Predictors of normotension on withdrawal of antihypertensive drugs in elderly patients: prospective study in second Australian national blood pressure study cohort
BMJ 2002; 325 doi: https://doi.org/10.1136/bmj.325.7368.815 (Published 12 October 2002) Cite this as: BMJ 2002;325:815
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Dear Sir,
As definitions of hypertension have changed since the mid 90's, a 37%
normotensive patients is probably an overestimation. it would be very
helpful for me as a clinician to know the end-of-trial mean blood
pressure of the "normotensive" group as well as the precentage of patients
with Blood Pressure of less then 140/90 at that point.
thank you
Competing interests:
None declared
Competing interests: No competing interests
Re: The primary Role of Microcirculatoy Bed "CLINICAL" Evaluation in Monitoring Drugs
Withdrawal.
I thank Dr Stagnaro for his comments. While microvascular factors are
important in the pathogenesis of hypertension, in the elderly it is
becoming more evident that it is large vessel compliance that is the
principal factor in this age group. This is suggested in our study by
higher on treatment systolic blood pressure being the most important
predictor of return to hypertension.
Re: Highly selected population
We thank Jacobs for his comments. An analysis of all patients
screened in Victoria over the period during which the substudy in the
second Australian national blood pressure study was conducted revealed
that three quarters of the subjects who completed drug withdrawal
recommenced medication prior to the qualifying period for the substudy and
subsequently only 10% of all subjects who completed drug withdrawal
remained 'normotensive' 54 weeks later. This figure however has to be
interpreted with caution. Eighty-five of the subjects in the published
study were not included in this analysis as they had been screened prior
to the start date of the substudy. Patients were also offered drug
withdrawal as part of the run in phase for second Australian national
blood pressure study, i.e. the investigators wanted them to be
hypertensive off medication so they could enter the study. Therefore
patients were offered withdrawal who would not be offered withdrawal in
normal clinical practice, for example those with known cardiovascular
disease and those who were hypertensive on drug therapy.
Patients were
also not given behavioural interventions that would assist maintenance of
normotension as shown in our systematic review1. The experience of the
initial period of drug withdrawal of the entire second Australian national
blood pressure study screening population is to be published elsewhere2.
1. Nelson MR, Krum H, Reid CM, McNeil JJ. A systematic review of
subject baseline characteristics as predictors of maintenance of
normotension after withdrawal of antihypertensive drugs. Am J Hypertens.
2001;14: 98-105.
2. Nelson MR, Reid CM, Krum H, Ryan P, Wing LMH, McNeil JJ. Short term
predictors of maintenance of normotension post withdrawal of
antihypertensive drugs in the Second Australian National Blood Pressure
Study (ANBP2). Am J Hypertens. In press.
Competing interests:
None declared
Competing interests: No competing interests
Nelson et al present interesting data about the probability of
remaining normotensive after withdrawal of antihypertensive treatment in
their study population. However, their study population is highly
selected, which may limit the generalisability of their results. To be
eligible for entry into their study, patients had to have remained
normotensive for two weeks after withdrawal of medication, so anyone with
a rapid return to hypertension was automatically excluded from their
study.
Do the authors have any data on what proportion of patients who
withdrew from medication were still normotensive at two weeks and
therefore eligible for inclusion in their study? If this is large, their
conclusions are probably reasonable. However, if only a small number of
patients maintain normotension for two weeks, then their conclusion that
'the findings of this study emphasise the value of a trial of withdrawal
of antihypertensive treatment' may not be justified, as the proportion of
patients remaining normotensive at one year in their study may be a
substantial overestimate of the probability of remaining normotensive in
unselected patients.
Competing interests: No competing interests
Sirs,
There is to-day an easy, but really efficacious, clinical method, reliable
and useful to identify elderly patients, who will possibly show
maintenance of normotension after withdrawal of antihypertensive drugs in
general practice. Doctors, however, must know (or learn) a new physical
semeiotics, based on the old auscultatory percussion: biophysical
semeiotics (http://digilander.iol.it/microangiologia and
http://digilander.iol.it/semeioticabiofisica).
We must bear in mind that
microcirculatory bed or, more scientifically speaking, tissue
microvascular unit, an overlooked biological system, represents the
“peripheral heart”, which increases its sphygmic, autonomous and
autocthonus, activity when local blood supply decreases, even in a very
small amount, due to either haematologic (anemia) and/or vascular
(obstruction, increased arteriolar resistance, a.s.o.) causes, and/or
cardiac insufficiency, which act up-wards.
