ambulatory blood pressure monitoring for every hypertensive patient: it's about time!

8
THE JOURNAL OF CLINICAL HYPERTENSION VOL. VI NO. XII DECEMBER 2004 708 THE ARGUMENT FOR—Lawrence R. Krakoff, MD, Professor of Medicine, Mount Sinai School of Medicine and Chief of Medicine, Englewood Hospital and Medical Center, Englewood, NJ S ince the end of the 19th century, measure- ment of arterial blood pressure (BP) as a basis for diagnosis and treatment of hypertension (HTN) has, in most clinics, relied on the methods described by Riva-Rocci and Korotkov, namely the stethoscope and mercury column (or equivalent). 1 Yet clinic BPs, even carefully taken, are not repre- sentative of usual or average pressures during ordi- nary activity. Ayman and Goldshine recognized in 1940 that measurements of pressure at home, outside the clinic, might provide a more accurate assessment of patients’ usual BP. 2 Development of new portable technologies for measurement and recording of BP during ordinary activities has been achieved over the past 30 years. These technologies have been used in prospective studies that now establish the superiority of ambu- latory BP monitoring (ABPM), compared to clinic pressures, for predicting risk of cardiovascular (CV) disease. 3–5 The most recent study indicates that a 24-hour average BP <135 mm Hg systolic pres- sure is associated with a very low future risk of CV disease, even when adjusted for higher or lower clinic pressures. 5 ABPM has been shown to guide the diagnosis of refractory HTN 6 and, on occasion, assist in the detection of secondary HTN. ABPM provides average pressures during the entire day (24 hours) and during various distinct periods within the day, wakefulness, sleep, or upon awakening, when there is a rapid increase in pres- sure or “surge.” This latter period has been asso- ciated with greater risk of CV events. Normally, sleep pressures are <10% 3 lower than awake pressures. A less than normal fall in pressure dur- ing sleep has been associated with greater risk of stroke in prospective studies. 4 In a small series of type 1 diabetic participants, a diminished fall in pressure during sleep was prospectively associated with increased risk of diabetic nephropathy. 7 Thus use of ABPM provides valuable diagnostic and prognostic information that can guide manage- ment of HTN and related high-risk conditions, particularly diabetes. These facts alone imply that there is a strong case for making ABPM available to many, if not all, hypertensive patients. Most of those who manage hypertensive patients are primary care providers, cardiologists, and nephrologists. They may not yet be familiar with ABPM. The technology is new, yet little dif- ferent and simpler than such widely used tests as Holter electrocardiographic (ECG) monitoring. For ABPM to be implemented, quality control and appropriate training and supervision of personnel are necessary; however, ABPM is now recognized in the United States by the Center for Medicare and Medicaid Services (CMMS) as a legitimate diagnostic procedure that is reimbursable. The primary indication for ABPM is detection of white coat HTN, i.e., HTN that is isolated to the office or clinic. After nearly 30 years of development, ABPM is no longer just a research activity. Concern about potential costs for ABPM, if included for care of hypertensive patients, has been raised in the past. The CMMS approved limits for charges for ABPM. Actual experience indicates that the total individual charges and reimbursements will be in the range of $55–$95 8 (information provided by Center for Medicare Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It’s About Time! Hypertension Management: Differing Points of View • CME Robert A. Phillips, MD, PhD, Section Editor www.lejacq.com ID: 3941 The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

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Page 1: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

THE JOURNAL OF CLINICAL HYPERTENSION VOL. VI NO. XII DECEMBER 2004708

THE ARGUMENT FOR—Lawrence R. Krakoff, MD, Professor of Medicine, Mount Sinai School of Medicine and Chief of Medicine, Englewood Hospital and Medical Center, Englewood, NJ

Since the end of the 19th century, measure-ment of arterial blood pressure (BP) as a

basis for diagnosis and treatment of hypertension (HTN) has, in most clinics, relied on the methods described by Riva-Rocci and Korotkov, namely the stethoscope and mercury column (or equivalent).1 Yet clinic BPs, even carefully taken, are not repre-sentative of usual or average pressures during ordi-nary activity. Ayman and Goldshine recognized in 1940 that measurements of pressure at home, outside the clinic, might provide a more accurate assessment of patients’ usual BP.2

