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.     

White coat effect and white coat hypertension in community pharmacy practice

OBJECTIVE: The aim of the present study was to investigate whether a white coat effect (WCE) can be observed and quantified in community pharmacy practice. METHODS: In five community pharmacies of Basel, Switzerland, clients asking for blood pressure (BP) measurement were recruited to participate in a free of charge study. Blood pressure was measured in four different settings: pharmacy (using mercury sphygmomanometers), outpatient clinic (measurement by a nurse using mercury sphygmomanometers), self-measurement at home (using automated wrist devices) and daytime ambulatory BP (ABP) monitoring (using SpaceLabs 90207 monitors). WCE was defined as the difference between pharmacy or outpatient and daytime ABP. RESULTS: A total of 50 subjects completed all measurements (42% male, mean age 53.7 years+/-14.0). Blood pressure values of the different settings: (means in mmHg+/-SD, systolic; diastolic): pharmacy BP 129+/-19; 82+/-10, outpatient clinic BP 127+/-15; 82+/-10, home BP 119+/-15; 73+/-9, daytime ABP 124+/-10; 79+/-8. Pharmacy BP was significantly higher (P=0.03 systolic; P=0.02 diastolic) compared with daytime ABP and differences among subjects with antihypertensive medication (n=22) were even more significant (P<0.01). Individual differences were found between pharmacy BP and daytime ABP: +4.6+/-14.8; +2.9+/-8.3. Outpatient BP was significantly higher compared with daytime ABP in diastolic (P=0.04) but not in systolic values. Individual differences between outpatient BP and daytime ABP were +2.5+/-13.1; +2.8+/-9.2. 'Clinically important WCE' (>or=20 mmHg systolic or >or=10 mmHg diastolic) was observed in 24% of all subjects in the pharmacy and in 20% in the outpatient clinic. CONCLUSIONS: Our findings show that WCE and white coat hypertension exist in community pharmacy practice and are similar to the effects in an outpatient clinic.     

Endothelial function in sustained and white coat hypertension

BACKGROUND: Endothelial dysfunction is a frequent finding in essential hypertension. The aim of this study was to assess endothelial function, by evaluating circulating nitric oxide metabolites, nitrate plus nitrite (NOx), and endothelium-dependent vasodilation (EDD), in white coat hypertension in comparison with sustained hypertension and normotension. METHODS: We selected 22 sustained hypertensive, 22 white coat hypertensive, and 22 normotensive subjects matched for age, gender, body mass index, and occupation. Women were also matched for menopausal status. Subjects with smoking habit, dyslipidemia, and diabetes mellitus were excluded from the study. White coat hypertension was defined as clinical hypertension and daytime ambulatory blood pressure (BP) <135/85 mm Hg. Groups received for 2 days a low-nitrate diet before obtaining blood samples for laboratory measurements. The NOx levels were measured by using the Griess reagent after enzymatic conversion of all nitrate to nitrite. Subjects also underwent brachial artery study by ultrasonography to evaluate EDD and endothelium-independent vasodilation. RESULTS: White coat hypertensive subjects had significantly higher levels of NOx than sustained hypertensive patients (30.8 +/- 12 v 22 +/- 8.5 micromol/L, P <.05) and significantly higher EDD (7.8% +/- 3.1% v 4.6% +/- 3.0%, P <.05). No significant difference was observed between white coat hypertensive and normotensive subjects regarding these parameters. Endothelium-independent vasodilation was not significantly different among sustained hypertensives, white coat hypertensives, and normotensives (18% +/- 4.2% v 18.3% +/- 3.9% v 18.6% +/- 4.8%, respectively, P = not significant). CONCLUSIONS: Our data suggest that middle-aged white coat hypertensive subjects without other cardiovascular risk factors do not show endothelial dysfunction in contrast with sustained hypertensive patients.     

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.     

Syndrome of white coat hypertension in pregnant women

Among 127 pregnant women with hypertension 17 (13.4%) were found to have white coat hypertension because they had elevated blood pressure (BP) according to office measurements and normal BP during 24-hour BP monitoring. Investigation of b-adrenoreception of erythrocyte membranes and analysis of calculated parameters of 24-hour BP monitoring demonstrated normal physiological level of functioning of sympathico-adrenal system. However the study of psychological status evidenced for the presence of intrapersonality conflicts and anxiety in the majority of patients. This can be a factor, provoking BP elevation.     

Association of thyroid function with white coat hypertension and sustained hypertension

This study aimed to explore the relationship of thyroid‐stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) levels with hypertension subtypes. 1056 euthyroid adults were included as research samples. They underwent measurement of clinic blood pressure and 24‐hours ambulatory blood pressure monitoring. Then, they were divided into normotension (NT), white coat hypertension (WCH), masked hypertension (MHT), and sustained hypertension (SHT) groups. The 24‐hours dynamic electrocardiogram was performed to analyze the heart rate variability (HRV), so as to reflect the cardiac autonomic function. The relationship between hypertension subtypes, thyroid function, and HRV was analyzed. The TSH concentration was significantly higher in the SHT group than in the NT group (P = 0.001). The FT3 concentration was higher in the SHT group than in the NT and MHT groups (P = 0.013, P = 0.008), while the FT4 concentration was significantly higher in the WCH group than in the NT group (P = 0.002). The changes in HRV were observed between the SHT, WCH, and MHT groups and the NT groups, as well as between the SHT and the MHT groups. The multiple linear regression analysis also showed that FT3, HRV (RMSSD and PNN50), and blood pressure levels linearly correlated with one another (P < 0.05). Meanwhile, the linear regression analysis showed a linear negative correlation between FT4 and HRV (SDANN) in the WCH + NT group (P = 0.001). Thyroid function was closely related to hypertension subtypes such as WCH probably due to the changes in the cardiac autonomic function.     

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.     

枣庄市白大衣高血压流行病学调查

目的:研究中国枣庄市人群白大衣高血压(WCH)患病率及相关危险因素。方法:1873例门诊发现血压增高的患者填写调查表,包括年龄、性别、教育程度、婚姻状况、高血压家族史、心脑血管疾病与生活方式,同时进行体格检查及生化检查。结果:枣庄市WCH患病率为31.6%,女性患病率显著高于男性(P<0.01),WCH患者超重及高脂血症较正常血压人群显著增多(P<0.01),不同教育程度、婚姻状况及职业其WCH患病率不同,城市人群WCH患病率显著高于农村人群。结论:枣庄市人群WCH患病率较高与性别、职业、教育程度、婚姻状况及城乡分布等有关。     

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.     

白大衣性高血压的特征和临床意义

目的 :确定白大衣效应和白大衣性高血压的特征及其临床意义。方法 :应用心理行为方法探讨白大衣性高血压的机制。结果 :报道白大衣效应和白大衣性高血压的发生率及其与原发性高血压的联系。结论 :白大衣性高血压的发生与心理行为因素有关 ,宜进一步探讨其防治方法