Is white coat hypertension innocent? Structure and function of the heart in the elderly

Cardiovascular Alterations and Management of Patients With White Coat Hypertension: A Meta-Analysis

A large and growing body of literature has focused on the association between "white coat hypertension" (WCH) and the underlying target organ damage. The evidence suggests that WCH is may not an entirely benign phenomenon. However, whether patients with WCH should receive antihypertensive drugs is unresolved. Therefore, we performed a meta-analysis to fully determine the ability of WCH to alter cardiovascular structure and to determine whether patients with WCH could benefit from drug intervention. Medline, EMBASE, and the Cochrane Library were searched from inception through 21 Oct 2019. A total of 25 studies (8,100 individuals) were included. In participants with WCH, values of aortic pulse wave velocity, augmentation index, intima-media thickness, interventricular septum thickness, left ventricular posterior wall thickness, and left ventricular mass index were lower than those with sustained hypertension, but greater than those in the normotensive group. Of note, antihypertensive drug therapy did not reduce the risk of cardiovascular events in patients with WCH. WCH is accompanied by alterations of cardiovascular structure; however, the benefits from antihypertensive therapy are limited.

Central pressures and central hemodynamic values in white coat hypertensives are closer to those of normotensives than to those of controlled hypertensives for similar age, gender, and 24-h and nocturnal blood pressures

INTRODUCTION

There is disagreement whether white coat hypertensives (WCH) have different hemodynamic and structural characteristics compared to normotensives (NT) and hypertensives (HT).

METHODS

We compared cardiovascular prognostic markers (pulse wave velocity [PWV] and aortic stiffness index [ASI]) and data on central hemodynamics and central pressures (augmentation index [AIx], augmentation pressure [AugP] and pulse pressure amplification [PPA]) from aortic pulse wave analysis between NT (n=175), WCH (n=315) and treated HT (n=691), all with 24-h blood pressure (BP) <130/80 and nocturnal BP <120/70 mmHg after matching for age, gender, body mass index (BMI) and and nocturnal BP. The groups were also compared separately in terms of 24-h systolic BP <120 mmHg and 120-129 mmHg.

RESULTS

The percentage of non-dippers was 40.1% in NT, 34.5% in WCH and 38.3 in HT. For similar 24-h and nocturnal systolic BP (NT 109/64±7/5, WCH 110/66±7/6, HT 109/64±7/5 mmHg), aortic stiffness was greater in HT (n=691, PWV 10.8±2.6 m/s and ASI 0.33±0.16, p<0.01) than in WCH (n=316, PWV 9.7±2.4 m/s and ASI 0.28±0.17) and NT (n=175, PWV 9.5±2.0 m/s and ASI 0.29±0.15); AugP and AIx were higher (p<0.01) in HT (13.9±8.2 and 29.6±12.6 mmHg) than in WCH (11.5±8.5 mmHg and 24.9±15.2) and NT (11.0±6.4 mmHg and 26.6±11.5). PPA was lower (p<0.01) in HT (11.3±5.5 mmHg) than in WCH (13.2±7.1 mmHg) and in NT (12.4±4.9 mmHg). The findings were similar when the 24-h systolic BP <120 mmHg and 120-129 mmHg subgroups were analyzed separately.

CONCLUSION

Our data suggest that for similar age, gender distribution, BMI, and 24-h and nocturnal BP, aortic stiffness, central aortic pressures and wave reflection in WCH are closer to those of NT than to those with treated HT. This supports the idea that white coat hypertension may be a more benign condition than treated hypertension for similar 24-h and particularly nocturnal BP levels.

White-coat hypertension, as defined by ambulatory blood pressure monitoring, and subclinical cardiac organ damage: a meta-analysis

AIM

: The clinical and prognostic relevance of white-coat hypertension (WCH) has not been fully elucidated; in particular, the association of this blood pressure phenotype with suclinical organ damage remains unclear. We performed a systematic meta-analysis in order to provide a comprehensive information on cardiac structural and functional changes in WCH, as defined by ambulatory blood pressure monitoring.

DESIGN

Studies were identified by the following search terms: 'white-coat hypertension', 'isolated clinic hypertension', 'cardiac organ damage', 'target organ damage', 'left ventricle', 'left ventricular hypertrophy', 'cardiac hypertrophy', 'ventricular dysfunction', and 'echocardiography'.

RESULTS

A total of 7382 untreated adult patients (2493 normotensive, 1705 WCH, and 3184 hypertensive individuals) included in 25 studies were considered. Left ventricular mass index was higher in WCH than in normotensive patients [standardized difference in mean (SDM) 0.50, P < 0.01]; mitral E/A ratio was lower (SDM -0.27, P < 0.01) and left atrium larger (SDM 0.29, P < 0.05) in WCH than in the normotensive counterparts. Hypertensive patients showed a greater left ventricular mass index (SDM 0.42, P < 0.01), reduced E/A (SDM -0.15, P < 0.01), and larger left atrium diameter (SDM 0.27, P < 0.01) than WCH patients.

CONCLUSIONS

Our meta-analysis shows that alterations in cardiac structure and function in WCH patients, as defined by ambulatory blood pressure monitoring, are intermediate between sustained hypertensive patients and normotensive controls. The study supports the view that WCH should not be further considered a fully benign entity.

Isolated increases in in-office pressure account for a significant proportion of nurse-derived blood pressure-target organ relations

AIMS

We determined the extent to which relationships between nurse-derived blood pressures (BPs) and cardiovascular damage may be attributed to isolated increases in in-office SBP independent of ambulatory BP.

METHODS

In 750 participants from a community sample, nurse-derived office BP, ambulatory BP, carotid-femoral pulse wave velocity (PWV; applanation tonometry and SphygmoCor software; n=662), and left ventricular mass indexed to height (LVMI; echocardiography; n=463) were determined.

RESULTS

Nurse-derived office BP was associated with organ changes independent of 24-h BP (LVMI; partial r=0.15, P<0.005, PWV; partial r=0.21, P<0.0001) and day BP. However, in both unadjusted (P<0.0001 for both) and multivariate adjusted models (including adjustments for 24-h BP; LVMI; partial r=0.14, P<0.01, PWV; partial r=0.21, P<0.0001), nurse office-day SBP (an index of isolated increases in in-office BP) was associated with target organ changes independent of ambulatory BP and additional confounders, with the highest quartile (≥15 mmHg) showing the most marked increases in LVMI (P<0.0005) and PWV (P<0.0001) as compared to the lowest quartile (<-5 mmHg). These relationships were reproduced in those with normotensive day BP values and the quantitative effect of nurse office-day BP on target organ changes was at least equivalent to that of ambulatory BP.

CONCLUSION

Nurse-elicited isolated increases in in-office BP account for a significant proportion of the relationship between nurse-derived BP and target organ changes independent of ambulatory BP. Therefore, high quality nurse-derived BP measurements do not approximate the impact of BP effects per se on cardiovascular damage.

Hypertension 2005: an evidence-based approach to diagnosis and treatment – an American perspective

Midway into the first decade of the 21st century, evidence-based medicine has become the predominant methodology for the education and practice of medicine. In the ascent to this pre-eminent position, evidence-based medicine has challenged several methodologies through which medicine was taught and practiced throughout the 20th century, including the clinical anecdote, the concept that medicine is an art, the notion that the physician acts as the filter through which medical knowledge is individualized for the patient, and to some extent, the application of principles of pathophysiology to guide individual patient care. Indeed, it appears that in many cases, this mechanism-based approach to disease has been replaced by a broad strokes population-based approach based on outcomes research. However, as in the law, evidence is open to interpretation, varying opinion and nuance. Perhaps nowhere is this more evident than in the field of hypertension, which arguably can be credited with developing the field of evidence-based medicine with randomized clinical trials in the early 1960s and early adaptation and promotion of outcomes-based research, beginning with the first Joint National Committee report on prevention, detection, evaluation and treatment of high blood pressure in the 1970s. The purpose of this chapter is to review the evidence in the diagnosis and treatment of essential hypertension, focusing on the following areas. First, use of ambulatory and home blood pressure monitoring as diagnostic and prognostic tools; second, recent clinical trials in the treatment of essential hypertension that form the basis of evidence-based therapeutics; and third, presentation of the key features of the Joint National Committee (JNC) 7, which forms the current basis of treatment for essential hypertension.