Development of new portable technologies for measurement and recording of BP during ordinary activities has been achieved over the past 30 years. These technologies have been used in prospective studies that now establish the superiority of ambu-latory BP monitoring (ABPM), compared to clinic pressures, for predicting risk of cardiovascular (CV) disease.3–5 The most recent study indicates that a 24-hour average BP <135 mm Hg systolic pres-sure is associated with a very low future risk of CV disease, even when adjusted for higher or lower clinic pressures.5 ABPM has been shown to guide the diagnosis of refractory HTN6 and, on occasion, assist in the detection of secondary HTN.

ABPM provides average pressures during the entire day (24 hours) and during various distinct periods within the day, wakefulness, sleep, or upon awakening, when there is a rapid increase in pres-

sure or “surge.” This latter period has been asso-ciated with greater risk of CV events. Normally, sleep pressures are <10%3 lower than awake pressures. A less than normal fall in pressure dur-ing sleep has been associated with greater risk of stroke in prospective studies.4 In a small series of type 1 diabetic participants, a diminished fall in pressure during sleep was prospectively associated with increased risk of diabetic nephropathy.7 Thus use of ABPM provides valuable diagnostic and prognostic information that can guide manage-ment of HTN and related high-risk conditions, particularly diabetes. These facts alone imply that there is a strong case for making ABPM available to many, if not all, hypertensive patients.

Most of those who manage hypertensive patients are primary care providers, cardiologists, and nephrologists. They may not yet be familiar with ABPM. The technology is new, yet little dif-ferent and simpler than such widely used tests as Holter electrocardiographic (ECG) monitoring. For ABPM to be implemented, quality control and appropriate training and supervision of personnel are necessary; however, ABPM is now recognized in the United States by the Center for Medicare and Medicaid Services (CMMS) as a legitimate diagnostic procedure that is reimbursable. The primary indication for ABPM is detection of white coat HTN, i.e., HTN that is isolated to the office or clinic. After nearly 30 years of development, ABPM is no longer just a research activity.

Concern about potential costs for ABPM, if included for care of hypertensive patients, has been raised in the past. The CMMS approved limits for charges for ABPM. Actual experience indicates that the total individual charges and reimbursements will be in the range of $55–$958 (information provided by Center for Medicare

Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It’s About Time!

H y p e r t e n s i o n M a n a g e m e n t : D i f f e r i n g P o i n t s o f V i e w • C M ER o b e r t A . P h i l l i p s , M D , P h D , S e c t i o n E d i t o r

www.lejacq.com ID: 3941

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 2: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

VOL. VI NO. XII DECEMBER 2004 THE JOURNAL OF CLINICAL HYPERTENSION 709

& Medicaid Services, www.cms.hhs/physicians.mpfsopp). Isolated clinic or office HTN (ICOH) occurs in 20%–30% of newly-detected hyperten-sives. If ABPM is not used to detect ICOH, these patients will receive unnecessary additional tests and treatment. However, the use of ABPM incurs the costs for testing but results in a smaller frac-tion of patients with HTN outside of the office or usual HTN (UH) who will need drug treatment and additional tests.

Estimating long-term cost-effectiveness for add-ing ABPM to initial assessment of hypertensive patients requires several assumptions. For example, it is not known how many with ICOH will become established hypertensives (i.e., UH) during surveil-lance over many years. We have developed a simple model for calculation of costs of management for HTN, including or excluding ABPM, to detect ICOH that has been updated from an earlier ver-sion.9 This model takes into account current costs for ABPM, estimated costs for annual treatment of HTN, a drop-out rate or “discount” rate for all groups, and two annual conversion rates for those with ICOH to UH. The estimated days of treatment and costs over 5 years for this model are shown in the Table. For the lower conversion rate of 12.5%/yr from ICOH to UH (probably the more realistic estimate),10 use of ABPM and each year after that for those not yet becoming UH, there is a 23% reduction in days of treatment and 16% reduction

(nearly $300,000) in cost of treatment over 5 years for 1000 patients. Given the very low cardiovascu-lar event rates and infrequent cardiovascular organ damage in ICOH, these estimates for cost saving must be taken seriously in planning overall manage-ment for recently detected hypertensive individuals by health care providers.

