2 of 3 [Part 1,
Treating Numbers Instead of a Person
Authoritative advice for treating blood pressure has changed dramatically
over the years. Forty years ago, the chapter on hypertension in
Harrison's Textbook of Medicine stated:
"Whatever the form of therapy selected, it must not be forgotten
that the physician who treats hypertension is treating the patient
as a whole, rather than the separate manifestations of a disease.
The first principle of the therapy of
hypertension is the knowledge of when to treat and when not to
treat... A woman who has tolerated her diastolic pressure
of 120 for 10 years without symptoms or deterioration does not
need immediate treatment for hypertension. Marked elevation of
systolic pressure, with little or no rise in diastolic, does not
constitute an indication for depressor therapy. This is particularly
true in the elderly or arteriosclerotic patient, even though the
diastolic pressure may also be moderately elevated."
Today, that would be grounds for malpractice. The chapter, which
was written by John Merrill, a leading authority on hypertension
from Harvard, goes on to emphasize that:
"The physician must constantly weigh the value of making
his patient 'blood pressure conscious' by a specific regimen and
regular follow-up, against real need for any particular form of
therapy. Above all, in treatment or prognostication,
he must avoid engendering in the patient a fear of the disease
which may be unwarranted in our present state of knowledge."
Contrast this with the current cookie cutter approach of treating
numbers that are often meaningless instead of people. There is absolutely
nothing new about prehypertension, which was previously referred
to as "high normal" at levels higher than 120/80. This
would still be a preferable description since nobody knows whether
these individuals will go on to develop sustained hypertension or
are at any significantly increased risk for its complications.
All these new guidelines essentially accomplish
are to convert 45 million healthy Americans into new patients by
creating fear. This is precisely what the experts emphasized
we should take pains never to do! How could so many doctors have
been so wrong for so many years?
Whatever happened to the Hippocratic dictum
Primum non nocere (First of all, do no harm)? It used
to be the primary concern of all doctors but seems to have now been
sidelined or forgotten in the frenetic and impersonal pace of modern
medical practice. The recommendations in this new Seventh Report
of the Joint National Committee on Prevention, Detection, Evaluation,
and Treatment of High Blood Pressure (JNC 7) are not very different
from the first JNC report. This was published on 1977 following
several studies showing that blood pressure could be lowered with
thiazide diuretics. Subsequent JNC reports repeatedly recommended
the use of diuretics as initial treatment based on additional reports
demonstrating their efficacy.
Despite this, the use of diuretics actually declined over the next
decade or so, possibly because many went off patent and were no
longer profitable. In addition, newer drugs were being vigorously
promoted and the 1993 JNC 5 guidelines added angiotensin-converting
enzyme (ACE) inhibitors and beta blockers as first-line therapy.
Their sponsors argued that these more expensive drugs might be preferable
since thiazide therapy could be associated with diabetes and abnormal
heart rhythms, especially at higher doses. These medications had
other side effects but it was claimed that they were more likely
to reduce complications such as heart attacks and stroke.
However, many were not as effective even at higher doses or when
combined with other new anithypertensives. Specialists soon found
that half of such patients with pressures greater than 160/100 on
two or more of these drugs improved rapidly when diuretics were
added or their dosage was increased. ACE inhibitors and beta blockers
were removed in JNC 6 and the new guidelines are about the same
as those proposed over 25 years ago, save for this new and confusing
diagnosis of prehypertension.
However, diuretics are not the most effective or safest treatment
for all hypertensives and other drugs are clearly superior for certain
patients. What is wrong is that physicians
are treating a reading on a blood pressure machine in a cookbook
fashion rather than the patient or the cause of the problem.
What Causes Hypertension?
Blood pressure (BP) is essentially determined by cardiac output
(CO) or the force with which blood is pumped out of the left ventricle
and the degree of systemic vascular resistance (SVR) that is encountered.
This is much like Ohm's law governing the strength of an electrical
current, so that BP=COxSVR. Hypertension can be caused by increased
cardiac output, increased vascular resistance or both. Although
the cause of essential or primary hypertension in a patient may
not be known it is safe to say that it is mediated by one or both
of these two mechanisms.
Prior to these new guidelines, 120/80 was considered to be optimal
and 120-129/80-84 was within the normal range. High normal was 130-139/85-89
and Stage 1 or mild hypertension was 140-159/90-99. Stage 2 (160-179/100-109),
Stage 3 (179-209/100-110) and Stage 4 (>210/>120) reflected
increasing degrees of severity.
What should you do if one number is high
and the other is normal or low? Which is more important, the systolic
(upper) or diastolic (lower) measurement? The previous
emphasis on diastolic pressure was based on early studies on young
people. Diastolic pressure, which is the pressure when your heart
relaxes between beats, rises until around age 55 and then starts
to decline. Systolic pressure is the pressure when your heart beats
and it increases steadily with age.
A systolic pressure above 140 with a diastolic pressure below 90
is referred to as isolated systolic hypertension. It is common in
older individuals due to hardening of the arteries and slight elevations
were not considered serious. Studies now show that an elevated systolic
pressure is an independent risk factor for complications that is
far greater than the risk associated with a high diastolic pressure
in older patients with hypertension.
Most patients with hypertension have no symptoms and blood pressure
elevations are often discovered during a routine physical examination
or if measurements are obtained in connection with application for
life insurance, employment or blood donation rather than any complaint
due to its presence.
It is important to reemphasize that blood pressures are very variable
and that emotional stress and numerous other factors such as smoking,
coffee, over the counter drugs containing caffeine or decongestants,
a cold room, full bladder, improper cuff size, etc. can all give
false high readings. Measurements should be taken with the arm supported
at the level of the heart and not until the patient has been sitting
for at least five minutes. If an elevation is found, the blood pressure
should be taken after five minutes in the supine position and then
immediately on standing and two minutes later to rule out postural
At least two readings should be made at
each visit separated by as much time as possible. Three sets of
readings at least one week apart are advised before prescribing
drugs that may have to be taken perpetually. Measurements
should be made in both arms and the higher one selected to monitor.
Every effort should be made to rule out known causes of hypertension,
such as coarctation of the aorta, sleep apnea, obesity, pregnancy,
oral contraceptives and other medications.
Narrowing of the renal artery and kidney disease can cause the
release of renin, a powerful hormone that can increase sodium retention
and vascular resistance. Up to 10 percent of hypertension may be
due to endocrine disorders. Primary aldosteronism and Cushing's
disease can result in an increase of adrenal cortical hormones that
also cause sodium retention. Pheochromocytoma is a tumor of the
adrenal medulla that secretes excess amounts of catecholamines like
noradrenalin and adrenaline that can increase peripheral resistance
as well as cardiac output.
Blood tests can identify these endocrine abnormalities and levels
of chemicals like renin and angiotensin that might determine the
cause of hypertension or provide a clue as to the best treatment.
High renin hypertension is thought to be associated with higher
rates of complications and might respond better to angiotensin converting
enzyme (ACE) inhibitors than diuretics. However, busy doctors don't
have time to go through all the above. It's much easier to prescribe
a drug and hope it works. If not, there are plenty of others to
Read the remainder
of this article in the next newsletter issue.