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

Arsenic Exposure-Related Hypertension in Bangladesh and Reduced Circulating Nitric Oxide Bioavailability

BACKGROUND

Hypertension is a major cause of death worldwide. Although arsenic exposure has been associated with the risk of hypertension, this association appears nonuniform due to inconsistent results from studies conducted in different populations. Moreover, hypertension is a complex condition with multiple underlying mechanisms and factors. One factor is impaired production and bioavailability of vascular nitric oxide (NO). However, the implications of the effects of arsenic exposure on circulating NO and its association with hypertension in humans are largely unknown.

OBJECTIVE

We investigated the dose-response relationship between arsenic exposure and hypertension with vascular NO levels as a potential mediator of arsenic-related hypertension in individuals exposed to a broad range of arsenic.

METHODS

A total of 828 participants were recruited from low- and high-arsenic exposure areas in Bangladesh. Participants' drinking water, hair, and nail arsenic concentrations were measured by inductively coupled plasma mass spectroscopy. Hypertension was defined as a systolic blood pressure (SBP) value of ≥ 140 and a diastolic (DBP) value of ≥ 90  mmHg . Serum NO levels reflected by total serum nitrite concentrations were measured by immunoassay. A formal causal mediation analysis was used to assess NO as a mediator of the association between arsenic level and hypertension.

RESULTS

Increasing concentrations of arsenic measured in drinking water, hair, and nails were associated with the increasing levels of SBP and DBP. The odds of hypertension were dose-dependently increased by arsenic even in participants exposed to relatively low to moderate levels (10 - 50 μ g / L ) of water arsenic [odds ratios (ORs) and 95% confidence intervals (CIs): 2.87 (95% CI: 1.28, 6.44), 2.67 (95% CI: 1.27, 5.60), and 5.04 (95% CI: 2.71, 9.35) for the 10 - 50 μ g / L , 50.01 - 150 μ g / L , and > 150 μ g / L groups, respectively]. Causal mediation analysis showed a significant mediating effect of NO on arsenic-related SBP, DBP, and hypertension.

CONCLUSION

Increasing exposure to arsenic was associated with increasing odds of hypertension. The association was mediated through the reduction of vascular NO bioavailability, suggesting that impaired NO bioavailability was a plausible underlying mechanism of arsenic-induced hypertension in this Bangladeshi population. https://doi.org/10.1289/EHP13018.

White-coat hypertension in pregnant women: risk factors, pregnancy outcomes, and biomarkers

Hypertensive disorders of pregnancy are a worldwide health problem for women. They cause complications in up to 10% of pregnancies and are associated with increased maternal and neonatal morbidity and mortality. Traditional blood pressure measurement in clinical practice is the most commonly used procedure for diagnosing and monitoring hypertension treatment, but it is prone to significant inaccuracies caused, on the one hand, by the inherent variability of blood pressure and, on the other, by errors arising from measurement technique and conditions. Some studies have demonstrated a better estimate of the prognosis for the development of cardiovascular diseases using ambulatory blood pressure monitoring. We can detect white-coat hypertension using this method, which helps to avoid overdiagnosis and overtreatment in many cases, and we can also detect masked hypertension, which helps to avoid underdiagnosis and a lack of prescribed treatment if needed. White-coat hypertension is not a benign condition - it has been shown to be associated with higher risks of developing preeclampsia, preterm birth, and small-for-gestational-age babies. In this regard, it is extremely important for clinicians to be aware of the risk factors and outcomes associated with this condition. Pregnant women should be medically monitored both during pregnancy and after delivery to detect target organ damage, cardiovascular risk factors, or a metabolic syndrome.

The association of dynamic thiol-disulphide balance with white-coat hypertension

OBJECTIVE

Dynamic thiol-disulphide homeostasis is an indicator of the antioxidant system that interacts early with the oxidative environment. This study aimed to assess the dynamic thiol/disulphide balance in individuals with white-coat hypertension (WCH).

METHODS

This cross-sectional study included a total of 117 individuals who presented to our outpatient cardiology clinic. Seventy patients were diagnosed with WCH. All blood samples were obtained from the patients after a minimum of 8 h of fasting, centrifuged immediately, stored in Eppendorf tubes, and protected at -80°C.

