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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this paper, several clinical problems associated with the diagnosis of hypertension are discussed. Blood pressure variability and reactivity are factors underlying the difficulties in the diagnosis of hypertension. These phenomena are interrelated and mixed. White coat hypertension (WCH), referring to the phenomenon of a high diastolic pressure at the doctor's office and a normal diurnal diastolic pressure when it is measured by ambulatory monitoring, is the most important clinical problem of diagnosis. Blood pressure variability is described, since it is essential to understand changes in pressure throughout the day, and its phasic and tonic components. Blood pressure differences between activity and rest, usually seen as daytime/night-time differences, allow for blood pressure control in most patients with moderate hypertension. Prevalence of WCH depends on the cut-off point used by the investigators for normal diurnal blood pressure; thus, between 53% and 12% of patients may have WCH. In our studies, a prevalence of 35% has been found. The alert reaction, labile and borderline hypertension and WCH result from a mix of both variability and reactivity, and patients with these conditions are at a higher cardiovascular risk than normotensive controls. Ambulatory blood pressure monitoring, which enables true hypertensives to be distinguished from false hypertensives, is the most useful technique available to date for the diagnosis of hypertension.
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PMID:White coat hypertension and related phenomena. A clinical approach. 751 90

The rise in blood pressure (BP) associated with clinical visit (white coat effect) may be one basic mechanism of white coat hypertension (persistently raised clinic BP together with a normal BP outside the clinic), but the relations between white coat hypertension, white coat effect, and target organ damage have not yet been assessed on large populations. Thus, we performed 24-h noninvasive ambulatory BP monitoring and 2D-guided M-mode echocardiography in 1,333 untreated subjects with essential hypertension and 178 control normotensive subjects. White coat hypertension was defined by an average daytime ambulatory BP < 131/86 mm Hg in women and < 136/87 mm Hg in men and its prevalence was 18.9% (n = 252). The white coat effect was calculated for systolic and diastolic BP as the difference between clinic BP and average daytime ambulatory BP. Echocardiographic left ventricular mass was slightly but not significantly greater in the group with white coat hypertension than in the normotensive group (93 v 87 g/m2, P = NS), and increased in the group with ambulatory hypertension (112 g/m2, P < .01). The prevalence of white coat hypertension markedly decreased from the first to the fourth Joint National Committee V (JNC V) stage of severity of hypertension (186/559 subjects (33%) in I; 59/501 (11%) in II; 7/230 (3%) in III; 0/43 (0%) in IV; P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:White coat hypertension and white coat effect. Similarities and differences. 757 95

Target organ status and serum lipids were investigated in white coat hypertension in comparison with sustained hypertension and normotension. We selected three groups balanced for sex, age, body mass index, and smoking habit: 50 sustained hypertensives (clinical hypertension and 24-hour ambulatory blood pressure > 135/85 mm Hg, a cutoff limit obtained from a normotensive population), 25 white coat hypertensives (clinical hypertension and 24-hour ambulatory blood pressure < 135/85 mm Hg), and normotensives. Subjects underwent echocardiographic examinations to assess left ventricular mass index, carotid ultrasonography to evaluate intima-media thickness and atherosclerotic plaques, venous occlusion plethysmography to record minimum forearm vascular resistance, and determinations of serum lipid profile and 24-hour urinary albumin excretion. Compared with sustained hypertensives, the white coat hypertensives had significantly lower values of left ventricular mass index (125.9 +/- 20 versus 97.6 +/- 11.5 g/m2, P < .05, intima-media thickness (0.85 +/- 0.18 versus 0.71 +/- 0.15 mm, P < .05), minimum forearm vascular resistance (2.33 +/- 0.11 versus 2.04 +/- 0.08 resistance units, P < .05), urinary albumin excretion values (15.1 +/- 13.8 versus 4.45 +/- 1.48 mg per 24 hours, P < .0001), prevalence of left ventricular hypertrophy (versus 4%, P < .002), intima-media thickening 28% versus 4%, P < .015), and microalbuminuria (22% versus 0%, P < .015). No significant difference, however, was observed between the white coat hypertensives and the normotensives. Serum lipid profile was similar in the white coat hypertensives and in the normotensives.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1995 Nov
PMID:Target organ status and serum lipids in patients with white coat hypertension. 759 Oct 21

