The significance of Chlamydia pneumoniae in symptomatic carotid stenosis

An association between symptomatic carotid stenosis and recent infection wi th Chlamydia pneumoniae is reported. Thirty-five patients (20 symptomatic a nd 15 asymptomatic) with carotid stenosis of 70% to 90% underwent carotid e ndarterectomy. Endarterectomy was performed without patch and shunt; the av erage occlusion time of the internal carotid artery was 14 +/- 3 min. The a theromatic plaque and a portion of the thyroid artery were examined with po lymerase chain reaction and peripheral vein blood was obtained for serologi c detection of systematic infection, and IgG and IgM antibodies to C. pneum oniae by enzyme-linked immunosorbent assay. Twenty of 35 patients (57.1%) had increased titers of IgG antibodies to C p neumoniae. Eight patients revealed IgG plus IgM antibodies; two of the eigh t had IgG, IgM, and positive findings on polymerase chain reaction. No C pn eumoniae was detected on the thyroid arteries. Sixty-five percent (13/20) o f the patients with increased IgG antibodies to C pneumoniae, 87.5% (7/8) w ith IgG + IgM, and 100% with IgG + IgM + positive polymerase chain reaction were symptomatic. Plaque morphology in association with symptoms did not r eveal a significant correlation between soft plaques and symptoms, whereas the majority of the symptomatic patients had plaques of type III-V. Patient s having recent contamination and positive polymerase chain reaction had a significant relationship between C pneumoniae infection and symptomatic car otid disease. This supports the hypothesis that C pneumoniae infection can produce a kind of instability of the carotid plaque. The results of this st udy demonstrate that patients with advanced atherosclerotic carotid disease have an increased incidence of C pneumoniae infection. Recent infection co uld be responsible for instability of the carotid plaque, causing cerebral ischemic episodes.