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

Orthostatic Hypertension: A Newcomer Among the Hypertension Phenotypes

The prognostic role and the clinical significance of orthostatic hypertension (OHT) remained undefined for long because data were sparse and often inconsistent. In recent years, evidence has been accumulating that OHT is associated with an increased risk of masked and sustained hypertension, hypertension-mediated organ damage, cardiovascular disease, and mortality. Most evidence came from studies in which OHT was defined using systolic blood pressure (BP) whereas the clinical relevance of diastolic OHT is still unclear. Recently, the American Autonomic Society and the Japanese Society of Hypertension defined OHT as an orthostatic systolic BP increase ≥20 mm Hg associated with a systolic BP of at least 140 mm Hg while standing. However, also smaller orthostatic BP increases have shown clinical relevance especially in people ≤45 years of age. A possible limitation of the BP response to standing is poor reproducibility. OHT concordance is better when the between-assessment interval is shorter, when OHT is evaluated using a larger number of BP readings, and if home BP measurement is used. The pathogenetic mechanisms leading to OHT are still controversial and may vary according to age. Excessive neurohumoral activation seems to be the main determinant in younger adults whereas vascular stiffness plays a more important role in older individuals. Conditions associated with higher activity of the sympathetic nervous system and/or baroreflex dysregulation, such as diabetes, essential hypertension, and aging have been found to be often associated with OHT. Measurement of orthostatic BP should be included in routine clinical practice especially in people with high-normal BP.

Exaggerated blood pressure response to standing in young-to-middle-age subjects: prevalence and factors involved

PURPOSE

To investigate the prevalence of orthostatic hypertension and the association of the blood pressure (BP) level, supine BP decline, and white-coat effect with the orthostatic pressor response.

METHODS

We studied 1275 young-to-middle-age individuals with stage-1 hypertension. Orthostatic response was assessed three times over a 3 month period. The white-coat effect was assessed at baseline and after 3 months, and was calculated as the difference between office and average 24 h BP. In 660 participants, urinary epinephrine and norepinephrine were also measured.

RESULTS

An orthostatic systolic BP increase ≥ 20 mmHg was observed in 0.6-1.2% of the subjects during the three visits. Using the 20 mmHg cut-off, the prevalence of orthostatic hypertension was 0.6%. An orthostatic BP increase of ≥ 5 mmHg was found in 14.4% of participants. At baseline, the orthostatic response to standing showed an independent negative association with the supine BP level (p < 0.001), the supine BP change from the first to third measurement (p < 0.001), and the white-coat effect (p < 0.001). Similar results were obtained in the 1080 participants assessed at the third visit. Urinary epinephrine showed higher values in the top BP response decile (systolic BP increase ≥ 6 mmHg, p = 0.002 versus rest of the group).

CONCLUSION

An orthostatic systolic BP reaction ≥ 20 mmHg is rare in young adults. However, even lower BP increases may be clinically relevant. The BP level, the supine BP decline over repeated measurement, and the white-coat effect can influence the estimate of the BP response to standing and should be considered in clinical and pathogenetic studies.

Main Factors Related with the White Coat Effect Level in Patients with Arterial Hypertension and Bronchial Asthma

Aim. To study the main relationships of the white coat effect (WCE) levels in patients with arterial hypertension (AH) with bronchial asthma (BA) who treated with AH and BA drugs in routine clinical practice.

Material and Methods. We analyzed the prospective cohort study data of AH patients, some of them had BA without exacerbation. We have formed two groups of patients:1 - control group, patients with AH without BA, the second - with AH + BA. The study consisted of three visits (first visit, 6 months and 12 months visits) and data collection period (30.1±7.6 months of follow-up). The following procedures were performed at the first and 12 month visits: clinical blood pressure (BP) measurements (sitting and standing), 24-hour monitoring ambulatory (ABPM), spirometry, clinical and biochemical blood tests, BA control questionnaires (ACQ) and quality of life (QL) questionnaire (GWBQ), at the second visit clinical BP measurement was performed and, if necessary, the drug dose was corrected.

Results. The study included 125 patients, 28 men, 97 women. The first group of AH patients without BA included 85 people, the second (AH + BA) - 40. In AH patients without BA with ischemic heart disease, arterial revascularization, regular alcohol intake and smoking we identified the association with the lower WCE levels. In AH+BA patients with diabetes mellitus, gastrointestinal diseases, higher education was identified WCE decrease. In AH patients without asthma we found inverse relationships WCE levels with respiratory function parameters, the nighttime BP decrease, heart rate and the difference between standing and sitting BP levels, and correlations with the EchoCG variables (the left ventricular hypertrophy (LVH) indices), with age, AH duration and body mass index (BMI). In patients with AH + BA we found inverse correlations between WCE levels and some EchoCG variables, the difference between standing and sitting BP levels, and correlations with body weight, BMI.