Relations between white coat effects and left ventricular mass index or arterial stiffness: role of nocturnal blood pressure dipping

BACKGROUND

Whether independent relationships between white coat effects (office minus day (office-day blood pressure (BP))) and organ damage or arterial stiffness may be explained by associations with an attenuated nocturnal BP dipping, has not been determined.

METHODS

In 750 participants from a sample of African ancestry, office and 24-hour BP, carotid-femoral pulse wave velocity (PWV) (applanation tonometry and SphygmoCor software) (n = 662), and left ventricular mass indexed to height(2.7) (LVMI) (echocardiography) (n = 463) were determined.

RESULTS

Office-day systolic BP (SBP) was correlated with day minus night (day-night) SBP, percentage night divided by day (night/day) SBP, and night SBP (P < 0.0005), and these relationships persisted with adjustments for confounders, including day SBP (P < 0.005). With adjustments for 24-hour SBP and additional confounders, office-day SBP was associated with LVMI (P < 0.01) and PWV (P < 0.0001). With adjustments for day SBP and additional confounders, day-night SBP, percentage night/day SBP, and night SBP were related to PWV (P < 0.05) but not to LVMI (P > 0.44). The relationships between office-day SBP and LVMI or PWV persisted with adjustments for either day-night or percentage night/day SBP (LVMI: P = 0.01; PWV: P < 0.0001) or night SBP (LVMI: P < 0.01; PWV: P = 0.0001), and in product of coefficient mediation analysis with appropriate adjustments, neither indexes of nocturnal BP dipping nor nocturnal BP per se contributed toward the impact of office-day BP on LVMI or PWV (P > 0.09).

CONCLUSIONS

In a group of African ancestry, although white coat effects are independently associated with an attenuated nocturnal decrease in SBP, neither decreased BP dipping nor nocturnal BP contribute toward the independent relationships between white coat effects and LVMI or arterial stiffness.

Left ventricular mass index in children with white coat hypertension

OBJECTIVES

To determine whether children with white coat hypertension (WCH) have evidence of target-organ damage by comparing the left ventricular mass index (LVMI) of subjects with WCH with that of matched normotensive and hypertensive controls.

STUDY DESIGN

Each subject in the WCH group was matched by body mass index (BMI; +/- 10%), age (+/- 1 year), and sex to a normotensive control and a hypertensive control. Echocardiograms were reviewed to determine the LVMI for each subject. These triple matches were analyzed using repeated-measures analysis of variance to detect differences in LVMI among the 3 groups.

RESULTS

A total of 27 matched triplets were established. The groups were comparable for sex, age, and BMI. Mean LVMI was 29.2 g/m(2.7) for the normotensive group, 32.3 g/m(2.7) for the WCH group, and 35.1 g/m(2.7) for the sustained hypertensive group (normotensive vs WCH, P = .028; WCH vs sustained hypertension, P = .07). Left ventricular hypertrophy was not present in any subject in the normotensive or WCH groups, but was found in 26% of the sustained hypertensive subjects (P < .001).

CONCLUSIONS

After controlling closely for BMI, the LVMI in the subjects with WCH was between that of the normotensives and sustained hypertensives, suggesting that WCH may be associated with hypertensive end-organ effects.

Detecting white coat and reverse white coat effects in clinic settings using measures of blood pressure habituation in the clinic and patient self-monitoring of blood pressure

To examine the utility of blood pressure (BP) habituation within and across multiple clinic visits and patient-determined home BP monitoring for detecting white coat (WCE) and reverse white coat effects (RWCE) commonly observed in medical settings, 54 patients undergoing evaluation for hypertension in an internal medicine group practice were categorized according to the magnitude of differences between systolic BP (SBP) and diastolic BP (DBP) obtained in the clinic and through ambulatory BP monitoring. BPs were measured four times during three separate clinic visits, during a 1-week home BP monitoring period, and during a single 24-h ambulatory monitoring period. Patients whose mean clinic and average daytime BPs were within +/-5 mm Hg were categorized as having stable BP; patients whose clinic BPs were >5 mm Hg of their daytime BPs were categorized as showing a WCE and patients whose average daytime BPs were >5 mm Hg of their clinic BPs were categorized as showing a RWCE. Results revealed that degree of habituation occurring between the first and third clinic visits significantly predicted magnitude of both the WCE and RWCE for SBP, with greater habituation being associated with the WCE and lesser habituation associated with the RWCE. Greater SBP habituation within clinic visits was associated with the WCE for SBP and greater DBP habituation within clinic visits was associated with the WCE for DBP. Lesser DBP habituation within clinic visits was associated with the RWCE for both SBP and DBP. Home BP monitoring did not contribute to predicting either WCE or RWCE.

[Factors correlated with left ventricular mass in hypertensive patients]

Left ventricular hypertrophy (LVH) is an independent risk factor in hypertensive patient.

THE AIM

Of our study is to evaluate prospectively the relationship between left ventricular mass and clinical, echocardiographical and ambulatory blood pressure data in hypertensive subjects.

METHODS

We studied 88 hypertensive patient who underwent clinical and laboratory investigation, echocardiography and 24 hours ambulatory blood pressure monitoring. Correlations were made between these data and left ventricular mass.

RESULTS

Clinical data, which correlated well with left ventricular mass, were duration of hypertension, systolic arterial pressure and pulse arterial pressure. In echocardiography left atrial area and left ventricular dysfunction correlated significatively with left ventricular mass. Data from 24 hours blood pressure monitoring as daytime systolic pressure, nighttimes diastolic pressure, ambulatory systolic pressure and ambulatory pulse pressure.

CONCLUSION

In hypertensive patient, left ventricular mass correlated well with left atrial dilation and diastolic left ventricular dysfunction. It also correlated with 24 hours ambulatory blood pressure monitoring data.

Transiently elevated diastolic blood pressure is associated with a gender-dependent effect on cardiovascular risk

We assessed the morbidity and mortality of subjects with transiently elevated diastolic pressure in the General Practice Hypertension Study Group (GPHSG) population. A total of 23 578 patients (aged 18-65 years) from seven UK general practices were screened in 1974 for a diastolic blood pressure (DBP4) of > or = 90 mmHg. Two further readings of DBP4 determined hypertensive (either DBP4 > or = 90 mmHg) or transient hypertensive (both DBP4 < 90 mmHg) status. Transients (n = 850) were matched with normotensive controls (n = 824) and risk ratios calculated over a mean follow-up of 18.7 years. Rescreening was conducted in six of the practices (n = 20 942) after 7.7 years. Male transients had a higher relative hazard for cardiovascular mortality than controls (11.8%, 8.6%, adjusted relative hazard 1.59, P = 0.056). Female transients had a lower relative hazard for cardiovascular mortality than controls (3.6%, 5.4%, adjusted relative hazard 0.39, P = 0.018). In all, 422 patients with transient hypertension were rescreened along with 367 matched controls. Significantly more transients were on antihypertensive treatment compared with their controls (odds ratio (OR) [95% CI]) for both male (4.2 [1.6-11.1]) and female patients (2.4 [1.0-5.56]) and more untreated female transients developed hypertension. Male transients had a higher rates of diabetes mellitus (adj OR = 5.1, P = 0.04) and stroke (adj OR 15.9, P = 0.03). This study has shown that transiently elevated DBP in GPHSG is associated with a significantly higher risk of later hypertension in men and women and of diabetes, stroke and cardiovascular mortality in men. Women with this condition have a significantly lower cardiovascular mortality.

