Task Force II: blood pressure measurement and cardiovascular outcome

Rationale and methodology of monitoring ambulatory blood pressure and arterial compliance in the Hypertension in the Very Elderly Trial

OBJECTIVE

This article describes the rationale and methodology for the monitoring of ambulatory blood pressure and arterial compliance in hypertensive patients aged 80 years and above. This is a side project of the Hypertension in the Very Elderly Trial.

METHODS

The hypertension in the Very Elderly Trial is a multicentre, double-blind, randomized, placebo-controlled trial aiming to investigate the effect of active treatment on cardiovascular and other outcomes in hypertensive patients aged 80 years or more. Patients are randomized to placebo or active treatment starting with the diuretic indapamide and adding the angiotensin-converting enzyme inhibitor perindopril if required. This study has completed a pilot trial and the main trial is now underway. Six hundred patients will have two ABPM recordings, the first at baseline and the second a year after randomization. Arterial compliance is measured using the Q wave (electrocardiogram) to Korotkoff diastole sound interval.

RESULTS

Baseline characteristics for the first 50 patients recruited are presented.

CONCLUSION

This side project will allow the investigation of 24-h ambulatory measures of blood pressure and arterial compliance as predictors of cerebrovascular and cardiovascular events in the very elderly. The project will also allow the investigation of the blood pressure and vascular compliance profiles in the very elderly and their changes with posture. The association between these measurements and mortality and morbidity in this age group will be addressed.

Chronic stress influences ambulatory blood pressure in adolescents

BACKGROUND

High ambulatory blood pressure (ABP) predicts cardiovascular events, even after controlling for clinic BP and other established risk factors.

PURPOSE

This study examined whether chronic or discrete stress in the past year was associated with greater ABP in adolescents.

METHOD

Participants were 217 male and female Black and White adolescents who wore ABP monitors on 2 consecutive school days and completed a survey of life events.

RESULTS

Report of discrete, negative events was not associated with ABP. Adolescents experiencing greater numbers of chronic, negative life events exhibited greater systolic blood pressure (SBP), independent of ethnicity; sex; body mass index; and location, position, physical activity, and consumption of food/caffeine/nicotine at time of measurement. Greater numbers of chronic, negative events were associated with greater diastolic blood pressure (DBP) among boys. When resting clinic BP was introduced into the model, the main effect of chronic, negative life events on ambulatory SBP became nonsignificant, whereas the effect of chronic, negative life events on male adolescents' DBP persisted.

CONCLUSIONS

Chronic stress is associated with greater ambulatory SBP among male and female adolescents and with greater ambulatory DBP among male adolescents. The latter association persisted after controlling for clinic BP, suggesting that males may be more vulnerable to chronic stress as a determinant of BP regulation than females early in life.

Recommendations for blood pressure measurement in humans and experimental animals: part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research

Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure-related risk, and to guide management. The auscultatory technique with a trained observer and mercury sphygmomanometer continues to be the method of choice for measurement in the office, using the first and fifth phases of the Korotkoff sounds, including in pregnant women. The use of mercury is declining, and alternatives are needed. Aneroid devices are suitable, but they require frequent calibration. Hybrid devices that use electronic transducers instead of mercury have promise. The oscillometric method can be used for office measurement, but only devices independently validated according to standard protocols should be used, and individual calibration is recommended. They have the advantage of being able to take multiple measurements. Proper training of observers, positioning of the patient, and selection of cuff size are all essential. It is increasingly recognized that office measurements correlate poorly with blood pressure measured in other settings, and that they can be supplemented by self-measured readings taken with validated devices at home. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. Twenty-four-hour ambulatory monitoring gives a better prediction of risk than office measurements and is useful for diagnosing white-coat hypertension. There is increasing evidence that a failure of blood pressure to fall during the night may be associated with increased risk. In obese patients and children, the use of an appropriate cuff size is of paramount importance.

Association of blunted nocturnal blood pressure dip with intracerebral hemorrhage

OBJECTIVES

Nondipping pattern of nocturnal blood pressure is associated with silent ischemic cerebrovascular lesions and lacunar infarctions. In this case-control study, we aimed to evaluate the association of diurnal blood pressure variation with the occurrence of intracerebral hemorrhage.