Apart from the potential cost savings for the detection of ICOH through using ABPM, does this technology have other advantages? Two benefits that are related to quality of life may be linked to 1) lack of need for drug treatment and potential adverse effects for those with ICOH and 2) lack of need to change treatment (add drugs) for those on the treatment with apparent refractory HTN who, by ABPM, have well-controlled BP. Detection of abnor-mal sleep-awake pressures may define those at a higher risk of stroke for whom a change in treatment may be considered. A failure of BP to fall normally during sleep also suggests specific forms of reversible HTN, including the sleep apnea syndrome.11 Thus the likely benefits of ABPM extend far beyond issues of cost alone for many hypertensives.

ABPM requires a new technology for clinics and willingness by patients to accept a test that may briefly intrude on some daily activities. Are there alternatives that disclose similar information with regard to average or usual pressures during ordinary activity outside of the clinic? The measurement of BP at home using recording instruments, over

Figure. Hourly recording of systolic and diastolic pressure (upper panel) and heart rate (HR) (lower panel) by noninvasive 24-hour ambulatory blood pressure (BP) monitoring. Average pressures can be calculated for the entire 24 hours: daytime when the subject is awake, during sleep at night, and during arousal and awakening defined as the morning “surge.”

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 3: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

THE JOURNAL OF CLINICAL HYPERTENSION VOL. VI NO. XII DECEMBER 2004710

several days to weeks, offers promise.12,13 However, home pressure measurement does not include pres-sures during sleep and thus omits information that may have value. Use of recording devices that take multiple measurements in the clinic and calculate short-term average pressures may be helpful for reducing the white coat effect (and potential for measurement error) when compared to a few pres-sures taken by a physician or nurse. Such devices are being evaluated and compared to home pressures and ABPM.14 It is, however, most likely that ABPM will maintain its predominance as the gold standard for diagnosis of HTN until alternative methods have proven their value.

HTN is a disorder of arterial BP that is clearly linked to reversible CV risk. The diagnosis of HTN should be as accurate and precise as modern technology can provide. ABPM has matured from a research exploration to applicable and evidence-supported technology for improved management of HTN in developed countries. ABPM should be made available to many, if not all, of those with HTN for optimal health care.

REFERENCES 1 Postel-Vinay N. Measuring Blood Pressure. In: A Century

of Arterial Hypertension 1896–1996. New York, NY: John Wiley & Sons; 1997:5–30.

2 Ayman D, Goldshine AD. Blood pressure determinations

by patients with essential hypertension: the difference between clinic and home readings before treatment. Am J Med Sci.1940;200:465–470.

3 Perloff D, Sokolow M, Cowan R. The prognostic value of ambulatory blood pressures. JAMA. 1983;249:2792–2798.

4 Verdecchia P, Porcellati C, Schillaci G, et al. Ambulatory blood pressure: an independent predictor of prognosis in essential hypertension. Hypertension. 1994;24:793–801.

5 Clement D, De Buyzere M, De Bacqer DA, et al. Prognostic value of ambulatory blood-pressure recordings in patients with treated hypertension. N Engl J Med. 2003;348:2407–2415.

6 Redon J, Campos C, Rodicio JL, et al. Prognostic value of ambulatory blood pressure monitoring in refractory hyperten-sion: a prospective study. Hypertension. 1998;31:712–718.

7 Lurbe E, Redon J, Kesani A, et al. Increase in nocturnal blood pressure and progression to microalbuminuria in type 1 diabetes. N Engl J Med. 2002;347:797–805.

8 Center for Medicare and Medicaid Services. Available at: www.cms.hhh.gov/physicians/mpfsapp. Accessed November 5, 2004.