Conclusion. Thereby, in AH patients without BA with ischemic heart disease, revascularization, regular alcohol intake, smoking we identified the association with the lower WCE levels. This patients WCE indices had inverse correlations with height, respiratory function parameters, the BP nighttime decrease, the difference between standing and sitting BP levels and direct relationships with EchoCG variables of LVH, age, AH duration and BMI. In AH + BA patients with diabetes, gastrointestinal diseases, higher education we found relationships with lesser WCE manifestation. WCE levels in this group had inverse correlations with some EchoCG indicators, the standing and sitting BP difference and direct relations with weight and BMI.

Long-Term Risk of Progression to Sustained Hypertension in White-Coat Hypertension with Normal Night-Time Blood Pressure Values

Background

The long-term prognosis and transition towards sustained ambulatory hypertension (SHT) of white-coat hypertension (WCHT) remain uncertain particularly in those with both normal nighttime and daytime blood pressure (BP) values. Different classification criteria and the use of antihypertensive drugs may contribute to conflicting results. Patients and Methods. We prospectively evaluated for a 7.1 year transition to SHT in 899 nondiabetic subjects free from cardiovascular (CV) events: normotensive (NT) (n = 344; 52, 9% female; ageing 48 ± 14 years); untreated WCHT (UnWCHT n = 399; 50, 1% female; ageing 51 ± 14 years); and treated WCHT with antihypertensive drugs after baseline (TxWCHT n = 156; 54, 4% female; ageing 51 ± 15 years). All underwent 24 h ambulatory BP monitoring (24 h-ABPM) at baseline, at 30 to 60 months, and at 70 to 120 months thereafter. WCHT was at baseline (with no treatment) as office BP ≥ 140/or 90 mm·Hg, daytime BP < 135/85 mm·Hg, and nighttime BP < 120/70 mm·Hg. Development of SHT was considered if daytime BP ≥ 135/or 85 mm Hg and/or nighttime BP ≥ 120/or 70 mm·Hg.

Results

Baseline metabolic parameters did not differ among groups. At 30–60 months and at the end of follow-up, development of SHT occurred, respectively, in NT (3.8% (n = 13) and 9.6% (n = 33)) and in UnWCHT (10.1% (n = 40) and 16.5% (n = 66)) (p < 0.009). The mean annual increase of average 24 h-systolic BP was 0.48 + 0.93 in NT and 0.73 + 1.06 in UnWCHT, whereas annual SBP in office increased in NT by 1.2 + 0.95 but decreased in UnWCHT by 1.36 + 1.35 mm Hg (p < 0.01).

Conclusion

Untreated WCHT patients exhibit a faster and a higher risk of developing SHT compared to NT with TxWCHT assuming an intermediate position between them.

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.

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.

Treated hypertension and the white coat phenomenon: Office readings are inadequate measures of efficacy

To better define the prevalence of white coat hypertension (WCH) among patients with type 2 diabetes mellitus and to estimate the magnitude of white coat effect (WCE), before and after antihypertensive therapy, we gathered data from an open-label forced-titration study of a combination of antihypertensive drugs that was titrated sequentially, in the order amlodipine, olmesartan, and hydrochlorothiazide, over an 18-week period among 187 patients with type 2 diabetes mellitus. WCH was defined as daytime ambulatory blood pressure (BP) of 135/85 mm Hg or less, but clinic BP of 140/90 mm Hg or more. WCE was obtained as the mean difference between clinic and daytime ambulatory BP. At baseline, the prevalence of WCH was 12%; all but one subject had WCE of >10/5 mm Hg. After treatment, the prevalence of WCH had increased to 39% (P < .001). In the overall population, at baseline, the mean (±SD) WCE for systolic BP was 10.4 ± 10.9 mm Hg and 3.7 ± 8.6 mm Hg for diastolic BP. After treatment, the reduction in systolic WCE was 3.01 ± 0.93 (SE; P < .0001); no reduction was seen for diastolic WCE. Among patients treated with amlodipine-olmesartan combination, WCE at baseline was 11 mm Hg systolic and was attenuated to -0.9 mm Hg. Among patients treated with amlodipine-olmesartan-hydrochlorothiazide combination, systolic WCE was similar at baseline (10.1 mm Hg) and at end of therapy (8.1 mm Hg). Mean systolic difference between dual and triple therapy of 9.9 mm Hg, SE 2.98 was significant (P < .001). The drop in diastolic WCE from 6.4 with dual therapy to -1.2 with triple therapy was also significant (mean difference 7.6, SE 2.2; P < .001). In conclusion, the prevalence of WCH increases three-fold with treatment as a result of fewer patients having sustained hypertension. Thus, out-of-office BP monitoring especially among treated hypertensive patients with type 2 diabetes is necessary to provide better assessment of overall BP and response to treatment.

The white coat effect is not associated with additional increase of target organ damage in true resistant hypertension

BACKGROUND AND OBJECTIVE

White coat effect (WCE) (i.e., the difference between office blood pressure [OBP] and awake ambulatory blood pressure monitoring [ABPM]) may be present in hypertensive individuals. The relationship between occurrence of WCE and target organ damage (TOD) has not yet been assessed in true resistant hypertension (RHTN).