Although white coat hypertension may be present in 20% or more of hypertensive individuals, its prognostic significance is unknown. We compared prognostically relevant measures of target-organ damage among 24 individuals with white coat hypertension and age- and sex-matched groups of sustained hypertensive and normotensive subjects classified by clinical and 24-hour ambulatory blood pressures. Left ventricular and carotid artery structure and function were evaluated by ultrasonography. Left ventricular mass index was similar in white coat hypertensive (82 +/- 17 g/m2) and normotensive (78 +/- 15 g/m2) subjects but was higher in sustained hypertensive subjects (97 +/- 19 g/m2, P < .02 and P < .002, respectively). Similarly, carotid artery intimal-medial thickness was greater in the sustained hypertensive group (0.98 +/- 0.21 mm) than in the white coat hypertensive (0.84 +/- 0.16 mm, P < .05) and normotensive (0.76 +/- 0.18 mm, P < .001) groups. The prevalence of discrete atherosclerotic plaques was higher in the sustained hypertensive group (58%) than in the white coat hypertensive (25%, P < .05) and normotensive (21%, P < .02) groups. Cardiac and carotid structure in individuals with white coat hypertension resemble findings in normotensive subjects and differ significantly from those in age- and sex-matched sustained hypertensive subjects. These findings suggest that white coat hypertension may be a benign condition for which pharmacological intervention may not be necessary, a hypothesis that needs to be tested in longitudinal studies with clinical end points.
Hypertension 1995 Sep
PMID:Is white coat hypertension associated with arterial disease or left ventricular hypertrophy? 764 75

In this study the effects of a single daily dose of doxazosin (an alpha-adrenergic blocker) given at night were evaluated in 112 patients with mild hypertension. Patients were studied first on no medication, and a second time after being treated for up to 16 weeks with doxazosin. Blood pressure (BP) was measured by noninvasive ambulatory monitoring at the beginning and end of the study. Before treatment, the white coat effect (clinic-ambulatory BP) was greater in women than in men (significant for systolic pressure but not diastolic), and greater in elderly (aged over 65 years) than in younger patients (significant for both systolic and diastolic pressure). Clinic and ambulatory BP were reduced to a similar extent in men and women by doxazosin, but in the elderly the fall in clinic BP was associated with a much smaller fall of ambulatory BP. In patients with white coat hypertension (elevated clinic but normal ambulatory BP) doxazosin lowered clinic but not ambulatory BP, while in those with sustained hypertension it lowered both.
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PMID:Differential effects of doxazosin on clinic and ambulatory pressure according to age, gender, and presence of white coat hypertension. Results of the HALT Study. Hypertension and Lipid Trial Study Group. 781 46

There are major problems with blood pressure (BP) measurement that must be addressed in the diagnosis and treatment of hypertension. Errors in taking BP are widespread and failure to allow for regression to the norm often leads to premature treatment. 'White coat hypertension', a condition in which raised BP levels in the presence of a doctor or nurse do not regress towards the norm on repeated measurement, may be responsible for between 10-20% of our patients being given medication unnecessarily. Ambulatory measurement is becoming an accepted method of attempting to deal with these problems whereas self measurement at home is little used. Used properly, both methods prevent most observer error and bias, eliminate regression to the norm, and allow the diagnosis of 'white coat hypertension'. Both curtail the period necessary to establish patients' 'true' BP. Ambulatory measurement has established scientific advantages but is expensive in time, equipment and staffing. Home measurement at the moment is less reliable but is easier and cheaper. Problems with the accuracy of instruments for home measurement can be solved and, even in their present form, enable the diagnosis of white coat hypertension and help in the diagnosis of many hypertensive patients. Ambulatory monitoring is already undergoing trials in primary care. It is suggested that home measurement should also be more widely used where most patients with hypertension are exclusively managed.
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PMID:Ambulatory or self blood pressure measurement? Improving the diagnosis of hypertension. 795 86

To determine the prognostic significance of ambulatory blood pressure, we prospectively followed for up to 7.5 years (mean, 3.2) 1187 subjects with essential hypertension and 205 healthy normotensive control subjects who had baseline off-therapy 24-hour noninvasive ambulatory blood pressure monitoring. Prevalence of white coat hypertension, defined by an average daytime ambulatory blood pressure lower than 131/86 mm Hg in women and 136/87 mm Hg in men in clinically hypertensive subjects, was 19.2%. Cardiovascular morbidity, expressed as the number of combined fatal and nonfatal cardiovascular events per 100 patient-years, was 0.47 in the normotensive group, 0.49 in the white coat hypertension group, 1.79 in dippers with ambulatory hypertension, and 4.99 in nondippers with ambulatory hypertension. After adjustment for traditional risk markers for cardiovascular disease, morbidity did not differ between the normotensive and white coat hypertension groups (P = .83). Compared with the white coat hypertension group, cardiovascular morbidity increased in ambulatory hypertension in dippers (relative risk, 3.70; 95% confidence interval, 1.13 to 12.5), with a further increase of morbidity in nondippers (relative risk, 6.26; 95% confidence interval, 1.92 to 20.32). After adjustment for age, sex, diabetes, and echocardiographic left ventricular hypertrophy (relative risk versus subjects with normal left ventricular mass, 1.82; 95% confidence interval, 1.02 to 3.22), cardiovascular morbidity in ambulatory hypertension was higher (P = .0002) in nondippers than in dippers in women (relative risk, 6.79; 95% confidence interval, 2.45 to 18.82) but not in men (P = .91). Our findings suggest that ambulatory blood pressures stratifies cardiovascular risk in essential hypertension independent of clinic blood pressure and other traditional risk markers including echocardiographic left ventricular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1994 Dec
PMID:Ambulatory blood pressure. An independent predictor of prognosis in essential hypertension. 773 25

