Use and interpretation of ambulatory blood pressure monitoring: recommendations of the British hypertension society

Effect of social support on nocturnal blood pressure dipping

OBJECTIVE

To determine if nocturnal blood pressure (BP) dipping among non-Hispanic blacks is influenced by social support. Non-Hispanic blacks have higher rates of cardiovascular morbidity and mortality from hypertension and are more likely to have ambulatory blood pressure (ABP) that remains high at night (nondipping).

METHODS

A total of 68 non-Hispanic black normotensive and 13 untreated hypertensive participants (age 72 +/- 10 years, 48% female) free of clinical cardiovascular disease completed 24-hour ABP monitoring and a questionnaire that included a modified version of the CARDIA Study Social Support Scale (CSSS). Nondipping was defined as a decrease of <10% in the ratio between average awake and average asleep systolic BP. Analyses were adjusted for age, gender, and systolic BP.

RESULTS

The prevalence of nondipping was 26.8% in subjects in the highest CSSS tertile versus 41.1% in the lowest CSSS tertile (p = .009). On adjusted analysis, CSSS was analyzed as a continuous variable and remained independently and inversely associated with nondipping (odds ratio 0.27, 95% Confidence Interval 0.08-0.94, p = .04).

CONCLUSIONS

Social support may be an important predictor of BP dipping at night. These findings suggest that social support may have positive health affects through physiologic (autonomic) pathways.

Endothelial dysfunction, ambulatory pulse pressure and albuminuria are associated in Type 2 diabetic subjects

AIM

Elevated pulse pressure (PP) is associated with microvascular complications in Type 2 diabetic patients. In non-diabetic subjects, elevated PP has been associated with endothelial dysfunction. The relation between endothelial dysfunction and PP in diabetic subjects has not previously been examined. We examined the relation between PP, markers of endothelial activation and albuminuria in Type 2 diabetic patients.

METHODS

In 46 Type 2 diabetic patients and 19 non-diabetic subjects, we performed 24-h ambulatory blood pressure (AMBP) monitoring. Urinary albumin excretion rate was measured as three urinary albumin/creatinine ratios. Von Willebrand factor (vWF), fibrinogen, E-selectin and soluble intercellular adhesion molecule 1 (ICAM-1) were measured in plasma.

RESULTS

Thirty-four patients had normoalbuminuria (group N) and 12 had micro- or macroalbuminuria (group A). PP levels increased in a stepwise manner from the control group (group C) to group N and group A; night PP 43 +/- 5, 48 +/- 10 and 59 +/- 12 mmHg (groups C, N and A, respectively, P < 0.001). Likewise, plasma levels of vWF, fibrinogen, E-selectin and ICAM-1 increased from group C to group A; e.g. ICAM-1 [median (interquartile range)] 191 (160-217), 213 (189-262) and 316 (260-417) ng/ml, groups C, N and A, respectively, P < 0.001). In diabetic patients, night PP and plasma levels of E-selectin and ICAM-1 correlated (r = 0.38, P < 0.01 and r = 0.37, P = 0.01, night PP with E-selectin and ICAM-1, respectively).

CONCLUSION

Increased PP is associated with endothelial activation and albuminuria in Type 2 diabetic patients. Thus, endothelial dysfunction may represent a pathophysiological link between an elevated PP and microvascular complications in these subjects. Prospective studies are needed to further elucidate these associations.

Circadian Blood Pressure Variation and Antihypertensive Medication Adjustment in Normoalbuminuric Type 2 Diabetes Patients

BACKGROUND/AIMS

The aim of the study was to assess the effect of an antihypertensive treatment adjustment on 24-hour blood pressure variation in type 2 diabetes patients.

METHODS

The study group included 59 hypertensive type 2 diabetes patients subjected to a single one-step antihypertensive agent dose adjustment (increase or decrease). Ambulatory blood pressure monitoring was performed at baseline and 4-6 weeks after the treatment modification. Controls were 41 matched patients, in whom antihypertensive treatment remained unchanged.

RESULTS

At baseline, 45 (76%) study group patients and 29 (71%) controls were 'non-dippers'; a similar number of patients in both groups converted to 'dipping' or vice versa: 11 (19%) from the study group and 7 (17%) controls. 'Converters' from the study group were significantly younger (47.5 +/- 3.9 vs. 56.4 +/- 12.2 years; p < 0.05) and had lower 24-hour systolic blood pressure than 'non-converters': 113.7 +/- 7.2 vs. 127.7 +/- 20.3 mm Hg (p < 0.01).

CONCLUSION

A single one-step antihypertensive medication adjustment does not affect 'dipping' status in type 2 diabetes patients. However, the assessment of blood pressure variation should be made with greater caution in younger type 2 diabetes subjects with low systolic blood pressure.

Cognitive function by brain event-related potentials (ERP) in elderly with borderline isolated systolic hypertension (BISH)

Several studies have shown a relationship between BISH and cerebrovascular events, but no studies have investigated a relationship with cognitive function. The aim was to assess the cognitive function in the elderly with recent BISH. According to WHO Guidelines (1999), we selected 10 elderly normotensives, 10 elderly with recently diagnosed (<2 years) BISH, and 10 elderly with recently diagnosed (<2 years) isolated systolic hypertension (ISH). They were submitted to 24-hr ambulatory blood pressure (BP) monitoring (ABPM) and to cognitive assessment by mini mental state examination (MMSE) and the recording of brain ERP, of type N2 and P300. The elderly with BISH, compared to normotensives, showed N2 wave latency values significantly higher, but similar P300 potential latency values and MMSE scores. The elderly with ISH showed N2 and P300 latency significantly higher than the normotensives. The gradual increase of the ERP latency values of the BISH and ISH elderly, in comparison to the normotensives, seems to indicate a gradual alteration of the cognitive processes related to the increase of BP.

Ambulatory blood pressure monitoring in hypertensive patients with high cardiovascular risk: a cross-sectional analysis of a 20 000-patient database in Spain

OBJECTIVE

To evaluate ambulatory blood pressure monitoring (ABPM) parameters in a broad sample of high-risk hypertensive patients.

METHODS

The Spanish Society of Hypertension is developing a nationwide project in which more than 900 physicians send ABPM registries and corresponding clinical records to a central database via www.cardiorisc.com. Between June 2004 and July 2005 a 20 000-patient database was obtained; 17 219 were valid for analysis.

RESULTS

We identified 6534 patients with high cardiovascular risk according to the 2003 European Society of Hypertension/European Society of Cardiology guidelines stratification score. Office blood pressure (BP) was 158.8/89.9 mmHg and 24-h BP was 135.8/77.0 mmHg. Patients with grade 3 BP in the office showed ambulatory systolic BP values less than 160 mmHg in more than 80%. A non-dipping pattern was observed in 3836 cases (58.7%), whereas this abnormality was present in 47.9% of patients with low-to-moderate risk [odds ratio (OR) 1.54; 95% confidence interval (CI) 1.45-1.64]. The prevalence of non-dippers was higher as ambulatory BP increased ( approximately 70% when 24-h systolic BP > 155 mmHg) and was similar in both groups. At the lowest levels of BP (24-h systolic BP < 135 mmHg) a non-dipping pattern was more prevalent in high-risk cases (56.6 versus 45.7%; OR 1.51; 95% CI 1.40-1.64).

CONCLUSION

There was a remarkable discrepancy between office and ambulatory BP in high-risk hypertensive patients. The prevalence of a non-dipper BP pattern was almost 60%. In the lowest levels of ambulatory BP, high-risk patients showed a higher prevalence of non-dipping BP than lower-risk cases. These observations support the recommendation of a wider use of ABPM in high-risk hypertensive patients.