RESULTS

The two groups were well-balanced in terms of age, gender, and BMI. Native thiol and total thiol levels were lower in the WCH group than in normotensive individuals. However, disulphide levels were higher in the former. Serum disulphide concentration positively correlated with 24-h SBP, and 24-h DBP. In backward stepwise logistic regression analysis, serum disulphide [odds ratio (OR) = 1.165 (1.089-1.245), 95% confidence interval (CI), P < 0.001] and serum total thiol levels [OR = 0.992 (0.984-1.000), 95% CI, P = 0.050] were independently associated with WCH.

CONCLUSION

We demonstrated that dynamic thiol/disulphide balance shifted strongly towards disulphide formation due to thiol oxidation in patients with WCH.

Ambulatory blood pressure monitoring in living kidney donors: What changes in 10 years?

In renal transplantation, living donations have more significant benefits compared to cadaveric donations. However, a probable increase in blood pressure following donation should also be kept in mind. In this study, we investigated the long-term changes in blood pressure in living kidney donors using ambulatory blood pressure monitoring and we explored the e-GFR and albuminuria/proteinuria measurements at 3 time points. Twenty-eight living kidney donors and 39 healthy individuals were evaluated and compared at the baseline and later at the 10th year. At the 10th year, creatinine levels were higher and eGFR levels were lower in the donors, whereas the systolic and diastolic measurements of the donors and controls and the prevalence of nondipping in the donors and controls were similar. Our study may be underpowered due to its small population size. However, our results at the 10th year follow-up indicated that the risk of hypertension might not seem to have increased in the well-selected donors. In addition, the majority of our donors had preserved their GFR values. Therefore, we can suggest that living kidney donation appears to be safe in well-selected patients over a 10-year time frame.

Subclinical Organ Damage in White-Coat Hypertension: The Possible Role of Cystatin C

The authors investigated the relationship of white-coat hypertension (WCH) with subclinical organ damage and potential relevant mechanisms. A total of 386 untreated patients were enrolled and divided into 204 patients with WCH and 183 with normotension. Flow-mediated dilation (FMD), pulse wave velocity (PWV), intima-media thickness, left ventricular mass index (LVMI), and cystatin C levels were measured. All tests were two-sided, and a P value <.05 was considered statistically significant. The WCH group exhibited higher LVMI and PWV values, decreased E/A ratio and FMD values, and increased prevalence for left ventricular hypertrophy compared with controls (P<.001 for all). Cystatin C was significantly higher in the WCH group compared with controls (P=.035) and was positively associated with LVMI (P<.05 for both). The presence of WCH is associated with more pronounced subclinical organ damage compared with normotension. Cystatin C may play a significant role and therefore warrants further investigation.

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.

White-Coat and Reverse White-Coat Effects Correlate with 24-h Pulse Pressure and Systolic Blood Pressure Variability in Children and Young Adults

Masked hypertension (MH) and white-coat hypertension (WCH) are associated with organ damage. In the present study, we examined the correlation between the magnitude of white-coat effect (WCE) or reverse WCE (RWCE) and 24-h pulse pressure (PP), an indicator of target organ damage and arterial stiffness, in children and young adults. We also examined the relationship of WCE or RWCE and blood pressure (BP) variability, another predictor of clinical outcomes. One hundred and ninety-eight subjects were studied. According to the office BP and ambulatory BP, they were divided into normotension, WCH, MH, and hypertension. The magnitude of WCE or RWCE, along with male gender and 24-h systolic BP, was the determinant of 24-h PP. In subjects with 24-h PP ≥ 61 mmHg, the magnitude of WCE or RWCE, age, male ratio, height, weight, BMI, the percentage of secondary hypertension, that of MH, office systolic BP, and 24-h systolic BP were significantly greater. There was a progressive increase in 24-h PP from normotension, WCH, MH, to hypertension. BP variability in subjects with MH was numerically highest in both systolic and diastolic. Diastolic BP variability of WCH, MH, and hypertension was significantly higher than that of normotension. Finally, the magnitude of WCE or RWCE in systolic showed a significant correlation with systolic BP variability. In conclusion, the magnitude of WCE or RWCE correlates with 24-h PP and systolic BP variability, which may suggest increased arterial stiffness in WCH and MH.