PATIENTS AND METHODS

RHTN patients were divided into two groups: RHTN with WCE (WCE, n=66) and RHTN without WCE (non-WCE, n=61). All patients were submitted to OBP measurement, ABPM, echocardiography and renal function evaluation in three visits.

RESULTS

No differences were observed between the WCE and non-WCE groups regarding age, body mass index or gender. OBP were 169.8±15.8/95.1±14.0 (WCE) and 161.9±9.0/90.1±10.4mmHg (non-WCE), ABPM=143.0±12.8/86.1±9.9 (WCE) and 146.1±13.6/85.1±14.9mmHg (non-WCE). No statistical differences were observed between WCE and non-WCE subgroups with respect to left ventricular mass index (LVMI) (WCE=131±4.7; non-WCE=125±2.9g/m(2)), creatinine clearance (WCE=78±4.7; non-WCE=80±3.6ml/min/m(2)) and microalbuminuria (MA) (WCE=44±8.4; non-WCE=49±6.8mg/g Cr).

CONCLUSIONS

This finding may suggest that WCE is not associated with additional increase of TOD in true RHTN subjects.

Factors associated with glomerular hyperfiltration in the early stage of hypertension

BACKGROUND

Glomerular hyperfiltration predicts development of nephropathy in hypertension but the factors responsible for increased glomerular filtration rate (GFR) are not well known. Aim of this study was to examine which clinical variables influence GFR in the early stage of hypertension.

METHODS

Participants were 1,106 young-to-middle-age hypertensive adults with creatinine clearance >60 ml/min/1.73 m(2). Clinic and ambulatory blood pressures (BPs) were measured and the difference between clinic and 24-h systolic BP was defined as the white-coat effect (WCE). In 606 participants, 24-h urinary epinephrine and norepinephrine were also measured. Glomerular hyperfiltration, defined as a GFR ≥150 ml/min/1.73 m(2), was present in 201 subjects.

RESULTS

Patients' mean age was 33.1 ± 8.5 years and office BP was 146 ± 10.5/94 ± 5.0 mm Hg. In multivariable linear regression, significant predictors of GFR were younger age (P < 0.0001), male gender (P < 0.0001), 24-h systolic BP (P = 0.0001), body mass (P < 0.0001), WCE (P = 0.02), log-epinephrine (P = 0.01), and coffee use (P < 0.01). In a logistic model, independent predictors of glomerular hyperfiltration were obesity (odds ratio, 95% confidence interval = 6.1, 3.8-9.8), male gender (2.9, 1.8-4.9), age <33 years (2.1, 1.5-3.1), ambulatory hypertension (2.0, 1.4-3.0), WCE >15 mm Hg (1.6, 1.1-2.3), heavy coffee use (2.0, 1.1-3.8), and epinephrine >25 mcg/24 h (1.9, 1.2-3.1).

CONCLUSIONS

The novel finding of this study is that hyper-reactivity to stress, as determined by urinary epinephrine level and WCE, and coffee use contribute to determining glomerular hyperfiltration in the early stage of hypertension. Our data may help to identify a subset of patients with glomerular hyperfiltration, who may be at increased risk of chronic kidney disease and may benefit from antihypertensive treatment.

Reproducibility of blood pressure variability, white‐coat effect and dipping pattern in untreated, uncomplicated and newly diagnosed essential hypertension

OBJECTIVE

To investigate the reproducibility of blood pressure (BP) variability, white-coat effect (WCE) and nocturnal dipping pattern in untreated patients with uncomplicated essential hypertension using 24-hour ambulatory BP monitoring (ABPM).

METHODS

Seventy-five newly diagnosed, untreated essential hypertensive subjects (54 men, 21 women 47.6 +/- 9.3 years) were recruited for the study based on conventional measured BP from a total of 180 patients referred for ABPM. Of these, 65 patients underwent repeated ABPM after 4 weeks observation without treatment. Reproducibility of BP, nocturnal dipping pattern, WCE and BP variability were assessed using different methods.

RESULTS

The average 24-hour BP (140.8 +/- 11.9/91.8 +/- 6.4 vs. 140.5 +/- 14.5/90.7 +/- 7.6 mmHg, ns) or PP (49.6 +/- 10.8 vs. 49.8 +/- 9.8 mmHg, ns) did not change, nor did daytime BP or PP. The WCE diminished significantly during the observation period (reduction in SBP WCE delta8.2 +/- 12.5 mmHg, p < 0.0001, in DBP WCE, delta3.3 +/- 9.2 mmHg, p = 0.008 and in PP WCE delta4.8 +/- 11.2 mmHg, p = 0.002). Variability in SBP, DBP and PP decreased consistently and significantly during the observation period. The nocturnal dipping pattern was unchanged in 82% of the patients. In 12% non-dipping pattern was converted to dipping pattern after repeated measurement.