CYP3A5 and ABCB1 genes influence blood pressure and response to treatment, and their effect is modified by salt

The permeability-glycoprotein efflux-transporter encoded by the multidrug resistance 1 (ABCB1) gene and the cytochromes P450 3A4/5 encoded by the CYP3A4/5 genes are known to interact in the transport and metabolism of many drugs. Recent data have shown that the CYP3A5 genotypes influence blood pressure and that permeability-glycoprotein activity might influence the activity of the renin-angiotensin system. Hence, these 2 genes may contribute to blood pressure regulation in humans. We analyzed the association of variants of the ABCB1 and CYP3A5 genes with ambulatory blood pressure, plasma renin activity, plasma aldosterone, endogenous lithium clearance, and blood pressure response to treatment in 72 families (373 individuals; 55% women; mean age: 46 years) of East African descent. The ABCB1 and CYP3A5 genes interact with urinary sodium excretion in their effect on ambulatory blood pressure (daytime systolic: P=0.05; nighttime systolic and diastolic: P<0.01), suggesting a gene-gene-environment interaction. The combined action of these genes is also associated with postproximal tubular sodium reabsorption, plasma renin activity, plasma aldosterone, and with an altered blood pressure response to the angiotensin-converting enzyme inhibitor lisinopril (P<0.05). This is the first reported association of the ABCB1 gene with blood pressure in humans and demonstration that genes encoding for proteins metabolizing and transporting drugs and endogenous substrates contribute to blood pressure regulation.

Usefulness of ambulatory blood pressure monitoring in predicting the presence of autonomic neuropathy in type I diabetic patients

This study investigated whether nondipping (defined as a day-night change in blood pressure (BP) <or=0%) could be assumed as a diagnostic index for autonomic neuropathy, and assessed its accuracy in discriminating between type I diabetic patients with and without autonomic neuropathy. In 87 type I diabetic patients with normal renal function (age 36+/-11, duration 17+/-9 years, serum creatinine 67.2+/-15.9 micromol/l), four cardiovascular tests and 24-h BP monitoring were performed, and the percentage day-night change (Delta) in systolic (SBP) and diastolic BP (DBP) was calculated. Sixteen patients had DeltaSBP and/or DeltaDBP <or=0%. In a multiple logistic regression with adjustment for sex, age, and body mass index, the odds ratio for having autonomic neuropathy was seven times higher in patients with DeltaSBP <or=0% as opposed to those without (odds ratio 6.97, CI 1.4-34.9, P=0.018). Using Receiver Operating Characteristic (ROC) analysis, DeltaBP showed an acceptable accuracy in discriminating between patients with and without autonomic neuropathy (area under the ROC curve 0.69+/-0.06 and 0.72+/-0.05 for DeltaSBP and DeltaDBP, respectively). Adequate cutoff values were 0% for DeltaSBP (sensitivity, 26%; specificity, 95%; positive predictive value, 87%) and 5% for DeltaDBP (sensitivity, 26%; specificity, 92%; positive predictive value, 81%). In type I diabetic patients with normal renal function, a value of DeltaSBP <or=0% identifies the presence of autonomic neuropathy with a very high chance. Nondipping at the cutoff proposed could be considered an adjunctive marker of autonomic neuropathy provided with a high specificity and low sensitivity.

Oxidative stress in human in sustained and white coat hypertension

Oxidative stress is thought to play a critical role in the pathogenesis of hypertension. Protein oxidation is defined here as the covalent modification of a protein induced either directly by reactive oxygen species or indirectly by reaction with secondary by-products of oxidative stress. The aim of our study was to evaluate the protein oxidation and to examine the function of the antioxidative system in sustained and white coat hypertensives (WCH) and compare with normotensives. This study was designed to investigate the protein oxidation parameters [protein carbonyls (PCOs)] in sustained hypertensives (17 males and 20 females) and WCH (18 males and 19 females). PCO and the endogenous antioxidant components protein thiol (P-SH), CuZn-superoxide dismutase (CuZn-SOD) and glutathione (GSH) were analysed using spectrophotometric and kinetic methods. Sustained hypertensive and WCH groups exhibited higher protein oxidation and lower P-SH, CuZn-SOD and GSH activities than normotensives. With regard to these parameters, there was no significant difference between sustained hypertensive and WCH groups. Blood pressure correlates positively with PCO groups and negatively with others. There exists an imbalance between oxidants and antioxidants in WCH because of the increase of oxidants associated with the decrease of antioxidant capacity. This may cause endothelial dysfunction just like in sustained hypertension. It may be necessary to add antioxidants to conventional antihypertensive therapy to balance the oxidative status in WCH.

Prevalence and clinical implications of the inter-arm blood pressure difference: a systematic review

A blood pressure (BP) difference between arms was first reported over 100 years ago. Knowledge of its prevalence and relevance to the accurate measurement of BP remains poor. Current hypertension guidelines do not emphasise it. The objectives of this study were to establish the best estimate of prevalence of the inter-arm difference (IAD) in the population, to consider its implications for accurate BP measurement and treatment, and to discuss its aetiology and potential as a risk marker for cardiovascular disease. Systematic literature review was carried out. The data sources were Medline EMBASE and CINAHL databases, and Index of Theses. Studies reporting prevalence rates of IAD were retrieved and considered for inclusion against explicit methodological criteria. Point prevalence rates were extracted and weighted mean prevalence rates calculated. The main outcome measures were weighted mean prevalences of systolic IAD > or =10 and > or =20 mm Hg and of diastolic IAD > or =10 mm Hg. Thirty-one studies were identified. Most had methodological weaknesses; only four met the inclusion criteria. Pooled prevalences of the IAD from these four studies were 19.6% systolic > or =10 mm Hg (95% CI 18.0-21.3%), 4.2% systolic > or =20 mm Hg (95% CI 3.4-5.1%) and 8.1% diastolic > or =10 mm Hg (95%CI 6.9-9.2%). In conclusion, an IAD is present in a substantial number of patients and should be looked for whenever diagnosis and treatment depend on accurate measurements of BP. The importance of an IAD should be better emphasised in current hypertension management guidelines. There is evidence associating an IAD with peripheral vascular disease, raising the possibility that its presence may predict cardiovascular events.

White coat phenomenon, anxiety and endothelial function in healthy normotensive elderly subjects

OBJECTIVE

The white coat phenomenon (WCP) is a blood pressure (BP) elevation specifically observed in the clinical setting. Though WCP has been suggested to associate with emotional responses such as anxiety or with cardiovascular complications, its pathogenesis and clinical significance are unclear. We studied the possible association between WCP and anxiety or vascular function in normotensive elderly subjects without major cardiovascular risk factors.

METHODS

As a parameter of anxiety, the State and Trait Anxiety Inventory (STAI) was used. WCP was evaluated by calculating the difference between the clinic BP and mean daytime ambulatory BP. As parameters of vascular function, brachial artery endothelium-dependent flow-mediated dilation (FMD) and the endothelium-independent dilation response to sublingual glyceryl trinitrate (GTN) were measured using high-resolution ultrasound.

RESULTS

Using confounding factors as covariates, no association was observed between WCP and the STAI-trait or STAI-state score. There was a significant negative association between WCP and the percent change of FMD but no association between WCP and the percent change of GTN.

CONCLUSION

WCP in the healthy normotensive elderly subjects may reflect a decrease in endothelial function, i.e. initial stage atherosclerosis, rather than anxiety.

Cost-effectiveness of ambulatory blood pressure monitoring in the follow-up of hypertension

AIMS

To study the cost of the follow-up of hypertension in primary care (PC) using clinical blood pressure (CBP) and ambulatory blood pressure monitoring (ABPM), and to analyse the cost-effectiveness (CE) of both methods.

MAJOR FINDINGS AND PRINCIPAL CONCLUSION

Good control of hypertension was achieved in 8.3% with CBP (95% CI 4.8-11.8) and in 55.6% with ABPM (95% CI 49.3-61.9). The cost of one patient with good control of hypertension is almost four times higher with CBP than with ABPM (Euro 940 vs Euro 238). Reaching the gold standard (ABPM) involved an after-cost of Euro 115 per patient. The results for a 5% discount rate showed a saving of Euro 68,883 if ABPM was performed in all the patients included in the study (n = 241, Euro 285 per patient). An analysis of sensitivity, changing the discount rate and life expectancy indicated that ABPM provides a better CE ratio and a lower global cost. ABPM is more cost-effective than CBP. However, if we include the new treatment cost of poorly monitored patients, it is less cost-effective. Excellent control of hypertension is still an important challenge for all healthcare professionals, especially for those working in PC, where most monitoring of hypertensive patients takes place.

