| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Hypertension. 1999;34:267-272.)
© 1999 American Heart Association, Inc.
Scientific Contributions |
Diagnosis of White Coat Hypertension by Ambulatory Blood Pressure Monitoring
From the Blood Pressure Unit, Beaumont Hospital, Dublin, Ireland.
Correspondence to Eoin O'Brien, MB, Blood Pressure Unit, Beaumont Hospital, PO Box 1297, Beaumont Road, Dublin 9, Ireland. E-mail eobrien{at}iol.ie
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Abstract—White coat hypertension (WCH) is common in referred hypertensive patients. Ambulatory blood pressure monitoring (ABPM) is not free from the white coat syndrome. We examined the use of the elevation of the first and last measurements of ABPM for diagnosis of WCH in a hypertensive population that had been referred to a hospital-based hypertension unit. Data were obtained on 1350 patients for clinic and ABPM parameters. WCH, as diagnosed by conventional clinic blood pressure (BP) measurement, was compared with a variety of alternative methods determined from ABPM. In all cases, mean daytime pressure was <135 mm Hg/85 mm Hg with an elevation of clinic BP
140 mm Hg systolic or
90 mm Hg diastolic. The definitions tested for this
elevation were first hour mean pressure, first reading, maximum reading
in first hour, last hour mean pressure, last reading, maximum reading
in the last hour and maximum reading in first or last hour. Elevation
of the maximum pressure in the first hour or last hour above 140
mm Hg systolic or 90 mm Hg diastolic showed
a high level of agreement (
=0.91) with classical WCH for diagnosis
of the white coat syndrome. Termed ambulatory white coat hypertension,
patients with this finding were older than classic white coat patients
and had higher daytime (127±6/78±5 mm Hg versus
121±5.5/74±6 mm Hg, P<0.005 for
systolic and diastolic) and nighttime
(114±11/67±8 mm Hg versus 106±9/61±6 mm Hg,
P<0.005 for systolic and diastolic)
pressures. They also had a significantly greater Sokolow-Lyon index
(leads V1+V5, 21±7 mV versus 18±6 mV).
Elevation of BP above 140 mm Hg systolic or 90
mm Hg diastolic in the first or last hour of monitoring
diagnoses patients with a white coat response in whom there is a higher
BP profile than in patients with classic white coat response alone. We
suggest, therefore, that this is a better measure of the white
coat phenomenon.
Key Words: blood pressure monitoring, ambulatory • hypertension, white coat
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
White coat hypertension is a common finding in hypertensive populations and in the population at large. The incidence has variably been recorded between 12% and 50%, depending on definitions.1 The importance of the condition lies in the relatively benign cardiovascular risk with which it is associated compared with established hypertension.2 The phenomenon of white coat hypertension may reflect an abnormally vigorous sympathetic response to the environment of the measurement,3 especially the presence of the measuring nurse or physician.4
Ambulatory blood pressure (BP) is the most frequent mechanism used in measuring the presence of the white coat effect. The standard definition of white coat hypertension is an elevation of clinic pressure with a normal daytime ambulatory profile.5 However, our experience has been that the initial few measurements on the ambulatory monitor, and, indeed, the final measurement, which reflect the patient's attention to attaching and removal of the monitoring device, respectively, are frequently abnormal also. A typical ambulatory monitor recording from such a patient is shown in Figure 1. This study has been undertaken, therefore, to establish the clinical usefulness of the first and last measurement of ambulatory monitoring in the diagnosis of white coat hypertension.
|
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The patient population used in this study was a cohort of 1350 patients, drawn from a total database population of 2425 patients, who attended the "shared care" hypertension management program in our institution for assessment of their hypertension. The patient exclusion protocol is depicted in Figure 2. All patients were classified as hypertensive if the referral physician-recorded clinic BP was
140 mm Hg systolic
or 90 mm Hg diastolic.6 None of the
patients were on vasoactive medications at the time of monitoring, and
subjects were excluded if antihypertensive drugs had been taken within
2 weeks of the study.
|
Upon arrival for ambulatory monitoring, the patient had clinic BP measurement performed by the attending nurse in the BP unit. BP was measured in the nondominant arm after 5 minutes of quiet sitting; the BP measurement was taken in accordance with the recommendations of the British Hypertension Society.7 Only patients in whom both this clinic BP and the original referral BP were above normal were included in the analysis. ECG was performed with the use of a standard 12 lead placement within 1 week of attendance at the BP unit, and left ventricular voltage criteria for ventricular mass were determined with Sokolow-Lyon V1+V5 and V1+V6 voltage summation.