9 Krakoff LR, Schechter C, Fahs M, et al. Ambulatory blood pressure monitoring: is it cost-effective? J Hypertens. 1991;9:S28–S30.

10 Vassan RS, Larson MG, Leip E, et al. Assessment of frequen-cy to hypertension in non-hypertensive participants in the Framingham Heart Study. Lancet. 2001;358:1682–1686.

11 Hla KM, Young TB, Bidwell T, et al. Sleep apnea and hypertension. Ann Intern Med. 1994;120:382–388.

12 Jain A, Krakoff LR. Effect of recorded home blood pressure measurements on staging of hypertensive patients. Blood Press Monit. 2002;7:157–161.

13 Bobrie G, Genes N, Vaur L, et al. Is “isolated home” hyperten-sion as opposed to “isolated office” hypertension a sign of greater cardiovascular risk? Arch Intern Med. 2001;161:2205–2211.

14 Myers MG, Valdivieso MA. Use of an automated blood pressure recording device, the BpTRU, to reduce the “white coat effect” in routine practice. Am J Hypertens. 2003;16:494–497.

Table. Estimated Effect of Ambulatory Blood Pressure Monitoring (ABPM) of Cost of Treatment Over 5 Years for 1000 Participants With Recently-Discovered Hypertension (HTN)

DAYS OF TREATMENT COST OF TREATMENT (US$) SAVINGS (%)No ABPM 4524 1,900,240 —ABPM, 25% new HTN each year of follow-up 3673 1,672,641 12ABPM, 12.5% new HTN each year of follow-up 3505 1,602405 16Estimates used to make the calculations shown in this table are: prevalence of initial office/clinic hypertension (IOCH) to usual hypertension (UH)=30%; cost for ABPM=$75; cost for 1 year of treatment=$420; annual loss rate of participants=5%; and annual conversion rate from IOCH to UH, 12.5% or 25%.

THE ARGUMENT AGAINST—William B. White, MD, Professor and Chief, Section of Hypertension & Clinical Pharmacology, Pat and Jim Calhoun Cardiology Center, University of Connecticut School of Medicine, Farmington, CT

Given the considerable consensus in the scien-tific literature and clinical community and the

guidance thereof, hypertension (HTN) diagnosed by ambulatory blood pressure (BP) recordings has been recently considered as a superior tool to clinical mea-surements in clinical trials of antihypertensive drugs

as well as for the assessment of hypertensive patients in clinical practice.1 While numerous studies have demonstrated that ambulatory BP is the best means to identify patients with suspected white coat HTN, the method is not necessarily required for the evalua-tion of every general hypertensive patient.

Methods of clinical BP measurement improve precision and reduce the need for ambulatory BP monitoring in many patients

Poor Measurement TechniqueOne of the pitfalls in BP measurement in the clinic is a lack of attention to important details. Small

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 4: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

VOL. VI NO. XII DECEMBER 2004 THE JOURNAL OF CLINICAL HYPERTENSION 711

modifications in measuring technique could lead to a substantial improvement in precision. For example, it is imperative that the BP be measured in a supported arm at the level of the heart to avoid the effects of isometric exercise (from the patient) and hydrostatic pressure (from improper arm posi-tion) on the arterial pressure.2 Additionally, neither the patient nor the observer should be talking or moving during the actual measurement as it will raise the BP and could give the impression of an elevated BP in a patient who is otherwise nor-motensive or well-controlled on antihypertensive therapy. The patient should be seated comfortably with both feet on the floor. The area of the upper arm where the cuff and bladder are placed should not be clothed, nor should it have a tight band of material from a shirt or blouse obstructing venous flow. Attention to these simple details will result in a more accurate BP in the medical environment.

Terminal Digit BiasAnother concern for accurate office BP measure-ment is terminal digit bias. Numerous studies have shown that clinical observers will conveniently round off both the systolic and diastolic BP to zero rather than use 2, 4, 6, or 8 mm Hg as the terminal

digit. This phenomenon of “zero bias” may occur in as many as 70%–90% of BP readings in the office setting and is due to a lack of attention and forgetfulness on the part of the observer. In a recent retrospective evaluation in our own HTN practice,3 terminal digit preference favored 0, 2, and 8 mm Hg, but there was only a 30% incidence of zero digit bias (Figure 1). Nevertheless, the terminal digit was not randomly distributed, so even HTN special-ists can improve in their technique!

