) as a tool for long-term prediction of future blood pressure (BP) status in high normal and low stage 1 hypertensives.

DESIGN, SETTING AND PARTICIPANTS

A total of 165 men from a population screening program with diastolic BP (DBP) 85-94 mmHg and a systolic BP (SBP) < 150 mmHg performed a 24-h ABPM. Ten years later, 120 participants (73%) returned for renewed measurements.

MAIN OUTCOME MEASURES

Blood pressure status at 10 years.

RESULTS

At the 10-year follow-up, 53% of the participants were classified as hypertensive (HT) (BP > or = 140/90 or taking anti-hypertensive medication) and 47% were classified as normotensive (NT) (BP < 140/90 mmHg). There was no significant baseline differences in office SBP levels between those who were normotensive or hypertensive at follow-up (136/91 versus 138/92 mmHg), whereas both SBP and DBP night-time levels were significantly lower in the future normotensives as compared to the future hypertensives (107/69 versus 112/74 mmHg, P < 0.01). Using recommended normalcy night-time ABP levels of < 120/75 mmHg in addition to office BP (140/90) at baseline, over 85% of the subjects were correctly classified provided they met both clinic and ambulatory night-time criteria for HT and NT classification at baseline.

CONCLUSION

The use of ABPM in addition to office BP's in patients with borderline hypertension greatly increases the possibility of identifying those individuals who are at a very small risk of developing future hypertension. This could potentially lead to considerable savings in both patient anxiety, physician time and resource consumption.

Marital status and quality in middle-aged women: Associations with levels and trajectories of cardiovascular risk factors

The current study compared cardiovascular risk profiles and trajectories (i.e., within-person changes) of women who were married or cohabitating and who had high relationship satisfaction with those of women with moderate or low satisfaction and with those of women who were single, divorced, and widowed. Participants were 493 women from the Healthy Women Study, a prospective investigation of health during and after the menopausal transition. Risk factors were measured across more than 5 occasions and 13 years, on average. Data were analyzed using a multilevel modeling technique. Overall, women in relationships with high satisfaction had lower levels of biological, lifestyle, and psychosocial risk factors when compared with the other groups. In some cases, women in satisfying marriages also showed a lower risk trajectory on risk factors relative to other women. Hence, marriage appears to confer health benefits for women, but only when marital satisfaction is high.

The effects of KT3-671, a new angiotensin II (AT 1) receptor blocker in mild to moderate hypertension

AIMS

To compare the antihypertensive effect, and tolerability and safety of once daily doses of KT3-671 with that of placebo in patients with mild to moderate uncomplicated essential hypertension.

METHODS

A randomised, multicentre, double blind, parallel-group comparison of KT3-671 with placebo. Hypertensive patients [Ambulatory Blood Pressure Monitoring (ABPM), mean daytime DBP > 90 mmHg, Office sitting mean DBP 95-114 after a 7-28 day washout period] entered a 2-week, single blind, run-in phase. Patients eligible for the double-blind phase were randomised to receive KT3-671 40 mg, 80 mg, 160 mg or placebo once daily over 4 weeks. The primary end-point was trough mean sitting office DBP. The study had 90% power to detect a 5 mmHg change between treatments and placebo at the 5% level of significance. The secondary end-points were 24 hour, daytime and night time mean ABPM.

RESULTS

Office DBP was significantly lower with KT3-671 40 mg but not the other 2 dosage groups (-3.2; 95% CL -6.1 : -0.3 P < 0.03). Office SBP was significantly reduced with all dosage groups (40 mg -5.9, 95% CL -11 : -0.9; 80 mg -4.9, 95% CL -9.9 : 0.1 and 160 mg -5.7, 95% CL -10.8 : -0.7 P < 0.05). All doses of KT3-671 reduced systolic and diastolic ABPM. The number of patients with treatment related adverse events were comparable to placebo (38.8% KT3-671 vs 32.8% placebo). There was some evidence of a dose-response relationship with fall in nocturnal ABPM.

CONCLUSIONS

Oral KT3-671 was well tolerated. KT3-671 reduced office systolic BP at all doses and diastolic BP at some of the doses. Due to greater precision and power, the falls in mean ambulatory systolic and diastolic pressure were all significantly lower than placebo.

Prognostic significance of isolated, non-specific left ventricular repolarization abnormalities in hypertension

OBJECTIVE

Clinicians are often confronted with the incidental finding of isolated minor, non-specific repolarization changes on the electrocardiogram (ECG) in hypertensive patients. The aim of this study was to investigate the prognostic significance of such changes.

DESIGN

Prospective, observational study.

METHODS

A total of 1970 hypertensive patients without prevalent cardiovascular disease were followed for up to 9.1 years (mean 4.7 years). Patients with ECG abnormalities including ischaemia, previous infarction, bundle branch block, atrial fibrillation and ventricular pre-excitation were excluded. Patients were divided into three groups: normal left ventricular (LV) repolarization (n = 1355); minor repolarization changes (n = 504); and typical LV strain (n = 111).