Sequential follow-up clinic and ambulatory blood pressure evaluation in a low risk population of white-coat hypertensive patients and in normotensives

BACKGROUND

In subjects with white-coat hypertension (WCH) it is unclear how ambulatory blood pressure (ABPM) progresses over time and whether they exhibit an increased cardiovascular risk.

METHODS

We prospectively evaluated the transition of clinic and ABPM values in 39 clinic and ABPM normotensive subjects (NT) (clinic BP<140/90 mmHg and awake BP<130/85 mmHg, ages 43.4+/-2.6 y) and in 79 untreated subjects (47.2+/-2.4 y) with WCH (clinic BP>140/90, awake ABP<130/85 mmHg) with no other major cardiovascular risk factors. Ambulatory blood pressure was evaluated at baseline and on at least two further occasions during follow-up.

RESULTS

At baseline all subjects were untreated and groups did not differ on values of metabolic parameters, BMI, left ventricular mass index, and ABPM values. Subjects were revaluated for ABPM half way through and at the end of follow-up, 35+/-3 and 86+/-4 months in NT and 49+/-4 and 90+/-4 months in WCH. Thirty-six WCH were on antihypertensive treatment (AH) after baseline until the end of follow-up (WCH-tr), whereas 43 WCH (WCH-untr) were free from AH throughout the study. In a similar way all groups showed a significant (p<0.01) progressive increase in 24-h ABPM systolic blood pressure (SBP)/diastolic blood pressure (DBP) from baseline throughout the follow-up in NT (+4.9/2.1+/-0.8/0.9 mmHg), average annual increase of 0.72/0.37 mmHg/y, in WCH-tr (+ 5.0/1.2+/-1.1/1.5 mmHg), average annual increase of 0.66/0.31 mmHg/y and in WCH-untr (+5.4/3.2+/-0.9/1.1 mmHg), average annual increase of 0.74/0.39 mmHg/y. During the follow-up office SBP/DBP (mmHg) significantly rose in NT (+5.7/3.9) but was reduced in WCH-tr (-7.8/5.2) and in WCH-untr (-4.7/1.1). Development of ambulatory hypertension (daytime BP >130 and/or >85 mmHg) occurred in 15.4% (6/39) of NT, in 22.7% (8/36) of WCH-tr and in 26.1% (11/43) of WCH-untr (NS). First cardiovascular events recorded were three in subjects with WCH and none in NT.

CONCLUSIONS

After 7.4 years of follow-up, both the progressive increase in ABPM and the rate of transition to ambulatory hypertension in subjects with WCH (either treated or untreated), who were selected under strict criteria were similar to that of normotensive subjects. Also there was no evidence that WCH exhibited a clear higher risk of development cardiovascular events.

White-coat hypertension: a clinical review

White-coat hypertension (WCHT), also called 'isolated office or clinic hypertension', is defined as the occurrence of blood pressure (BP) values higher than normal when measured in the medical environment, but within the normal range during daily life, usually defined as average daytime ambulatory BP (ABP) or home BP values (<135 mm Hg systolic and <85 mm Hg diastolic). The prevalence of WCHT varies from 15% to over 50% of all patients with mildly elevated office BP (OBP) values. In untreated hypertensive patients, the probability of WCHT especially increases with female gender and a mildly elevated OBP level. The value of other possible determinants such as (non) smoking status, duration of hypertension, left ventricular mass, number of OBP measurements, educational level, etc. is less consistently shown. Although, for various reasons, studies evaluating the long-term effects of WCHT are not always easy to interpret, most data indicate that persons with WCHT have a worse or equal cardiovascular prognosis than normotensives, but a better one than those with sustained hypertension. WCHT is sometimes considered a prehypertensive state, but data on the long-term evolution of subjects with WCHT are scarce. Patients with WCHT and a high cardiovascular risk or proven target organ damage should be pharmacologically treated. Subjects with uncomplicated WCHT should probably not receive medical therapy, but a close follow-up, including regular assessment of other risk factors and measurement of OBP (every 6 months) and ABP (every 1 or 2 years), is warranted.

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.

White-Coat Hypertension Contributes to the Presence of Carotid Arteriosclerosis

It remains unclear whether white-coat hypertension is associated with vascular organ damage (e.g., carotid arteriosclerosis) in the same way sustained hypertension is. We therefore compared the progression of carotid arteriosclerosis among Japanese individuals showing normal blood pressures, sustained hypertension or white-coat hypertension. A total of 30 subjects (mean age, 58 years) with white-coat hypertension, 30 (mean age, 54 years) with untreated sustained hypertension who had no plaque formation in the carotid arteries, and 30 normotensive subjects (mean age, 58 years) were enrolled in this study. The white-coat and sustained hypertensive subjects were matched with respect to their clinical blood pressures, but their ambulatory blood pressures differed. Conversely, white-coat hypertensive and normotensive subjects were matched with respect to ambulatory blood pressures, but their clinical blood pressures differed. Carotid intimal-medial thickness was measured by B-mode ultrasonography, and the cross-sectional area of the common carotid artery was calculated. The three groups were similar with respect to age, sex ratio, height, laboratory data and the incidence of smoking. Body weights and body mass indexes were significantly higher among patients with sustained hypertension than among either normotensive or white-coat hypertensive patients. Intimal-medial thicknesses and carotid cross-sectional areas were similar in patients with white-coat and sustained hypertension and significantly higher than in normotensive subjects. Collectively, these findings suggest that white-coat hypertension contributed to the presence of carotid arteriosclerosis in our subjects in a manner similar to sustained hypertension. Thus, clinical evaluation of white-coat hypertension should be conducted with the potential for target organ damage in mind.

Left ventricular hypertrophy in treated hypertensive patients with good blood pressure control outside the clinic, but poor clinic blood pressure control

OBJECTIVE

The aim of the study was to evaluate the prevalence of left ventricular hypertrophy (LVH) in treated patients with good blood pressure (BP) control during multiple home BP (HBP) measurements and during 24-h ambulatory BP monitoring (ABPM), but with unsatisfactory BP control in the clinic. These patients were compared with treated hypertensives whose BP was well controlled under the three circumstances.

METHODS

Seventy-two treated consecutive patients (group I, age 56 +/- 10 years) with clinic BP values > or = 140/90 mmHg, and a difference between clinic and self-measured HBP > 10 mmHg for diastolic blood pressure (DBP) and/or > 20 mmHg for systolic blood pressure (SBP), underwent the following procedures: (1) clinic BP measurement; (2) routine diagnostic work-up; (3) HBP monitoring; (4) 24-h ABPM; (5) echocardiography. Thirty-five hypertensive patients with satisfactory BP control according to clinic (< 140/90 mmHg), HBP (< or = 131/82 mmHg) and ABP criteria (< or = 125/79 mmHg) were included as the control group (group II, age 55 +/- 9 years).

RESULTS

In group I, 33 subjects out of the 72 (46%) with clinic BP > 140/90 mmHg had BP values controlled outside the clinic (23 according to HBP criteria and 22 according to ABP criteria). The prevalence of LVH (LV mass index > 134 g/m2 in men and > 110 g/m2 in women) was significantly higher in these patients (15.1 versus 2.8%, P < 0.01) than in group II (BP also controlled in the clinic), despite the fact that HBP and ABP were reduced to similar levels in the two groups. CONCLUSIONS Our data provide evidence that treated hypertensive patients with good BP control at home or during ambulatory monitoring, but incomplete BP control in the clinic, have more pronounced cardiac alterations than patients with both clinic and out of the clinic BP control. This finding offers a new piece of information about the diagnostic value of BP measurement in the clinic to assess BP control during antihypertensive treatment.