METHODS

Ambulatory blood pressure monitoring was performed at 21-28 days after ictus in 78 first-ever unselective consecutive patients with intracerebral hemorrhage and in 80 age-adjusted and sex-adjusted controls who were referred to the hypertension center of our institution. The degree of nocturnal blood pressure dip was calculated as [(mean daytime values-mean night-time values)/mean daytime values]x100. Nondippers were defined as patients who exhibited a <10% nocturnal dip in systolic blood pressure. Logistic regression models were constructed to assess the association of nondipping status with intracerebral hemorrhage after adjusting for potential confounders (cardiovascular risk factors, office and ambulatory blood pressure levels).

RESULTS

Prevalence of nondipping was significantly greater among cases than among controls (74.4% vs. 43.8%, P<0.001). Nondipping status was independently (P=0.033) associated with intracerebral hemorrhage (OR: 2.326, 95% CI: 1.068-5.050) in a multiple variable logistic regression model that adjusted for baseline characteristics, cardiovascular risk factors, office and ambulatory blood pressure variables. The magnitude of the nocturnal systolic blood pressure dipping was inversely related to the risk of intracerebral bleeding; the odds ratio for intracerebral hemorrhage associated with every 1% decrease in nocturnal systolic blood pressure dip was 1.143 (95% CI: 1.058-1.235, P=0.001).

CONCLUSIONS

Given the previous reports that nondipping contributes to the risk of cerebral infarction, our results indicate that blunted nocturnal blood pressure dip may be also associated with the occurrence of intracerebral hemorrhage.

Prognosis of "masked" hypertension and "white-coat" hypertension detected by 24-h ambulatory blood pressure monitoring 10-year follow-up from the Ohasama study

OBJECTIVES

We sought to investigate the prognosis in subjects with "white-coat" hypertension (WCHT) and "masked" hypertension (MHT), in which blood pressure (BP) is lower in clinical measurements than during ambulatory monitoring.

BACKGROUND

The prognostic significance of WCHT remains controversial, and little is known about MHT.

METHODS

We obtained 24-h ambulatory BP and "casual" BP (i.e., obtained in clinical scenarios) values from 1,332 subjects (872 women, 460 men) > or =40 years old in a representative sample of the general population of a Japanese community. Survival and stroke morbidity were then followed up for a mean duration of 10 years.

RESULTS

Composite risk of cardiovascular mortality and stroke morbidity examined using a Cox proportional hazards regression model for subjects with WCHT (casual BP > or =140/90 mm Hg, daytime BP <135/85 mm Hg; relative hazards [RH])1.28; 95% confidence interval [CI] 0.76 to 2.14) was no different from risk for subjects with sustained normal BP (casual BP <140/90 mm Hg, daytime BP <135/85 mm Hg). However, risk was significantly higher for subjects with MHT (casual BP <140/90 mm Hg, daytime BP > or =135/85 mm Hg; RH 2.13; 95% CI 1.38 to 3.29) or sustained hypertension (casual BP > or =140/90 mm Hg, daytime BP > or =135/85 mm Hg; RH 2.26; 95% CI 1.49 to 3.41) than for subjects with sustained normal BP. Similar findings were observed for cardiovascular mortality and stroke morbidity among subgroups by gender, use of antihypertensive medication, and risk factor level (all p for heterogeneity >0.2).

CONCLUSIONS

Conventional BP measurements may not identify some individuals at high or low risk, but these people may be identifiable by the use of ambulatory BP.

Is prehypertension a risk factor for cardiovascular diseases?

BACKGROUND AND PURPOSE

The Joint National Committee on High Blood Pressure identified a new category of blood pressure in adults termed prehypertension. Our objective was to determine the long-term risk of cardiovascular diseases associated with this new category in a well-defined cohort of adults.

METHODS

We evaluated the association of prehypertension (120 to 139/80 to 89 mm Hg) and hypertension (>140/90 mm Hg) with the incidence of atherothrombotic brain infarction (ABI), all strokes, myocardial infarction (MI), and coronary artery disease (CAD) using pooled repeated measures and Cox proportional hazards analyses during follow-up after adjusting for age, gender, obesity, diabetes mellitus, hypercholesterolemia, cigarette smoking, and study period in a cohort of 5181 persons who participated in the Framingham Study.