CONCLUSION

Average ABPs are highly reproducible in patients with uncomplicated essential hypertension of limited duration. Similarly, nocturnal dipping pattern reproduced satisfactorily. These measures have important clinical applicability. The white-coat effect as well as variability are greatly attenuated during repeated measurements, and these measures may thus be of less utility in clinical practice.

Does blood pressure change in treated hypertensive patients depending on whether it is measured by a physician or a nurse?

OBJECTIVES

To determine whether there are differences between blood pressure (BP) measured by the nurse (NBP), BP measured by the physician (PBP) and self-measured BP in treated hypertensive patients and, if found, to evaluate their clinical importance.

METHOD

An observational study is carried out with hypertensive patients recruited from two village-based community health centres in Catalonia (Spain) serving an area with a total population of 2800 inhabitants. All patients treated for hypertension visiting the health centre on a specific day of the week and during the same timetable between October 2000 and May 2001 were included.

RESULTS

The difference between physician-systolic BP and nurse-systolic BP was 5.16 mmHg (95% CI 2.62-7.7; p<0.001). The difference between physician-systolic BP and self-measured systolic BP was 4.67 mmHg (95% CI 0.89-8.44; p=0.016). The differences between nurse-systolic BP and self-measured systolic BP were not significant (0.49 mmHg; 95% CI 3.71-2.71; p=0.758). With regards to diastolic BP, no significant differences were found between the different ways of measurement. NBP gave the following values: sensitivity (Sn) of 92% and specificity (Sp) of 60%; positive predictive value (PPV) of 65.7% and negative predictive value (NPV) of 90% with a positive coefficient of probability (CP+) of 2.3 and a negative coefficient of probability (CP-) of 0.133. PBP gave the following results: Sn=72%; Sp=66.7%; PPV=64.3%; NPV=74.1%; CP+=2.16 and CP- = 0.420.

CONCLUSION

Systolic BP measured by the nurse in treated hypertensive patients is significantly lower than the readings obtained by the physician, and are almost identical to ambulatory BP monitoring. Blood pressure determination by the nurse is desirable not only for diagnosis but also to evaluate the level of control of blood pressure during the follow-up of treated hypertensive patients.

Assessment of long-term antihypertensive treatment by clinic and ambulatory blood pressure: data from the European Lacidipine Study on Atherosclerosis

OBJECTIVES

Information on the features of long-term modifications of clinic and 24-h ambulatory blood pressure (ABP) by treatment is limited. The present study aimed to address this issue.

METHODS

Ambulatory BP monitoring and clinic BP (CBP) measurements were performed at baseline and at yearly intervals over a 4-year follow-up period in 1523 hypertensives (56.1 +/- 7.6 years) randomized to treatment with lacidipine or atenolol in the European Lacidipine Study on Atherosclerosis (ELSA).

RESULTS

CBP was always greater than ABP, while reductions in all BP values (greater for CBP than for ABP) were on average maintained throughout 4 years, CBP changes showing limited relationship with ABP changes (r = 0.14-0.27). BP reductions by treatment during daytime and night-time were correlated (r = 0.63-0.73). BP normalization was achieved in a greater percentage of patients for CBP (41.7%) than for ABP (25.3%), with systolic BP control being always less common than diastolic BP control. BP normalization was more frequent at single yearly visits than throughout the 4 years. Twenty-four-hour BP variability was reduced by treatment over 4 years in absolute but not in normalized units.

CONCLUSIONS

The present study provides the best evidence available on long-term effect of antihypertensive treatment on both ABP and CBP. On average, ABP was sustainedly reduced by treatment throughout the follow-up period, but 24-h BP was more difficult to control than CBP. In several patients, ABP control was unstable between visits, the percentage of patients under control over 4 years being much less than that of those controlled at each year. Treatment induced a reduction in absolute but not in normalized BP variability estimates. This has clinical implications because of the prognostic importance of ABP mean values and variability.

Comparison of agreement between clinic and home-measured blood pressure in the Finnish population: the Finn-HOME Study

BACKGROUND

The purpose of this study was to assess the agreement, mean difference, and the detection and control rates of hypertension, between home and clinic blood pressure (BP) measurement in the Finnish population. Variation in home BP during the measurements was also examined.

METHODS

We studied a representative sample of the adult population (2051 45-74-year-old individuals) in Finland. Subjects included in the study underwent a clinical interview and measurement of clinic and home BP. Thresholds for elevated clinic and home BP were 140/90 and 135/85 mmHg.

RESULTS

The mean difference between home and clinic BP, which increased with BP, was 7.7/3.4 mmHg. Overall agreement in diagnosis was only 75.2% (kappa coefficient 0.50). As compared with home BP, clinic BP overestimated the prevalence of hypertension (48.8 versus 42.5%, P < 0.001) and non-significantly underestimated the control of hypertension (28.7 versus 32.8%, P = 0.11). Evening home BP was 4.1/0.4 mmHg higher than morning BP among untreated subjects, but this difference was non-existent or reversed (0.5/-1.4 mmHg) among treated hypertensive individuals. Home BP decreased with an increasing number of measurements.