Ambulatory BP monitoring was performed with the SpaceLabs 90207 ambulatory blood pressure monitor (ABPM).8 The monitor was applied to the nondominant arm between 9:00 AM and noon. The patient was instructed to perform normal activities between measurements but to rest the arm at heart level during measurements. Monitors were programmed to measure BP at 30-minute intervals day and night. The monitor was removed the next day after 8:00 AM, and the data were transferred to a personal computer and loaded into a specialized software package (DABL).9 Mean systolic BPs (SBPs) and diastolic BPs (DBPs) were calculated for the initial, daytime, nighttime, and final hour periods. The initial period was defined as the first hour of recording. Daytime was defined as the hours between 9:00 AM and 9:00 PM (excluding the initial period), and nighttime as the hours between 1:00 AM and 6:00 AM. The transition time (9:01 PM to 0:59 AM) was not included in the estimation of day and night mean pressures because this period represents time during which bed rest is inconsistent and, therefore, cannot be categorized reliably.10 Readings obtained during the second day of recording were not included in the definition of the daytime period. Acceptable BP limits are shown in Table 1.
|
White coat parameters examined in the present study are defined in Table 2. The first reading is the reading obtained by direct actuation of the monitor by the attending nurse when the patient was still in the BP unit. The last reading is the reading obtained just before removal of the monitor by the patient or by the attending nurse when the patient was in the BP unit the next day for removal of the unit. Recordings that did not show data for nighttime BP were not included in the analysis. Furthermore, patients on night shift work, or within 4 weeks of completing night shift duty, were not included in the analysis because shift work may result in an artificially reversed diurnal rhythm.11 Recordings were not included if there were <14 valid readings during the day or <7 valid readings during the night. The device used was validated by and passed both the Association for the Advancement of Medical Instrumentation12 and British Hypertension Society13 protocols, and all instruments were serviced regularly to ensure that they maintained their performance.
|
Statistical Analysis
The ABPM data were processed by use of a commercially available
statistical analysis software package (SPSS, SPSS Inc).
Agreement between categorical variables was determined by
calculation of the kappa () statistic. Continuous data were compared
using the Student t test.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Records from 1350 patients were available for studies, all of whom, by definition, had elevated physician referral pressures and those pressures were confirmed on repeat measurement by the nurse in the BP unit. Of the initial 2425 patients noted to be hypertensive by their physician, 2244 (92.5%) were again found to be hypertensive by the nurse. Reasonable uniformity was found among the start time (minimum, 8:20 AM; 5th percentile, 9:08 AM; median, 10:41 AM; 95th percentile, 12:21 PM; maximum, 1:52 PM), end time (minimum, 8:05 AM; 5th percentile, 8:50 AM; median, 10:30 AM; 95th percentile, 12:30 PM; maximum, 4:49 PM) and duration in hours (minimum, 20 h, 59 min; 5th percentile, 22 h, 53 min; median, 23 h, 56 min; 95th percentile, 24 h, 51 min; maximum, 30 h, 09 min) for ambulatory recordings. The mean age was 50.9 (±12.4) years, and 56.6% of the patients were female. Table 3 shows the baseline clinical and pressure data for the study population. On the basis of physician BPs, 148 (11.0%) patients fulfilled the classic definition for white coat hypertension (WCH-C), according to the definitions set out in Table 2.
|
First ABPM Readings as Markers for WCH
Table 4 shows that a total of 74
(5.5%) patients were categorized as having first reading WCH (WCH-FR).
The agreement between WCH-FR and WCH-C was good (=0.64), although
50% of WCH-C patients were not identified as WCH-FR. Measurement of
first hour WCH (WCH-FH) identified 88 (6.5%) patients in this
population. The agreement between WCH-FH and WCH-C was very good
(=0.75). Because WCH-FH could conceivably miss the white coat effect
due to averaging of a high value with a low value, the highest pressure
in the first hour (WCH-FHmax) was then examined.