Relevance of blood pressure variation in the circadian onset of cardiovascular events

Ambulatory blood pressure monitoring (ABPM) is a highly useful diagnostic tool as it can detect non-dipping and can distinguish masked hypertension, white-coat hypertension and sustained hypertension. Furthermore, measurement of blood pressure using ABPM has greater prognostic strength than single clinic blood pressure measurements. The Systolic Hypertension in Europe study, for example, found that elevation of ambulatory systolic blood pressure, but not conventional single cuff systolic blood pressure, by 10 mmHg was associated with adverse cardiovascular outcomes. Blood pressure follows a circadian rhythm, with peak levels during the morning hours. The morning period has also been associated with a greater risk for cardiovascular events compared with the rest of the 24 h. The morning surge in blood pressure, along with haemostatic changes that promote thrombosis, is believed to contribute to this heightened risk. Long-acting antihypertensive agents that provide blood pressure control throughout the 24-h dosing interval, including the morning hours, are the most appropriate therapeutic approach to hypertension. Direct comparative studies with telmisartan and other angiotensin-II receptor blockers and with amlodipine have shown that telmisartan has a long duration of action and controls blood pressure over the 24-h dosing period.

Circulating homocysteine levels in sustained and white coat hypertension

Although white coat hypertension has been widely studied in the last years, its risk profile is not yet completely clear. The aim of this study was to evaluate circulating homocysteine levels, an emerging cardiovascular risk factor, in subjects with white coat and sustained hypertension. We selected 31 sustained hypertensive subjects, 31 white coat hypertensive subjects and 31 normotensive subjects matched for age, gender, body mass index and occupation. Women were also matched for menopausal status. Subjects with smoking habit, dyslipidaemia and diabetes mellitus were excluded from the study. White coat hypertension was defined as clinical hypertension and daytime ambulatory blood pressure <135/85 mmHg. Blood samples were drawn after a fasting period of 12 h for routine laboratory tests and homocysteine determination. Homocysteine levels were evaluated by fluorescence polarization immunoassay. Creatinine, glucose, cholesterol and triglycerides were not different among the groups. White coat hypertensive subjects had significantly lower homocysteine levels than sustained hypertensive patients (8.2+/-2.0 vs 12.6+/-3.9 micromol/l, P=0.0003). No significant difference was observed between white coat hypertensive and normotensive subjects regarding this parameter (8.2+/-2.0 vs 7.6+/-1.9 micromol/l, P=0.9). In conclusion, our data show that middle-aged white coat hypertensive subjects without other cardiovascular risk factors have lower circulating homocysteine levels than sustained hypertensive patients suggesting that they are at lower cardiovascular risk.

Noninvasive study of endothelial function in white coat hypertension

Several studies have demonstrated that endothelial dysfunction is present in patients with essential hypertension. However, the presence of endothelial dysfunction in patients with white coat hypertension has not been studied. We evaluated the variation in the diameter of the brachial artery produced by flow-mediated dilation after a mechanical stimulus in patients with recently diagnosed mild to moderate sustained essential hypertension compared with patients with white coat hypertension. A total of 29 patients fulfilled inclusion criteria; 15 healthy volunteers were also included. After 24-hour ambulatory blood pressure monitoring, 15 patients were classified with sustained essential hypertension; 14 patients with white coat hypertension. Vascular ultrasound scans were performed according to the method described by Celermajer et al, with modification for noninvasive determination of endothelial dysfunction. Basal brachial artery diameter did not differ significantly among the 3 groups. Changes in arterial diameter 60 seconds after cuff deflation were higher in the control group compared with both hypertensive groups, but no significant differences were found between the sustained essential hypertension group and the white coat hypertension group. Flow-mediated dilation was similar in white coat hypertensives and sustained essential hypertensives. The presence of endothelial dysfunction in subjects with white coat hypertension suggests that it should not be considered a harmless trait and that white coat hypertension has common features with sustained essential hypertension.

Clinic and ambulatory heart rate in sustained and white-coat hypertension

BACKGROUND

Sustained and white-coat hypertensives show hypertension in the office setting but different blood pressure values outside the clinical environment. So far, only a few incomplete data on heart rate are available inside and outside the clinical setting in these groups of patient. The aim of this study was to evaluate clinic and ambulatory heart in sustained hypertensives, white-coat hypertensives and normotensives.

METHODS

We selected 236 sustained hypertensives, 236 white-coat hypertensives and 236 normotensives matched for age, gender and body mass index, and with a similar occupation. The subjects had been submitted to clinic evaluation and the non-invasive monitoring of blood pressure and heart rate. White-coat hypertension was defined as clinic hypertension and a daytime blood pressure of less than 135/85 mmHg.

RESULTS

The clinic heart rate was significantly higher in sustained hypertensives and white-coat hypertensives than in normotensives (76 +/- 11 versus 75.5 +/- 10 versus 70 +/- 9 beats/min [bpm], respectively, P < 0.05). The daytime heart rate was significantly higher in sustained hypertensives than in white-coat hypertensives and normotensives (79.4 +/- 10 versus 74.6 +/- 8.5 versus 74.5 +/- 8.5 bpm, respectively, P < 0.05), as were the night-time heart rate (67 +/- 8.5 versus 63 +/- 8 versus 63 +/- 8 bpm, respectively, P < 0.05) and 24 h heart rate (76.3 +/- 9 versus 72 +/- 7.8 versus 72 +/- 8 bpm, respectively, P < 0.05). When men and women were analyzed separately, the same trend was observed.

CONCLUSIONS

The clinic heart rate is similar in sustained and white-coat hypertensives, but the ambulatory heart rate is lower in white-coat hypertensives. As ambulatory heart rate is more representative of 24 h heart rate load and may be a better indicator of the detrimental effect of heart rate, our findings suggest that white-coat hypertensives are at lower cardiovascular risk than sustained hypertensives.

Silent and clinically overt stroke in older Japanese subjects with white-coat and sustained hypertension

OBJECTIVES

We investigated whether white-coat hypertension is a risk factor for stroke in relation to silent cerebral infarct (SCI) in an older Japanese population.

BACKGROUND

It remains uncertain whether white-coat hypertension in older subjects is a benign condition or is associated with an increased risk of stroke.

METHODS

We studied the prognosis for stroke in 958 older Japanese subjects (147 normotensives [NT], 236 white-coat hypertensives [WCHT] and 575 sustained hypertensives [SHT]) in whom ambulatory blood pressure monitoring was performed in the absence of antihypertensive treatment. In 585 subjects (61%), we also assessed SCI using brain magnetic resonance imaging.

RESULTS

Silent cerebral infarcts were found in 36% of NT (n = 70), 42% of WCHT (n = 154), and 53% of SHT (n = 361); multiple SCIs (the presence of > or =2 SCIs) were found in 24% of NT, 25% of WCHT and 39% of SHT. During a mean 42-month follow-up period, clinically overt strokes occurred in 62 subjects (NT: three [2.0%]; WCHT: five [2.1%]; SHT: 54 [9.4%]), with 14 fatal cases (NT: one [0.7%]; WCHT: 0 [0%]; SHT: 13 [2.3%]). A Cox regression analysis showed that age (p = 0.0001) and SHT (relative risk, [RR] [95% confidence interval, CI]: 4.3 [1.3-14.2], p = 0.018) were independent stroke predictors, whereas WCHT was not significant. When we added presence/absence of SCI at baseline into this model, the RR (95% CI) for SCI was 4.6 (2.0-10.5) (p = 0.003) and that of SHT was 5.5 (1.8-18.9) versus WCHT (p = 0.004) and 3.8 (0.88-16.7) versus NT (p = 0.07).

