Objective: We determined the effect of prolonged treatment with clopidogrel on C-reactive protein (CRP) concentrations and blood thrombogenicity after percutaneous transluminal coronary angioplasty followed by intracoronary brachytherapy in the porcine model. ANIMAL MODEL: All 48 pigs received antiplatelet therapy, including aspirin (325 mg, daily) and clopidogrel (300 mg, loading dose) 1 day before PCI, followed by a daily dose of clopidogrel (75 mg/day) in addition to aspirin. During PCI, one of two balloon-injured arteries was randomly assigned to receive immediate radiation treatment. Animals were sacrificed after 24 h, 1 month, and 3 months post-PCI. The pigs, which were sacrificed 3 months post-PCI, were divided into two groups. The first group received clopidogrel in addition to aspirin for 3 months, and the second group received clopidogrel in addition to aspirin for only 1 month after PCI and then aspirin alone.
Methods: Blood was taken from all pigs before intervention, immediately after intervention, and before sacrifice. Serum CRP was measured by enzyme-linked immunosorbent assay. To analyze the procoagulant effects of PCI on blood thrombogenicity, a one-stage clotting assay was performed.
Results: Clopidogrel treatment for 3 months reduced CRP levels more than did clopidogrel therapy for 1 month only at 3 months post-PCI (27.9+/-3.9 vs. 56.6+/-11.3 microg/ml; P=.019). Baseline CRP levels were found to be 50.4+/-4.8 microg/ml. Plasma clotting was not affected by prolonged clopidogrel therapy (322.8+/-59.3 s vs. 295.2+/-52.5 s; P=ns).
Conclusions: Prolonged treatment with clopidogrel reduced CRP levels post-PCI.