WCH-FHmax identified 115 (8.5%) patients from
the population. The agreement between WCH-FHmax
and WCH-C was excellent (=0.86).
|
Last ABPM Readings as Markers for WCH
Table 4 shows that a total of 60 (4.4%) patients were
identified as having last reading WCH (WCH-LR). Agreement for WCH-LR
and WCH-C was modest (=0.55). Only 33 (2.4%) patients had last hour
WCH (WCH-LH), with the poor agreement between WCH-LH and WCH-C
(=0.34). Finally, the maximum pressure recorded in the last hour
(WCH-LHmax) was also examined as a marker for
WCH. This identified 82 (6.1%) patients in the population. Agreement
between WCH-LHmax and WCH-C was better
(=0.69).
Combination of WCH- FHmax and
WCH-LHmax
WCH- FHmax and
WCH-LHmax were combined in an inclusive
relationship to optimize agreement between WCH-C and ABPM
parameters of WCH (Table 4). This
parameter, called ambulatory WCH (WCH-A), identified 126
(9.3%) patients in the population, and had an excellent agreement with
WCH-C(=0.91) (P<0.0001).
Clinical Differences Between WCH-C With and Without WCH-A
There were subjects with WCH-A but without WCH-C. When the
physician referral BP was compared to BPs of WCH-C patients who were
and were not identified by WCH-A, SBPs were significantly higher
in those with WCH-A versus those without WCH-A (Table 5). DBP did not differ significantly.
Comparisons of ABPM mean daytime and nighttime pressures showed
significantly higher daytime and nighttime systolic and
diastolic mean pressures in patients with WCH-A versus
those without WCH-A. Age was also significantly greater in the former
versus the latter. Height and weight tended to be higher in WCH-A
patients, but not significantly so.
|
To determine independent predictors of WCH-A, a logistic regression model was fitted to the data with WCH-A as the dependent variable, age, height, weight, and daytime and nighttime SBP and DBP as independent variables, and gender as a covariate. Age (ß=0.06, R=0.26, P=0.001), daytime SBP (ß=0.12, R=0.22, P=0.0047), and daytime DBP (ß=0.12, R=0.17, P=0.019) remained independent predictors of WCH-A.
ECG voltages for left ventricular mass, namely V1+V5 summation, were significantly greater in WCH-A patients than non–WCH-A patients (21.3±7.5 mV versus 18.1±6.3 mV, respectively; P<0.038). However, on multiple regression modeling with V1+V5 summation as the dependent variable, WCH-A as a predictor of left ventricular voltage was not independently predictive.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
WCH is a relatively common finding in patients with elevated BP. The specific numerical definitions vary, but the essential component of the diagnosis is an elevated clinic BP above accepted normal levels, in association with a normal ambulatory BP profile. A variety of normal values are used for ambulatory BP monitoring14 and, as a result, the proportion of any given population diagnosed as having white coat hypertension has varied widely in the literature.15
Our experience of ambulatory measurement has been that it is not entirely free from the white coat effect. This has been suggested by previous investigators.16 Specifically, the first or final measurements may be elevated above the mean value for the day. This raises the question of whether these parameters may be useful as markers for the presence of the white coat phenomenon, and, indeed, whether they might identify a separate substratum of patients.
Our data, taken from a large cohort of unmedicated hypertensive patients referred for ambulatory monitoring, show that certain ABPM derived measurements agree well with the traditional methodology of categorization of white coat syndrome. Indeed, it could be suggested that the finding of an elevated reading in the first or last hour of measurement above 140 mm Hg systolic or 90 mm Hg diastolic, when the ambulatory daytime means are normal, is diagnostic of white coat hypertension. The agreement between this methodology and traditional categorization of WCH is not perfect, however, so we propose the term "ambulatory white coat hypertension" as an appropriate label for this finding.
What of the 21.5% of WCH-C patients not identified by WCH-A? Does WCH-A identify a different stratum of true white coat hypertensive patients? We found that there is a large difference in the measured clinic referral pressure between patients who are WCH-A and those who are WCH-C only, with the former having significantly higher pressures. Furthermore, the WCH-A group was older and exhibited significantly higher daytime and nighttime SBPs and DBPs. This suggests that WCH-A identifies a very different stratum of white coat hypertensive patients and identifies patients with more severe white coat hypertension.