CONCLUSIONS

In older subjects the incidence of stroke in WCHT is similar to that of NT and one-fourth the risk in SHT. Although SCI is a strong predictor of stroke, the difference in stroke prognosis between SHT and WCHT was independent of SCI. It is clinically important to distinguish WCHT from SHT even after assessment of target organ damage in the elderly.

Modern approaches to blood pressure measurement

BACKGROUND

Blood pressure (BP) is usually measured by conventional sphygmomanometry. Although apparently simple, this procedure is fraught with many potential sources of error. This review focuses on two alternative techniques of BP measurement: ambulatory monitoring and self measurement.

REVIEW

BP values obtained by ambulatory monitoring or self measurement are characterised by high reproducibility, are not subject to digit preference or observer bias, and minimise the transient rise of the blood pressure in response to the surroundings of the clinic or the presence of the observer, the so called white coat effect. For ambulatory monitoring, the upper limits of systolic/diastolic normotension in adults include 130/80 mm Hg for the 24 hour BP and 135/85 and 120/70 mm Hg for the daytime BP and night time BP, respectively. For the the self measured BP these thresholds include 135/85 mm Hg. Automated BP measurement is most useful to identify patients with white coat hypertension. Whether or not white coat hypertension predisposes to sustained hypertension remains debated. However, outcome is better correlated with the ambulatory BP than with the conventional BP. In patients with white coat hypertension, antihypertensive drugs lower the BP in the clinic, but not the ambulatory BP, and also do not improve prognosis. Ambulatory BP monitoring is also better than conventional BP measurement in assessing the effects of treatment. Ambulatory BP monitoring is necessary to diagnose nocturnal hypertension and is especially indicated in patients with borderline hypertension, elderly patients, pregnant women, patients with treatment resistant hypertension, and also in patients with symptoms suggestive of hypotension.

CONCLUSIONS

The newer techniques of BP measurement are now well established in clinical research, for diagnosis in clinical practice, and will increasingly make their appearance in occupational and environmental medicine.

Treatment of white coat hypertension

White coat hypertension has been defined as the persistent elevation of blood pressure at the clinic or office only. It usually implies that daily ambulatory blood pressure is normal. The accepted cutoff for normal daytime ambulatory blood pressure is 135/85 mm Hg. The prevalence of white coat hypertension is high and varies from 20% to 45%. It appears to be more frequent in women, older patients, and persons with mild hypertension. White coat hypertension should not be confused with the white coat effect. The white coat effect signifies the difference in blood pressure between the office and daytime ambulatory blood pressure and occurs in patients with white coat hypertension as well as in patients with sustained hypertension that is treated or untreated. White coat hypertension is a benign condition, and the incidence of target-organ damage or cardiovascular morbidity and death is not significantly different from that in normotensive persons. Pharmacologic treatment should be withheld; instead, treatment should consist of lifestyle modification, moderate salt restriction, weight reduction, regular exercise, smoking cessation, and correction of glucose and lipid abnormalities. In addition, semiannual or annual follow-up with ambulatory blood pressure monitoring is advised.

Clinical value of microalbuminuria in hypertension

Microalbuminuria (MA) is a well recognized marker of cardiovascular complications in hypertension, but whether MA can predict adverse outcome in this clinical condition is still a subject for debate. The fact that in hypertensive cohorts those patients who showed an increase in albumin excretion rate also manifested an increased incidence of morbid events indicates that the presence of MA in hypertension may carry an increased cardiovascular risk. However, the prognostic significance of MA remains controversial because no results of prospective studies performed in hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of MA in hypertension, including severity of the disease, selection procedures, concomitant risk factors, degree of obesity, age, and sex distribution. This accounts for the large differences in the prevalence of MA that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 40%. There is still conflict over whether MA in hypertension is due to increased intraglomerular pressure or to glomerular damage. The data from the literature suggest that in subjects with mild hypertension the main determinant of albumin excretion rate is the haemodynamic load. In subjects with more severe hypertension and hypertensive complications, the augmented urinary albumin leak is probably the consequence of a systemic microvascular disturbance which involves the glomeruli. In this respect, the insulin resistance state often associated to high blood pressure appears as one of the main pathogenetic factors. Whether management of hypertensive populations may be improved by monitoring of albumin excretion rate and whether antihypertensive drugs which are more effective in decreasing urinary albumin can be more beneficial in patients with MA remains to be determined.

Difference between office and ambulatory blood pressure or real white coat effect: does it matter in terms of prognosis?

OBJECTIVE

The blood pressure (BP) response to the doctor's visit, generally referred as the white coat (WC) response, is usually estimated by the difference between office BP (OBP) and ambulatory BP (ABP). The purpose of this study was to determine the validity of this estimation. To that end, we compared the real WC effect and the estimated WC effect (OBP-ABP) in terms of magnitude and consequences on target organs.

DESIGN

The study comprised 88 patients referred for hypertension. The real WC effect was measured using a Finapres device and expressed as the maximal WC effect (Max WC) or the average WC effect (Aver WC). For the estimation of target organ damages, the whole hypertensive group was separated into two groups according to the medians of the Aver WC, the Max WC, and the estimated WC effects, successively. Left ventricular mass index, E to A mitral wave ratio and pulse wave velocity were compared between groups as were serum creatinine, cholesterol and glucose levels.

RESULTS

The estimated WC effect proved to be a bad index of the real response to the doctor's visit as assessed by their difference of magnitude between the two (20 +/- 17, 12 +/- 12 and 30 +/- 14 mmHg as estimated WC, Aver WC and Max WC effects, respectively), their loose correlations (r=0.31, P=0.004 between estimated WC and Aver WC effects; r=0.27, P=0.01 between estimated WC and Max WC effects), and finally by the fact that they were in agreement in less than two-thirds of the patients for the categorization of the WC response. Concerning target organ damages, no difference in terms of cardiac mass, diastolic function, arterial distensibility, renal function and cardiovascular risk profile could be discerned between the groups with a high and a low WC effect, either real or estimated, when age and ABP were taken into account.

CONCLUSION

The present work supports the view that the true WC effect and its estimation are not equivalent. However, the way in which the WC response is defined does not alter its effect on target organs or cardiovascular risk profile.

Hypertension after liver transplantation: a predictive role for pretreatment hemodynamics and effects of isradipine on the systemic and renal circulations

Hypertension developing after liver transplantation during immunosuppression with cyclosporine A reflects an unusual hemodynamic transition from peripheral vasodilation to systemic and renal vasoconstriction. Although dihydropyridine calcium channel blockers are often administered for their efficacy in promoting vasodilation, some liver transplant recipients report marked symptomatic intolerance to these agents. In the present study we examined systemic and renal responses to isradipine using systemic (thoracic bioimpedance) and renal hemodynamic measurements in 15 liver transplant recipients studied at the time of initial diagnosis of posttransplant hypertension and after 3 months of treatment. Circadian blood pressure patterns were examined by overnight ambulatory blood pressure monitoring before and during antihypertensive therapy. During isradipine administration, blood pressure decreased from 151 +/- 3/91 +/- 2 to 130 +/-3/81 +/- 2 mm Hg (P < .01) without change in renal blood flow (406 +/- 43 to 425 +/- 52 mL/min/1.73m2, P = NS) or renal vascular resistance index (25,674 +/-3312 to 20,520 +/- 2311 dynes x sec x cm(-5)/m2, P = NS). Pre-treatment differences in systemic vascular tone persisted during treatment and predicted the tendency for symptomatic tachycardia and flushing, predominantly in those with hyperdynamic circulations. Twice daily dosing of isradipine was associated with partial and significant restoration of the nocturnal decrease in blood pressure (systolic blood pressure decreased 5.5%, normal 13%), usually absent early after transplantation. Our results demonstrate the ability of hemodynamic measurements to predict the symptomatic response to antihypertensive therapy in the posttransplant setting.

