Serologic markers of persistent Chlamydia pneumonia infection and long-term prognosis after successful coronary stenting

Background Previous studies have shown an incremental role of inflammation in late prognosis following coronary stenting (CS). In particular, high preprocedural levels of plasma C-reactive protein (CRP) have been related to increased hazard of late ischemic complications. Persistent Chlamydia pneumoniae (Cp) infection, detected by positive IgA anti-Cp titers, may be associated with this inflammatory process and portend a high risk of late adverse prognosis after CS. Methods A total of 483 consecutive patients with either stable or unstable coronary syndromes were followed-up for I year after successful CS. The composite of cardiac death, myocardial infarction, rehospitalization for rest-unstable angina, and exertional angina, whichever occurred first, was the clinical end point. Additionally, the rate of in-stent restenosis and progression of coronary artery disease during this period were evaluated. Anti-Cp titers and plasma CRP levels were measured before the procedure. Results Positive immunoglobulin A (IgA), but not positive immunoglobulin G (IgG), titers were significantly associated with high plasma CRP levels in patients with unstable coronary syndromes (P =.005), but not in those with stable angina (P =.7). Moreover, positive IgA titers were significantly related to increased risk of both the composite clinical end point (P =.04) and progression of coronary artery disease (P <.001) in patients with unstable coronary syndromes but not in those with stable angina. Neither positive IgA nor positive IgG titers were associated with the rate of in-stent restenosis. Conclusions Persistent Cp infection may drive an inflammatory response in the coronary vasculature and portends an adverse late outcome after CS in patients with unstable coronary syndromes.