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The top number in a blood pressure
reading is the best way to determine a man's heart attack and stroke risk,
and should be used to guide treatment. But many doctors continue to treat
patients based on the lower number, and the study authors believe this
practice should change.
The top number measures systolic
blood pressure, the force on blood vessel walls during a heart beat. The
bottom, or diastolic, number gauges pressure when the heart is at rest
between beats. High blood pressure is defined as a systolic reading of
140 millimeters of mercury (mm Hg) or greater or a diastolic reading of
90 mm Hg or above.
The diastolic number has conventionally
been viewed as a more sensitive indicator of hypertension, and is the
reading that commonly influences clinical decision-making regarding degree
of disease present and what therapeutic steps should be taken.
In the current study researchers
found that patients with uncontrolled systolic blood pressure were almost
2.5 times more likely to die
of heart disease than patients with controlled blood
pressure.
But risk of death from cardiovascular
disease was not associated with diastolic blood pressure.
The study also revealed that
85.5% of men being treated for high blood pressure had uncontrolled systolic
or diastolic blood pressure, or both. These patients had a 66% greater
risk of death associated with heart disease than those men with controlled
blood pressure.
This
clearly confirms that, as measured in a clinical setting, a controlled
blood pressure, especially systolic blood pressure, is uncommon.
Nevertheless, the authors emphasize
that treating systolic blood pressure is of greater value than treating
diastolic blood pressure since it has been shown to be a better predictor
of death from heart disease.
The results show that in clinical
practice a well-controlled systolic blood pressure (less than 140 mm Hg)
should be the goal of antihypertensive treatment.
As advised in the recent recommendations
of the National High Blood Pressure Education program, it is crucial for
healthcare providers to focus on systolic blood pressure for diagnosis,
staging and therapeutic strategy in hypertension, particularly in the
elderly.
Archives
of Internal Medicine March 11, 2002;162:506-508, 577-581
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