Comprehensive automatic assessment of retinal vascular abnormalities for computer-assisted retinopathy grading

One of the most important signs of systemic disease that presents on the retina is vascular abnormalities such as in hypertensive retinopathy. Manual analysis of fundus images by human readers is qualitative and lacks in accuracy, consistency and repeatability. Present semi-automatic methods for vascular evaluation are reported to increase accuracy and reduce reader variability, but require extensive reader interaction; thus limiting the software-aided efficiency. Automation thus holds a twofold promise. First, decrease variability while increasing accuracy, and second, increasing the efficiency. In this paper we propose fully automated software as a second reader system for comprehensive assessment of retinal vasculature; which aids the readers in the quantitative characterization of vessel abnormalities in fundus images. This system provides the reader with objective measures of vascular morphology such as tortuosity, branching angles, as well as highlights of areas with abnormalities such as artery-venous nicking, copper and silver wiring, and retinal emboli; in order for the reader to make a final screening decision. To test the efficacy of our system, we evaluated the change in performance of a newly certified retinal reader when grading a set of 40 color fundus images with and without the assistance of the software. The results demonstrated an improvement in reader's performance with the software assistance, in terms of accuracy of detection of vessel abnormalities, determination of retinopathy, and reading time. This system enables the reader in making computer-assisted vasculature assessment with high accuracy and consistency, at a reduced reading time.

Closer look at white-coat hypertension

This review aims to clarify novel concepts regarding the clinical and laboratory aspects of white-coat hypertension (WCHT). Recent studies on the clinical and biological implications of WCHT were compared with existing knowledge. Studies were included if the WCHT patients were defined according to the 2013 European Society of Hypertension guidelines, i.e., an office blood pressure (BP) of ≥ 140/90 mmHg, a home BP of ≤ 135/85 mmHg, and a mean 24-h ambulatory BP of ≤ 130/80 mmHg. WCHT studies published since 2000 were selected, although a few studies performed before 2000 were used for comparative purposes. True WCHT was defined as normal ABPM and home BP readings, and partial WCHT was defined as an abnormality in one of these two readings. The reported prevalence of WCHT was 15%-45%. The incidence of WCHT tended to be higher in females and in non-smokers. Compared with normotensive (NT) patients, WCHT was associated with a higher left ventricular mass index, higher lipid levels, impaired fasting glucose, and decreased arterial compliance. The circadian rhythm in WCHT patients was more variable than in NT patient’s, with a higher pulse pressure and non-dipping characteristics. Compared with sustained hypertension patients, WCHT patients have a better 10-year prognosis; compared with NT patients, WCHT patients have a similar stroke risk, but receive more frequent drug treatment. There are conflicting results regarding WCHT and markers of endothelial damage, oxidative stress and inflammation, and the data imply that WCHT patients may have a worse prognosis. Nitric oxide levels are lower, and oxidative stress parameters are higher in WCHT patients than in NT patients, whereas the antioxidant capacity is lower in WCHT patients than in NT patients. Clinicians should be aware of the risk factors associated with WCHT and patients should be closely monitored especially to identify target organ damage and metabolic syndrome.

C-reactive protein and nitric oxide level in patients with white coat hypertension

BACKGROUND

There are controversial results regarding the endothelial function in patients with white coat hypertension (WCH). The aim of this study was to assess endothelial function measuring nitric oxide (NO) and C-reactive protein (CRP) level in WCH and to compare those with essential hypertension (EH) and healthy subjects.

METHODS

The 40 newly diagnosed patients with EH, 40 patients with WCH and 40 healthy volunteers were included to study. Plasma CRP levels were measured by immunonephelometery method. Plasma NO level was also detected by using the Griess method.

RESULTS

Plasma CRP level was significantly higher in patients with EH when compared with those with WCH and healthy subjects (6.3 ± 2.1 mg/l, 2.1 ± 0.9 mg/l and 1.6 ± 1.3 mg/l, p < 0.05, respectively). However, there was no significant difference with respect to CRP level between those with WCH and healthy subjects. NO level was significantly lower in patients with EH when compared with those with WCH and healthy subjects (4.6 ± 1.1 µmol/l, 6.9 ± 1.2 µmol/l and 8.1 ± 1.5 µmol/l, p < 0.05, respectively). There was no significant difference with respect to NO level between those with WCH and healthy subjects. Plasma CRP level was positively correlated with office, daytime, night-time and 24-h blood pressure values, whereas NO level was inversely correlated with these parameters. Plasma CRP level was also inversely correlated with NO level.

CONCLUSIONS

Our data suggest that CRP concentration is significantly higher and NO level is meaningfully lower in patients with essential hypertension when compared with those with WCH and controls. This may suggest that endothelial functions are preserved in patients with WCH in contrast to essential hypertension.

