Low, Low Blood Pressure Heals Heart
Blood pressure
experts say new research suggests doctors need to target lower goals for
blood pressure to reverse heart damage caused by hypertension.
The lower-is-better
approach to blood pressure treatment has been bandied about by physicians
for years but recently several studies have provided evidence that only
aggressive approaches to blood pressure lowering are really effective.
One such study,
from a team of Japanese researchers, reinforces this growing sentiment,
said Ernesto Schiffrin, who served as program chair at the recent American
Heart Association's 56th Annual Conference on High Blood Pressure Research.
Atsuhiro Ichihara,
of Keio University School of Medicine in Tokyo, said his study of 142 patients
with high blood pressure or hypertension has convinced him the target for
blood pressure treatment should be a pressure of less than 130/85 milligrams
of mercury. Most physicians attempt to get blood pressure below 140/90
mmHg, the level designated as high blood pressure by the AHA and the National
Heart Lung and Blood Institute.
Ichihara's
study attempted to find out if lowering blood pressure could reverse or
ease one of its dangerous effects -- stiffening of the arteries. He measured
an indicator of arterial stiffness called pulse wave velocity or PWV. This
measures, in centimeters per second, how fast blood rushes between the
brachial artery in the arm and the tibial artery in the ankle.
As the PWV
increases, arteries stiffen. When the blood slows, the walls relax.
He randomized
half of 142 high blood pressure patients to a group in which the goal was
a pressure below 130/85 and the other half to a group with the standard
treatment goal of blood pressure less than 140/90.
After 12 months,
patients who had the lower blood pressure goal had an average PWV decline
from 1,779 cm/sec to 1,621 cm/sec.
"Healthy people
with normal blood pressure have PWV in the 1,600 cm/sec range," Ichihara
said. But patients in the normal treatment group had no difference in PWV.
These patients, however, also had achieved very healthy blood pressures
averaging 129/78 mmHg.
While physicians
are moving toward general agreement about the need for aggressive lowering
of blood pressure in people with hypertension, it is not so clear if they
think healthy people need to take a few points off their blood pressure
readings.
Schiffrin said
he thinks it may be two different situations. People with a history of
high blood pressure have "already damaged their blood vessels, so normal
may be different for these people."
He said to
"get back what one has damaged, it may require some extra help" such as
really low blood pressure.
Schiffrin also
said he believes the medical community is moving toward resetting blood
pressure goals and he expects those changes to become official by late
next year.
Blood pressure
recommendations are made by a quasi-governmental body called the Joint
National Committee on Prevention, Detection, Evaluation, and Treatment
of High Blood Pressure or JNC. It has reworked the blood pressure guidelines
six times in the past 20 years, each time redefining normal blood pressure
by lowering the recommended blood pressure.
Schiffrin said
the JNC is expected to huddle early in 2003 to begin considering new recommendations,
which he predicted would be issued by late next year. Before the JNC makes
it recommendations, however, another group of blood pressure researchers
will announce results of the largest blood pressure study to date -- a
study most researchers think will not only provide a definite answer to
the "how low should we go" question but also will name the type of drug
effective at getting patients to that goal.
The massive
study -- which is called the Antihypertensive and Lipid-Lowering Treatment
to Prevent Heart Attack Trial or ALLHAT -- enrolled more than 42,000 patients.
Results of the study are expected in December.
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Copyright 2002 by United
Press International.
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