Comparison of inflammatory markers for the prediction of neointimal hyperplasia after drug-eluting stent implantation.

BACKGROUND: We compared the relationship between inflammatory markers and neointimal hyperplasia (NIH) after drug-eluting stent (DES) implantation. METHODS: We implanted a single DES in 42 consecutive patients with stable angina. The plasma high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and matrix metalloproteinase-9 (MMP-9) levels were measured before, and 24 and 72 h after the procedure. Angiography and intravascular ultrasound were performed. RESULTS: No relationship was noted between the baseline hs-CRP level and NIH. A significant positive correlation was noted between NIH and the hs-CRP level obtained at 24 h (r=0.435, P=0.004), and 72 h (r=0.334, P=0.031) after the procedure. Interestingly, there was a positive correlation between the change (Δ) in the hs-CRP level and NIH at 24 h (r=0.414, P=0.006). The fourth quartile of the hs-CRP at 24 h after percutaneous coronary intervention (PCI) had significantly larger volume of NIH than the first quartile (20.1±25.1 vs. 2.7±6.4 mm, P<0.05). Moreover, NIH in the fourth quartile (20.9±26.4 mm) was higher than the first quartile (3.3±8.6 mm) of the Δ hs-CRP level at 24 h (P<0.05) after the procedure. Although the IL-6 level at the baseline and 72 h after the procedure were positively correlated with NIH (r=0.337, P=0.029 and r=0.435, P=0.004, respectively), the Δ IL-6 level at any stage was not correlated with NIH. Neither the MMP-9 level nor the Δ MMP-9 level at any stage was correlated with NIH. CONCLUSION: This prospective intravascular ultrasound study showed the inflammatory response after PCI, as measured by hs-CRP levels, but not the baseline hs-CRP level, predict NIH after DES implantation. Neither a change in the IL-6 nor MMP-9 levels at any stage after PCI reflected NIH.