Factors affecting the use of cumulative sums in the analysis of circadian blood pressure

The assessment of circadian blood pressure change by ambulatory blood pressure monitoring has potential as a predictor for cardiovascular events, but its evaluation is problematic due to the difficulty in defining day and night periods for individual subjects. The cumulative sums (cusums) method has the advantage of simplicity over mathematical modelling techniques and is reported to give more reproducible results than methods that use time-dependent sleep and wake periods. However, cusum parameters (cusum-derived circadian alteration magnitude (CDCAM) and cusum plot height (CPH)) are affected by the implementation of the method and by the quality of ambulatory blood pressure recordings. This study quantifies the effects of using interval blood pressure values, changing the time used for calculating the cusum plot slope (CPS) and using incomplete data recordings. Significant effects are reported in all cases. Using interval rather than recorded blood pressures causes a mean reduction in CPH and CDCAM of approximately 6%. Altering the CPS time by 1 h (from 6 h) results in a mean change in CDCAM of approximately 7%. In recordings with hourly readings, the coefficient of variation in CPH and CDCAM ranges from 4% (one missing reading) to 13% (five missing readings).

Reactivity of Ambulatory Blood Pressure to Physical Activity Varies With Time of Day

Blood pressure (BP) fluctuates over a 24-hour period, but it is unclear to what extent this variation is governed completely by changes in physical activity. Our aim was to use a BP “reactivity index” to investigate whether the BP response to a given level of physical activity changes during a normal sleep-wake cycle. Hypertensive patients (n=440) underwent simultaneous 24-hour ambulatory BP, heart rate (HR), and activity monitoring. BP and HR were measured every 20 minutes. Actigraphy data were averaged over the 15 minutes that preceded a BP measurement. Individual BP and HR reactivity indices were calculated using least-squares regression for twelve 2-hour periods. These indices were then analyzed for time-of-day differences using a general linear model. Systolic BP and HR were generally more reactive to physical activity than diastolic BP. The highest reactivity of systolic BP (mean±SE=4±1 mm Hg per logged unit change in activity) was observed between 8:00 am and 10:00 am ( P =0.014). Between 10:00 am and 12:00 pm , BP reactivity then decreased ( P =0.048) and showed a secondary rise in the early afternoon. These 24-hour changes in BP reactivity did not differ significantly between groups formed on the basis of early and late wake times ( P =0.485), medication use, age, and sex ( P >0.350). In conclusion, under conditions of normal living, the reactivity of BP and HR to a given unit change in activity is highest in the morning and shows a secondary rise in the afternoon.

Improving patient outcomes with ambulatory blood pressure monitoring in elderly with hypertension

PURPOSE

The purpose of this article is to review the current knowledge regarding ambulatory blood pressure monitoring (ABPM) use in clinical practice and to provide example cases for its use in a hypertension (HTN) specialty clinic.

DATA SOURCES

Published research trials, medical literature, and cases from the Center for Senior Hypertension.

CONCLUSIONS

The knowledge of ABPM benefits to using ABPM are substantial and improves the care and management of many conditions, including white coat HTN, white coat normotension, resistant, borderline, episodic, paroxysmal HTN, and finally orthostatic hypotension. Third-party payers only cover ABPM for "white coat" HTN.

IMPLICATIONS FOR PRACTICE

This article reviews previous studies and explains the benefit to changing our current practice to match the knowledge we have gained through research through case studies.

Applications of 24-hour Noninvasive Ambulatory Blood Pressure Monitoring

Casual blood pressure (CBP) measurements using a standard sphygmomanometer have traditionally constituted the principal modality for the assessment and management of hypertension. However, CBP measurement has shortcomings. Ambulatory blood pressure monitoring (ABPM) provides abundant information on blood pressure (BP), including heart rate, all BP readings for test periods, BP average, BP variability, BP load, load index, distribution pattern of BP, reduction percentage of BP, trough/peak ratio, and summary statistics for overall 24-hour, daytime and nighttime periods. Over the last three decades, ABPM has evolved from a research device to an established and valuable clinical tool for assessment and management of hypertension. This technology has been proven to be useful in terms of the distribution pattern of BP, characterization of BP profiles in normotensive and hypertensive patients, evaluation of patients with mild or labile hypertension, physiologic and psychologic factors for fluctuation of BP, load index study, study of white coat hypertension, etiology of hypertension, prognosis of hypertension, and assessment of antihypertensive management. Nevertheless, the technology remains underused due to lack of insurance reimbursement in most countries. Accordingly, insurance reimbursement is crucial to promote increased utility of ABPM. Clinicians should be familiar with the role of this technology in the care of patients with abnormal BP. This review is an attempt to increase clinicians' understanding of ABPM and the appropriate use of this technology.

Is the area under blood pressure curve the best parameter to evaluate 24-h ambulatory blood pressure monitoring data?

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) provides relevant data about blood pressure over a 24-h period. The analysis of parameters to determine the blood pressure profile from these data is of great importance.

OBJECTIVES

To calculate areas under systolic and diastolic blood pressure curves (SBP-AUC/DBP-AUC) and compare with systolic and diastolic blood pressure load (SBPL/DBPL) and 24-h systolic and diastolic blood pressure (24-h SBP/24-h DBP) in order to determine which provides the best correlation with left ventricular mass index (LVMI).

METHODS

ABPM measurements (1143 individuals) were analyzed to obtain 24-h SBP/24-h DBP, SBPL/DBPL, and SBP-AUC/ DBP-AUC, using Spacelabs (90207) and CardioSistemas devices. Left ventricular mass was determined using an echocardiograph HP Sonos 5500 and LVMI was calculated.

RESULTS

The correlations between all possible pairs within the group 24-h SBP/SBPL/SBP-AUC and 24-h DBP/DBPL/DBP-AUC were high and statistically significant. The correlations between 24-h SBP/24-h DBP and SBP-AUC/DBP-AUC with SBPL/DBPL close to 100%, were lower than those mentioned above. The correlations of the parameters obtained by ABPM with LVMI were also high and statistically significant, except for blood pressure load between 90 and 100%, and for 24-h SBP of 135 mmHg or less and SBPL higher than 50%.

CONCLUSIONS

SBPL/DBPL and SBP-AUC/DBP-AUC can be used for the evaluation of ABPM data owing to the strong correlation with 24-h SBP/24-h DBP and with LVMI, except when SBPL is close to 100% or 24-h SBP is below 135 mmHg but SBPL is above 50%. SBP-AUC/DBP-AUC, however, are a better alternative because they do not have the limitations of blood pressure load or even of 24-h blood pressure present.

Increased circulating concentrations of asymmetric dimethylarginine (ADMA) in white coat hypertension

Elevated plasma levels of the endogenous nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) contribute to endothelial dysfunction and seem to be a predictor for cardiovascular mortality. Elevated ADMA plasma concentrations have been demonstrated in patients with hypertension. However, the plasma concentrations of ADMA in white coat hypertension (WCH) has not been previously studied. The aim of this study was to evaluate ADMA in WCH and compare with normotensive (NT) and hypertensive (HT) patients. We also evaluated the relation between ADMA and NO in these three groups. For this purpose, 34 NT, 34 white coat hypertensive (clinical hypertension and ambulatory daytime blood pressure <135/85 mmHg) and 34 HT patients were recruited in this study. The subjects were matched for age, gender, body mass index (BMI) and the patients with smoking habit, dyslipidaemia and diabetes mellitus were excluded. The ADMA levels were determined by high performance liquid chromatography. Plasma ADMA levels were significantly higher in WCH group than in the NT group (3.21+/-0.49 micromol/l vs 2.84+/-0.58 micromol/l, P=0.046). It was significantly higher in the HT group than in the NTs (4.24+/-0.38 micromol/l, P<0.001). There was also a significant difference between the HT and WCH groups (P<0.001). The WCH subjects had significantly higher levels of NO than the HTs (41.68+/-2.23 vs 32.18+/-2.68 micromol/l; P<0.001) and significantly lower values than the NTs (48.24+/-4.29 micromol/l; P<0.001). In WCH and HT group, there was a negative correlation between ADMA and NO (r=-0.515, P=0.003 and r=-0.389, P=0.034, respectively). In NT subjects, there was no correlation between these two parameters (r=-0.287, P=0.124). The correlation between ADMA and NO was stronger in WCH group than in HT group. Although NO levels in HT patients were lower than WCHs and ADMA levels were higher in HT patients than WCHs, the negative correlation of these two parameters were more pronounced in WCH group. Decreased NO and increased ADMA levels in WCH may indicate endothelial dysfunction. Our data indicate also that WCH represent an intermediate group between NT and HT when endothelial dysfunction is concerned.