The literature remains inconclusive on the subject of whether white coat hypertension carries a pathological risk. Studies for17 18 19 20 21 22 and against2 23 24 25 this hypothesis have been propounded. The truth most likely lies in the middle, with the risk associated with white coat hypertension substantially less than the risk associated with sustained hypertension, but greater than the risk of true normotensive patients. A methodology that identifies a higher risk white coat group, which WCH-A may well do, would therefore be of significant value in the context of follow-up for this group of patients. The voltage summation of V1+V5 for left ventricular mass was higher in our patients with WCH-A than in those with WCH-C only. This reflected the higher BP in these patients, and a difference in body habitus. The definitive statement on this would require a longitudinal outcome study, with WCH-C and WCH-A analyzed as prognostic variables.
A number of caveats need to be considered in interpreting this data. First, although it is reasonable to assume that the stresses that give rise to white coat hypertension might carry over to the first hour of monitoring (when the monitor is applied in a hospital setting), it is perhaps less obvious that these factors would recur in the last hour of monitoring. It was unfortunately not possible, in this study population, to determine which patients returned to the hospital to have their monitors removed (other than to state that it would have been the great majority) and which patients removed the monitors themselves. Therefore, it is possible that the stress of revisiting the hospital, which presumably gave rise to high end pressures on the ABPM, was absent in an undetermined number of our patients. This suggests that if all patients returned to the hospital for removal of their monitors, the agreement between WCH-C and WCH-A would have been higher still. Alternatively, it may be that the approach of the end of the monitoring session was perceived as a stressor in itself, independent of the environment in which it was removed. Second, an obvious choice at the outset of this study was to approach it with a view toward determining the sensitivity and specificity of the ABPM parameters for diagnosis of WCH-C. This, however, involved ascribing the status of "gold standard" to the WCH-C methodology. We felt that this was inappropriate, because the spirit of the definition of white coat hypertension is what is important (measurement of environment-related hypertension with normal average pressures during daily life), rather than a definition strictly involving clinic measurement. Therefore, we took the approach of measuring agreement between 2 potentially complimentary measurement modalities. Finally, there have been concerns expressed over the repeatability of classic white coat hypertension.26 The reproducibility of WCH-A as defined here has not been formally tested and, thus, also requires formal prospective study.
In conclusion, we have shown that the ABPM can completely and sufficiently diagnose the white coat phenomenon independently of clinic measurement, and we suggest that WCH-A be adopted as a marker of the presence of the white coat syndrome. Furthermore, we have shown that WCH-A identifies a white coat hypertensive subgroup with significantly higher pressures and we speculate that it may stratify patients with white coat hypertension into those who are at very low risk and those who may require more intensive follow-up. Manufacturers of ABPM devices, those who use ABPMs in research, and anybody who provides or uses software for ABPM analysis should allow for this phenomenon, both in the analysis of separate statistics and in the calculation of mean daytime values.
|
Acknowledgments |
|---|
The authors wish to thank the Charitable Infirmary Charitable Trust, the Irish Heart Foundation, the Research Committee of the Royal College of Surgeons of Ireland, and the Clinical Investigation Committee of Beaumont Hospital for continued support.
Received August 20, 1998; first decision September 8, 1998; accepted April 13, 1999.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Pickering TG, James GD, Boddie C, Harshfield GA, Blank S, Laragh JH. How common is white coat hypertension? JAMA. 1988;259:225–228.
2. Verdecchia P, Schillaci G, Borgioni C, Ciucci A, Zampi I, Gattobigio R, Sacchi N, Porcellati C. White coat hypertension and white coat effect: similarities and differences. Am J Hypertens. 1995;8:790–798.[Medline] [Order article via Infotrieve]
3. Middeke M, Lemmer B. Office Hypertension: abnormal blood pressure regulation and increased sympathetic activity compared with normotension. Blood Pressure Monitoring. 1996;1:403–407.[Medline] [Order article via Infotrieve]
4.
Mancia G, Parati G, Pomidossi G, Grassi G, Casadei R,
Zanchetti A. Alerting reaction and rise in blood pressure during
measurement by physician and nurse. Hypertension. 1987;9:209–215.
5. Pickering TG. White coat hypertension. Cur Opin Nephrol Hypertens. 1996;5:192–198.
6. British Hypertension Society working party. Report of the British Hypertension Society working party: treating mild hypertension. BMJ. 1989;298:694–8.