"White coat hypertension" in adolescents: increased values of urinary cortisol and endothelin

OBJECTIVE

To investigate whether "white coat hypertension" (WCH) in adolescents is an innocent phenomenon or is associated with early changes of the vascular system and/or increased stress response, reflected in the urinary endothelin and cortisol values, respectively.

STUDY DESIGN

The study group included 36 subjects, 14 with WCH (8 males and 6 females) aged 12.9 +/- 3 years and 22 normotensive control subjects (12 males and 10 females) aged 13 +/- 3.5 years. WCH was defined as systolic and/or diastolic blood pressure (BP) > or =95th percentile for age, sex, and height and with reported normal BP measurements at home. Urinary endothelin (UET1), urinary free cortisol (UFC), and plasma renin levels were determined by radioimmunoassay; and urinary albumin levels were determined by nephelometry. For statistical analysis, the Mann Whitney U test, Spearman correlation coefficient, and multivariate analysis of variance/multivariate analysis of covariance were used, as applicable.

RESULTS

The 24-hour values of UET1 and UFC were greater in male subjects with WCH than in male control subjects (P =.02), whereas no such difference was found in female subjects. The difference in UFC values in male subjects was accounted for by the day values. In subjects with WCH, and not in control subjects, a positive correlation of UET1 to UFC (r = 0.59, P =.027), diastolic BP (r = 0.55, P =.04), and mean BP (r = 0.65, P =.012) was detected.

CONCLUSIONS

Our data indicate that WCH in adolescence may not be an innocent phenomenon and may represent a prelude to permanent idiopathic hypertension of adulthood.

Attenuation of the "white-coat effect" by antihypertensive treatment and regression of target organ damage

This study assessed whether 2 common surrogate measures of the "white-coat effect," namely the clinic-daytime and the clinic-home differences in blood pressure (BP), were attenuated by long-term antihypertensive treatment and whether this attenuation is relevant to the treatment-induced regression of left ventricular hypertrophy, thus having clinical significance. We considered data from 206 patients with essential hypertension (aged 20 to 65 years) who had a diastolic BP between 95 and 115 mm Hg and echocardiographic evidence of left ventricular hypertrophy. In each patient, clinic BP, 24-hour ambulatory BP, and left ventricular mass index were assessed at baseline, after 3 and 12 months of treatment with an angiotensin-converting enzyme inhibitor, and after a final 4-week placebo run-off period. At baseline, the clinic-daytime differences in systolic and diastolic BP were 12.1+/-15.4 and 6.8+/-10.1 mm Hg, respectively; the corresponding values for the clinic-home differences were 5.7+/-10.6 and 2.9+/-6.1 mm Hg, respectively. These differences were reduced by 57.6% and 77.1% (P<0.01) and by 65.7% and 64.3% (P<0.01), respectively, after 12 months of treatment, with a partial return toward the pretreatment differences after the final placebo period. The observed treatment-induced reductions in left ventricular mass index and those in the clinic-daytime or clinic-home differences for systolic and diastolic BP showed no significant relationship when tested by multiple regression analysis. This provides the first longitudinal evidence that clinic-daytime and clinic-home differences in BP have no substantial value in predicting the regression of target organ damage, such as left ventricular hypertrophy, that has prognostic relevance.

Blood pressure biofeedback treatment of white-coat hypertension

OBJECTIVE

The objective of the study was to compare blood pressure (BP) biofeedback treatment (BF) effects between white-coat hypertension and essential hypertension.

METHODS

Fifteen white-coat hypertensive out-patients and 23 essential hypertensive out-patients were randomly assigned to groups A or B. Subjects in group A underwent BF once a week for a total of four sessions. Those in group B visited the clinic only to measure BP and later underwent the same BF.

RESULTS

In group A, BPs of white-coat hypertensives and essential hypertensives were significantly reduced by 22/11 and 14/8 mmHg, respectively. In group B, they were unchanged during the same period but later suppressed by BF. Under BF, pulse and respiratory rates were significantly higher, and elevation of diastolic BP due to mental stress testing was better suppressed in white-coat hypertensives than in essential hypertensives.

CONCLUSION

This treatment was effective in both types of hypertension, and pressor response to stress seems to be important in the differentiated BF effect.

White coat hypertension and carotid atherosclerosis

To investigate further the relationship between atherosclerotic vascular disease and blood pressure, and the phenomenon of white coat hypertension, we performed a cross-sectional study of patients referred for carotid Doppler scanning, to determine the relationship between ambulatory blood pressure monitoring (ABPM) and carotid atherosclerosis. We studied 79 patients (51 men, 28 women) undergoing Doppler ultrasound examination of the carotid arteries: 44 (56%) had evidence of carotid atherosclerosis on Doppler ultrasound examination ("disease group"), whilst 35 (44%) had normal carotid arteries ("controls"). "Adequate" ABPM recordings, defined by > 90% of recordings over the 24 h, were available in 51 patients (30 positive, 21 negative). There were no significant differences in mean daytime, mean night-time or mean 24 h ABPM recordings between those with and without carotid atherosclerosis. Mean manual clinic systolic blood pressure was significantly greater in those with carotid atherosclerosis than in controls (146.7 +/- 25.2 vs 131.1 +/- 35 mmHg, p < 0.005). In patients with carotid atherosclerosis, the first systolic blood pressure ABPM recording was not significantly different from the mean manual clinic recording (mean difference -1.5 mmHg, 95% confidence interval (CI) -7.9 to 4.8 mmHg). The initial diastolic blood pressure ABPM recording was significantly higher than the mean manual recording. Carotid atherosclerosis was identified in 53% of normotensive controls compared with 56% of white coat hypertensives and 75% of persistent hypertensives. One-third (9/27) of the patients with normal carotid arteries did not have nocturnal dipping ("non-dippers") compared with 50% (12/24) of the atherosclerotic patients. This study suggests that carotid atherosclerosis may be associated with white coat hypertension. Our study adds to the body of evidence that white coat hypertension is associated with end-organ damage and is not simply a benign disease. Such patients should be screened for other cardiovascular risk factors and should be monitored for the development of persistent hypertension.

Diagnosis of white coat hypertension by ambulatory blood pressure monitoring

White coat hypertension (WCH) is common in referred hypertensive patients. Ambulatory blood pressure monitoring (ABPM) is not free from the white coat syndrome. We examined the use of the elevation of the first and last measurements of ABPM for diagnosis of WCH in a hypertensive population that had been referred to a hospital-based hypertension unit. Data were obtained on 1350 patients for clinic and ABPM parameters. WCH, as diagnosed by conventional clinic blood pressure (BP) measurement, was compared with a variety of alternative methods determined from ABPM. In all cases, mean daytime pressure was <135 mm Hg/85 mm Hg with an elevation of clinic BP >/=140 mm Hg systolic or 90 mm Hg diastolic. The definitions tested for this elevation were first hour mean pressure, first reading, maximum reading in first hour, last hour mean pressure, last reading, maximum reading in the last hour and maximum reading in first or last hour. Elevation of the maximum pressure in the first hour or last hour above 140 mm Hg systolic or 90 mm Hg diastolic showed a high level of agreement (kappa=0.91) with classical WCH for diagnosis of the white coat syndrome. Termed ambulatory white coat hypertension, patients with this finding were older than classic white coat patients and had higher daytime (127+/-6/78+/-5 mm Hg versus 121+/-5.5/74+/-6 mm Hg, P<0.005 for systolic and diastolic) and nighttime (114+/-11/67+/-8 mm Hg versus 106+/-9/61+/-6 mm Hg, P<0.005 for systolic and diastolic) pressures. They also had a significantly greater Sokolow-Lyon index (leads V(1)+V(5), 21+/-7 mV versus 18+/-6 mV). Elevation of BP above 140 mm Hg systolic or 90 mm Hg diastolic in the first or last hour of monitoring diagnoses patients with a white coat response in whom there is a higher BP profile than in patients with classic white coat response alone. We suggest, therefore, that this is a better measure of the white coat phenomenon.