The Importance of 24 Hour Ambulatory Blood Pressure Monitoring After Thoracic Organ Transplantation

BACKGROUND

Hypertension is a significant complication after thoracic organ transplantation. In the non-transplant population, 24-hour ambulatory blood pressure monitoring (24ABPM) is useful in the diagnosis of white-coat hypertension, the assessment of resistant hypertension, and the monitoring of anti-hypertensive therapy. The loss of nocturnal reductions in blood pressure is associated with hypertensive end-organ damage. This study investigated the role of 24ABPM after orthotopic cardiac transplantation.

METHODS

Thirty-three transplant recipients underwent 24ABPM. Clinical blood pressure (CPB) was measured by using a sphygmomanometer before 24ABPM. Clinical data were collected and analyzed by a single observer with p values of less than 0.05 being taken as significant.

RESULTS

The incidence of hypertension (diastolic pressure > 90 mm Hg) in the CPB and 24ABPM groups was 33% and 52% (p =0.002). Thirty-two percent of recipients who were normotensive by clinical measurement were found to be hypertensive after 24ABPM. The converse was true in 1 case. We identified no specific risk factors for 24ABPM hypertension. One recipient failed to complete the 24-hour monitoring period.

CONCLUSION

This study demonstrates that conventional blood pressure monitoring underestimates the incidence of post-transplantation hypertension. Twenty-four hour ambulatory blood pressure monitoring is well tolerated and may improve the management of post-transplantation hypertension. White-coat hypertension is an uncommon diagnosis after cardiac transplantation, and those recipients who are hypertensive in the clinic setting should be considered true hypertensives.

Convenience of ambulatory blood pressure monitoring: comparison of different devices

OBJECTIVE

Twenty-four-hour ambulatory blood pressure monitoring has emerged as an important tool supporting physicians in the diagnosis and management of arterial hypertension. Compared with office measurements and self-measurements, however, ambulatory blood pressure monitoring shows the lowest patients' acceptance. The present study compares the convenience of different monitors in order to examine whether the patients benefit from new technologies.

METHODS

In a prospective randomized study, we compared the side effects of the Spacelabs 90207 with the I.E.M. Mobilograph monitor in 250 patients by means of a questionnaire that covered the following aspects: restriction in everyday activities, noise, sleep disturbance, pain and mobility. Complaints were measured by a five-point scale ranging from 'no complaints at all' to 'severe complaints'.

RESULTS

In all, 205 patients returned completed surveys (101 patients of the I.E.M. group, 104 patients of the Spacelabs group), yielding an 82% final response rate. The overall mean complaint score was significantly higher in the Spacelabs group than in the I.E.M group (2.24 vs. 1.78; P<0.001). The Mobilograph revealed less discomfort in every single question and differences were significant for restrictions in everyday activities, noise, pain, disturbance of the patient's or the patient's partner's sleep and restrictions in walking. Sleep disturbance was the aspect with the highest difference in the two groups.

CONCLUSION

The present work confirms that ambulatory blood pressure monitoring monitors are cumbersome to wear. Devices, however, differ in their comfort. Monitors with an improved convenience might lead to a higher patients' acceptance of this powerful diagnostic tool.

Fixed combination of manidipine and delapril in the treatment of mild to moderate essential hypertension: evaluation by 24-hour ambulatory blood pressure monitoring

This present study assessed the antihypertensive efficacy of the fixed combination of manidipine and delapril by ambulatory blood pressure monitoring in patients with hypertension inadequately controlled by monotherapy with either component. After a 2-week placebo period, 55 mild to moderate hypertensive patients were randomized to manidipine 20 mg o.d. or delapril 30 mg b.i.d. for 4 weeks. After this period, 30 patients, aged 30-76 years (18 males and 12 females) whose diastolic blood pressure was not adequately controlled (> or = 90 mmHg) by monotherapy were treated with the fixed combination of manidipine 10 mg plus delapril 30 mg o.d. for 8 weeks. A 24-h ambulatory blood pressure monitoring recording was performed at the end of the placebo washout, of the monotherapy and of the combination therapy. Blood pressure control over the 24 h was quantified by the trough-to-peak ratio and the smoothness index. As compared to placebo, the fixed combination of manidipine and delapril produced a statistically significant (p<0.01) decrease in sitting clinic (18 +/- 9/14 +/- 5 mmHg) and 24-h blood pressure (12 +/- 7/10 +/- 5 mmHg) without affecting heart rate. This reduction was greater than that observed with single components. At the end of the 8-week combination treatment period, the rate of normalilized patients was 73%. Treatment with the fixed combination was associated with a positively high smoothness index (1.2 +/- 0.7/13.8 +/- 0.8) and with a relatively good trough-to-peak ratio (0.46/0.60). The combination of manidipine and delapril produced significant and smooth reductions in blood pressure values, which persisted over the 24-h dosing interval. These results support the use of fixed manidipine-delapril combination in the treatment of mild to moderate hypertensive patients inadequately controlled by monotherapy.

Does nocturnal blood pressure fall in people of African and South Asian descent differ from that in European white populations? A systematic review and meta-analysis

OBJECTIVE

To assess whether nocturnal blood pressure fall in people of African (Black) and South Asian descent differs from that of the European origin white populations (White).

METHODS

A systematic literature review was carried out using Medline 1966-2003 and Embase 1980-2003, and citations from references. The meta-analysis was performed using Cochrane review manager software (RevMan version 4.2; The Cochrane Collaboration, Oxford, UK).

RESULTS

Seventeen studies were identified; 11 studies from the USA, one from the USA and Canada, and six studies from the United Kingdom. The mean percentage systolic blood pressure (SBP) nocturnal fall was below 10% (non-dipping) in 10 of 17 studies (59%) and the diastolic blood pressure (DBP) nocturnal fall was below 10% in four of 16 studies (25%) in Blacks compared with four of 17 studies (24%) in SBP and none in DBP nocturnal falls in Whites. Compared with Whites, Blacks had a significantly lower mean percentage nocturnal fall; the overall weighted mean difference in SBP was -3.07 (95% confidence interval, -3.81, -2.33; P < 0.00001) and in DBP was -2.98 (95% confidence interval, -3.97, -2.00; P < 0.00001). Two studies on South Asians showed a higher SBP but a similar mean DBP nocturnal fall compared with Whites.

CONCLUSION

Smaller nocturnal blood pressure falls and a higher prevalence of non-dipping may contribute to the higher levels of hypertension complications seen in Black people. No such phenomenon was seen in South Asians but more research is needed to explore their higher stroke mortality.

