Chlamydia pneumoniae seropositivity predicts the risk of restenosis after percutaneous transluminal coronary angioplasty

This study was done to evaluate whether anti-Chlamydia pneumoniae seropositivity can be a predictor of restenosis after coronary intervention. Recent studies indicate that latent infection with C. pneumoniae is associated with and could possibly cause atherosclerosis. However, it is unknown whether chronic infection with this micro-organism is involved in the mechanism of restenosis after percutaneous transluminal coronary angioplasty. We prospectively studied 78 consecutive patients (90 target lesions) with symptomatic coronary artery disease who underwent successful coronary intervention to a de novo lesion (conventional balloon angioplasty to 31 lesions and stent implantation to 59 lesions). At angioplasty, blood samples were collected to measure the serum level of anti-C. pneumoniae IgG to examine whether seropositive patients were prone to restenosis and whether the seropositivity could predict the risk of restenosis determined by follow-up coronary angiography performed within 6 months after the angioplasty. Restenosis, defined as more than 50% stenosis with an increase of 15% or more in the degree of stenosis from that measured on cineangiograms after angioplasty, developed in 36 of 62 seropositive patients and in 4 of 16 seronegative patients (58% vs 25%, P = 0.025). Lesions in the seropositive patients had a greater mean loss index (mean ± SD 0.75 ± 0.45 vs 0.35 ± 0.41, P < 0.001), which was defined as late loss (luminal diameter reduction at follow-up angiography) divided by acute gain (luminal diameter gain by angioplasty), in late loss (1.07 ± 0.64 mm vs 0.65 ± 0.79 mm, P = 0.019), in percentage of diameter stenosis (57% ± 20% vs 41% ± 21%, P = 0.003) and a lesser mean in minimal luminal diameter (1.18 ± 0.58 mm vs 1.67 ± 0.63 mm, P = 0.002) at follow-up angiography. In a multivariate logistic regression model, anti-C. pneumoniae IgG seropositivity was a strong independent predictor of restenosis compared to the other risk factors (odds ratio = 6.2, P = 0.01). C. pneumoniae could play an important role in the mechanism of restenosis and evaluation of the IgG seropositivity and may help to identify patients at high risk for restenosis.