RESULTS

Among the 11,116 person observations with a mean follow-up period of 9.9+/-1.0 years, prehypertension was not associated with an increased risk for ABI (relative risk [RR], 2.2; 95% CI, 0.5 to 9.3). Among the 11,802 person observations with a mean follow-up period of 9.7+/-1.5 years, prehypertension was associated with an increased risk for MI (RR, 3.5; 95% CI, 1.6 to 7.5). Prehypertension was also associated with an increased risk of CADs among the 11,570 person observations (RR, 1.7; 95% CI, 1.2 to 2.4).

CONCLUSIONS

Prehypertension appears to be associated with an increased risk of MI and CAD but not stroke. Further studies are required to confirm the anticipated benefits of identifying and intervening in persons with prehypertension.

The natural history of white coat hypertension during pregnancy

OBJECTIVE

White coat hypertension (WCH) is a common phenomenon with a long term prognosis intermediate between those with true hypertension and true normotension. The natural history of this phenomenon throughout pregnancy remains unknown. We assessed the likelihood of women with an initial diagnosis of WCH developing pre-eclampsia (PE) as their pregnancy progressed.

DESIGN

Prospective observational study.

SETTING

St George Hospital, a teaching and University hospital.

POPULATION

Two hundred and forty-one pregnant women with an early pregnancy diagnosis of essential hypertension (EH).

METHODS

Eighty-six women had this diagnosis (EH) confirmed pre-pregnancy by 24-hour ambulatory blood pressure monitoring (ABPM) or repeated automated home blood pressure (BP) self-measurement. The remaining 155 underwent 24-hour ABPM in early pregnancy to establish their diagnosis. Women found to have WCH did not receive antihypertensives during their pregnancy, whereas those with confirmed EH received oxprenolol or methyldopa. Women with WCH had repeated 24-hour ABPM and/or BP assessments in a pregnancy day assessment unit until delivery.

MAIN OUTCOME MEASURE

The development of PE in women with WCH or EH.

RESULTS

The overall prevalence of WCH was 32%. Half retained this phenomenon throughout pregnancy and had good pregnancy outcomes. Forty percent developed (benign) gestational hypertension and also had good pregnancy outcomes while 8% developed proteinuric PE, significantly fewer than in women with confirmed EH (22%), P= 0.008. No BP parameter at study entry permitted discrimination between those women with WCH who retained this phenomenon and those who developed GH or PE.

CONCLUSION

WCH is a common phenomenon in pregnant women who appear to have EH according to routine BP measurement early in pregnancy. Antihypertensives may be withheld from this group initially and they can be advised they will have better pregnancy outcomes than women with true EH. However, continued monitoring throughout pregnancy remains important to detect the small group of white coat hypertensives who develop PE.

Time Rate of Blood Pressure Variation Is Associated With Increased Common Carotid Artery Intima-Media Thickness

The extent of target-organ damage has been positively associated with the magnitude of blood pressure (BP) variability in essential hypertension. However, the clinical implications of the rate of BP changes have never been investigated. We evaluated the association between the rate of systolic BP (SBP) variation derived from ambulatory BP monitoring (ABPM) data analysis and the extent of common carotid artery (CCA) intima-media thickness (IMT) in normotensive (n=280) and in uncomplicated hypertensive subjects (n=234). The 24-hour rate of SBP variation was significantly ( P <0.001) higher in hypertensive (0.608 mm Hg/min; 95% confidence interval [CI], 0.595 to 0.622) than in normotensive individuals (0.567 mm Hg/min; 95% CI, 0.555 to 0.578), even after adjusting for baseline characteristics, day–night BP changes, 24-hour heart rate (HR), SBP, and HR variability. In the entire group of patients, multiple linear regression models revealed independent determinants of CCA-IMT in the following rank order: age ( P <0.001), 24-hour rate of SBP variation ( P <0.001), male gender ( P =0.004), cholesterol ( P =0.009), and smoking ( P =0.014). A 0.1 mm Hg/min increase in the 24-hour rate of SBP variation was associated to an increment of 0.029 mm (95% CI, 0.018 to 0.040) in CCA-IMT independent of BP and HR levels, BP and HR variability, and dipping status. The rate of SBP variation during the morning BP surge correlated independently ( P <0.001) to larger CCA-IMT values after adjustment for baseline characteristics and other ABPM parameters. Thus, the rate of BP fluctuations is greater in hypertensive patients and correlates to increased CCA-IMT. This finding indicates that steeper BP variations may produce a greater stress on the vessel wall and consequently result in medial hypertrophy of the large arteries.