DATA SUPPORTING THE USEFULNESS OF AMBULATORY BP MONITORING IN CERTAIN PATIENTSAmbulatory BP values have been shown to pro-vide reasonably accurate information regarding a patient’s risk of cardiovascular (CV) events as compared with office BP measurements alone. None of these studies, however, has been able to demonstrate at precisely what values events are negligible or clinically acceptable. In the instance of evaluating cardiac target organ disease, Grandi et al.4 showed that left ventricular mass index could be mildly elevated in patients with white coat HTN even when the 24-hour BP was quite normotensive (Table). Admittedly, the findings in this particular study are contrary to numerous cross-sectional trials published in the past, but they do give the clinician concern about the robustness and validity of analyses that evaluate patients at just one point in time.

Prospective Outcome StudiesThe most well-designed studies in this field are from Verdecchia et al.,5–8 which are, in general, used as the basis for most of the guidelines and/or recommendations by specialty societies. While these studies have substantial value, none of them had randomization of patients to a group in whom management or treatment decisions were made based on ambulatory BP as compared with clinical BP. Verdecchia et al. have shown in a prospective

Table. Left Ventricular Changes in Isolated Office Hypertension (HTN)

PARAMETER NORMOTENSIVES ISOLATED OFFICE HTNSUSTAINED

HYPERTENSIVES P VALUEClinic BP (mm Hg) 124/73±5/7 154/93±16/14 153/92±15/12 <0.00124-hour BP (mm Hg) 119/71±6/6 120/70±5/5 144/92±13/8 <0.001Septal wall thickness (mm) 8.2±1.5 9.1±1.7 10±2.1 <0.001Posterior wall thickness (mm) 7.8±1.6 8.8±1.5 9.8±1.9 <0.001LVMI (g/m2) 85±24 103±35 124±41 <0.001Age (yr) 42±6 42±7 42±7 0.99BP=blood pressure; LVMI=left ventricular mass index

0

20

40

60

0 2 4 6 8 Other

Last digit of blood pressure reading

Per

cent

of

read

ings

(%

)

Systolic

DiastolicN=Physician readings in 103 patients

Figure 1. Terminal digit bias in a hypertension faculty practice based on results from 103 patients. Adapted from J Hum Hypertens. 2003;17:819–822.3

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 5: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

THE JOURNAL OF CLINICAL HYPERTENSION VOL. VI NO. XII DECEMBER 2004712

cohort study design that men with BP <136/87 and women with BP <131/86 on ambulatory BP moni-toring did not have increased CV risk, as compared with patients with normal office BPs.5 The follow-up period in this study, however, was <5 years. Fagard et al.6 studied 353 subjects in a random-ized, double-blind, placebo-controlled trial in which he demonstrated that subjects with non-sustained HTN were at a lower risk of a poor outcome than subjects with sustained HTN, but a greater risk than normotensive individuals. The study was too small

to determine at which level of BP one could safely avoid antihypertensive therapy.

The Office vs. Ambulatory study (OvA)8 was a prospective cohort study in ≈2000 treated hyper-tensive patients that was initiated in 1988 and completed in 2002. The purpose of this study was to evaluate whether CV events were more likely to be predicted by the 24-hour BP as compared with the clinic BP. Physicians treating the patients were not guided by the results of the ambulatory BP values. As is shown in Figure 2, the ambula-tory BP was a superior predictor of CV outcomes when compared with the office (or clinic) BP. Nevertheless, as the level of the clinic BP increases, it is noteworthy that the event rates increase even when the 24-hour BP is <135/85 mm Hg, which suggests that this value is probably too high and that the goal of therapy should be significantly lower, especially in patients with underlying CV morbidities or diabetes mellitus.

