BACKGROUND AND OBJECTIVES: Elevated hs-CRP (high sensitivity C-reactive protein) is well known as a biomarker reflecting the inflammatory process that might evoke the potential for microembolization of an atheromatous plaque, and imparts a poor prognosis in patients with coronary artery disease. We designed this study to evaluate whether the preprocedural hs-CRP level was associated with procedure-related myocardial injury following coronary stenting. SUBJECTS AND METHODS: We obtained the plasma hs-CRP level from angina patient, who underwent coronary stenting, within 24 hours prior to the procedure, and divided the patients into either the normal CRP (hs-CRP <3 mg/L) or elevated CRP groups (hs-CRP > or =3 mg/L). We defined the reduction of TMP (TIMI myocardial perfusion) grade as at least one decrease in the TMP grade following coronary stenting compared with the pre-procedural TMP. We also evaluate the procedure-related myocardial damage by measuring CK-MB leakage after stenting. RESULTS: We enrolled 279 lesions in 226 patients, who were divided into two groups: the normal CRP group (n=137, 1.28+/-0.71 mg/L) and the elevated CRP group (n=89, 6.89+/-4.23 mg/L). A reduction in the TMP grade was significantly more prevalent in the elevated CRP (20 lesions, 17.4%) compared to the normal CRP group (6 lesions, 3.7%, p=0.001). An elevated CRP level was related to an increased CK-MB leakage following stenting (elevated CRP group; 23 patients, 25.8%, normal CRP group; 21 patients, 15.3%, p=0.041). In a multivariable analysis, the only significant predictor of a reduction in the TMP grade following stenting was an elevated CRP level. CONCLUSION: Systemically detectable inflammatory activity, served by the plasma hs-CRP level, is associated with procedure-related microvascular injury, as assessed by a reduction in the TMP grade and CK-MB elevation following coronary stenting.