Hyperhomocysteinemia: an additional risk factor in white coat hypertension

The association between homocysteine and sustained hypertension (HT) has been studied. The aim of this study was to assess homocysteine levels in white coat hypertension (WCH) as an indicator of increased risk in the development of cardiovascular diseases. WCH was defined as clinical hypertension and a daytime ambulatory blood pressure of < 135/85 mmHg. Plasma levels of homocysteine were determined in patients with WCH, hypertension, and normotension (NT). The study group included 100 subjects, 33 with WCH (16 males, 17 females) aged 49.1 +/- 1.9; 35 sustained hypertensives (17 males,18 females) aged 48.5 +/- 1.7 and 32 normotensive control subjects (15 males, 17 females) aged 48.8 +/- 2.2. The subjects were matched for age, gender, and body mass index. Patients with a smoking habit, dyslipidemia, or diabetes mellitus were not included in the study. Homocysteine levels were analyzed by ELISA. Plasma homocysteine levels were significantly higher in the WCH group compared to the controls (12.32 +/- 1.07 versus 5.35 +/- 1.38 micromol/L; P < 0.001) and the WCH group had significantly lower homocysteine values than the hypertensives (19.03 +/- 0.76 micromol/L P < 0.001). Total cholesterol and tri-glycerides were not different among the groups. There were no statistically significant differences in urinary albumin excretion (UAE) or creatinine clearance between the three groups. Hypertensive retinopathy was observed in the WCH group, but was less severe and less frequent compared to HTs. LVMI was greater in the WCH group compared to the NTs, but significantly less than HTs. The data demonstrate that WCH is associated with high levels of homocysteine. The increase in homocysteine level in WCH is not as high as in SHT. Since an elevated plasma homocysteine level is a strong risk factor for coronary artery disease and there was target organ damage in our WCH group, we conclude that WCH should not be considered to be an innocent trait.

Beyond the Evidence of the New Hypertension Guidelines. Blood pressure measurement - is it good enough for accurate diagnosis of hypertension? Time might be in, for a paradigm shift (I)

Despite widespread availability of a large body of evidence in the area of hypertension, the translation of that evidence into viable recommendations aimed at improving the quality of health care is very difficult, sometimes to the point of questionable acceptability and overall credibility of the guidelines advocating those recommendations.

The scientific community world-wide and especially professionals interested in the topic of hypertension are witnessing currently an unprecedented debate over the issue of appropriateness of using different drugs/drug classes for the treatment of hypertension. An endless supply of recent and less recent "drug-news", some in support of, others against the current guidelines, justifying the use of selected types of drug treatment or criticising other, are coming out in the scientific literature on an almost weekly basis. The latest of such debate (at the time of writing this paper) pertains the safety profile of ARBs vs ACE inhibitors.

To great extent, the factual situation has been fuelled by the new hypertension guidelines (different for USA, Europe, New Zeeland and UK) through, apparently small inconsistencies and conflicting messages, that might have generated substantial and perpetuating confusion among both prescribing physicians and their patients, regardless of their country of origin.

The overwhelming message conveyed by most guidelines and opinion leaders is the widespread use of diuretics as first-line agents in all patients with blood pressure above a certain cut-off level and the increasingly aggressive approach towards diagnosis and treatment of hypertension. This, apparently well-justified, logical and easily comprehensible message is unfortunately miss-obeyed by most physicians, on both parts of the Atlantic.

Amazingly, the message assumes a universal simplicity of both diagnosis and treatment of hypertension, while ignoring several hypertension-specific variables, commonly known to have high level of complexity, such as:

- accuracy of recorded blood pressure and the great inter-observer variability,

- diversity in the competency and training of diagnosing physician,

- individual patient/disease profile with highly subjective preferences,

- difficulty in reaching consensus among opinion leaders,

- pharmaceutical industry's influence, and, nonetheless,

- the large variability in the efficacy and safety of the antihypertensive drugs.

The present 2-series article attempts to identify and review possible causes that might have, at least in part, generated the current healthcare anachronism (I); to highlight the current trend to account for the uncertainties related to the fixed blood pressure cut-off point and the possible solutions to improve accuracy of diagnosis and treatment of hypertension (II).

The Blood Pressure "Uncertainty Range" - a pragmatic approach to overcome current diagnostic uncertainties (II)

A tremendous amount of scientific evidence regarding the physiology and physiopathology of high blood pressure combined with a sophisticated therapeutic arsenal is at the disposal of the medical community to counteract the overall public health burden of hypertension. Ample evidence has also been gathered from a multitude of large-scale randomized trials indicating the beneficial effects of current treatment strategies in terms of reduced hypertension-related morbidity and mortality.In spite of these impressive advances and, deeply disappointingly from a public health perspective, the real picture of hypertension management is overshadowed by widespread diagnostic inaccuracies (underdiagnosis, overdiagnosis) as well as by treatment failures generated by undertreatment, overtreatment, and misuse of medications.The scientific, medical and patient communities as well as decision-makers worldwide are striving for greatest possible health gains from available resources.A seemingly well-crystallised reasoning is that comprehensive strategic approaches must not only target hypertension as a pathological entity, but rather, take into account the wider environment in which hypertension is a major risk factor for cardiovascular disease carrying a great deal of our inheritance, and its interplay in the constellation of other, well-known, modifiable risk factors, i.e., attention is to be switched from one's "blood pressure level" to one's absolute cardiovascular risk and its determinants. Likewise, a risk/benefit assessment in each individual case is required in order to achieve best possible results.Nevertheless, it is of paramount importance to insure generalizability of ABPM use in clinical practice with the aim of improving the accuracy of a first diagnosis for both individual treatment and clinical research purposes. Widespread adoption of the method requires quick adjustment of current guidelines, development of appropriate technology infrastructure and training of staff (i.e., education, decision support, and information systems for practitioners and patients). Progress can be achieved in a few years, or in the next 25 years.

Bendrofluazide Fails to Reduce Elevated Blood Pressure Levels in the Immediate Post-Stroke Period

INTRODUCTION

Blood pressure (BP) levels, beat-to-beat blood pressure variability, dynamic cerebral autoregulation and cardiac baroreceptor sensitivity are frequently abnormal following acute stroke and are associated with an adverse short- and long-term prognosis. Thiazide diuretics are effective antihypertensive agents in preventing primary and secondary stroke, but their hypotensive and cerebral autoregulatory effects in the immediate post-stroke period have not been studied.

METHODS

Thirty-seven hypertensive neuroradiologically proven ischaemic stroke patients were randomized in a double-blind, placebo controlled, parallel group study to bendrofluazide 2.5 mg daily or matching placebo, within 96 h of stroke onset, for a 7-day period. Casual and non-invasive beat-to-beat arterial BP levels, cerebral blood flow velocity, ECG and transcutaneous carbon dioxide levels were measured within 70 +/- 20 h of cerebral infarction and again 7 days later. Dynamic cerebral autoregulatory indices, pulse interval, BP variability and cardiac baroreceptor sensitivity were also calculated.

RESULTS

Small, non-significant falls were seen in casual and beat-to-beat BP levels over the 7-day period in both active and placebo-treated patients with no differences between treatments. No significant changes were seen in dynamic cerebral autoregulation or in cardiac baroreceptor sensitivity during the follow-up in either group.

CONCLUSION

Following acute ischaemic stroke, the standard dose of bendrofluazide at 2.5 mg daily in this study sample did not lower systemic BP levels over the subsequent 7-day period. There was no evidence that bendrofluazide significantly altered cerebral autoregulation or improved cardiac baroreceptor sensitivity post-ictus. Bendrofluazide appears to be an ineffective hypotensive agent at the standard dosage in the initial post-stroke period.

Reliability of automated blood pressure devices used by hypertensive patients

Automated blood pressure (BP) devices are used by many hypertensive patients in Hong Kong, with or without medical advice. At two community clinics, we invited hypertensive patients aged between 40 and 70 years who used such a device to fill in a questionnaire and to have four sets of BP measurements, automated and mercury, at two visits. Of 290 hypertensive patients 120 fulfilled the criteria, and 73 of these agreed to participate. 53 devices measured arm BP, 21 measured forearm BP. The agreement between the mercury sphygmomanometer and the automated devices was poor, with average differences of 9.5 mmHg for systolic and 9.4 mmHg for diastolic and no clear advantage for either site of measurement. As a means of screening for BP >140/90 mmHg the sensitivity of the automated devices was 81% and the specificity was 80%. There were large variations in how often and under what circumstances the devices had been used. One-fifth of the devices had been acquired on medical advice but only 11% of the participants were aware of the three important conditions for operating such devices. Discussion of automated devices, their role and proper use, should now be part of routine hypertensive care.