7. O'Brien ET, Petrie JC, Littler WA, de Sweit M, Padfield PL, Dillon MJ, Coats A, Mee F. Blood Pressure Measurement: recommendations of the British Hypertension Society. 3rd ed. London, UK: BMJ Books; 1997.
8. O'Brien E, Mee F, Atkins N, O'Malley K. Accuracy of the SpaceLabs 90207 determined by the British Hypertension Society Protocol. J Hypertens. 1991;9:573–574.[Medline] [Order article via Infotrieve]
9. Atkins N, Mee F, O'Brien E. A customized international database system for storing and analyzing ambulatory blood pressure measurements and related data. J Hypertens. 1994;12:S23. Abstract.
10. Staessen J, Bulpitt CJ, Fagard R, Mancia G, O'Brien ET, Thijs L, Vyncke G, Amery A. Reference values for the ambulatory blood pressure and the blood pressure measured at home: a population study. J Hum Hypertens. 1991;5:355–361.[Medline] [Order article via Infotrieve]
11. Sternberg H, Rosenthal T, Shamiss A, Green M. Altered circadian rhythm of blood pressure in shift workers. J Hum Hypertens. 1995;9:349–53.[Medline] [Order article via Infotrieve]
12. Association For The Advancement Of Medical Instrumentation. American National Standard for Electronic or Automated Sphygmomanometers: ANSI/AAMI SP10–1987. Arlington, VA: 1993;P40.
13. O'Brien E, Petrie J, Littler WA, de Swiet M, Padfield PL, Altman D, Bland M, Coats A, Atkins N. The British Hypertension Society protocol for the evaluation of blood pressure measuring devices. J Hypertens. 1993;11(suppl 2):S43–S63.
14. O'Brien ET, Owens P, Staessen JA, Imai Y, Kawasaki T, Kuwajima I. What are the normal levels for ambulatory blood pressure measurement? Blood Pressure Monitoring. 1998;3:131–132.[Medline] [Order article via Infotrieve]
15. Hoegholm A, Kristensen KS, Madsen NH, Svendsen TL. White coat hypertension diagnosed by 24-hour ambulatory monitoring: examination of 159 newly diagnosed hypertensive patients. Am J Hypertens. 1992;5:64–70.[Medline] [Order article via Infotrieve]
16. Prasad N, MacFadyen, Ogston SA, MacDonald TM. Elevated blood pressure during the first two hours of ambulatory monitoring: a study comparing consecutive twenty-four-hour monitoring periods. J Hypertens. 1995;13:291–295.[Medline] [Order article via Infotrieve]
17. Glen SK, Elliott HL, Curzio JL, Lees KR, Reid JL. White coat hypertension as a cause of cardiovascular dysfunction. Lancet. 1996;348:654–657.[Medline] [Order article via Infotrieve]
18.
Kuwajima I, Suzuki Y, Fujisawa A, Kuramoto K. Is white
coat hypertension innocent: structure and function of the heart in the
elderly. Hypertension. 1993;22:826–831.
19.
Burnier M, Biollaz J, Magnin JL, Bidlingmeyer M,
Brunner HR. Renal sodium handling in patients with untreated
hypertension and white coat hypertension. Hypertension. 1993;23:496–502.
20. Cerasola G, Cottone S, Nardi E, D'Ignoto G, Volpe V, Mule G, Carollo C. White coat hypertension and cardiovascular risk. J Cardiovasc Risk. 1995;2:545–549.[Medline] [Order article via Infotrieve]
21.
Cardillo C, De Felice F, Campia U, Folli G.
Psychophysiological reactivity and cardiac
end-organ changes in white coat hypertension. Hypertension. 1993;21:836–844.
22.
Hoegholm A, Bang LE, Kristensen KS, Nielsen JW, Holm J.
Microalbuminuria in 411 untreated individuals with
established hypertension, white coat hypertension, and normotension.
Hypertension. 1994;24:101–105.
23.
Pierdomenico SD, Lapenna D, Guglielmi MD,
Antidormi T, Schiavone C, Cuccurullo F, Mezzetti A. Target organ status
and serum lipids in patients with white coat hypertension.
Hypertension. 1995;26:801–807.
24.
