Aim To detect the level of a disintegrin and metalloproteinase with thrombospondin motifs 4(ADAMTS4) and high sensitivity C-reactive protein (hs-CRP) using coronary sinus sampling and to assess the effect of PCI on ADAMTS4 and hs-CRP levels. Methods The 81 subjects were classified according to their coronary angiographic findings into control, simple, and complex groups. PCI was performed in 30 patients. Blood samples were taken from the coronary sinus. ADAMTS4 and hs-CRP levels were measured by ELISA and turbidometry respectively. Results ADAMTS4 showed a higher level in complex group (100.1±41.3 μg/L) than in control (55.9±17.9 μg/L) and simple group (79.5±34.8 μg/L). The ADAMTS4 level showed a positive correlation with the hs-CRP level whether from all patients or from patients with CAD (r₁=0.73, r₂=0.76). The ADAMTS4 value was higher after PCI than before PCI (108.9±39.5 μg/L vs 84.4±35.3 μg/L, P＜0.001), and the same was found regarding hs-CRP (3.1±1.4 mg/L vs 2.6±1.2 mg/L, P＜0.001). Conclusion Coronary ADAMTS4 level elevated in patients with CAD. The increase of ADAMTS4 and hs-CRP levels after PCI might be attributed to their release from the coronary atheroma.