White-coat effect on systemic blood pressure in retired racing Greyhounds

BACKGROUND

Greyhounds are known to have a higher systemic arterial blood pressure (BP) than non-Greyhound dogs.

OBJECTIVES

The purpose of this study was to determine whether the high systemic BP was because of the white-coat effect.

ANIMALS

Twenty-two healthy retired racing Greyhounds (RRG) enrolled in a blood donation program.

MATERIALS/METHODS

We prospectively measured systemic BP in 3 environments: in the hospital by the investigator (Hosp), in the home by the investigator (H/I), and in the home by the owner (H/O). Five serial measurements of systolic, diastolic, and mean arterial pressures (SAP, DAP, MAP) as well as heart rate (HR) were measured by an oscillometric method on the distal forelimb and distal hind limb in all 3 environments.

RESULTS

There was a significant difference for SAP, MAP, and HR between the Hosp and both H/I and H/O (P < .001); there were no significant differences for any of the parameters between the H/I and H/O environments. HR, but not SAP, MAP, or DAP (P < .05) decreased in RRG with multiple hospital visits for blood donation before this study. The hind limb SAP was significantly higher than the forelimb SAP (P < .05).

CONCLUSIONS AND CLINICAL IMPORTANCE

We conclude that the high SAP, MAP, and HR seen in the hospital setting are likely because of a white-coat effect. Furthermore, consideration should be given to defining the parameters of normal BP in RRG according to the environment in which they are obtained.

How does hypertension affect your eyes?

Hypertension has profound effects on various parts of the eye. Classically, elevated blood pressure results in a series of retinal microvascular changes called hypertensive retinopathy, comprising of generalized and focal retinal arteriolar narrowing, arteriovenous nicking, retinal hemorrhages, microaneurysms and, in severe cases, optic disc and macular edema. Studies have shown that mild hypertensive retinopathy signs are common and seen in nearly 10% of the general adult non-diabetic population. Hypertensive retinopathy signs are associated with other indicators of end-organ damage (for example, left ventricular hypertrophy, renal impairment) and may be a risk marker of future clinical events, such as stroke, congestive heart failure and cardiovascular mortality. Furthermore, hypertension is one of the major risk factors for development and progression of diabetic retinopathy, and control of blood pressure has been shown in large clinical trials to prevent visual loss from diabetic retinopathy. In addition, several retinal diseases such as retinal vascular occlusion (artery and vein occlusion), retinal arteriolar emboli, macroaneurysm, ischemic optic neuropathy and age-related macular degeneration may also be related to hypertension; however, there is as yet no evidence that treatment of hypertension prevents vision loss from these conditions. In management of patients with hypertension, physicians should be aware of the full spectrum of the relationship of blood pressure and the eye.

Is There Any Correlation between Insulin Resistance and Nitrate Plasma Concentration in White Coat Hypertensive Patients?

We evaluated a relationship between nitric oxide plasma correlation and insulin resistance in white coat hypertensive patients. Patients were screened for white coat hypertension using an ambulatory blood pressure monitoring. The homeostasis model assessment insulin resistance index (HOMA-IR) was used to assess insulin resistance, and plasma nitrate concentrations were determined by chemiluminescence. The HOMA-IR was significantly higher in hypertensive (3.84 ± 0.62) when compared to white coat (2.11 ± 0.36) and normotensive (1.40 ± 0.21). We found no correlation between HOMA-IR and plasma nitrate levels in all three groups. We suggest that the more important issue for these patients is to focus on the metabolic abnormalities where lifestyle interventions such as weight control and exercise have proven effective.

Isolated office hypertension: A 3‐year follow‐up study

The study aimed to evaluate, over a 3-year period, the progression towards sustained hypertension and left ventricular (LV) changes in patients with isolated office (IO) hypertension (office BP>140 and/or 90 mmHg, daytime BP<130/80 mmHg). After 3 years from the basal evaluation, 38 subjects with basal normal BP and 42 subjects with basal IO hypertension underwent a second 24-h BP monitoring and echocardiography; 19 patients of the basal IO hypertension group were not revaluated because they had already developed ambulatory hypertension and were on antihypertensive treatment. At the second evaluation, the 38 normotensive subjects had unchanged BP and LV parameters; 25 IO hypertensives have developed sustained hypertension. Considering them together with the 19 patients already treated, 72% of 61 IO hypertensives developed ambulatory hypertension over a 3-year period. The patients who subsequently developed hypertension differed from the group who did not only for lower basal values of LV diastolic parameters; all the patients with basal LV hypertrophy and/or preclinical diastolic impairment subsequently developed sustained hypertension. In conclusion, IO hypertensive patients show a high rate of progression towards sustained hypertension. Basal LV hypertrophy and/or preclinical diastolic dysfunction were the only markers of a greater risk of becoming hypertensives.