Cavallini MC, Roman MJ, Pickering TG, Schwartz JE, Pini
R, Devereux RB. Is white coat hypertension associated with
arterial disease or left ventricular
hypertrophy? Hypertension. 1995;26:413–419.
25.
Gosse P, Promax H, Durandet P, Clementy J. "White
Coat" Hypertension; no harm for the heart. Hypertension. 1993;22:766–770.
26. Parati G, Omboni S, Staessen J, Thijs L, Fagard R, Ulian L, Mancia G, on behalf of the Systolic Hypertension in Europe (Syst-Eur) Trial investigators. Limitations of the difference between clinic and daytime blood pressure as a surrogate measure of the `white-coat' effect. J Hypertens. 1998;16:23–29.[Medline] [Order article via Infotrieve]
This article has been cited by other articles:
 |
|
 |
|
  I. Z. Ben-Dov, J. D. Kark, D. Ben-Ishay, J. Mekler, L. Ben-Arie, and M. Bursztyn Blunted Heart Rate Dip During Sleep and All-Cause Mortality Arch Intern Med, October 22, 2007; 167(19): 2116 - 2121. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Z. Ben-Dov, J. D. Kark, D. Ben-Ishay, J. Mekler, L. Ben-Arie, and M. Bursztyn Predictors of All-Cause Mortality in Clinical Ambulatory Monitoring: Unique Aspects of Blood Pressure During Sleep Hypertension, June 1, 2007; 49(6): 1235 - 1241. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. O'Brien Ambulatory Blood Pressure Measurement: A Trove of Hidden Gems? Hypertension, September 1, 2006; 48(3): 364 - 365. [Full Text] [PDF]
|
|
|
|
|
|
W. B. White Expanding the Use of Ambulatory Blood Pressure Monitoring for the Diagnosis and Management of Patients With Hypertension Hypertension, January 1, 2006; 47(1): 14 - 15. [Full Text] [PDF]
|
|
|
|
 |
|
 A Grosso, F Veglio, M Porta, F M Grignolo, and T Y Wong Hypertensive retinopathy revisited: some answers, more questions Br J Ophthalmol, December 1, 2005; 89(12): 1646 - 1654. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Z. Ben-Dov, M. Bursztyn, V. Kotsis, S. Stabouli, M. Bouldin, A. Low, S. Toumanidis, and N. Zakopoulos Body Mass Index and Ambulatory Blood Pressure Monitoring Hypertension, July 1, 2005; 46(1): e1 - e2. [Full Text] [PDF]
|
|
|
|
|
|
E. Dolan, A. Stanton, L. Thijs, K. Hinedi, N. Atkins, S. McClory, E. D. Hond, P. McCormack, J. A. Staessen, and E. O'Brien Superiority of Ambulatory Over Clinic Blood Pressure Measurement in Predicting Mortality: The Dublin Outcome Study Hypertension, July 1, 2005; 46(1): 156 - 161. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Verdecchia, G. P. Reboldi, F. Angeli, G. Schillaci, J. E. Schwartz, T. G. Pickering, Y. Imai, T. Ohkubo, and K. Kario Short- and Long-Term Incidence of Stroke in White-Coat Hypertension Hypertension, February 1, 2005; 45(2): 203 - 208. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Stanton, C. Jensen, J. Nussberger, and E. O'Brien Blood Pressure Lowering in Essential Hypertension With an Oral Renin Inhibitor, Aliskiren Hypertension, December 1, 2003; 42(6): 1137 - 1143. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. O'Brien Ambulatory blood pressure monitoring in the management of hypertension Heart, May 1, 2003; 89(5): 571 - 576. [Full Text] [PDF]
|
|
|
|
 |
|
 E. O'Brien, G. Beevers, and G. Y H Lip ABC of hypertension: Blood pressure measurement BMJ, May 5, 2001; 322(7294): 1110 - 1114. [Full Text]
|
|
|
|
|
|
E. O'BRIEN Blood pressure measurement is changing! Heart, January 1, 2001; 85(1): 3 - 5. [Full Text]
|
|
|
|
|
|
E. O'Brien, A. Coats, P. Owens, J. Petrie, P. L Padfield, W. A Littler, M. de Swiet, and F. Mee Use and interpretation of ambulatory blood pressure monitoring: recommendations of the British Hypertension Society BMJ, April 22, 2000; 320(7242): 1128 - 1134. [Full Text]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||