RESULTS

During follow-up, 78 patients developed new-onset ischaemic heart disease. The event rates were 0.50, 1.28 and 3.08 per 100 patient-years in the groups with normal repolarization, minor changes, and typical LV strain, respectively (P < 0.001). After adjustment for the effect of age, sex, diabetes, serum cholesterol, smoking, LV hypertrophy and 24-h pulse pressure, the risk for developing coronary events was higher in patients with minor repolarization changes (hazard ratio 2.07, 95% confidence interval 1.23-3.47; P < 0.01) or LV strain (hazard ratio 4.00, 95% confidence interval 2.09-7.65; P < 0.001) than in patients with normal repolarization (reference category). Population-attributable risks were 21 and 14%, respectively. Minor ST-T changes also retained an adverse prognostic value among patients without LV hypertrophy (hazard ratio 1.90, 95% confidence interval 1.08-3.33; P = 0.026).

CONCLUSION

We have identified minor, non-specific LV repolarization changes as a novel, independent risk factor for ischaemic heart disease in patients with uncomplicated hypertension.

Cognitive processing among mothers of children undergoing bone marrow/stem cell transplantation

OBJECTIVE

This study investigated the role of cognitive processing in maternal adjustment to a life-threatening pediatric medical procedure (bone marrow/stem cell transplantation: BMT/SCT).

METHODS

Ninety-one mothers participated in structured interviews about their fears, intrusions, avoidance, and distress regarding their child's BMT/SCT at two time points: during their child's hospitalization and during his/her recovery. Structural equation modeling was used to determine the role of fears, intrusions, and avoidance in mothers' distress.

RESULTS

Mothers' fears played a primary role in their adjustment to their child's transplantation. Intrusions mediated the relations of fears with distress at both time points. Mothers' avoidance of thoughts, feelings, and reminders of their child's illness during the child's transplantation was associated with their distress three months later. The child's risk for an unsuccessful transplantation outcome was not associated with mothers' fears or distress during the child's hospitalization, but was associated with mothers' distress during the child's posthospital course of recovery.

CONCLUSIONS

The results of this study indicate the critical role of mothers' fears, intrusions, avoidance, and the child's transplant risk in maternal distress and have treatment implications for reducing maternal distress during pediatric transplantation.

Event-Related Brain Potentials in Elderly Dippers and Nondippers with Recently Diagnosed Hypertension

Several studies have shown a relationship between blood pressure (BP) and cognitive function. Yet very few studies have addressed circadian BP patterns in this context, perhaps due to poor availability of suitable methods to detect slight changes in the cognitive state. Today, brain event-related potentials (ERPs) allow us to detect subclinical changes in cognitive function. We enrolled 30 elderly patients with recently diagnosed hypertension (<2 years) that had never been treated: 18 dippers and 12 nondippers. Patients underwent 24-h ambulatory blood pressure monitoring (ABPM). Careful assessment of their cognitive state was carried out using the mini mental state examination (MMSE), and the recording of P300 and N2 ERPs. No significant differences between the two groups were found. MMSE scores in dippers and nondippers were similar (29.5+/-0.71 vs. 29.3+/-1.07, respectively; p =0.611), as were P300 latency values (377.78+/-33.28 vs. 364.67+/-35.12 in the central (Cz) position, p =0.310; 379.22+/-32.94 vs. 365.25+/-35.07 in the occipital (Pz) position, p =0.277) and N2 wave latency values (253.83+/-24.9 vs. 249.17+/-24.47 in the Cz position, p =0.617; 251.56+/-25.86 vs. 246.58+/-25.46 in the Pz position, p =0.608). These data show no association between the nondipping pattern and lower cognitive function in elderly subjects with recent hypertension.

Ambulatory blood pressure monitoring: is the daytime period enough for making clinical decisions?

AIM

To assess the agreement between the clinical information provided by the ambulatory daytime average and 24 h average blood pressure value for diagnosing hypertension and assessing the effects of antihypertensive treatment.

METHODS

We analysed 261 24 h ambulatory monitoring records (SpaceLabs 90207, SpaceLabs, Redmond, Washington, USA) obtained from hypertensives over 18 years of age (mean age 55.8 years) in order to make a diagnosis of hypertension or assess its control in response to treatment. Recording was programmed to occur every 20 min during waking periods and every 30 min during sleep, daily activity also being registered. The criteria compared in the diagnosis of hypertension were: (1) the evaluation criterion: an average blood pressure for the activity period of less than 135/85 mmHg (Joint National Committee VI); (2) the gold standard: an average blood pressure over 24 h of less than 125/80 mmHg (World Health Organization-International Society of Hypertension, 1999).