CONCLUSIONS

The agreement between home and clinic BP in diagnosing hypertension according to the current guidelines is moderate at best, and the difference between home and clinic BP becomes larger at higher levels of BP. Because of the noticeable differences between these two methods, and the better prognostic accuracy of home BP, we endorse the use of home measurements in clinical practice.

Prevalence and clinical significance of a greater ambulatory versus office blood pressure (‘reversed white coat’ condition) in a general population

BACKGROUND

Attention has recently been directed to a condition termed 'reversed white coat' because of an average 24 h ambulatory blood pressure (BP) uncharacteristically greater than office BP. No data are available, however, on the prevalence of this condition in the general population, as well as on its relationship to BP, age, gender, antihypertensive treatment and cardiac organ damage.

METHODS

In 3200 individuals (participation rate 64%), randomly selected to be representative of the residents of Monza (Milan, Italy) for sex and decades of age (25 to 74 years), we measured office BP (average of three measurements, sphygmomanometry), ambulatory BP (automatic readings every 20 min, Spacelabs 90207) and left ventricular mass (echocardiography).

RESULTS

A 'reversed white coat' condition (identified when 24-h average ambulatory systolic, diastolic or mean were higher than the corresponding office values) was seen in 15% (diastolic) to 26% (systolic) of the population as a whole. Prevalence was greater (34-40%) when the difference between office and daytime BP was considered but in both instances it remained less than the prevalence of the white-coat phenomenon. A reversed white-coat condition was similarly frequent in males and females and showed a steep reduction with age and increasing office BP values. Prevalence was greater in hypertensive subjects in whom treatment achieved BP control than in untreated or unsatisfactorily treated individuals. Within each quartile of 24-h or office BP, left ventricular mass index adjusted for demographic and biochemical values was similar in reversed white coat versus the remaining subjects. The absence of any association with left ventricular hypertrophy scores against the clinical significance of this phenomenon.

Office compared with ambulatory blood pressure in assessing response to antihypertensive treatment: a meta-analysis

OBJECTIVE

To undertake a systematic review of the studies on the effect of antihypertensive treatment on ambulatory (ABP) and office blood pressure in order to obtain a differential assessment of the magnitude of the reduction in (1) office blood pressure compared with 24-h average ABP values, and (2) daytime compared with night-time average blood pressure values.

DATA SOURCES

Medline search, Cochrane Library.

REVIEW METHODS

This review is based on a meta-analysis (carried out according to the Quality of Reports of Meta-analyses of Randomized Controlled Trials Group statement, whenever applicable) of papers on the effect of antihypertensive drugs on blood pressure. Papers were selected if they provided information on drug-induced changes in one or both of: (1) both office blood pressure and 24-h ABP, and/or (2) both daytime and night-time average blood pressure. Additional inclusion criteria were administration of antihypertensive drugs for at least 1 week and good quality ABP, according to current guidelines. Comparison between the effect of treatment on blood pressure values was made by meta-regression of the data provided by the individual studies (weighted by their size) and by calculating differences between weighted average values obtained by pooling the results of individual papers.

RESULTS

We identified 984 papers on this issue by Medline search, with no additional information from the Cochrane Library. The inclusion criteria were satisfied by only 44 papers, which were included in the final analysis. The results showed that treatment-induced reduction in blood pressure is both smaller for the 24-h average than for the office systolic and diastolic blood pressure and smaller for night-time than for daytime average diastolic blood pressure, the average ratio ranging from 0.67 to 0.75. A different ratio characterized the treatment-induced changes in office blood pressure and ABP in the Heart Outcomes Prevention Evaluation (HOPE) ABP substudy.

CONCLUSIONS

The effect of antihypertensive treatment is greater on office blood pressure than on ABP, and is unevenly distributed between day and night. This suggests caution when interpreting trials on cardiovascular protection by antihypertensive treatment that are based only on office blood pressure readings, and advocates a more systematic adoption of ABP monitoring in these trials. The conflicting data provided by the main HOPE study and by the HOPE-ABP monitoring substudy on the role of blood pressure reduction in explaining the reduced event rates associated with treatment by angiotensin-converting enzyme inhibitors are a clear example of the importance of performing ABP monitoring in trials on cardiovascular protection.

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.

Assessing autonomic disturbances of hypertension in the general practitioner's office: a transtelephonic approach to spectral analysis of heart rate variability

OBJECTIVES

Spectral analysis of heart rate variability (HRV) provides potentially useful information on autonomic disturbances of human hypertension. However, its practical use outside the clinical laboratory is largely unexplored. The aim of this study was to test the feasibility of assessing HRV from the general practitioner's (GP's) office, using a novel transtelephonic approach.

