Abstract
BACKGROUND: We tested the hypothesis that increased levels of cathepsin S and decreased levels of cystatin C in plasma at the time of percutaneous transluminal angioplasty (PTA) are associated with the occurrence of 6-months' restenosis of the femoropopliteal artery (FPA). METHODS: 20 patients with restenosis and 24 matched patients with patent FPA after a 6-months follow-up were in - cluded in this study. They all exhibited disabling claudication or critical limb ischemia and had undergone technically successful PTA. They were all receiving statins and ACE in hi - bitors (or angiotensin II receptor antagonist) before the PTA and the therapy did not change throughout the observational period. Plasma concentrations of C-reactive protein were < 10 mg/L and of creatinine within the reference range at the time of the PTA. Plasma concentration and activity of cathepsin S, together with its potent inhibitor cystatin C, were measured the day before and the day after the PTA. RESULTS: The increased plasma concentration and activity of cathepsin S at the time of PTA was associated with the occurrence of 6-months' restenosis of FPA, independently of established risk factors (lesion complexity, infrapopliteal run-off vessels, type of PTA, age, gender, smoking, diabetes, lipids) and of cystatin C. Plasma cystatin C concentration was not associated with restenosis and did not correlate with cathepsin S activity and concentration in the plasma. CONCLUSION: Increased level of plasma cathepsin S at the time of PTA is associated with 6-months' restenosis of PTA, independently of established risk factors.