RESULTS

In 90% of the records, there was agreement between both criteria. In 7.2%, the awake blood pressure average was normal and the 24 h average high. Values obtained were: sensitivity, 89% (95% confidence interval 84-89%); specificity, 92% (95% CI 88-95%); positive predictive value, 95.6% (95% CI 93-98%); negative predictive value, 81% (95% CI 75-85%); pretest probability, 66% (95% CI 60-72%); positive likelihood ratio, 11; and negative likelihood ratio, 0.3. There were no significant differences in age, gender or percentage of treated subjects between the groups with and without agreement.

CONCLUSIONS

Daytime and 24 h average blood pressure may indeed carry similar information for diagnosing hypertension and assessing the effects of antihypertensive treatment in clinical practice. Ambulatory blood pressure monitoring used only during the daytime period could be better tolerated and agreed to by patients than 24 h monitoring.

Large-scale ensemble averaging of ambulatory impedance cardiograms

Impedance cardiography has been used increasingly to measure human physiological responses to emotional and mentally engaging stimuli. The validity of large-scale ensemble averaging of ambulatory impedance cardiograms was evaluated for preejection period (PEP), interbeat interval, and dZ/dt(min) amplitude. We tested whether the average of "classical" 60-sec ensemble averages across periods with fixed activity, posture, physical load, social situation, and location could be accurately estimated from a single large-scale ensemble average spanning these entire periods. Impedance and electrocardiograms were recorded for about 24-h from 21 subjects. Recordings were scored by seven raters, using both methods for each subject. Good agreement (average intraclass correlation coefficient was .91) between both ensemble averaging methods was found for all three cardiac function measures. The results indicate that for unambiguous ambulatory impedance cardiograms, large-scale ensemble averaging is valid, which makes measuring prolonged changes in cardiac sympathetic activity by measuring ambulatory PEP feasible even in large epidemiological samples.

Cardiovascular reactivity and left ventricular mass: An integrative review

Left ventricular hypertrophy has been shown to be an independent predictor of risk for cardiovascular morbidity and mortality. Behavioral scientists have focused on how hemodynamic factors influenced by psychosocial stress may be associated with left ventricular mass (LVM). We reviewed existing studies examining stress-related cardiovascular reactivity (CVR) and LVM, with a goal of examining the moderating role of population (age and hypertensive status) and methodological factors (task type, sample size, and study design) explaining the observed results. Twenty-one studies met the criteria for this review. Results showed only a modestly consistent relationship between CVR and LVM. Forty-three percent of the studies reported 1 or more significant results linking systolic blood pressure reactivity with LVM, and 14% of the studies showed that diastolic blood pressure reactivity was significantly related to LVM. Hypertensive status, task type, and sample size did not play a major role in moderating the relationship between LVM and CVR. A somewhat larger percentage of positive results was shown in prospective and adult studies. The association between CVR and LVM may be real, although the effect size is modest, and we discuss methodological strategies for enhancing statistical power in future investigations. Additional sampling factors (e.g., race, gender) may also impact this relationship. Finally, greater attention is warranted to the role of the psychosocial environment, as this may interact with reactivity to influence LVM.

24-Hour BP in Children With Congenital Central Hypoventilation Syndrome

OBJECTIVE

To study circadian BP patterns in patients with congenital central hypoventilation syndrome (CCHS).

DESIGN

Case-control study.

SETTING

Teaching hospital in Paris, France.

PATIENTS

Eleven patients with CCHS (median age, 13 years; range, 6 to 18 years) and 11 sex- and height-matched control subjects.

INTERVENTION

None.

METHODS

Each subject underwent 24-h ambulatory BP monitoring. Oxygen saturation and end-tidal PCO(2) were monitored noninvasively. Polysomnography was performed to determine sleep times. All patients with CCHS received mechanical ventilation during sleep. Mean values for systolic BP (SBP) and diastolic BP (DBP) during wakefulness and sleep were analyzed. Nocturnal BP "dipping" was defined as the difference in mean SBP (and/or DBP) between wakefulness and sleep, divided by individual waking mean values. BP "dippers" were defined as subjects showing at least 10% nocturnal dipping.

RESULTS

Patients with CCHS had BPs in the low normal range of normative data. As compared to control subjects, patients with CCHS had lower BP during wakefulness (p = 0.003 and p = 0.016 for SBP and DBP, respectively), and higher BP during sleep (p = 0.016 and p = 0.002). Nocturnal BP dipping was abnormally reduced in patients with CCHS (p = 0.000). Ten of the 11 patients with CCHS were BP nondippers, compared to none of the control subjects.

CONCLUSION

The abnormal circadian BP pattern observed in children and adolescents with CCHS may be related to autonomic nervous dysfunction. Lifelong cardiovascular follow-up is recommended for patients with CCHS.

An international database of prospective ambulatory blood pressure monitoring studies

An international database of prospective studies of ambulatory blood pressure monitoring was set up in 2001, and will include at least eight individual studies. The goals are to enable analyses that cannot be made reliably from the individual studies, such as the predictive value of different measures of blood pressure, for example the morning surge and blood pressure variability, the ability to look at the prediction of specific endpoints, for example stroke versus myocardial infarction, and also to look at differences in different populations.