DESIGN

Parallel study on two similar groups: 150 subjects (100 hypertensives and 50 normotensives) studied in our hospital clinic and compared with 150 subjects studied in an out-of-hospital practice (100 hypertensive subjects from GPs' surgeries and 50 normotensive subjects participating in a multinational company's health maintenance programme).

METHODS

Spectral analysis of RR interval variability was used to assess autonomic regulation of the sino-atrial (SA) node, both at rest and during standing. For the out-of-hospital practice, strings of continuous electrocardiograms (ECGs), recorded with a microminiature instrument, were fed, off line, through standard telephone lines to our laboratory for subsequent spectral analysis.

RESULTS

RR spectral profiles obtained from healthy controls or hypertensive patients examined in their GPs' surgeries were similar to those obtained in a hospital clinic, both at rest and when standing up.

CONCLUSIONS

The present study shows the feasibility of using a transtelephonic approach to perform spectral analysis of heart rate variability from physicians' surgeries. This method could favour a more widespread use of autonomic assessment in the clinical management of hypertension.

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

OBJECTIVE

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

SUBJECTS

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

MAIN OUTCOME MEASURES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

White coat hypertension: understanding the concept and examining the significance

Because the concept of white coat hypertension is evolving, a variety of definitions appear in the literature. There has also been continuing debate as to whether white coat hypertension is a benign clinical condition or is associated with increased hypertensive complications. This paper summarizes and evaluates the literature on white coat effect/hypertension, with a focus on the following aspects of the concepts: (1) alternative definitions, (2) prevalence and predictors, (3) prognostic significance, and (4) implications for clinical practice. The evidence suggests that white coat hypertension is not a harmless phenomenon. It is frequently associated with increased target-organ damage and often coexists with other cardiovascular risk factors. The extent of the presence of other risk factors may determine the risks associated with white coat hypertension. It is important for clinicians to understand the concept, learn to diagnose it properly, and develop strategies for evaluating risk levels so that patients receive the proper treatment.

White-coat effect in normotension and hypertension

OBJECTIVES

The difference between clinic and daytime ambulatory blood pressure is referred to as the white-coat effect. In this study, we investigated (i) the magnitude of the white-coat effect in subjects with different daytime ambulatory blood pressure levels, and (ii) the association of the white-coat effect with left ventricular mass.

METHODS

A total of 1581 subjects underwent clinic blood pressure readings, 24-h ambulatory blood pressure monitoring and left ventricular echocardiographic assessment. Their mean daytime systolic blood pressure varied from 88.0 to 208.9 mmHg and their mean daytime diastolic blood pressure from 40.3 to 133.0 mmHg.

RESULTS

A negative correlation was found between the systolic or diastolic white-coat effect and the systolic or diastolic daytime ambulatory blood pressure (r = -0.22, P < 0.000 and r = -0.50, P < 0.000, respectively). Left ventricular mass significantly correlated with ambulatory blood pressure (P < 0.001), but there was no association between left ventricular mass and clinic blood pressure or white-coat effect. Furthermore, the white-coat effect was reversed at the highest level of systolic or diastolic daytime ambulatory blood pressure (systolic over 170 mmHg or diastolic over 100 mmHg) when systolic or diastolic daytime ambulatory blood pressure was higher than systolic or diastolic clinic blood pressure (ambulatory blood pressure hypertension).

CONCLUSIONS

The white-coat effect shows an inverse association with daytime ambulatory blood pressure level (systolic or diastolic), being significantly more prominent for levels below 140/80 mmHg for systolic/diastolic daytime ambulatory blood pressure and reversed with daytime ambulatory blood pressure levels above 170/100 mmHg.

[Impact of components and methods of measurement of blood pressure on damage of target organs and cardiovascular complications in arterial hypertension]

BACKGROUND

The goal of this study was to evaluate the relative association of several components of blood pressure (BP), as measured in the office and by ambulatory monitoring (ABPM), with clinically useful indicators of target organ damage and cardiovascular events (CE) in essential hypertensive patients.

PATIENTS AND METHOD

We retrospectively included 390 hypertensives (55% men; mean age: 56 years) between 1989 and 1998. All them had a baseline office BP measurement and a valid 24-hour ABPM record, both performed while the patient was free of antihypertensive therapy. Estimates of target organ damage included electrocardiographic indexes of left ventricular hypertrophy (Cornell and Sokolow-Lyon), serum creatinine, 24-hour urine protein excretion and creatinine clearance. Multiple linear regression and logistic regression analyses were used to evaluate the relationship between BP and target organ damage or CE.

RESULTS

Forty-nine patients had CE (26 stroke, 18 myocardial infarction and 5 both). The BP parameter correlating better with cardiovascular events was office pulse pressure (multivariate odds ratio: 1.03; CI 95%: 1.00-1.05; p = 0.0095). Nevertheless, cardiac growth indexes correlated better with ABPM measurements. In fact, Cornell index correlated with night-time systolic BP (standardized regression coefficient beta: 0.260; p < 0.001) and Sokolow-Lyon index correlated with day-time systolic BP ( beta: 0.257; p < 0.001). Creatinine clearance inversely correlated with night-time pulse pressure ( beta: 0.122; p = 0.017) while proteinuria correlated better with 24-hour systolic BP ( beta: 0.390; p < 0.001).