Ambulatory blood pressure monitoring and echocardiography--noninvasive techniques for evaluation of the hypertensive patient

Clinic blood pressure measurements have only limited ability to determine which hypertensive patients are at greatest risk of cardiovascular events. Ambulatory blood pressure monitoring allows for noninvasive measurement of blood pressure throughout the 24-hour period. This may help to clarify discrepancies between blood pressure values obtained in and out of the clinic and confirm the presence of white-coat hypertension, broadly defined as an elevated clinic blood pressure but a normal ambulatory blood pressure. Ambulatory blood pressure values have been shown to have a better relationship to cardiovascular morbidity and mortality and end-organ damage than clinic blood pressure values. Further, patients with white-coat hypertension appear to be at greater risk of cardiovascular morbidity and end-organ damage than a normotensive population, although they are at less overall risk than a hypertensive population. Hypertensive heart disease is characterized by diastolic dysfunction, increased left ventricular mass, and coronary flow abnormalities. Left ventricular hypertrophy increases the risk of coronary heart disease, congestive heart failure, stroke, ventricular arrhythmias, and sudden death. A variety of invasive and noninvasive techniques are described herein that measure left ventricular mass, diastolic function, and coronary blood flow abnormalities. Most antihypertensive treatments promote regression of left ventricular hypertrophy and reversal of diastolic dysfunction, which may decrease symptoms of congestive heart failure and improve survival.

Clinical value of ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) has now become an established clinical tool. It is appropriate to take stock and assess the situation of this technique. UPDATE ON EQUIPMENT: Important improvements in equipment have occurred, with reductions in weight, in awkwardness and in noisiness of the machines, better acceptability and tolerance by the patients, and better reliability. Validation programmes have been proposed and should be referred to. Limitations of the technique persist with intermittent recording in current practice. The reproducibility is limited in the short-term while recording over 24 h is acceptable. DIAGNOSIS AND PROGNOSIS: White-coat effect (WCE) is manifested as a transient elevation in blood pressure during the medical visit The frequency of this phenomenon, the size of the effect, age, sex and level of blood pressure (BP) or the situation of occurrence (general practitioner, specialist or nurse) have been interpreted differently. It does not seem that WCE predicts cardiovascular morbidity or mortality. White-coat hypertension (WCH) is diagnosed on the evidence of abnormal clinical measures of BP and normal ABPM. The latest upper limits of normality by ABPM recommended by the JNCVI are < 135/85 mmHg while patients are awake and < 120/75 mmHg while patients are asleep. If we accept these upper limits of normality in ABPM, WCH does not appear to be a real problem as regards risk factors or end-organ effects. In terms of prognosis, data are limited. Cardiovascular morbidity seems low in WCH but identical to that of hypertensive subjects in these studies. However, further studies are needed to confirm these results. WCH does not appear to benefit from anti-hypertensive treatment. It is obvious that the lower the BP regarded as the limit of normality, the less likely the occurrence of secondary effects of metabolism, or end-organ effects or complications in those classified as hypertensive. 24 HOUR CYCLE: One of the most specific characteristics of ABPM is the possibility of being able to discover modification or alteration of the 24 h cycle of BP. Non-dippers are classically defined as those who show a reduction in BP of less than 10/5 mmHg or 10% between the day (06.00-22.00 h) and the night, or an elevation in BP. In contrast, extreme dippers are those in whom the BP reduction is greater than 20%. CARDIOVASCULAR SYSTEM: The data remain inconclusive with regard to the existence of a consistent relationship between the lack of a nocturnal dip in blood pressure and target organ damage. As regards prognosis, it seems that an inversion of the day-night cycle is of pejorative significance. CEREBROVASCULAR SYSTEM: Almost all studies have shown that non-dippers had a significantly higher frequency of stroke than dippers. In contrast, too great a fall in nocturnal BP may be responsible for more marked cerebral ischaemia. RENAL SYSTEM: Non-dippers have a significantly elevated median urinary excretion of albumin. There is a significant correlation between the systolic BP and nocturnal diastolic BP, and urinary excretion of albumin. Various studies have confirmed the increased frequency of change in the 24 h cycle in hypertensive subjects at the stage of renal failure.

DIABETES

BP abnormalities should be considered as markers of an elevated risk in diabetic subjects but cannot be considered at present as predictive of the appearance of micro-albuminuria or other abnormalities. ABPM is thus of interest in type I or type II diabetes both in the initial assessment and in the follow-up and adaptation of treatment. PHARMACO-THERAPEUTIC USES: The introduction of ABPM has truly changed the means and possibilities of approach to the study of the effects of anti-hypertensive medications, with new possibilities of analysis such as trough-peak ratio smoothness index, etc.

Clinic-daytime blood pressure difference and cardiovascular damage

OBJECTIVE

To investigate whether the clinic-daytime blood pressure difference can provide information on vascular reactivity to stress comparable to that of simple noninvasive stimuli such as a cold pressor test and isometric exercise, and whether there is any relationship between this blood pressure difference and noninvasive measurements of the left ventricular mass and carotid arterial wall.

DESIGN

Patients with newly discovered, never-treated, sustained hypertension were included in the study after a 1 month run-in, during which time their blood pressure was measured three times at 2 week intervals.

METHODS

Blood pressure was measured by a noninvasive procedure at rest and during a cold pressor test and an isometric exercise. The difference was calculated for systolic, diastolic and mean blood pressure as resting minus daytime ambulatory blood pressure. Parameters of the posterior wall and septal thickness of the left ventricle, aortic root and left atrium were studied by M-mode echocardiography. Carotid wall thickness and diameter were measured using ultrasound.

RESULTS

The 90 patients enrolled in the study were divided into tertiles of clinic-daytime blood pressure difference. The composition of the groups differed in sex, since the majority of women were in the highest tertile, but was comparable for age, body mass index, renin-aldosterone axis and lipid and carbohydrate metabolism. Blood pressure responses to cold and isometric exercise were more pronounced in patients in the lowest tertile of blood pressure difference. No intergroup differences were detected in echocardiographic parameters of ventricular (left ventricular mass, tertiles I-III: 46.5 +/- 10, 42.3 +/- 8, 44.8 +/- 13 g/m2.7, respectively) and carotid (intima-media thickness, tertiles I-III 0.58 +/- 0.1, 0.54 +/- 0.1, 0.62 +/- 0.1 mm, respectively) structure.

CONCLUSIONS

The present study indicates that the clinic-daytime blood pressure difference provides different information on cardiovascular reactivity compared with that obtained from the cold pressor test and isometric exercise. Moreover, it does not seem to have any relationship with ventricular hypertrophy and/or carotid wall thickening.

Hypertension and the development of heart failure

Hypertension is a well-known risk factor that predisposes to the development of left ventricular hypertrophy, coronary flow abnormalities, and systolic and diastolic dysfunction. This complex of abnormalities is known as hypertensive heart disease and eventually leads to heart failure. Structural lesions underlying this process include excess deposition of collagens and cellular infiltration, with an increase in the size of cardiac myocytes (remodeling). The occurrence of arteriolar lesions may lead to impediments of flow. Clinically, hypertensive heart disease manifests itself by anginal complaints and sometimes by silent ischemia, arrhythmias, and sudden death. Alterations in systolic and/or diastolic function may be associated with symptoms of heart failure. Although successful treatment of hypertension can probably retard the process of cardiac impairment, there is as yet no evidence that heart failure can be prevented.