Cost-effectiveness of ambulatory blood pressure monitoring in the initial evaluation of hypertension in children

OBJECTIVE

The goal was to determine the cost-effectiveness of ambulatory blood pressure monitoring in the initial evaluation of stage 1 hypertension.

METHODS

Retrospective chart review of data for children referred to Texas Children's Hospital hypertension clinic between January 2005 and August 2006 was performed. We compared the costs of standard evaluations versus the initial use of ambulatory blood pressure monitoring for children with clinic blood pressure measurements suggesting stage 1 hypertension. Charges for clinic visits, laboratory tests, and imaging were obtained from the Texas Children's Hospital billing department.

RESULTS

A total of 267 children were referred. One hundred thirty-nine children did not receive ambulatory blood pressure monitoring; 54 met clinical indications for ambulatory blood pressure monitoring but did not receive it because it was not a covered expense (44 children) or the family refused the study (10 children). One hundred twenty-six children received clinically indicated ambulatory blood pressure monitoring, paid for either through insurance or by the family. Fifty-eight children (46%) had confirmed white-coat hypertension, 62 (49%) stage 1 hypertension, and 6 (5%) stage 2 hypertension. With the observed prevalence of white-coat hypertension, initial ambulatory blood pressure monitoring use yielded net savings after evaluation of 3 patients, with projected savings of $2.4 million per 1000 patients.

CONCLUSIONS

Ambulatory blood pressure monitoring in the initial evaluation of suspected childhood hypertension is highly cost-effective. Awareness of cost saving potential may increase the availability of ambulatory blood pressure monitoring for evaluation of new-onset hypertension.

Prevalence of white coat hypertension in underweight and overweight subjects

The aim of the present study was to determine if there is any association between white coat hypertension (WCH) and body mass index. The study was performed in two phases. In the first phase, we studied consecutive underweight patients, while in the second phase, age-matched consecutive normal weight, overweight, and obese cases were studied. Although we detected 61 cases in the underweight group with a mean age of 24.1 years, we could only detect 12 age-matched cases in the obesity group, and thus the obesity group was not used for comparison. When we looked at the prevalences of sustained normotension (NT), WCH, and HT in the groups, there were gradual and significant increases in the prevalences of WCH in addition to the gradual and significant decreases in the sustained NT from the underweight towards the normal weight and overweight groups. Eventually, only 31.5% of the overweight group had sustained NT, even though the mean age of the cases was very young. Due to the gradually increased prevalence of WCH from the underweight towards the normal weight and overweight groups, parallel to the already known increasing prevalences of HT, type 2 diabetes mellitus, hyperbetalipoproteinemia, dyslipidemia, and coronary heart disease and the very low prevalence of sustained NT among the overweight cases even in the early decades here, WCH should preferentially be accepted as an alarming sign of excess weight and many associated disorders in the future, rather than just being considered a predisposing factor of HT or atherosclerosis alone.

Prevalence, predictive factor, and clinical significance of white-coat hypertension and masked hypertension in Korean hypertensive patients

BACKGROUND

The prevalence and clinical significance of white-coat hypertension (WCHT) and masked hypertension (MHT) are unknown in Koreans. Here we measure the frequency of WCHT and MHT in hypertensive subjects and identify the epidemiologic and/or clinical factors that predict it in Korean subjects.

METHODS

This study is a retrospective analysis of a random sample from February 2004 to October 2005. All patients had measurements of blood pressure (BP) in the clinic and 24-hour ambulatory blood pressure monitoring (ABPM). Subjects were classified into four groups on the basis of daytime ambulatory BP and clinic BP level: 1) Normotension (NT), 2) MHT, 3) WCHT, and 4) sustained hypertension (SHT).