Relation of nocturnal blood pressure dipping to cellular adhesion, inflammation and hemostasis

BACKGROUND

Subjects who fail to dip their nocturnal blood pressure (BP) are at substantially increased risk for cardiovascular diseases. The pathogenetic mechanisms of this relationship have not been elucidated. We investigated whether non-dipping would relate to procoagulant and proinflammatory activity.

DESIGN

Study participants were 76 unmedicated normotensive and hypertensive subjects (44 male, 32 female; 41 white, 35 black; mean age, 36 +/- 8 years) who underwent 24-h outpatient ambulatory BP monitoring. Based on whether their average nocturnal systolic BP relative to their average daytime systolic BP declined by less than 10%, 34 subjects were categorized as non-dippers. D-dimer, plasminogen activator inhibitor-1, von Willebrand factor, soluble intercellular adhesion molecule-1, and interleukin-6 were measured in plasma.

RESULTS

Multivariate analyses showed that D-dimer (median/interquartile range, 242/162-419 ng/ml versus 175/132-254 ng/ml; P=0.041), plasminogen activator inhibitor-1 (36/19-61 ng/ml versus 17/6-44 ng/ml; P=0.010), von Willebrand factor (122/91-179% versus 92/66-110%; P=0.001), and soluble intercellular adhesion molecule-1(227/187-291 ng/ml versus 206/185-247 ng/ml; P=0.044) were all higher in non-dippers than in dippers. Adjustment for gender, ethnicity, age, body mass index, smoking status, hypertension status, and social class revealed independent effects of non-dipping. Non-dippers continued to have higher D-dimer (P=0.030) and von Willebrand factor (P=0.034) than dippers. A similar trend not reaching statistical significance emerged for soluble intercellular adhesion molecule-1 (P=0.055). In contrast, dipping status had no effect on interleukin-6.

CONCLUSION

Nocturnal BP non-dipping is associated with elevated levels of molecules related to endothelial dysfunction and atherosclerosis. The finding provides one possible mechanism linking non-dipping with cardiovascular disease.

Angiotensinogen promoter haplotypes are associated with blood pressure in untreated hypertensives

BACKGROUND

The polymorphic angiotensinogen (AGT) gene is one of the most promising candidates for blood pressure (BP) regulation and essential hypertension.

OBJECTIVES

To investigate whether AGT haplotype analysis adds significant information compared to single polymorphism analysis with respect to different BP phenotypes in an untreated hypertensive sample.

METHODS

Two hundred and twelve untreated hypertensive subjects of Caucasian origin were genotyped for the AGT polymorphisms C-532T, A-20C, C-18T, and G-6A.

RESULTS

In single variant analyses, untreated hypertensives, carrying the AGT -532T or -6A alleles had significantly higher systolic blood pressure (SBP) and diastolic blood pressure (DBP), as well as ambulatory BP values compared to respective non-carriers. In haplotype-based analyses, combining all four AGT promoter variants, we demonstrate that AGT haplotypes containing different allele combinations at positions -532 and -6 were significantly associated with different BP values: (1) -532T and -6A with higher, (2) -532C and -6G with lower, (3) -532C and -6A with intermediate BP values. Since the result for the -532C/-20A/-18C/-6G haplotype was due to differences between non-carriers and carriers of this haplotype on both chromosomes, a recessive inheritance model for BP effects could be assumed.

CONCLUSIONS

Our results designate the C-532T and G-6A as the best candidates for functional studies on the AGT gene. Haplotype-based analyses should greatly aid in the dissection of the genetic basis of complex traits, such as BP regulation and hypertension.