High Heritability of Ambulatory Blood Pressure in Families of East African Descent

We estimated the heritability of ambulatory systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP) in east African families with at least 2 hypertensive siblings and living in the Seychelles islands (Indian Ocean). The sample consisted of 314 individuals (147 men and 167 women), both normotensive and hypertensive, from 76 pedigrees (mean±SD of 4.1±2.8 persons per pedigree). After a 2-week off-treatment period, daytime and nighttime ambulatory blood pressure (BP) was monitored. Office BP was measured with a standard mercury sphygmomanometer. We estimated by maximum likelihood the age- and sex-adjusted heritabilities from the additive polygenic component of the variance of the traits allowing for the presence of other familial correlations. We also adjusted for ascertainment (ie, for the fact that 2 siblings had to be hypertensive) and examined the effect of adjusting for body mass index, 24-hour urinary excretion of sodium and potassium, plasma renin activity, and plasma aldosterone concentration. Heritability estimates (±SE) for ambulatory SBP, DBP, and PP were, respectively, 0.37±0.12/0.24±0.12/0.54±0.12 for daytime and 0.34±0.13/ 0.37±0.15/0.47±0.12 for nighttime measurements ( P <0.05 for all estimates). Heritability estimates for office SBP, DBP, and PP were, respectively, 0.20±0.11, 0.05±0.09, and 0.37±0.12. Heritability estimates for SBP varied markedly according to whether participants were treated for hypertension at baseline. The present data show that ambulatory BP and PP have a high heritability in families of African descent. They also demonstrate that antihypertensive treatment and the number of BP measurements have a major influence on the heritability estimates.

Endothelium and angiogenesis in white coat hypertension

Hypertensive patients are at particular risk of cardiovascular complications, possibly related to endothelial damage or dysfunction, or to abnormal angiogenesis. The aim of this study was to compare the risk conferred by white coat hypertension (WCH) vs sustained hypertension in the development of the endothelial dysfunction and abnormal angiogenesis by evaluating nitric oxide (NO=NO2+NO3), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and E-selectin levels in plasma. The study group included 102 subjects, 34 with WCH (17 male and 17 female patients) aged 49+/-11 years, 34 sustained hypertensives (HT) (15 male and 19 female patients) aged 47+/-11 years and 34 normotensive control subjects (NT) (16 male and 18 female patients) aged 48+/-10 years. WCH was defined as clinical hypertension and daytime ambulatory blood pressure less than 135/85 mmHg. The subjects were matched for age, gender, body mass index and the patients with smoking habit, dyslipidaemia, and diabetes mellitus were excluded from the study. The NO, ET-1, VEGF and E-selectin levels were analysed by ELISA technique. The WCH subjects had significantly higher levels of NO than the HT (41.68+/-2.23 vs 32.18+/-2.68 micromol/l; P<0.001) and significantly lower values than the NT (48.24+/-4.29 micromol/l; P<0.001). ET-1 levels of the WCH group were significantly higher than the NT (8.10+/-0.92 vs 5.95+/-0.26 ng/ml; P<0.001) and significantly lower than the HT (11.46+/-0.59 ng/ml; P<0.001). Considering with VEGF, the WCH group had significantly higher levels than the NT (195.88+/-11.84 vs 146.26+/-18.67 pg/ml; P<0.001), but the difference from the HT group was not significant (203.35+/-7.48 pg/ml; P=0.062). E-selectin in the WCH group was significantly lower than the HT (4.77+/-0.52 vs 8.49+/-2.85; P<0.001), but the difference from the NT group was not significant (3.86+/-0.67; P=0.077). Our data demonstrate that WCH is associated with endothelial dysfunction and abnormal angiogenesis. The degree of these changes is not as severe as observed in hypertensive population.

The systemic haemodynamic and cerebral autoregulatory effects of bendrofluazide in the subacute post-stroke period

INTRODUCTION

Little data exist on the efficacy in terms of blood pressure reduction or outcome measures for the various antihypertensive agents in patients post-stroke. In this study the effects of bendrofluazide on blood pressure levels and variability, dynamic cerebral autoregulation and cardiac baroreceptor sensitivity were assessed in the sub-acute stroke period.

METHODS

A total of 36 hypertensive ischaemic stroke patients were randomized to oral bendrofluazide 2.5 mg daily or matching placebo starting 10 days post-ictus and continued for 28 days. A total of 12 hypertensive controls were similarly randomized in a double-blind, crossover study, each limb being of 28 days duration. Cerebral blood flow velocity, non-invasive beat-to-beat blood pressure levels, electrocardiograms (ECGs) and transcutaneous carbon dioxide levels were measured before and at the end of each treatment period in stroke and control subjects.

RESULTS

Casual blood pressure levels were not significantly reduced in stroke patients with bendrofluazide, but in the placebo group levels increased by 13 +/- 13/6 +/- 7 mmHg (P < 0.001) at study termination. In the control group, casual systolic blood pressure fell during active treatment by 12 +/- 16 mmHg (P < 0.03) compared with placebo. Dynamic cerebral autoregulation, beat-to-beat blood pressure variability and cardiac baroreceptor sensitivity did not change with bendrofluazide or placebo in either the stroke patients or controls.

CONCLUSION

Bendrofluazide does not appear to be an effective hypotensive agent in the sub-acute post-stroke period but may limit the blood pressure rise seen during stroke recovery. Bendrofluazide however does not adversely influence dynamic cerebral autoregulation, blood pressure variability or cardiac baroreceptor sensitivity in either strokes or control subjects.

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.

Oxidative stress in white coat hypertension; role of paraoxonase

Oxidative stress in sustained hypertension was shown with several biochemical parameters. Oxidized low-density lipoprotein (oxLDL) plays an important role during the atherosclerosis process and paraoxonase (PON1) can significantly inhibit lipid peroxidation. Serum PON1 activity, oxLDL and malondialdehyde (MDA) concentrations and their relationship with serum lipid parameters and systolic and diastolic blood pressures (SBP and DBP) were determined in subjects with white coat hypertension (WCH), sustained hypertension (HT) and normotension (NT). The study group consisted of a total of 86 subjects, 30 with WCH (14 male, 16 female subjects), 30 with HT (13 male, 17 female subjects) and 26 with NT (12 male, 14 female subjects). Both white coat hypertensive and hypertensive subjects had significantly higher levels of MDA than normotensives (P<0.026 and P<0.001, respectively). The oxLDL level of the HT group was significantly higher than the NT group (P<0.023). The WCH group had an oxLDL level similar to both hypertensive and normotensive groups. HT and WCH groups had significantly lower PON1 levels than the normotensive group (P<0.001). oxLDL correlated with MDA positively (P=0.008), and PON1 negatively (P=0.008). A negative correlation between MDA and PON1 (P=0.014) was detected. MDA correlated positively with both SBP and DBP (P=0.001), while PON1 correlated with both of them negatively (P=0.01 and P=0.008, respectively). OxLDL correlated with diastolic blood pressure positively (P=0.008). Our data demonstrate that oxidative stress increase in WCH is associated with a decrease in PON1 activity. The reduction in PON1 activity may be one of the factors leading to an increase in oxidative status in WCH.

Target organ damage and changes in arterial compliance in white coat hypertension. Is white coat innocent?

The aim of this study was to perform an extensive evaluation of target organ status, metabolic abnormalities and hemodynamic alterations in white coat hypertension (WCH). Fifty normotensive (NT), 90 WCH (ambulatory daytime blood pressure < 135/85 mmHg) and 101 hypertensive (HT) subjects underwent extensive biochemical, echocardiographic, fundoscopic examination. In a subgroup study, arterial compliance and intima-media thickness (IMT) were measured by Doppler ultrasound in left common carotid artery. WCH subjects were found to have higher body mass index (BMI) than the NTs (p = 0.042). Left ventricle mass index (LVMI) was greater in the WCHs than the NTs (p < 0.001), but significantly less than the HTs (p < 0.001). Hypertensive retinopathy was observed in the WCHs, but was less severe and rare compared to the HTs (13% vs 27%). Both WCHs and HTs had high levels of urinary albumin excretion (UAE) (p = not significant). Total cholesterol was higher in WCHs than in the NTs (p = 0.04) The distensibility coefficient (DC) of the WCHs was significantly greater than the HTs (p < 0.01), while significantly smaller than the NTs (p < 0.01). The compliance coefficient (CC) of the WCHs was significantly higher than the HTs (p < 0.01), and significantly less than the NTs (p < 0.01). The IMT in the HTs was significantly higher than the WCHs (0.81 +/- 0.05 vs 0.70 +/- 0.04 mm; p < 0.001) and the NTs (p < 0.001). The difference between the NTs and the WCHs was not significant. Our data indicate that patients with WCH represent an intermediate group between NTs and sustained HTs where target organ damage and cardiovascular risk is concerned.