Assessment of overall blood pressure variability and its different components

Blood pressure (BP) is characterized by continuous fluctuations, including fast changes lasting only a few seconds as well as slower and more prolonged variations, with a time constant of minutes or hours. Assessing the relative contribution of these different components to overall blood pressure variance is now possible through a number of mathematical approaches, either in the time or in the frequency domain (spectral analysis). Due to its complex nature, a precise and detailed assessment of blood pressure variability can be obtained only from the analysis of continuous, beat-by-beat, blood pressure recordings. Some information, however, can also be derived from analysis of discontinuous blood pressure tracings, such as those commonly performed in a clinical setting. This would require that attention is paid both to the quality of the recordings and to the selection of suitable analysis methods that should cope with the discontinuous nature of the measurements to be processed and to their intrinsic low sampling frequency.

Blood pressure independent association of microalbuminuria and left ventricular hypertrophy in hypertensive men

BACKGROUND

Rather unique amongst the prognostic predictors, microalbuminuria (MA, albuminuria: 15-200 microg min-1) is associated with several cardiovascular risk factors including left ventricular hypertrophy (LVH). The relationship, usually assumed to reflect an increased blood pressure (BP) load on the heart and the kidney, may, however, represent more than a haemodynamic correlate.

METHODS

To evaluate this possibility, we related MA to left ventricular mass index (LVMI) and other functional and structural echocardiographic parameters, office and 24-h BP, weight, lipids and smoking status in 330 never treated nondiabetic hypertensive men.

RESULTS

The risk of MA increased linearly by ascending quartiles of LVMI and was 2.3-fold higher in the presence of LVH after adjustment for age, left atrial size, mean fractional shortening. Systolic BP, either office or 24 h, and smoking status were the only additional independent predictors in multivariate logistic regression models. The BP-adjusted risk of MA was about twofold higher in patients with LVH, either concentric or eccentric, and neutral in those with concentric remodelling compared with normal geometry.

CONCLUSIONS

The association between elevated LVMI and MA independent of several other potential confounders, systolic BP in particular, is consistent with the existence of cardiac albuminuric factors, possibly of hormonal nature, which are to be identified more precisely. The extent to which LVH explains the predictive power of MA for morbid events independent of the BP load remains unknown.

Ambulatory blood pressure, left ventricular mass, and conduit artery function late after successful repair of coarctation of the aorta

OBJECTIVES

We sought to evaluate the determinants of hypertension during daily life and left ventricular (LV) hypertrophy in patients with successfully repaired coarctation of the aorta (CoA), as well as their relationship to abnormalities of arterial function.

BACKGROUND

Arterial hypertension may recur late after repair of CoA, which is related to a more adverse outcome. Furthermore, patients with normal resting blood pressure (BP) may have hypertension during daily life and LV hypertrophy. The determinants of these two adverse prognostic factors have not been investigated.

METHODS

We studied 72 patients (9 to 58 years of age) who underwent coarctation repair at age 0.1 to 480 months (42 [60%] at <1 year) and had been followed up for 155 +/- 76 months. They underwent ambulatory BP monitoring, echocardiography for LV mass, studies of brachial artery responses to flow (i.e., flow-mediated dilation [FMD]) and glyceryl trinitrate (GTN), and determination of pulse wave velocity (PWV) and measures of arterial reactivity and stiffness. Findings were compared with those of 53 healthy volunteers.

RESULTS

Patients had higher 24-h systolic BP and LV mass than controls. Both endothelium-dependent FMD and the response to the smooth muscle dilator GTN were reduced, and PWV was increased. There was a negative independent correlation between GTN response and 24-h systolic BP in both patients and control subjects. Systolic BP at 24 h was an independent predictor of LV mass, having an accentuated impact in coarctation subjects as compared with controls.

CONCLUSIONS

In patients with repaired coarctation, reduced vascular reactivity is associated with hypertension during daily life and with increased LV mass, both of which are important predictors for late morbidity and mortality.

The ongoing telmisartan alone and in combination with ramipril global endpoint trial program