CONCLUSIONS

Whereas office BP (especially pulse pressure) is associated with the development of CE, ABPM estimates show a better association with target organ damage, especially systolic and pulse pressures.

Self-measured systolic blood pressure in the morning is a strong indicator of decline of renal function in hypertensive patients with non-diabetic chronic renal insufficiency

While blood pressure is a recognized major determinant of renal function deterioration, the role of self blood pressure measurement (BPM) in predicting the loss of renal function in hypertensive patients with chronic renal insufficiency (CRI) has not been adequately addressed. One hundred and thirteen patients (F/M: 46/67; 56 +/- 1 years) with CRI (mean serum creatinine: 1.87 +/- 0.08; range: 1.4 to 3.5 mg/dl; average urinary protein excretion: 1.2 +/- 0.2 g/24 hrs.) were followed for 3 years. The record of renal biopsy revealed that 74 patients had IgA nephropathy, 16 had chronic glomerulonephritis, and 6 had membranous nephropathy, while 17, unbiopsied patients had underlying renal disease of unknown origin. Self BPM were made at regular intervals throughout the course of the study. All recorded blood pressures were included in a stepwise multiple regression analysis in which the decline in GFR per year was the dependent variable. Patients were primarily treated with a combination of amlodipine (5 to 20 mg daily), a calcium antagonist, and benazepril (2.5 to 5 mg daily), an ACE inhibitor in an effort to reduce their blood pressure at the office to < 130/85 mmHg. The simple correlation between blood pressures (i.e., office, home morning and home evening) and the decline in GFR were all statistically significant. The correlation coefficients of determination for this model were as follows: r = 0.64 for home morning SBP; 0.43 for office SBP; 0.39 for office DBP; and 0.38 for home morning DBP. The level of urinary protein excretion did not correlate with the decline in GFR. These data suggest that self BPM improves prognostic ability in hypertensive patients with CRI.

[Medical stress and blood pressure]

BP measurement by a physician may trigger a blood pressure and heart rate increase often referred to as the white coat effect. This pressure response may occur both in normotensive and hypertensive subjects. The identification of such individuals is usually not possible on a clinical basis. This identification is however important because white coat effect and permanent hypertension do not share the same prognosis, the white coat effect being associated with a low rate of cardiovascular complications. To avoid an important overestimation of the real blood pressure level due to this white coat effect, it is possible to increase the delay before blood pressure measurements (beyond 15 minutes) or to take into account measurements made by nurses. Reading may also have a favorable consequence. However, a blood pressure recording outside the office, that is an ambulatory or a home blood pressure measurement, is the only way to confirm the presence of a white coat effect. The decision to treat is based on this measurement.

An ambulatory blood pressure monitoring study of the comparative antihypertensive efficacy of two angiotensin II receptor antagonists, irbesartan and valsartan

BACKGROUND

The primary objective of this study was to compare the change from baseline in mean diastolic ambulatory blood pressure (ABP) at 24 h post dose (trough measurement) after 8 weeks of treatment with irbesartan or valsartan in subjects with mild-to-moderate hypertension. Secondary objectives included comparing the mean changes from baseline in systolic ABP at trough; 24-h ABP; morning and night-time ABP; self-measured systolic blood pressure (SBP) and diastolic blood pressure (DBP); and office-measured SBP and DBP at trough.

DESIGN

After a 3-week, single blind, placebo lead-in period, 426 subjects were randomized to receive either irbesartan 150 mg or valsartan 80 mg for 8 weeks.

METHODS

Ambulatory blood pressure measurements were obtained at baseline and at week 8. Self-measured morning and evening DBP and SBP readings were obtained at home over a 7-day period at baseline and at week 8. Office-measured seated DBP and SBP measurements were obtained at trough, at baseline, and at week 8.

RESULTS

Irbesartan demonstrated significantly greater reductions than valsartan for mean change from baseline in diastolic ABP at trough (-6.73 versus -4.84 mmHg, respectively; P = 0.035). Irbesartan produced significantly greater reductions than valsartan for mean systolic ABP at trough (-11.62 versus -7.5 mmHg, respectively; P < 0.01) and for mean 24-h diastolic ABP (-6.38 versus -4.82 mmHg, respectively; P = 0.023) and systolic ABP (-10.24 versus -7.76 mmHg; P < 0.01). Irbesartan also produced significantly greater reductions than valsartan for office-measured seated DBP (-10.46 versus 7.28 mmHg, respectively; P < 0.01) and SBP (-16.23 versus -9.96 mmHg, respectively; P < 0.01) and for self-measured morning DBP (-6.28 versus -3.75 mmHg, respectively; P < 0.01) and SBP (-10.21 versus -6.97 mmHg, respectively; P < 0.01). Both drugs were well tolerated.

