Lower than normal blood pressure appears
to raise the risk of death in patients with heart failure,
according to a report in the American Heart Journal.
Previous studies have yielded different results regarding
the effect of low blood pressure on mortality in the general
population. Until now, however, no study had investigated
this association in patients with heart failure.
Using data from the Digitalis Investigation Group trial
database, Dr. Lana Tsao and colleagues, from Beth
Israel Deaconess Medical Center in Boston, evaluated
the association between blood pressure and mortality in
5,747 heart failure patients. All of the subjects had
a diagnosis of mild or moderate heart failure along with
a reduced amount of blood pumped out of their heart.
Patients with a systolic blood pressure - the top number
of the blood pressure reading - lower than 100 mmHg had
a mortality rate of 50 percent, significantly higher than
the 32-percent rate observed in a comparison group of
patients who had pressures between 130 and 139 mmHg.
The association was nonlinear, meaning than mortality
rates fell as blood pressure rose from greater than 100
mmHg, but mortality then increased slightly at 120 to
129 mmHg before falling again.
Low diastolic blood pressure - the lower number of a
blood pressure reading -- was also linked to increased
mortality. But in this case, the association was linear
with pressures lower than 60 mmHg conferring the greatest
risk and pressures higher than 89 mmHg conferring the
lowest risk.
While the findings suggest a range of blood pressures
that might be suitable targets for heart failure patients,
they should not lead doctors to change how they treat
their heart failure patients, the authors state. For this
to occur, data from more studies are needed, they add.
SOURCE: American Heart Journal, January 2006.