We compared urinary albumin excretion in normotensive subjects and patients with white coat and established hypertension. The study involved prospective comparison of office blood pressure, daytime ambulatory blood pressure, and urinary albumin excretion in consecutive patients (n = 284) who were selected from general practice with newly diagnosed mild to moderate hypertension before the institution of pharmacologic antihypertensive therapy. All patients had a diastolic office blood pressure above 90 mm Hg; 173 had a consistently elevated diastolic blood pressure (established hypertension), and 111 had an average daytime ambulatory blood pressure below 90 mm Hg (white coat hypertension). A sample of 127 subjects drawn from the Danish national register served as a normotensive control group. The main outcome measure was the ratio of early morning urinary albumin to creatinine. This ratio differed significantly among the three groups, being (on a molar basis) 21 +/- 69 x 10(-6) in the normotensive subjects, 22 +/- 39 x 10(-6) in the white coat hypertensive patients, and 51 +/- 177 x 10(-6) in patients with established hypertension. The difference remained significant after correction for covariables. The ratio of early morning urinary albumin to creatinine was weakly but significantly correlated to blood pressure, was more pronounced for ambulatory than for office measurements, was more pronounced for systolic than for diastolic pressure, and was more pronounced for hypertensive than for normotensive individuals. The ratio was as reproducible a measure as 24-hour albumin excretion. We conclude that white coat hypertensive patients have less renal involvement than patients with established hypertension but more than a normotensive control group.
Hypertension 1994 Jul
PMID:Microalbuminuria in 411 untreated individuals with established hypertension, white coat hypertension, and normotension. 784 48

Elevated BP in the clinical but not during daily activities (white coat hypertension) is a well recognised problem encountered in the diagnosis of mild hypertension. The aim of this study is to evaluate this phenomenon with a study population of 90 mild hypertensive patients subjected to 24h BP measurement, and to assess the effect of placebo on both the office and the daytime continual BP monitored values. For this purpose, 90 patients were evaluated after four weeks of single-blind placebo (Phase I) and, of these, 27 patients were evaluated after a further four weeks of double-blind placebo administration (Phase II). During Phase I treatment the mean office SBP (163.9 mmHg) and the mean office DBP (104.5 mmHg) were significantly higher than the average of the six readings obtained during the first two hours of automatic continual BP monitoring (158.6 and 98 mmHg respectively, P < 0.001) (white coat effect). These differences were much more pronounced when the comparison was made between office measurements and the average daytime values (SBP 152.8 mmHg, DBP 93.1 mmHg). At the end of Phase II, the average values of BP measurements obtained both in the office and from continual monitoring were significantly lower (placebo effect). However, the difference between the office and the daytime values persisted. Thus, notwithstanding the reduction in the BP measurements following placebo administration, the white coat effect persists.
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PMID:Effect of placebo on office and on 24 hour noninvasive ambulatory blood pressure measurements. 811 49

Renal tubular sodium handling was investigated prospectively in 48 normotensive subjects, 53 untreated hypertensive patients, and 13 patients with white coat hypertension using endogenous trace lithium as a marker of proximal sodium reabsorption. A 12-hour daytime ambulatory blood pressure recording was performed in all patients to confirm the diagnosis of hypertension. Patients were included in the white coat hypertension group if their office blood pressure was above 160/90 mm Hg but the mean value of their 12-hour ambulatory recording was lower than 140/90 mm Hg. All participants were studied on their normal diet and ate salt freely. Fractional excretions of sodium (FENa), lithium (FELi), and potassium (FEK) were measured simultaneously before blood pressure recording. FENa was significantly higher in hypertensive patients (0.84 +/- 0.05%, P < .05) than in normotensive control subjects (0.60 +/- 0.06%), and FELi was comparable in the two groups (15.4 +/- 0.65% in hypertensive patients and 17.0 +/- 0.9% in control subjects). However, the relation between FENa and FELi was significantly different in normotensive subjects and hypertensive patients (P < .001), so that for a given increase in FENa a smaller increase in FELi was observed in hypertensive patients. In addition, the ratios of urinary lithium to sodium and urinary potassium to sodium were significantly reduced in hypertensive patients, suggesting an increased proximal reabsorption of sodium. Similar alterations in renal tubular sodium handling were observed in patients with white coat hypertension. These results suggest that an increased sodium reabsorption in the proximal tubule may contribute to the maintenance of hypertension and that white coat hypertension might represent a prehypertensive state.
Hypertension 1994 Apr
PMID:Renal sodium handling in patients with untreated hypertension and white coat hypertension. 814 19


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