The renin-angiotensin system evolved to maintain volume homeostasis and blood pressure and to prevent ischemia during acute volume loss. But in the present age, these mechanisms are redundant, and the clinical significance of angiotensin II results from its pathologic effects, which are mediated by the angiotensin II type 1 (AT(1)) receptor. Activation of AT(1) receptors has been linked to pathologic processes that contribute to atherosclerosis and ischemic events, including oxidative stress, inflammatory processes, low-density lipoprotein cholesterol trafficking, and prothrombotic states. The Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) program will compare the efficacy of the angiotensin II receptor blocker (ARB) telmisartan, the angiotensin-converting enzyme (ACE) inhibitor ramipril, and combination therapy with telmisartan plus ramipril for reducing cardiovascular risk. The ARB telmisartan is distinguished by its long duration of action, which compares favorably with some other ARBs and conventional antihypertensives. Ramipril was shown in the Heart Outcomes Prevention Evaluation (HOPE) study to reduce the risk for myocardial infarction (MI) and other cardiovascular events in patients at high risk for cardiovascular events but without heart failure or a low ejection fraction. The ONTARGET program consists of 2 randomized, double-blind, multicenter international trials: a principal trial, ONTARGET, and a parallel trial, Telmisartan Randomized Assessment Study in ACE-I Intolerant Patients with Cardiovascular Disease (TRANSCEND). The treatment arms for the principal ONTARGET study are telmisartan 80 mg, ramipril 10 mg, and combination therapy with telmisartan 80 mg plus ramipril 10 mg; for the parallel study TRANSCEND, the treatment arms are telmisartan 80 mg and placebo. Both trials will assess cardiovascular outcomes in patients at high risk using the same criteria as that of the HOPE study, with a single exception: the TRANSCEND trial will enroll patients who do not tolerate ACE inhibitor treatment. The primary end points in both ONTARGET and TRANSCEND are death caused by cardiovascular disease, acute MI, stroke, and hospitalization because of congestive heart failure. The secondary end points include newly diagnosed heart failure, revascularization, new-onset type 2 diabetes mellitus, nephropathy, cognitive decrease and dementia, and newly diagnosed atrial fibrillation; these will be used for hypothesis generation.

Ambulatory blood pressure measurement is indispensable to good clinical practice

The traditional technique of blood pressure measurement is being phased out in most countries and is being replaced by automated measurement. The era of automated blood pressure measurement brings its own problems, not least being the need to evaluate blood pressure measuring devices independently for accuracy. Towards this end, the Working Group on Blood Pressure Monitoring of the European Society of Hypertension has published an international protocol with the aim of having all devices assessed for basic accuracy before being put on the market. The main thrust of this review is that if ambulatory blood pressure measurement has become indispensable to the management of patients with hypertension, it then becomes imperative to encourage the use of ambulatory blood pressure measurement (ABPM) in general practice rather than restricting its availability to specialist hospital centres. However, if ABPM is to be widely used in general practice, there is a need to establish appropriate educational processes and to improve the methods of presenting and analysing ABPM data.

Administration of raloxifene does not influence 24-hour ambulatory blood pressure of postmenopausal women with osteopenia: a double-blind placebo-controlled study

OBJECTIVE

Because estrogens may decrease 24-hour blood pressure of postmenopausal women, we tested the effect of the selective estrogen receptor modulator raloxifene on ambulatory blood pressure.

STUDY DESIGN

Postmenopausal women with osteopenia who were otherwise healthy were assigned randomly in a double blind-fashion to receive placebo (n = 16 women) or raloxifene (60 mg/d, n = 16 women). Before and after 4 months, the blood pressure of each woman was monitored every 30 minutes for 41 hours with the use of an ambulatory device.

RESULTS

Similar to the placebo outcome, the raloxifene administration did not modify 24-hour daytime (7 AM -11 PM) and nighttime (11 PM -7 AM) blood pressure and heart rate values. Day-night differences and the 24-hour rhythmic variation of mean blood pressure, which was evaluated by cosinor analysis, were also not affected by placebo or by raloxifene.

CONCLUSION

Raloxifene does not influence 24-hour blood pressure of postmenopausal women. These data are reassuring for the cardiovascular safety of the long-term raloxifene administration.

The white-coat effect is unrelated to the difference between clinic and daytime blood pressure and is associated with greater reactivity to public speaking

OBJECTIVE

To compare the blood pressure (BP) response to doctor's visit with the BP reaction to a psycho-social challenge and with the difference between clinic and daytime BP (DeltaC-D).

SUBJECTS

We studied 64 young stage-1 hypertensive subjects and 33 normotensive controls.

MAIN OUTCOME MEASURES

Relationship between direct and surrogate measure of white-coat effect (WCE) and assessment of BP response to public speaking in subjects with normal or increased reaction to BP measurement.

METHODS

The responses to BP measurement by a doctor and to public speaking were assessed with beat-to-beat Finapres recording. DeltaC-D was calculated on the basis of two BP monitorings and used as a surrogate measure of WCE.

RESULTS

BP and heart rate changes elicited by the visit were unrelated to DeltaC-D and were correlated to the changes caused by the speech test [P <0.001 for systolic BP (SBP), P = 0.01 for diastolic BP (DBP), and P <0.001 for heart rate]. Hypertensive subjects with SBP response to doctor's visit above the median (hyper-reactive) showed increased reactivity also to public speaking (61 +/- 15 mmHg), while those with BP response below the median (normo-reactive) had a response to the psycho-social challenge (40 +/- 21 mmHg, 0.001 versus hyper-reactive) similar to that of the normotensive controls (38 +/- 17 mmHg). Epinephrine urinary output was greater in the hyper-reactive than the normo-reactive subjects (23 versus 12 microg/24 h, = 0.01). The SBP response to public speaking was greater in the hypertensive subjects with higher systolic daytime BP than in those with lower daytime BP (55.3 +/- 20.9 versus 45.1 +/- 20.6 mmHg, = 0.046).

