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Cardiovascular Risk
Ambulatory Blood Pressure Measurement Should Be a
Routine Investigation in Patients with Renal Disease
a report by
Eoin O’Brien
Professor of Molecular Pharmacology, Conway Institute of Biomolecular and Biomedical Research, University College Dublin
What criteria must be fulfilled in order to make a technique made at each visit”. In addition, “there should be at least two blood
indispensable to clinical practice and the rule rather than the exception? pressure measurements taken outside the office, which are
It seems that ambulatory blood pressure measurement (ABPM) is in <140/90mmHg” and “there should be no evidence of end-organ
much the same historical position at the start of the 21st century as damage”.
6
Some believe these stipulations for reimbursement are too
conventional measurement with the mercury sphygmomanometer and restrictive and limit the wider use of ABPM. The CMS decision to permit
stethoscope was at the end of the 19th. At the time, sceptics expressed ABPM in suspected white coat hypertension ignores the fact that there are
doubt that the sphygmomanometer would ever be accepted by no clinical characteristics that lead the practising physician to suspect the
‘overworked, underpaid general practitioners’.
1
condition. A number of studies suggest that in untreated subjects with
essential hypertension, the probability of white coat hypertension increases
ABPM is not new to medicine; in fact, it has been with us in one form or in non-smoking female subjects with mild hypertension of recent origin
another for nearly half a century. In 1964, Sir George Pickering who have had a limited number of office blood pressure measurements
demonstrated for the first time the profound fall in blood pressure during
sleep and the fluctuations in pressure during the course of a 24-hour
period. Pickering’s group went on to develop an ambulatory technique
During the last decade the information
whereby pressure could be measured directly from the brachial artery with
that can be derived from ambulatory
a small plastic catheter. The first intra-arterial ABPM in unrestricted man
blood pressure measurement has
was performed in 1966. In 1962, Hinman and colleagues first described
the truly portable ambulatory system for non-invasive measurement of surprised even the most ardent
blood pressure. This was subsequently developed commercially by the
supporters of the technique.
Remler Company in California. So began non-invasive measurement of
ambulatory blood pressure.
2
We first used ABPM in 1979 when we
anticipated that “development of a cheap and accurate means of and who have small left ventricular masses.
6
However, these predictive
ambulatory recording would have a considerable impact on the diagnosis factors are vague and of little help to the physician. Another important
of borderline hypertension and the assessment of the efficacy of stipulation in the CMS directive is that potential ABPM patients should have
treatment”.
3
This forecast has been slow to materialise, but the evidence no evidence of target organ damage. However, the means whereby a
that ABPM is indispensable to clinical practice has been growing steadily. practising physician is to determine the target organ status of a patient are
During the last decade the information that can be derived from ABPM not stipulated. Should all patients being considered for ABPM undergo an
has surprised even the most ardent supporters of the technique.
4,5
echocardiograph or some other measure of target-organ involvement?
Indeed, four years on from the CMS directive, it is difficult not to reiterate
In clinical practice, the most common use of ABPM – and the only one for with greater conviction (because of stronger evidence) the conclusion from
which reimbursement is approved by the Centers for Medicare & Medicaid the European Society of Hypertension (ESH) statement on when to suspect
Services (CMS) in the US – is to identify patients with suspected white coat white coat hypertension: “In truth, it must be admitted that it is difficult to
hypertension. This is defined as “office blood pressure >140/90mm/hg on escape the conclusion that all patients in whom a diagnosis of hypertension
at least three separate clinic/office visits with two separate measurements is being contemplated based on office/clinic blood pressure, should have
ABPM to exclude white coat hypertension…”.
6
Eoin O’Brien is a Professor of Molecular Pharmacology at
the Conway Institute of Biomolecular and Biomedical
Continuing on the diagnostic front, ABPM can identify patients with
Research, University College Dublin. He is President of the masked hypertension (estimated to be present in as many as 10 million
Irish Heart Foundation (IHF) and Director of Clinical
people in the US) in whom conventionally measured blood pressure in
Hypertension Research at the Blood Pressure Unit at
St Michael’s Hospital, Dublin. Dr O’Brien has published
the clinic setting is normal but using ABPM is increased.
7
ABPM cannot
over 600 scientific papers on hypertension research,
be performed in everyone and there is a strong case for performing it in
especially in the areas of blood pressure measurement,
ambulatory monitoring and the management of
patients who have had a cardiovascular event. The consequence of not
hypertension in the elderly. He serves in an administrative capacity with a number of prescribing antihypertensive medication to a patient with, for example,
national and international bodies concerned with the global management of
a history of a previous stroke is to deny that patient the most potent
cardiovascular disease, being Co-Chair of the World Health Organization (WHO)
Committee on Blood Pressure Measurement in Low Resource Settings.
medication to prevent stroke recurring. It is a salutary thought that if
white coat hypertension is present in 20% of the population when
E: eobrien@iol.ie
blood pressure is measured conventionally in primary care, and if
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