Postural hypotension in hypertensive patients

BACKGROUND

The association between orthostatic hypotension and supine hypertension (Hypo-Hyper) has been reported in previous studies on selected populations. The present longitudinal study aimed to characterize the haemodynamic patterns, comorbidity, prognostic implications and eventual effect of therapy in patients with the Hypo-Hyper pattern.

METHODS

Ambulatory blood pressure monitoring (AMAP) and clinical evaluation were performed on 615 consecutive patients recruited from the Hypertension Clinics of five Italian Hospitals: 34 patents were identified as Hypo-Hyper, and underwent 10-month follow-up.

RESULTS

The incidence of the Hypo-Hyper pattern was 5.5% in the hypertensives studied. Hypo-Hyper was more frequent in the elderly (mean age 58 years), and the affected population exhibited different kinds of underlying pathologies. Multivariate analysis showed no association between antihypertensive treatment and Hypo-Hyper pattern. Patients with AMAP features of higher blood pressure values at night-time than at daytime displayed higher rates of myocardial hypertrophy and pacemaker implantation during the follow-up.

CONCLUSIONS

Although the study design did not aim to identify any pathophysiological mechanism for Hypo-Hyper pattern, these first data show that the Hypo-Hyper association is the effect of a particular subtype of hypertension, with significantly different prognostic implications.

Accuracy of SpaceLabs 90207 is altered by venous blood redistribution

Validation protocols that have been introduced for automated blood pressure (BP) measuring devices recommend procedures carried out at rest only. We aimed to determine whether venous blood redistribution affects the accuracy of the oscillometric method of BP measurement. For this purpose, we chose a popular oscillometric ambulatory BP monitor--the SpaceLabs 90207 (Osc). Lower body negative pressure (-40 mmHg) (LBNP) was used to simulate changes of body position. Fifty-one young healthy volunteers had their BP measured simultaneously by Osc and mercury sphygmomanometer (HgS) at rest (min 3 and 5), during LBNP (min 7 and 9) and after LBNP (min 11). Differences (delta, mmHg) between HgS and Osc for systolic (SBP) and diastolic BP (DBP) were calculated for every measurement minute. For SBP, deltaSBP-7 and deltaSBP-9 were significantly different from deltaSBP-5 (0.65 +/- 2.6 and 0.33 +/- 2.4 mmHg vs -0.80 +/- 2.9 mmHg, p < 0.003 and p < 0.02, respectively). deltaSBP-11 also differed significantly from deltaSBP-3 and deltaSBP-5 (1.16 +/- 2.5 mmHg vs -0.06 +/- 3.1 mmHg and -0.80 +/- 2.9, p < 0.01 and p < 0.00007, respectively). When graded according to British Hypertension Society protocol, Osc remained in the A class in every measurement minute. The accuracy of SpaceLabs 90207 is altered by venous blood redistribution. These inaccuracies may constitute an additional limitation of oscillometric ambulatory BP monitoring.

The role of ambulatory blood pressure measurements in adolescence and young adults

INTRODUCTION

Ambulatory blood pressure measurements (ABPM) are currently used for the diagnosis and treatment of hypertension. It is widely recognized that the casual/clinic blood pressure is less representative of the true blood pressure than the average ABP.

METHODS

Among the 15 records for 14 patients analyzed, 80% were obtained from type I diabetics. The overall age, ranged between 11 and 23 years (mean = 17.2 years). ABPM was performed using the Quiet Trak 98 model by Welch Allyn automatic auscultatory sphygmomanometer for a 24-hour period, for those with clinic documented hypertension. The BP was considered high if recorded as systolic > 140 and diastolic > 90 for the whole period or for period I (7 am to 11 pm), and >120 systolic and >85 diastolic for period II (11 pm to 7 am), or >130 systolic and >85 diastolic for diabetic patients.

RESULTS

The BP was recorded as normal in 20% of the patients; in 33% it was normal during the daytime but high during the nighttime, and 80% of the diabetic patient were found to be nondippers during night time.

CONCLUSION

ABPM is helpful to exclude White coat hypertension and nondippers especially among diabetic patients.

Hypertension, hypertensive heart disease and perioperative cardiac risk †

The evidence for an association between hypertensive disease, elevated admission arterial pressure, and perioperative cardiac outcome is reviewed. A systematic review and meta-analysis of 30 observational studies demonstrated an odds ratio for the association between hypertensive disease and perioperative cardiac outcomes of 1.35 (1.17-1.56). This association is statistically but not clinically significant. There is little evidence for an association between admission arterial pressures of less than 180 mm Hg systolic or 110 mm Hg diastolic and perioperative complications. The position is less clear in patients with admission arterial pressures above this level. Such patients are more prone to perioperative ischaemia, arrhythmias, and cardiovascular lability, but there is no clear evidence that deferring anaesthesia and surgery in such patients reduces perioperative risk. We recommend that anaesthesia and surgery should not be cancelled on the grounds of elevated preoperative arterial pressure. The intraoperative arterial pressure should be maintained within 20% of the best estimate of preoperative arterial pressure, especially in patients with markedly elevated preoperative pressures. As a result, attention should be paid to the presence of target organ damage, such as coronary artery disease, and this should be taken into account in preoperative risk evaluation. The anaesthetist should be aware of the potential errors in arterial pressure measurements and the impact of white coat hypertension on them. A number of measurements of arterial pressure, obtained by competent staff (ideally nursing staff), may be required to obtain an estimate of the "true" preoperative arterial pressure.

Diagnostic value of strategy for the detection of white coat hypertension based on ambulatory and home blood pressure monitoring

An algorithm has been proposed for the detection of white coat hypertension among subjects with elevated blood pressure (BP) on at least three clinic visits using home BP monitoring (screening test) and, if this is low, ambulatory BP monitoring (diagnostic test). This study aims to test this strategy in practice. The proposed algorithm was applied in 133 untreated subjects with elevated BP assessed in a previous prospective study using repeated clinic, home and ambulatory BP measurements. The proportions of detected and missed cases of white coat hypertension and the diagnostic value of the algorithm were calculated. By applying the algorithm, 99 subjects (74%) were found eligible for home measurements and 35 (26%) for ambulatory monitoring. There were 38 subjects with white coat hypertension (38%), of whom 15 (39%) were not detected by the proposed strategy. The sensitivity, specificity, and the positive and negative predictive value of the algorithm to diagnose white coat hypertension were 61, 81, 66 and 77%, respectively. Of the 34 subjects with normal BP on the third clinic visit, 15 (42%) had elevated home and/or ambulatory BP. These data suggest that, using the proposed strategy, many white coat hypertensives may remain undetected and may receive unnecessary long-term drug treatment. Therefore, more research is needed on the optimal strategy for detecting white coat hypertension in clinical practice.

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 measurement in kidney transplantation: an overview

Adequate control of hypertension is among the most important aims of medical management of the kidney transplant recipient, with the aim of reducing the risk of premature cardiovascular disease and preserving graft function. Antihypertensive therapy should be adjusted according to the best available estimates of usual resting blood pressure. If clinic measurements are used, care should be taken to ensure that these measurements are taken under optimal conditions. Home blood pressure monitoring is a useful adjunct in many patients. Ambulatory blood pressure monitoring gives valuable additional data; mean ambulatory blood pressure correlates better with markers of target organ damage such as left ventricular hypertrophy. However, current treatment thresholds and targets are based on clinic measurements. Ambulatory blood pressure monitoring is certainly a useful adjunct to clinic and home blood pressure measurement, but its role in routine clinical practice in the transplant clinic remains to be defined.