CONCLUSIONS

Subjects with increased WCE have an exaggerated response also to psycho-social stimuli. Average daytime BP, which incorporates the BP reactions to many psycho-social triggers can, thus, not be taken as the basal BP of an individual. This helps explain why DeltaC-D does not reflect the true WCE.

Determinants of left atrial size in patients with newly diagnosed untreated hypertension

The present study determined the relationships between ambulatory blood pressure, left ventricular mass, body mass index, and other clinical and demographic variables to left atrial size in previously untreated hypertensive and normotensive subjects. Left atrial size was measured uni-dimensionally using M-mode echocardiography in 58 newly diagnosed never-treated hypertensive patients (office blood pressure 149/96 +/- 15/7 mmHg) and 28 normotensive control subjects (office blood pressure, 122/78 +/- 8/8 mmHg). Left ventricular mass, septal and posterior wall thickness were significantly increased in hypertensive compared to normotensive subjects (230 +/- 63 g versus 181 +/- 45 g, 1.1 +/- 0.2 cm versus 0.94 +/- 0.2 cm, and 1.04 +/- 0.2 cm versus 0.92 +/- 0.2 cm respectively; all p < 0.001). Left ventricular internal diameter (4.9 +/- 0.6 versus 4.8 +/- 0.4 cm, = 0.54) and left atrial size (3.74 +/- 0.48 versus 3.70 +/- 0.34 cm, p = 0.86) were not different between the two groups respectively. Body mass index, weight, left ventricular mass, wall thickness, and 24-h pulse pressure were significant correlates of left atrial size in the entire group and in the hypertensive subgroup. In the normotensive subgroup, body weight, body mass index, 24-h systolic and pulse pressure, and left ventricular mass were significant correlates. Multiple regression analyses in the entire group and the hypertensive subgroup alone showed that body mass index and left ventricular mass were the two best predictors of left atrial dimension. These data demonstrate that body mass index and left ventricular mass were the main correlates of left atrial size in patients with previously untreated stage I-II hypertension.

Circadian changes in blood pressure and their relationships to the development of microalbuminuria in type 1 diabetic patients

Diabetic nephropathy in type I diabetic patients, as it is currently understood, progresses in a stepwise fashion from normoalbuminuria to microalbuminuria, then to overt proteinuria and progression to chronic renal failure, and ultimately to end-stage renal disease. The role of early blood pressure changes in relation to diabetic nephropathy is now better understood in light of recent data using ambulatory blood pressure monitoring as a means to monitor blood pressure changes noninvasively throughout the day. Cross-sectional studies with type I diabetic patients with microalbuminuria have shown that the normal nocturnal blood pressure often fails to fall normally during sleep. The question of which comes first, microalbuminuria or a rise in blood pressure in patients with type I diabetes, was recently addressed in a prospective study. An increase in systolic blood pressure during sleep precedes the development of microalbuminuria and may play a causative role in its development.

What is the white-coat effect and how should it be measured?

The white coat effect is conceived as a measure of the blood pressure response to a clinic visit, but there is no agreement as to exactly how it should be defined. The most widely used definition is the difference between the average clinic and daytime ambulatory blood pressures, but other methods that have been used include the difference between clinic and home pressures, measurements using ambulatory blood pressures only, clinic measurements only, and laboratory (reactivity) testing. Few studies have compared the different methods, but the reactivity method has reported bigger changes of blood pressure and heart rate than the others. The effect tends to be greater in older than younger patients, in women than in men, but is present to a greater or lesser degree in almost all hypertensive patients. It is diminished but not obliterated by drug treatment. It is not closely related to overall blood pressure variability, and does not predict cardiovascular risk. The white coat effect appears to be idiosyncratic to the clinic setting.

The tolerance-hyperbaric test: a chronobiologic approach for improved diagnosis of hypertension

Blood pressure (BP) displays predictable large-amplitude circadian variability. Thus, the identification and the proper definition of hypertension are highly ambiguous when based on single time-unspecified measurements. One way to deal with such variability in the diagnosis of hypertension is to replace the commonly used constant limits of BP by a time-specified reference interval based on the normal circadian BP rhythm assessed by ambulatory BP monitoring (ABPM). A proper reference limit can be constructed, for instance, as a tolerance interval computed for every specific time interval throughout the 24 h. Once such a threshold (given by the upper limit of the tolerance interval) is constructed, a hyperbaric index (HBI) can be computed by numerical integration of the total area of any given patient's BP profile above threshold. The HBI plus the duration of excess within the 24h day serves as nonparametric endpoints for assessing hypertension. Both retrospective and prospective evaluation of this tolerance-hyperbaric test validate its high sensitivity and specificity in the diagnosis of hypertension. We describe the theory of the HBI as well as a newly created dedicated software program that automatically derives the tolerance intervals from a reference database of normotensive subjects and calculates the HBI and other potentially valuable parameters based on data obtained by ABPM. The establishment of time-qualified tolerance limits and the assessment of the extent and timing of BP elevation represents a valuable tool for the more accurate diagnosis of hypertension as well as means of gauging response to treatment.