If these disorders, including hypertension, of course, are not promptly
eliminated, such activation of vasomotility (fluctuations of small
arteries and arterioles, according to Hammersen) and vasomotion
(“secondary” oscillations of nutritional capillaries and post-capillaries
venules) is slowly followed by interesting events (e.g., type II,
dissociated microcirculatory activation, beginning with its “variant”) of
paramount importance in causing tissue damage in hypertensive patients,
ending in the dangerous “microcirculatory insufficiency”, and, ultimately,
by failure of local microcirculatory bed, characterized by the so-called
pathological spatial inhomogeneity, according to Schmid-Schoenbein,
accurately illustrated in above-cited sites, from the biophysical-
semeiotic view-point.
As readers can easily understand, microcirculatory activation aims to
maintain physiological blood-flow in related nutritional capillaries and
post-capillary venules, under both physiological and pathological
conditions, and, thus, to supply local parenchyma with appropriate
material-energy-information.
In general, as regards diagnosis as well as prevention, it appears plain
the usefulness of bed-side knowledge of these adaptation microcirculatory
events, never observed untill now clinically, by the data collected with a
simple stethoscope during common physical examination. As clinical and
experimental evidence demonstrates, e.g., in case of partial, symptomless,
and incomplete occlusion of ileo-phemoral artery, even iatrogenetic, i.e.,
provoked by digital pressure upon a healthy artery, downwards cutaneous,
sub-cutaneous, muscular microcirculation is activated, at least in the
first time, according to type I, associated (both vasomotility and
vasomotion are clearly increased). Such events can be observed also in
case of non complete obstruction of whatever vessel, such as carotid
artery, which brings about in related distal tissues (cerebral
convolutions) the greatest increase of cerebral flow-motion (1,2,3,4).
Such methods represent simple predictors of success that are readily
available to general practitioners, also as regards hypertension therapy
withdrawal.
Sergio Stagnaro MD., Member NYAS.
1) Stagnaro S., Valutazione percusso-ascoltatoria della microcircolazione
cerebrale globale e regionale. Atti, XII Congr. Naz. Soc. It. di
Microangiologia e Microcircolazione. 13-15 Ottobre, Salerno, e Acta Medit.
145, 163, 1986.
2) Stagnaro-Neri M., Stagnaro S., Auscultatory Percussion Evaluation of
Arterio-venous Anastomoses Dysfunction in early Arteriosclerosis. Acta
Med. Medit. 5, 141, 1989.
3) Stagnaro-Neri M., Stagnaro S., Modificazioni della viscosità ematica
totale e della riserva funzionale microcircolatoria in individui a rischio
di arteriosclerosi valutate con la percussione ascoltata durante lavoro
muscolare isometrico. Acta Med. Medit. 6, 131-136, 1990.
4) Stagnaro-Neri M., Stagnaro S., Deterministic Chaos, Preconditioning and
Myocardial Oxygenation evaluated clinically with the aid of Biophysical
Semeiotics in the Diagnosis of ischaemic Heart Disease even silent. Acta
Med. Medit. 13, 109, 1997.
5) Stagnaro S., Stagnaro-Neri M., Valutazione percusso-ascoltatoria
degli attacchi ischemici transitori e della insufficienza cerebrovascolare
cronica in pazienti trattati con mesoglicano. Atti, IX Congr. Naz. It.
Patologia Vascolare. Copanello, 6-9 Gennaio 1987. A cura di R. Del
Guercio, G. Leonardo e G. Zanini. Pg. 765, Monduzzi Ed. Bologna, 1987.
Competing interests: No competing interests
Re: End-point Blood Pressures not Published
The end-of-trial blood pressure means for the maintain blood pressure
group was 142.4 mmHg systolic and 78.9 mmHg diastolic. The figures for
the return to hypertension group, most of whom were taking
antihypertensive medication, was 149.7/83.4 mmHg. Thirty-four percent of
the former group had blood pressures below 140/90 mmHg.
Using different hypertension definitions at entry and classification
naturally reduces the success rate. Our systematic review suggests that
the success rate is not affected by the level of blood pressure that
defines hypertension where this is used as an exclusion and classification
criterion (1).
1. Nelson MR, Krum H, Reid CM, McNeil JJ. A systematic review of
subject baseline characteristics as predictors
of maintenance of normotension after withdrawal of antihypertensive drugs.
Am J Hypertens. 2001;14: 98-105.
Competing interests:
None declared
Competing interests: No competing interests