RESULTS

For all 967 patients, the mean clinic BP was 157.7 +/- 22.0/ 95.3 +/- 13.1 mmHg, and the mean daytime ambulatory BP was 136.4 +/- 15.0/ 86.2 +/- 10.7 mmHg. The NT, MHT, WCHT, and SHT groups consisted of 51 (5.3%), 55 (5.7%), 273 (28.2%), and 588 (60.8%) subjects, respectively. The left ventricular mass index was significantly higher in SHT than in the other groups, and was positively correlated with BP, especially ABPM. Compared with NT, the factors associated with MHT were younger age, male gender, higher BMI, clinic BP > or = 130 mmHg, and alcohol consumption. Compared with SHT, the factors associated with WCHT were female gender, lower BMI, and clinic BP < 150 mmHg.

CONCLUSIONS

WCHT and MHT were prevalent in the hypertensive population. ABPM was more predictive of target organ damage than clinic BP, and could be useful in identifying subjects at risk for WCHT and MHT.

Estimate of white-coat effect and arterial stiffness

OBJECTIVES

Blood pressure (BP) measured in the office is usually higher than the average ambulatory BP, a difference generally taken as an estimate of the white-coat effect. This study was designed to assess whether such a difference is associated with impairment of the conduit arterial system.

METHODS

We calculated the difference between office and average daytime peak systolic blood pressure (DeltaSBP) in 2778 hypertensive participants (1240 women) of the Progetto Ipertensione Umbria Monitoraggio Ambulatoriale cohort. Arterial stiffness was evaluated using an adjusted office pulse pressure to stroke volume ratio (PP/SV), measured at rest, which has previously been shown to predict cardiovascular outcome independent of echocardiographic left ventricular hypertrophy. Effective arterial elastance was also estimated.

RESULTS

Across quintiles of PP/SV, significant linear, positive trends were found with age, the proportion of women, plasma glucose and triglyceride levels (0.05 > P < 0.0001). Heart rate measured in the office increased mildly with quintiles of PP/SV (P < 0.05). After adjusting for age, sex, body weight and office heart rate, DeltaSBP progressively increased with increasing quintiles of PP/SV (P for trend < 0.0001), whereas stroke volume decreased, paralleling the increase in left ventricular relative wall thickness (both P < 0.0001) and left ventricular mass index (P < 0.05). The significant increase in effective arterial elastance with quintiles of PP/SV was also independent of peak systolic BP, in addition to age, sex, heart rate and body weight.

CONCLUSIONS

The difference between office BP and ambulatory BP, an estimate of the white-coat effect, is strongly associated with increased arterial stiffness, evaluated by a two-element fluid system accumulator.

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

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

Hypertensive retinopathy revisited: some answers, more questions

Hypertension is associated with cardiovascular risk and systemic target organ damage. Retinopathy is considered one of the indicators of target organ damage. This review focuses on recent studies on hypertensive retinopathy and their implications for clinical care. Early recognition of hypertensive retinopathy signs remains an important step in the risk stratification of hypertensive patients.

White-coat and masked hypertension in children: association with target-organ damage

White-coat hypertension (WCH) and masked hypertension have been associated with increased cardiovascular risk in adults. In the current study, we investigated: (a) the prevalence of WCH and masked hypertension in pediatric patients and (b) the association of these conditions with target organ damage. A total of 85 children underwent office blood pressure measurements, 24-h ambulatory blood pressure monitoring, echocardiography and ultrasonography of the carotid arteries. Subjects with both office and ambulatory normotension or hypertension were characterized as confirmed normotensives or hypertensives, respectively; WCH was defined as office hypertension with ambulatory normotension and masked hypertension as office normotension and ambulatory hypertension. WCH was found in 12.9% and masked hypertension in 9.4% of the subjects. WCH was significantly more prevalent in obese subjects, while masked hypertension was only present in non-obese ones. Confirmed and masked hypertensives had significantly higher left ventricular mass index than confirmed normotensives (34.0+/-5.8 g/m(2.7), 31.9+/-2.9 g/m(2.7) and 25.3+/-5.6 g/m(2.7), respectively, P<0.05). White-coat hypertensives tended to have higher left ventricular mass index than confirmed normotensives, but the difference was not statistically significant (27.8+/-5.1 g/m(2.7) versus 25.3+/-5.6 g/m(2.7)). No significant differences were found in the intima-media thickness of the carotid arteries between confirmed normotensives, white-coat hypertensives, masked hypertensives and confirmed hypertensives. WCH and masked hypertension are common conditions in children. Confirmed and masked hypertension in pediatric patients are accompanied by increased left ventricular mass index.

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.