Exercise capacity and brain natruiretic peptide in hypertension

Brain natriuretic peptide (BNP) is increased and it is also released during exercise in hypertension, but its biologic role is unclear. However, since BNP is released from the left ventricule and it is known to reduce left ventricular filling pressure, it is possible that it exerts a favorable effect on exercise performance. We studied the relationship between endogenous BNP release and exercise capacity in hypertension with reference to left ventricular hypertrophy (LVH). Cardiopulmonary exercise study was carried out in 2 groups of hypertensives, 24 [16 men, aged 50 (SD 11) years] of whom had echocardiographic LVH and 25 [16 men, aged 41 ( 12)] who did not have LVH. In multiple regression analyses, the major determinants of peak oxygen uptake (VO max) were age (-), sex (male), peak exercise systolic BP (+) and post-exercise BNP (-). For the predicted adjusted %VO max as a measure of individualised exercise capacity, the significant predictors were the exercise-induced BNP rise (-) (p = 0.0003) and peak exercise systolic BP (+) (p = 0.001). In other words, subjects with greater myocardial dysfunction had a greater rise in BNP during exercise. LVH did not however relate to exercise capacity. The baseline, post-exercise and the % rise in BNP (pmol/L) with exercise were not statistically different in those with LVH compared with those without (median values of 11.2, 14.6 and 133% versus 10.6, 11.5 and 120% respectively). Similarly, there were no significant differences in exercise capacity between the groups: exercise time, oxygen uptakes at ventilatory threshold and at peak exercise (VO max) were 10.8 (2.5) min, 15.8 (4.6) and 33.6 (7.6) ml/min/kg in the LVH group against 11.4 (2.9) min, 18.6 (5.2) and 36 (11.1) ml/min/kg in the non-LVH group respectively. The estimated VO max was not different from that predicted from age, sex, weight and height in either group suggesting preserved exercise capacity in these subjects as a whole. In Conclusion, BNP may potentially act as a homeostatic mechanism that helps to limit exercise incapacity in hypertension irrespective of LVH.

Hypertension as a cardiovascular risk factor in end-stage renal failure

There is a paucity of high quality studies on the prognostic importance of arterial pressure in end-stage renal disease. Furthermore, the optimal timing for blood pressure (BP) measurements (pre- or postdialysis), and the prognostic value of 24-hour ambulatory BP monitoring in these patients remain to be established. In end-stage renal disease patients without diabetes and heart failure, predialysis systolic, diastolic, and pulse pressure are strongly and independently related to left ventricular mass, and the strength of these relationships is higher than that between the corresponding postdialysis values and left ventricular mass. Average predialysis systolic pressure (monthly average) is associated with left ventricular mass as strongly as 24-hour systolic BP, which suggests that the average routine predialysis BP taken over 1 month may be equally representative of the "true" BP (the integrated BP load) than 24-hour ambulatory BP monitoring. Mortality is U shaped in large hemodialysis databases. In the only prospective study that adequately controlled for cardiac function at baseline, it was shown that hypertension is associated with a higher risk of developing congestive heart failure, and that patients with left ventricular hypertrophy or chronic heart failure are at a much higher risk of mortality than patients without these complications. The role of arterial stiffening (pulse pressure) as a cardiovascular risk factor has been firmly established in an analysis of a very large dialysis database in the United States, and by recent studies based on direct measurements of pulse wave velocity.

Too much of a good thing? A critique of overemphasis on the use of ambulatory blood pressure monitoring in clinical practice

Ambulatory blood pressure monitoring (ABPM) can be considered a major achievement in clinical medicine. However, its superiority over traditional clinical measurement has often been overemphasized in the literature. In both cross-sectional and longitudinal studies, ABPM has been compared with clinical blood pressure calculated from only a few readings taken over a short period of time. For reasons of costs and practicality, ABPM should not be considered as a routine test in the assessment of the hypertensive patient. Most patients with borderline hypertension or isolated clinical hypertension can be profitably assessed with multiple clinical readings and self-blood pressure monitoring. Patients with large short-term or long-term blood pressure oscillations appear as optimal candidates to ABPM. The many methodological problems associated with the use of this technique suggest that ABPM is performed only by experienced doctors.