CONCLUSION

Irbesartan was more effective than valsartan in reducing DBP and SBP at trough and in providing greater overall 24-h blood pressure-lowering efficacy.

[Assessment of the effects of antihypertensive drugs on stress-induced cardiovascular changes]

The authors reviewed some of the most relevant studies dedicated to the assessment of the effects of the antihypertensive drugs on the stress-induced cardiovascular changes. The rises in both blood pressure and heart rate turned out not to be significantly altered by calcium channel blockers, ACE inhibitors, moxonidine, nor beta-blockers, whereas they seemed to be slightly blunted by alpha-blocking drugs. However, since baseline blood pressure was significantly lower in treated hypertensives than in placebo-given patients, all antihypertensive drugs eventually resulted in a lower blood pressure level during stress, as compared with untreated patients. Regarding white coat effect, which has to be considered as a very particular stress, it appeared to be lowered to the same extent by placebo and antihypertensive drugs; moreover, its changes were not associated with any clinical beneficial effect.

Relation between blood pressure variability and carotid artery damage in hypertension: baseline data from the European Lacidipine Study on Atherosclerosis (ELSA)

BACKGROUND

Baseline data from the European Lacidipine Study on Atherosclerosis (ELSA) have shown that carotid intima-media thickness (IMT) is not related to diastolic blood pressure (BP), but that it is related to clinic systolic (S) or pulse pressure (PP) and more so to their 24 h average values. The aim of the present study was to determine whether IMT independently relates to additional information obtained through ambulatory BP, in particular to SBP or PP variability.

METHODS AND RESULTS

In 1663 hypertensive patients, after a wash-out period from antihypertensive treatment (mean age 56.2 +/- 7.65 years), IMT was assessed from 12 different carotid sites. Ambulatory BP measurements were performed every 15 min (day) and every 20 min (night). IMT values were positively related to 24 h, day and night average SBP and PP. There was some relationship of IMT with day-night or clinic-day SBP and PP differences. The most important finding, however, was that IMT values were related with 24 h SBP or PP standard deviation (P < 0.001), a measure of overall SBP or PP variability. The relationship was seen also by multiple regression analysis, the standard deviation for SBP or PP only following age and 24 h average SBP or PP in accounting for IMT values.

CONCLUSIONS

This is the first demonstration from a large database that not only average 24 h PP and SBP values, but also 24 h BP fluctuations, are associated with, and possibly determinants of, the alterations of large artery structure in hypertension.

[Variations in the prevalence and patient profile of white-coat syndrome, according to its definition using self-measurement of blood pressure at home]

OBJECTIVE

To calculate the prevalence of white-coat syndrome (WCS) in patients with hypertension, comparing the two most common definitions and their effect on the profile of the patient with WCS.

DESIGN

Cross-sectional, descriptive study.Setting. Urban health centre.Patients. Hypertense patients selected by simple randomised sampling from among those included in the hypertension programme.

MEASUREMENTS

Clinical blood pressure (CBP) from the previous year was collected. Home blood pressure (HBP) was measured by the patient with an electronic sphygmomanometer. Age, sex, further tests (analysis and electrocardiogram) and other clinical features were also recorded. WCS was defined as when CBP was above/equal to 140/90 mmHg and HBP was under 135/85 mmHg or when the difference between CBP and HBP was more than/equal to 20 mmHg systolic and/or 10 mmHg diastolic pressure.

RESULTS

In 154 hypertense patients (60.4% women) between 38 and 92 years old, mean CBP (141.1/85.3) was higher than mean HBP (136.8/79.8). WCS prevalence varied (p = 0.001), depending on the definition used (20.1% and 36.4%). The systolic and diastolic mean CBP of the last year were higher in those patients with WCS (p < 0.001 for diastolic pressure). The profile of hypertense patients with WCS varied according to the definition used.

CONCLUSIONS

WCS is common in hypertense patients treated in Primary Care and may condition an inadequate assessment of the degree of blood pressure monitoring. As the way of defining WCS conditions its prevalence, its profile and clinical decision-taking, it is essential to agree a uniform definition for practical use.

Control of blood pressure in the ambulatory setting

Control of blood pressure still relies on conventional office or clinical blood pressure measurement using mercury sphygmomanometry. However, it has long been known that office measurement, even when repeated, does not fully reflect usual blood pressure. The additional use of ambulatory devices for prolonged periods of blood pressure measurement is now clinically feasible. Previous research has indicated that ambulatory blood pressure measurement is better than office measurement at predicting individual cardiovascular risk. Guidelines for clinical use of ambulatory blood pressure measurement and for quality control of devices are available. Ambulatory measurement has revealed characteristics of circadian rhythm and variability that are promising with regard both to improving our understanding of the aetiology of high blood pressure and to individual risk assessment. Some of the latest developments in research on ambulatory blood pressure measurement are discussed.