Recommendations for Blood Pressure Measurement in Humans and Experimental Animals

Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure-related risk, and to guide management. The auscultatory technique with a trained observer and mercury sphygmomanometer continues to be the method of choice for measurement in the office, using the first and fifth phases of the Korotkoff sounds, including in pregnant women. The use of mercury is declining, and alternatives are needed. Aneroid devices are suitable, but they require frequent calibration. Hybrid devices that use electronic transducers instead of mercury have promise. The oscillometric method can be used for office measurement, but only devices independently validated according to standard protocols should be used, and individual calibration is recommended. They have the advantage of being able to take multiple measurements. Proper training of observers, positioning of the patient, and selection of cuff size are all essential. It is increasingly recognized that office measurements correlate poorly with blood pressure measured in other settings, and that they can be supplemented by self-measured readings taken with validated devices at home. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. Twenty-four-hour ambulatory monitoring gives a better prediction of risk than office measurements and is useful for diagnosing white-coat hypertension. There is increasing evidence that a failure of blood pressure to fall during the night may be associated with increased risk. In obese patients and children, the use of an appropriate cuff size is of paramount importance.

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.

Contribution of blood pressure variability to the effect of nitrendipine on end-organ damage in spontaneously hypertensive rats

OBJECTIVE

It has been proposed that blood pressure variability (BPV) is positively related to end-organ damage (EOD) in hypertension. The present work was designed to observe the effects of long-term treatment with nitrendipine and hydralazine on BPV and EOD in spontaneously hypertensive rats (SHR), to examine the hypothesis that lowering BPV with an antihypertensive drug is an important factor in organ protection.

DESIGN AND METHODS

Drugs were mixed in rat chow. After 4 months of drug administration, blood pressure was recorded continuously in conscious freely moving rats for 24 h. The heart, kidneys, and brain were then isolated and examined.

RESULTS

It was found that nitrendipine significantly decreased blood pressure and BPV, and significantly decreased EOD score in SHR. Hydralazine decreased blood pressure, but did not lower BPV. No effect on EOD was found in hydralazine-treated rats. In control rats (n = 38), EOD score was weakly related to systolic blood pressure (r = 0.331, P < 0.05) and closely related to long-term systolic BPV (r = 0.551, P < 0.01). In nitrendipine-treated rats, EOD score was closely related to long-term systolic BPV (r = 0.602, P < 0.01), but not to BP level (r = 0.174, P > 0.05).

CONCLUSION

BPV plays an important role in the organ-protecting effects of nitrendipine.

Twenty-four-hour ambulatory blood pressure in children with sleep-disordered breathing

Obstructive sleep apnea causes intermittent elevation of systemic blood pressure (BP) during sleep. To determine whether obstructive apnea in children has a tonic effect on diurnal BP, 24-hour ambulatory blood pressure was obtained from 60 children with mean age of 10.8 +/- 3.5 years. Thirty-nine children had obstructive apnea and 21 had primary snoring. Children with obstructive apnea had significantly greater mean BP variability during wakefulness and sleep, a higher night-to-day systolic BP, and a smaller nocturnal dipping of mean BP. Variability of mean arterial pressure during wakefulness was predicted by the desaturation, body mass, and arousal indices, whereas variability during sleep was predicted by apnea-hypopnea and body mass indices. Nocturnal BP dipping was predicted by the desaturation index. There were no significant differences in systolic, diastolic, or mean arterial BP during sleep between the groups. Diastolic BP during wakefulness was significantly different between the groups and correlated negatively with apnea-hypopnea index. We conclude that obstructive apnea in children is associated with 24-hour BP dysregulation and that, independent of obesity, the frequency of obstructive apnea, oxygen desaturation, and arousal contributes to abnormal BP control.

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.

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.

How well are we managing and monitoring high blood pressure?

PURPOSE OF REVIEW

We will summarize the latest available data on hypertension control levels in different populations throughout the world, and review the factors that appear to contribute to the widespread lack of blood pressure control in identified hypertensive patients.