Changes in left ventricular structure and function in patients with white coat hypertension: cross sectional survey

OBJECTIVES

To assess the relation between white coat hypertension and alterations of left ventricular structure and function.

DESIGN

Cross sectional survey.

SETTING

Augsburg, Germany.

SUBJECTS

1677 subjects, aged 25 to 74 years, who participated in an echocardiographic substudy of the monitoring of trends and determinants in cardiovascular disease Augsburg study during 1994-5.

OUTCOME MEASURES

Blood pressure measurements and M mode, two dimensional, and Doppler echocardiography. After at least 30 minutes' rest blood pressure was measured three times by a technician, and once by a physician after echocardiography. Subjects were classified as normotensive (technician <140/90 mm Hg, physician <160/95 mm Hg; n=849), white coat hypertensive (technician <140/90 mm Hg, physician >=160/95 mm Hg; n=160), mildly hypertensive (technician >=140/90 mm Hg, physician <160/95 mm Hg; n=129), and sustained hypertensive (taking antihypertensive drugs or blood pressure measured by a technician >=140/90 mm Hg, and physician >=160/95 mm Hg; n=538).

RESULTS

White coat hypertension was more common in men than women (10.9% versus 8.2% respectively) and positively related to age and body mass index. After adjustment for these variables, white coat hypertension was associated with an increase in left ventricular mass and an increased prevalence of left ventricular hypertrophy (odds ratio 1.9, 95% confidence interval 1.2 to 3.2; P=0.009) compared with normotensive patients. The increase in left ventricular mass was secondary to significantly increased septal and posterior wall thicknesses whereas end diastolic diameters were similar in both groups with white coat hypertension or normotension. Additionally, the systolic white coat effect (difference between blood pressures recorded by a technician and physician) was associated with increased left ventricular mass and increased prevalence of left ventricular hypertrophy (P<0.05 each). Values for systolic left ventricular function (M mode fractional shortening) were above normal in subjects with white coat hypertension whereas diastolic filling and left atrial size were similar to those in normotension.

CONCLUSION

About 10% of the general population show exaggerated inotropic and blood pressure responses when mildly stressed. This is associated with an increased risk of left ventricular hypertrophy.

White-coat hypertension: a selection bias? Harvest Study Investigators. Hypertension and Ambulatory Recording Venetia Study

BACKGROUND

Results of several studies have shown that subjects with white-coat hypertension (WCH) have more target-organ damage than do normotensive controls with similar ambulatory blood pressures.

OBJECTIVE

To investigate whether this is due to a selection bias.

SETTING

Seventeen hypertension clinics in northeast Italy.

MAIN OUTCOME MEASURES

Echocardiographic data in relation to WCH status.

PATIENTS AND METHODS

Mild hypertensive subjects from the HARVEST (n = 565) who underwent two ambulatory blood pressure monitorings 3 months apart and M-mode echocardiography, and 95 normotensive control subjects.

RESULTS

From first ambulatory monitoring, 90 hypertensive subjects were classified as having WCH (mean daytime blood pressure < 130/80 mmHg). Their 24 h blood pressure was similar to that of the normotensive subjects, but their left ventricular mass index was greater. From second ambulatory monitoring, only 38 of the 90 subjects still had WCH, whereas 24 h blood pressure in the other 52 had risen beyond the limit of WCH. Left ventricular mass index (89.2 +/- 2.4 g/m2), wall thickness (18.1 +/- 0.3 mm), and relative wall thickness (0.359 +/- 0.006%) of the 38 subjects with WCH at both recordings were still greater than those of the normotensive subjects (82.4 +/- 1.5 g/m2, P = 0.02; 17.2 +/- 0.2 mm, P = 0.002; and 0.337 +/- 0.004%, P = 0.025) and similar to those of the 52 subjects who no longer had WCH (88.5 +/- 2.0 g/m2, 18.7 +/- 0.2 mm, and 0.375 +/- 0.005%, all NS).

CONCLUSIONS

Owing to regression toward the mean, over 50% of the subjects with WCH could no longer be classified as such from repeated ambulatory monitoring, indicating that the current diagnosis of WCH is subject to selection bias. Cardiac remodeling was present also in the subjects confirmed to have WCH by repeated blood pressure recording, suggesting that the effect of WCH has an actual impact on target organs.

Difference between clinic and daytime blood pressure is not a measure of the white coat effect

The purpose of the present study was to evaluate whether the difference between blood pressure measured in the clinic or physician's office and the average daytime blood pressure accurately reflects the blood pressure response of the patient to the physician ("white coat effect" or "white coat hypertension"). We studied 28 hypertensive outpatients (mean age, 41.8+/-11.2 years; age range, 21 to 64 years) of 35 consecutive patients attending our hypertension clinic, in whom (1) continuous noninvasive finger blood pressure was recorded before and during the visit, (2) blood pressure was measured according to the Riva-Rocci-Korotkoff method (mercury sphygmomanometer) with the patient in the supine position, and (3) daytime ambulatory blood pressure was monitored with a SpaceLabs 90207 device. The peak blood pressure increase recorded directly during the visit was compared with the difference between clinic and daytime average ambulatory blood pressures. Compared with previsit values, peak increases in finger systolic and diastolic blood pressures during the visit to the clinic were 38.2+/-3.1 and 20.7+/-1.6 mm Hg, respectively (mean+/-SEM, P<.01 for both). Daytime average systolic and diastolic blood pressures were 135.5+/-2.5 and 89.2+/-1.9 mm Hg, with both lower than the corresponding clinic blood pressure values (146.6+/-3.6 and 94.9+/-2.2 mm Hg, P<.01). These differences, however, were <30% of the peak finger blood pressure increases during the physician's visit, to which these increases showed no relation. Although the visit to the physician's office was associated with tachycardia (9.0+/-1.6 bpm, P<.01), there was no difference between clinic and daytime average heart rates. These data indicate that the clinic-daytime average blood pressure difference does not reflect the alerting reaction and the pressure response elicited by the physician's visit and thus is not a reliable measure of the white coat effect.

White coat effect and reactivity to stress: cardiovascular and autonomic nervous system responses

The aim of this study was to elucidate further the precise nature of the so-called "white coat" (WC) effect. We enrolled 88 hypertensive (46 men, 42 women) and 18 normotensive (4 men, 14 women) subjects in whom beat-to-beat blood pressure (BP) and heart rate (HR) were measured with a Finapres device at rest (R period) and during conventional BP measurement (WC period). The WC effect was defined as WC period minus R period values of Finapres systolic BP. Using the same method, we also measured the BP and HR variations induced by mental stress (MS period) and by assuming the standing position (S period). Variability was estimated in the frequency domain for BP (BPV) and HR (HRV) and gave indices of the autonomic nervous system. Pulse wave velocity was taken as an index of arterial distensibility. In hypertensive subjects, the WC effect was significantly and positively correlated with the BP response to stress (0.51, P<.0001) and standing (0.63, P<.0001). An increased BPV was observed in the low-frequency band (0 to 0.150 Hz) during WC, MS, and S periods. In normotensive subjects, the WC effect was very slight and not correlated with the responses to stress and standing. In this group, the WC period was not accompanied with an increased BPV, unlike the stress and standing periods. HRV was similar in normotensives and in hypertensives: decreased, unchanged, and increased during MS, S, and WC periods, respectively. The PWV was significantly increased in the hypertensives relative to the normotensives, even in the quartile of those with the lowest BP (on average similar to that of the normotensives). This work shows that the WC effect is associated with an enhanced BP response to standing and mental stress; these three situations are characterized by an increased BPV in the low frequencies, suggesting a similar modification of the sympathovagal balance. The WC effect may entail an increased risk because it is associated with impaired arterial distensibility.