Antibiotic may improve heart patients' blood flow

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Antibiotic may improve heart patients' blood flow

By Amy Norton

NEW YORK, Feb 25 (Reuters Health) - Treatment with the antibiotic

azithromycin may improve blood vessel function in some patients with

coronary artery disease, the results of a small study suggest.

UK researchers found that a 5-week course of the antibiotic appeared to

boost " flow-mediated dilation " in patients' arteries--a measure of how well

the blood vessel lining, or endothelium, reacts when the body needs more

oxygen-rich blood.

" This is the first study to report a beneficial effect of an antibiotic on

endothelial function, " the study's lead author, Dr. Kaski of St.

's Hospital in London, told Reuters Health.

All of the 40 male patients in the study had evidence of Chlamydia

pneumoniae bacteria in their blood. Growing evidence suggests that chronic

infection with certain bacteria, such as the respiratory bug C. pneumoniae,

plays a role in the development of artery blockages and in destabilizing

these blockages to help trigger heart attack and stroke. Because of this,

investigators have been studying whether bacteria-fighting antibiotics could

help treat artery disease.

The current findings " clearly show " that azithromycin can improve blood

vessel function in coronary artery disease patients who carry C. pneumoniae,

according to Kaski and his colleagues.

But whether this benefit will translate into improvements in patients'

artery disease and reduced risks of heart attack and stroke is far from

clear, the authors point out in the February 26th advance online issue of

Circulation: Journal of the American Heart Association. The report will be

published in the March 19th issue of the journal.

" It is too early to say if antibiotics are indicated for management of

coronary artery disease, " Kaski said.

Some researchers believe that chronic, low-grade infection with certain

germs contributes to artery disease by creating an inflammatory response

that damages the blood vessel lining and potentially contributes to artery

blockages. In addition, this inflammation could disturb unstable artery

blockages and help trigger a heart attack or stroke.

Whether antibiotics can get in the way of this process and cut heart

patients' risks remains unknown, but Kaski said researchers are " eagerly

awaiting " the results of ongoing large studies.

In his team's study, half of the men were randomly assigned to take

azithromycin for 5 weeks, while the other half took an inactive placebo. At

the end of the study, the antibiotic patients showed improved functioning in

an artery in the arm, while there were no significant changes in the placebo

patients.

Kaski said his team plans to look at the effects of other antibiotics and to

confirm the current findings in other groups of patients. In addition, he

noted, it will be important to find out why azithromycin improved blood

vessel function in this study, since effects other than its bacteria-killing

prowess could be at work.

SOURCE: Circulation 2002;105.

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