Certainly if a patient has a 24-hour ambulatory BP >135/85, he/she is likely to be at increased risk and should be treated with antihypertensive therapy. Little is known, however, about ambulatory BP val-ues between 125–135/75–85 mm Hg. Thus treatment may still be needed (Figure 3), and the ambulatory

OvA OvA TrialTrial

0

5

10

15

20

25

<140 140–159 >160

24-h ambulatorySBP <135 mm Hg24-h ambulatory

SBP ≥135 mm Hg

..

Office systolic blood pressure (mm Hg)

Eve

nts

per

100

0 p

erso

n-y

ears

Figure 2. Incidence of cardiovascular events based on office and ambulatory systolic blood pressures (SBPs) in the Office vs. Ambulatory (OvA) trial. Adapted from N Engl J Med. 2003;384:2407–2415.8

Office blood pressure> 140/90 mm Hg in low-risk patients (no target organ disease)

> 130/80 mm Hg in high-risk patients (target organ disease, diabetes)

Self-monitored BP <130/80 mm Hg Self-monitored BP >130/80 mm Hg

Perform ambulatory BP monitoring

24-h BP <130/80 mm Hg24-h BP <130/80 mm Hg 24-h BP >130/80 mm Hg

Follow-up with non-drug therapyon a 6–12 mo basis

Repeat ambulatory BP measurementEvery 1–2 yr

Initiate antihypertensive therapy

24-h BP <130/80 mm Hg 24-h BP >130/80 mm Hg

Maintain present therapyFollow-up with ABP

every 2 yr

Change antihypertensive therapy to improve control

Follow-up with ABP every 2 yr

Treated

ABPM not neededABPM not needed

Figure 3. Use of ambulatory blood pressure (ABP) in hypertension management. Algorithm for use of ABP in clinical practice by the author. BP=blood pressure; ABPM=ambulatory blood pressure monitoring. Adapted from N Engl J Med. 2003;348:2377–2378.1

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 6: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

VOL. VI NO. XII DECEMBER 2004 THE JOURNAL OF CLINICAL HYPERTENSION 713

BP values have not reduced the likelihood of drug therapy but have increased the cost of care.

Thus, while ambulatory BP monitoring will provide more information about a patient’s BP behavior in a variety of situations, CV risk in many patient populations, such as individuals with type 2 diabetes mellitus, kidney disease coronary heart disease, and cerebrovascular disease, have not been determined based on ambulatory BP vs. other forms of BP measurement.

INSURANCE COVERAGE OF AMBULATORY BP MONITORINGUnfortunately, coverage of ambulatory BP monitoring in clinical practice is relatively sparse by the various insurance programs in the United States. Medicare has been covering the study since April of 2002 for beneficiaries who have a suspected diagnosis of white coat HTN.9 A national coverage decision on other indications is not available at this time and prob-ably will not be until more data become available as to how ambulatory BP monitoring affects patient management. The one situation that should be cov-ered is for evaluation of the high-risk patient whose office BP is variable despite complex antihypertensive therapy. These patients require tight BP control; the ambulatory BP recording is helpful in making the diagnosis of uncontrolled HTN, especially toward the end of a drug’s dosing period.

WHO NEEDS AN AMBULATORY BP MONITORING STUDY AND WHO DOES NOT?Since the 24-hour BP measurement does give an enhanced prediction of CV risk for some patients, ambulatory BP monitoring clearly has a role in the diagnosis of patients with: 1) white coat HTN in the untreated state; 2) patients with marked variability in the BP in both the office and home setting, making diagnosis extremely difficult; and

3) selected, treated patients with significant comor-bidities who would be at great risk if the true BP was not optimal. In contrast, newly-diagnosed patients with severe HTN, especially those with overt target organ involvement, diabetes, and coro-nary or cerebrovascular events, need antihyperten-sive drug therapy, which should not be delayed. Patients who have had prior ambulatory BP studies in which the office or self-monitored BP values are similar to the daytime BP values can be followed by the more simple and less expensive office-based measurement. Finally, we do not believe that patients whose office and home BPs are elevated to a similar level require ambulatory BP recordings since it is likely that the 24-hour BP is abnormally high as well.

