Baroreflex sensitivity is impaired in patients with mild, bilateral
carotid atherosclerosis, researchers in France report in the
September issue of Stroke.

Baroreflex sensitivity is reduced in ageing, hypertension, diabetes,
and coronary artery disease, the authors explain, but few studies
have investigated the impact of carotid atherosclerosis on
baroreflex sensitivity.

Dr. Vincent Larrue and associates from Universite de Toulouse III
examined the impact of nonoperated carotid atherosclerosis on
baroreflex sensitivity and heart rate variability in 75 consecutive
patients undergoing carotid duplex examination.

Baroreflex sensitivity was significantly lower in patients with
bilateral carotid atherosclerosis (mean, 4.48 ms/mm Hg) than in
patients with unilateral carotid atherosclerosis (7.66 ms/mm Hg) and
controls (8.30 ms/mm Hg), the authors report. Patients with
unilateral carotid atherosclerosis did not differ significantly from
controls.

"To our knowledge," the investigators write, "this is the first
report to demonstrate that baroreflex sensitivity is impaired in
bilateral but not unilateral carotid atherosclerosis."

A total carotid atherosclerosis score above 1 (mild atherosclerosis)
was also associated with reduced baroreflex sensitivity, the report
indicates, though there was no further impairment of baroreflex
sensitivity as carotid atherosclerosis score increased beyond 1.

Compared with the other two groups, the researchers note, patients
with bilateral carotid atherosclerosis also showed reductions in the
power of high-frequency band during the study of heart rate
variability.

"The present study demonstrates a reduction in baroreflex
sensitivity and a shift of the sympathovagal balance toward a
relative decrease of the parasympathetic component of heart rate
variability in patients with bilateral carotid atherosclerosis," the
authors conclude. "These changes are already present when bilateral
carotid atherosclerosis is only mild."

"Further investigations are needed to assess the impact of
baroreflex sensitivity impairment on the risk of stroke and sudden
death in patients with carotid atherosclerosis," the researchers add.

Stroke 2005;36:1891-1895