The prevalence of Chlamydia pneumoniae in atherosclerotic and nonatherosclerotic blood vessels of patients attending for redo and first time coronaryartery bypass graft surgery

Objectives. To determine if Chlamydia pneumoniae (C. pneumoniae) is more pr evalent in atherosclerotic compared with normal blood vessels of patients r equiring redo and first the coronary artery bypass graft surgery (CABG). Background. Serological and pathological studies have associated atheroscle rosis with C. pneumoniae infection. As atherosclerosis is one of the causes of graft failure following CABG, then it may be expected that the prevalen ce of the organism in failed grafts and diseased native vessels should be g reater than in the new grafts. Methods. Endarterectomy specimens and failed and new grafts were collected from 49 patients with late graft failure. Endarterectomy specimens and new grafts were also collected from nine patients having first time CABG, The p resence of C. pneumoniae DNA was then checked for using a nested polymerase chain reaction. Results. The prevalence of C. pneumoniae DNA in failed venous grafts (38.2% ) was similar to that in endarterectomy specimens from native coronary arte ries (38.5%) and greater than that in new saphenous vein grafts (11.8%). Ho wever, it was similar to that in new internal mammary artery grafts (30.0%) . Also, the interval between surgery in redo patients was the same regardle ss of whether C. pneumoniae was present or not. Conclusions. Cross sectional studies cannot determine whether C. pneumoniae is a cause of atherosclerosis since they do not show whether infection pre cedes or follows its development. However, our results suggest that the org anism is not an important factor in graft failure or atherosclerosis. (C) 1 998 by the American College of Cardiology.