Favorable patient acceptance of ambulatory blood pressure monitoring in a primary care setting in the United States: a cross-sectional survey

Background

The use of ambulatory blood pressure monitoring (ABPM) in the diagnosis and management of hypertension in primary care settings in the United States is increasing. Insufficient information is available describing patients' experiences and acceptance of this technology in the United States, where medical insurance coverage of the procedure is often limited. The objective of this study was to describe patient satisfaction with ABPM performed in a primary care office in the United States, using modern ABPM technology.

Methods

Cross-sectional survey performed on consecutive patients referred to the ABPM service of the Family Care Center, University of Iowa Hospitals and Clinics, Iowa City, Iowa from January 2001 to July 2003. Measures of patient satisfaction and acceptance with the device, comfort, and overall session were assessed via a 9-question, Likert-scale response survey.

Results

Since its inception two and a half years ago, 245 total ABPM sessions have been conducted in 235 unique patients. Of the 235 eligible respondents, 177 returned completed surveys, yielding a 75% response rate. Three-fourths (75%) of patients believed that undergoing the test was worthwhile considering the time and monetary cost involved, while most (90%) reported they thought the information provided by the test would be helpful to their physician in making treatment decisions. Patients reporting that their physician had clearly explained the benefit of undergoing the testing were more likely to report that they thought the results of the test would be more helpful in making treatment decisions. Few patients (20%) found that wearing the monitor was uncomfortable.

Conclusions

When clinically indicated, clinicians should not hesitate to order ABPM testing for fear of subjecting patients to an uncomfortable test, or an uncovered insurance benefit. When ordering ABPM, they should be sure to educate the patient about the potential benefits of undergoing the testing. Most patients believe the test will provide useful information in making treatment decisions, despite probable lack of insurance coverage, and appear willing to experience some discomfort for the overall gain of the results obtained from undergoing the session.

Predictors for the white coat effect in general practice patients with suspected and treated hypertension

BACKGROUND

Ambulatory blood pressure monitoring was introduced more than 40 years ago and is accepted as a clinically useful method to evaluate the white coat effect in patients with suspected and established hypertension.

AIM

To study the differences between blood pressure readings taken in the physician's office in the primary healthcare setting, and ambulatory readings, and to find possible predictors.

DESIGN OF STUDY

Prospective study.

SETTING

Two primary healthcare centres in Norway.

METHOD

The study included 221 patients, 107 of whom were on antihypertensive treatment, and 114 of whom were under investigation for possible hypertension. Differences between blood pressure readings taken in the physician's office and ambulatory readings were calculated. Independent predictors for the white coat effect were calculated using linear regression analysis.

RESULTS

The difference between blood pressure readings taken in the office and ambulatory readings was 27 mmHg systolic and 11 mmHg diastolic. For the systolic readings, the following factors were independent predictors of the amount of the white coat effect: mean blood pressure, age, history of smoking, family history of cardiovascular disease, and antihypertensive treatment. For the diastolic readings, they were: mean blood pressure, history of smoking, and sex of the patient (with this being most significant for women).

CONCLUSION

Ambulatory blood pressure measurement is of significant value in identifying patients with white coat hypertension. It can be an important supplement for use in the diagnosis and follow-up of patients with hypertension in general practice.

Accuracy of telemedical home blood pressure measurement in the diagnosis of hypertension

This study was conducted to compare the accuracy of clinic blood pressure (CBP) and telemedical home blood pressure (HBP) measurement in the diagnosis of hypertension in primary care. The study subjects were 411 patients with average CBP > or =140 mmHg systolic or > or =90 mmHg diastolic, who performed telemedical HBP measurement (5 days, four times daily) and ambulatory blood pressure (ABP) monitoring in random order. Main outcome measure was the agreement of CBP and HBP with daytime ABP. CBP was much higher than daytime ABP and average HBP (P<0.001) with no difference between the latter two. The correlation between CBP and ABP was weak (systolic: r=0.499, diastolic: r=0.543), whereas strong correlations existed between HBP and ABP (systolic: r=0.847, diastolic: r=0.812). A progressive improvement in the strength of the linear regression between average HBP of single days and ABP was obtained from day 1 to day 4, with no further benefit obtained on the fifth day. The HBP readings taken at noon and in the afternoon showed significantly stronger correlations with ABP than the blood pressures measured in the morning and in the evening. In conclusion, the accuracy of telemedical HBP measurement was substantially better than that of CBP in the diagnosis of hypertension in primary care. HBP most accurately reflected ABP on the fourth day of monitoring, and the readings at noon and in the afternoon seemed to be most accurate.

Effects of losartan on diabetic maculopathy in type 2 diabetic patients: a randomized, double-masked study

OBJECTIVE

Diabetic maculopathy (DMa) is a leading cause of visual loss in the western world. Preliminary studies have suggested that angiotensin converting enzyme inhibitors might be effective in preventing the progression of diabetic retinopathy, but no studies have quantitatively assessed the effect of this treatment on macular oedema in patients with DMa. We evaluated the effect of treatment with the angiotensin II receptor antagonist losartan on macular oedema and hard exudates in patients with an advanced stage of DMa.

DESIGN

Randomized, placebo-controlled, double-masked and parallel-group trial.

SETTING

Academic medical centre.

SUBJECTS

Twenty-four type 2 diabetic patients with DMa.

INTERVENTION

Subjects were randomly assigned to a 4-month treatment with either losartan (50 mg o.d.) or placebo.

MAIN OUTCOME MEASURES

(i) Degree of macular oedema as estimated by optical coherence tomography scanning of the retina; (ii) fundus photography and flourescein angiography; (iii) 24-h ambulatory blood pressure (BP); (iv) urinary albumin excretion (UAE); and (v) transcapillary escape rate of albumin (TERalb).

RESULTS

Central retinal thickness increased from 244 +/- 16 to 256 +/- 31 microm in the losartan group, whilst there was no change in the placebo group (245 +/- 36 microm vs. 242 +/- 30 microm), P = 0.017. Day BP were lowered in the losartan group (from 144/83 +/- 17/10 to 138/78 +/- 20/11 mmHg) compared with the placebo group (140/81 +/- 14/5 to 139/82 +/- 13/9 mmHg), P = 0.27 for systolic and P = 0.009 for diastolic BP. Importantly, there were no changes in night BP in any of the groups. We found no changes in the number of hard exudates, semiquantitative retinopathy grade, visual acuity, UAE, or TERalb in any of the groups.

CONCLUSIONS

Type 2 diabetic patients with maculopathy do not seem to benefit from short-term treatment with losartan (50 mg once daily) as far as retinal thickness is concerned, as this dose may increase retinal thickness in the central macular area. Long-term studies are required to assess the clinical implications of these findings.

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 monitoring profile as a useful prognostic tool in patients with primary hypertension

Ambulatory blood pressure monitoring (ABPM) devices are increasingly being used in the assessment of hypertension. The purpose of the study was to investigate patient's diurnal BP variation and to further determine the differences of BP readings between male and female patients and the effects of age in patients who attended the clinic with essential hypertension. In addition, evidence of relationship between the parameters recorded by 24-hour ABPM was also investigated. This study was conducted in an outpatient specialist clinic. Two indices were used to demonstrate the diurnal BP variation. Firstly, the diurnal systolic blood pressure (SBP) and diastolic blood pressure (DBP) variations which were calculated as night/day BP ratio for SBP and DBP respectively. Anyone scoring less than 100% were categorised as dippers. Secondly, nocturnal falls in SBP and DBP were calculated as (awake SBP-sleep SBP)/awake SBP x 100 and (awake DBP-sleep DBP)/awake DBP x 100 respectively. The results showed that there was no significant difference in the mean BP between male and female patients. In general, the study sample were categorised as dippers and non dippers. There were more male dippers than female dippers. Finally correlation analysis revealed that age is related to SBP variables whilst night HR showed positive correlation with night time BP. It is concluded that ABPM was shown to be a useful tool to analyse the variation and prevalence of cardiovascular risk markers in hypertensive patients and can easily be done in an outpatient set-up.