REFERENCES 1 White WB. Ambulatory blood pressure monitoring in clini-

cal practice. N Engl J Med. 2003;348:2377–2378. 2 White WB. Effect of arm position on blood pressure mea-

surement. JAMA. 1987;258:1962–1963. ] 3 Thavarajah S, Mansoor GA, White WB. Terminal digit

bias in a specialty hypertension faculty practice. J Hum Hypertens. 2003;17:819–822.

4 Grandi AM, Broggi R, Colombo S, et al. Left ventricular changes in isolated office hypertension: a blood pressure-matched comparison with normotension and sustained hypertension. Arch Intern Med. 2001;161:2677–2681.

5 Verdecchia P, Porcellati C, Schillaci G, et al. Ambulatory blood pressure. An independent predictor of prognosis in essential hypertension. Hypertension. 1994;24:793–801.

6 Fagard RH, Staessen JA, Thijs L, et al. Response to anti-hypertensive therapy in older patients with sustained and nonsustained systolic hypertension. Systolic Hypertension in Europe (Syst-Eur) Trial Investigators. Circulation. 2000;102:1139–1144.

7 Ohkubo T, Hozawa A, Nagai K, et al. Prediction of stroke by ambulatory blood pressure monitoring versus screening blood pressure measurements in a general population: the Ohasama study. J Hypertens. 2000;18:847–854.

8 Clement DL, De Buyzere ML, De Bacquer DA, et al. Prognostic value of ambulatory blood-pressure record-ings in patients with treated hypertension. N Engl J Med. 2003;348:2407–2415.

9 CMS Decision Memo. HCFA.gov/coverage.8b3.htm. cms.gov/manual/pm_ABO2018.pdf. Accessed November 11, 2004.

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 7: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

THE JOURNAL OF CLINICAL HYPERTENSION VOL. VI NO. XII DECEMBER 2004714

1. A 45-year-old woman has a clinical blood pressure (BP) of 145/85 mm Hg on several occasions. Her average 24-hour ambulatory BP is 125/80 mm Hg. The daytime average is 130/83 mm Hg, and the nighttime average is 115/75 mm Hg. Which of the following statements is most accurate?A __ Her future risk of cardiovascular disease is best

related to the clinical pressure.B ___Her future risk of future cardiovascular disease is

best related to her 24-hour ambulatory pressure.C __ Her future risk of cardiovascular disease is

unrelated to her nighttime pressure.D __ Her future risk of cardiovascular disease is

unrelated to her daytime pressure.

2. The percentage of office readings that demonstrate terminal digit “zero bias,”i.e., rounding off both the systolic and diastolic BP to zero rather than using 2, 4, 6, or 8 mm Hg as the terminal digit, has been found to be as high as:A __ 10%B __ 50%C __ 70%–90%D __ 100%

3. A 55-year-old man has a clinic pressure of 135/85 mm Hg (average of two visits). His personal his-tory includes a recent change to a very demanding job and his supervisor constantly asking for greater productivity. The results of a 24-hour ambulatory BP recording on a work day are: 24-hour average 140/90 mm Hg, daytime (awake) 150/92 mm Hg, nighttime (asleep) 125/80 mm Hg. After awakening, his morning pressure is 155/95 mm Hg. The most accurate diagnosis is:

A __ White coat hypertensionB __ PrehypertensionC __ Stage 1 hypertensionD __ Masked hypertension

4. A 60-year-old woman has been treated for hyperten-sion with hydrochlorothiazide 12.5 mg, amlodipine 5 mg, and quinapril 20 mg for several months. Her pretreatment pressure in clinic was 155/95 mm Hg and had not changed despite the addition of medi-cations to her present regimen. Her serum glucose, creatinine, and electrolytes are normal. The physical examination is unremarkable. Which of the follow-ing diagnostic tests are likely to be most helpful for her management?A __ Renin-aldosterone profileB __ 24-hour ambulatory BPC __ 24-hour creatinine clearanceD __ Workup for pheochromocytoma and Cushing’s