Dissecting the genetic architecture of the cardiovascular and renal stress response

We review the evidence for a genetic basis of the cardiovascular and renal stress response. A bio-behavioral model of stress-induced hypertension is presented that explains how repeated exposure to stress in combination with genetic susceptibility might lead to the development of hypertension. In this model, we focus on three underlying physiological systems that mediate the stress response of the heart, vasculature and kidney: the sympathetic nervous system (SNS), the renin-angiotensin-aldosterone system (RAAS) and the endothelial system (ES). We then review the evidence for a genetic influence on cardiovascular reactivity to psychological stress and stress-induced sodium retention using data from twin and family studies and a limited number of candidate gene studies. Finally, by describing the underlying physiological systems of our model and their genetic underpinning we emphasize the importance of inclusion of genetic measurements in any future studies testing the reactivity hypothesis.

Clinic, home and ambulatory pulse pressure: comparison and reproducibility

OBJECTIVE

Recent evidence suggests that pulse pressure (PP) is an independent predictor of cardiovascular risk. The objective of this study was to compare mean values and reproducibility of PP obtained in the clinic (CPP), at home (HPP) and with ambulatory monitoring (APP) and to evaluate potential implications for trials aiming to assess drug effects on PP.

METHODS

A total of 393 hypertensive subjects [mean age 51.5 +/- 11.5 (SD) years, 59% men, 35% treated] measured CPP (two visits), HPP (6 days) and APP (24 h). The reproducibility of PP was assessed using the SD of differences (SDD) between measurements in 133 untreated subjects who had repeated CPP (five visits), HPP (6 days) and APP measurements (two occasions).

RESULTS

There was no difference between mean CPP (51.0 +/- 13.3 mmHg) and HPP (50.2 +/- 11.0) whereas APP (48.8 +/- 8.4) was lower than both CPP [mean difference 2.3 +/- 10.3 mmHg; 95% confidence interval (CI), 1.2, 3.3; P < 0.01] and HPP (1.5 +/- 7.8; 95% CI, 0.7, 2.3; P < 0.01). The SDD between repeated measurements was about 10 mmHg for CPP (one visit), 5.2 mmHg for HPP (2 days) and 4 mmHg for APP (24-h). For a parallel comparative trial aiming to detect a difference of 3 mmHg PP in the effect of two drugs, 415 subjects would be required when using CPP, compared to 127 using HPP and 63 using APP.

CONCLUSIONS

These data suggest that although differences among mean values of CPP, HPP and APP are small, differences in their reproducibility are important and should be taken into account in the design of trials assessing drug effects on PP.

Ambulatory blood pressure monitoring: is it necessary for the routine assessment of hypertension in people with diabetes?

AIMS

The British Hypertension Society (BHS) has recommended that, for people with diabetes, the target 'clinic' blood pressure should be < 140/80 mmHg. Ambulatory monitoring of blood pressure (ABPM) is used widely in the assessment of hypertension and the BHS has recommended that the target 'awake' ambulatory blood pressure for people with diabetes should be < 130/75 mmHg. The purpose of the present study was to determine the utility of ABPM in the assessment of hypertension in patients with diabetes, over and above a careful 'clinic' measurement of blood pressure.

METHODS

The records of 540 patients with diabetes who underwent ABPM (using SpaceLabs monitors) were retrospectively analysed. With respect to current BHS recommendations, the positive and negative predictive values of 'clinic' blood pressure (measured by trained nurses using mercury sphygmomanometers) on 'awake' ambulatory blood pressure (ABP) were calculated.

RESULTS

The positive predictive value of the 'clinic' BP, its ability to detect patients whose ABP was above BHS targets, was 99%. The negative predictive value of 'clinic' blood pressure was 27%.

CONCLUSIONS

With regard to current BHS guidelines, ABPM is generally unnecessary in the assessment of hypertension in patients with diabetes, provided careful 'clinic' measurements of blood pressure are made.

Ambulatory blood pressure monitoring in chronic renal disease: technical aspects and clinical relevance

PURPOSE OF REVIEW

To evaluate the current value of ambulatory blood pressure monitoring in patients with chronic renal disease and end-stage renal disease.

RECENT FINDINGS

Ambulatory blood pressure monitoring has become an important tool in hypertension research and clinical practice. Its use in essential hypertension shows a strong predictive ability in the assessment of cardiovascular outcomes. In chronic renal failure and end-stage renal disease, the role of ambulatory blood pressure monitoring is still being actively evaluated, and available evidence shows that it is better than office blood pressure in predicting left ventricular hypertrophy and progression of renal dysfunction in patients with chronic renal failure. In end-stage renal disease, preliminary data suggest better prediction of mortality in hemodialysis patients in comparison with clinic blood pressures. The most conspicuous problems with the literature on this subject are small sample sizes and the paucity of longitudinal observational studies and intervention trials.

SUMMARY

Preliminary data and extrapolations from essential hypertension have justified a growing excitement about the use of ambulatory blood pressure monitoring in renal disease. However, further research will have to address the limitations of the available literature before generalization of its use is implemented.