RECENT FINDINGS

Population surveys throughout the world indicate that the proportion of hypertensive patients with blood pressure controlled to below 140/90 mmHg ranges from 5% in Taiwan to 25% in the United States. Studies in the US have shown that the majority of hypertensive patients classified as uncontrolled have diastolic pressure below 90 mmHg with mild systolic elevation in the 140-160 mmHg range, and that these blood pressure levels rarely elicit a treatment intensification action by the physician. The results of the Antihypertensive and Lipid Lowering to Prevent Heart Attack Trial indicate that it is feasible to maintain average blood pressures on treatment to levels well below 140/90 mmHg in elderly hypertensive patients in primary care settings. Although the literature on automated blood pressure measurement and comparisons between office blood pressure and home blood pressure continues to grow, there has been little attention paid to practicing physicians' attitudes and beliefs about different blood pressure measurement methods, or to the feasibility of standardizing blood pressure measurement in typical practice settings.

SUMMARY

The experience in the US indicates that widely publicized treatment guidelines recommending blood pressure control targets and choice of first-line agents may have little influence on practicing physicians, even when based on solid evidence from clinical trials. Controversies in the literature regarding treatment targets, appropriate drug choices, and blood pressure monitoring methods are likely to delay improvements in overall population control.

Pulsatile and steady 24-h blood pressure components as determinants of left ventricular mass in young and middle-aged essential hypertensives

In order to explore the relations between left ventricular mass (LVM) and the pulsatile (pulse pressure) and steady (mean pressure) components of the blood pressure (BP) curve, 304 young and middle-aged essential hypertensive patients were studied by means of 24-h ambulatory BP monitoring and echocardiography. In the overall study population, both the BP components showed significant correlations with LVM. These correlations were unevenly distributed in the subgroups of subjects younger and in those older than 50 years. While in this latter subgroup, in multivariate analysis, both 24-h mean BP (24-MBP) (beta = 0.27; P = 0.008) and 24-h pulse pressure (24-h PP) (beta = 0.23; P = 0.02) were associated with LVM, in the subset of younger hypertensives only 24-h MBP (beta = 0.21; P = 0.009) was related to LVM, independent of other covariates. The relations observed between 24-h PP and LVM in the entire study population and in the patients older than 50 years lost statistical significance when the effect of 24-h systolic blood pressure (24-h SBP) was taken into account, in a multiple regression model in which 24-h MBP was replaced by 24-h SBP. Our findings seem to suggest that the association of PP with LVM in middle-aged hypertensives may partially explain the increased cardiovascular risk, documented in subjects with high PP. However, this relation is not independent, but is mediated by SBP.

What will replace the mercury sphygmomanometer?

Mercury sphygmomanometers are gradually being phased out, not because of any technological advances but because of environmental concerns. While mercury is still accepted as the 'gold standard' for routine clinical measurement, it suffers from two deficiencies: poor observer technique, and problems due to poor maintenance of the devices. At the same time, there is no generally accepted alternative; the most widely advocated candidates are aneroid or oscillometric devices. Oscillometric devices have the advantages of eliminating observer error and mechanical drift, but it is suggested that the inherent limitations of the oscillometric method mean that it cannot become the gold standard for clinical measurement in individual patients. Aneroid monitors have been found in practice to be frequently deficient, and are subject to the same deficiencies in observer technique as mercury devices. Two possible but so far untested techniques are a 'hybrid' sphygmomanometer, whereby the mercury column is replaced by an electronic transducer and display, and the wideband recording technique, which has the potential of using the same basic principle as the auscultatory technique, while eliminating the human observer.

Task Force I: methodological aspects of blood pressure measurement

OBJECTIVE

To reach a consensus on important methodological aspects of blood pressure measurement.

METHODS

A Task Force on the methodological aspects of blood pressure measurement wrote this review after the Eighth International Consensus Conference on Blood Pressure Monitoring, in Sendai, Japan (28-31 October 2001). This consensus paper is based on the papers presented by Task Force I and on the discussion sessions, and is therefore representative of a broad spectrum of expert opinion.

POINTS OF CONSENSUS

Consensus was reached on the following five issues: (1) there is an urgent need for a simplified protocol for the validation of blood pressure measuring devices; (2) there is a need for a means of updating the "state of the market" for validated devices so that users can have easy access to this information; (3) new devices must be validated independently, and existing devices that have not been validated must be reappraised; (4) manufacturers should confirm when new models use algorithms which have been validated previously; (5) the Food and Drug Administration now accepts that when ambulatory blood pressure measurement is used in clinical short-term trials in which side-effects are not being assessed, a placebo arm is not required.