syndrome

5. An insulin-dependent, diabetic, 30-year-old man has no complications of diabetes. A 24-hour ambulatory BP recording is made with the following results: 24-hour average 132/83 mm Hg, daytime (awake) 131/81 mm Hg, nighttime (asleep) 133/84 mm Hg. Based on these findings, which of the following statements is the most accurate?A __ The results predict a greater likelihood of dia-

betic neuropathyB __ The results predict a greater likelihood of dia-

betic retinopathyC __ The results predict a greater likelihood of dia-

betic microvascular coronary diseaseD __ The results predict a greater likelihood of dia-

betic nephropathy

Please Select the One Best Answer for Each Question and Place Your Selection on the Answer Grid.

CME QuestionsRobert A. Phillips, MD, PhD, Section Editor, Chairman, Department of Medicine, Lenox Hill Hospital, Professor of Medicine, NYU School of Medicine, New York, NY

INSTRUCTIONS FOR COMPLETING THIS FORM: Read the selected paper and answer all the questions that follow. After each question there is a series of possibly correct answers. Please select the one best answer for each and place your selection on the answer grid. YOU MUST ALSO COMPLETE THE CME EVALUATION SECTION and return the form within 6 months of the paper’s publication to receive credit. Letters of credit will be mailed to participants biannually.

ACCREDITATION STATEMENT: Lenox Hill Hospital (LHH) is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing medical education for physicians. LHH designates this Continuing Medical Education activity for a maximum of (1) credit hour in Category 1 credit towards the AMA Physicians’ Recognition Award. Each physician should claim only those hours of credit that he/she actually spent in the educational activity. LHH relies upon faculty participants in its CME programs to provide educational information that is objective and as free of bias as possible. In this spirit, and in accordance with the guidelines of the program sponsor, faculty participants are expected to indicate any commercial relationship that might be perceived as a real or apparent conflict of interest. The release date for this activity is December 2004.

OBJECTIVE AND TARGET AUDIENCE: All primary care physicians and cardiologists are eligible to receive credit. At the conclusion of this activity, participants should be able to: 1) summarize the important points discussed in the paper reviewed; 2) identify patients to whom the paper is relevant; 3) modify management practices as new information is learned; and 4) identify deficiencies in their knowledge

EDUCATIONAL GRANT: This Continuing Medical Education Activity is supported through an educational grant received from Pfizer.

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.

Page 8: Ambulatory Blood Pressure Monitoring for Every Hypertensive Patient: It's About Time!

VOL. VI NO. XII DECEMBER 2004 THE JOURNAL OF CLINICAL HYPERTENSION 715

Answer the questions from the previous page by selecting the best choice of A, B, C, or D.

Questions: 1.__ 2.__ 3.__ 4.__ 5.__

Agree Disagree

1. My knowledge was enhanced by this activity. 1.__ 2.__ 3.__ 4.__ 5.__

2. The activity helped to clarify issues specific to hypertensive patients. 1.__ 2.__ 3.__ 4.__ 5.__

3. The information obtained from this exercise will have an impact on my care of patients. 1.__ 2.__ 3.__ 4.__ 5.__

4. The format of the exercise was useful. 1.__ 2.__ 3.__ 4.__ 5.__

5. Suggestions for future topics:

CME Answer Grid

CME Evaluation

Please print all information. Please submit a $5 administrative fee in the form of a check

made out to Lenox Hill Hospital-CME.

SEND TO:Office of Medical AffairsLenox Hill Hospital100 East 77th StreetNew York, NY 10021

Re: Krakoff LR, White WB. Ambulatory blood pressure monitoring for every hypertensive patient: it’s about time! J Clin Hypertens (Greenwich). 2004;6:708–715.

Name: ___________________________________________________________________________

Address: _________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

Social Security Number: ___________________________________________________________

Where To Send The Completed CME Form

The Journal of Clinical Hypertension (ISSN 1524-6175) is published monthly by Le Jacq Communications, Inc., Three Parklands Drive, Darien, CT 06820-3652. Copyright ©2004 by Le Jacq Communications, Inc., All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Sarah Howell at [email protected] or 203.656.1711 x106.