Objective: At present, Percutaneous Coronary Intervention (PCI) has become an important treatment of coronary heart disease and plays an increasingly important role. However, interventional therapy would produce a certain degree of myocardial injury, thus affects the prognosis of patients. Therefore, predicting the extent of myocardial injury before interventional therapy is conductive to screening high-risk patients and guiding the interventional procedure to minimize operation-induced myocardial injury. Microalbuminuria is a very sensitive indicator of glomerular disease and injury, which has been used in diabetic and hypertensive nephropathy for many years. Recent studies suggest that microalbuminuria is a early performance of systemic vascular disease, it is also a risk factor for cardiovascular disease. Coronary heart disease patients with microalbuminuria may be associated with endothelial cell dysfunction or low-grade systemic inflammation and thus give rise to a wide range of systemic clinical manifestations of vascular damage. On this basis, we detected preoperative microalbuminuria level and preoperative and postoperative changes of myocardial injury markers (cTnI, CK-MB, MYO) of patients, compared the changes of myocardial injury markers between patients with different levels of microalbuminuria to explore the value of preoperative microalbuminuria level for predicting myocardial injury after selective coronary intervention.Methods: 64 patients who underwent PCI were enrolled between January and October 2008, including 57 males and 7 females, from 36 to 75 years old, with mean age of (58.41±9.59) years. Exclusion criteria:①Urinary system diseases patients such as nephritis, nephrotic syndrome, urinary tract infection;②Patients with significantly higher serum creatinine who indicating renal dysfunction;③Other heart disease such as rheumatic heart disease, cardiomyopathy, pericarditis;④Patients with specific blood system disease and Cancer;⑤Myocardial infarction patients within 3 weeks. All selected patients were conventionally collected history and underwent laboratory examination, given aspirin, clopidogrel, low molecular heparin and so on in PCI perioperative period. The quantity of uric microalbumin in 24 hours was detected by immunoturbidimetric assay, based on this results, patients were divided into MAU-positive group and negative group. Recorded lesion site of coronary artery, lesion number, the times of balloon dilatation, the total time, the maximum pressure, stent length et al. Blood samples were respectively collected immediately before and after PCI at 24 hours, myocardial creatine kinase isoenzyme MB (CK-MB), cardiac troponin I (cTnI) and myoglobin (MYO) were detected by enzyme-linked immunosorbent assay (ELISA), then we analyzed and compared the changes of myocardial injury markers between MAU- positive group and negative group.Results: The patients were divided into positive group when the quantity of uric microalbumin in 24hours≥30mg (28 cases) and into negative group when0.05).②Factors such as balloon dilatation total time, dilated maximum pressure, stent length, the number of stents showed no differences between two groups (P>0.05). the two groups were comparable.③One-vessel lesion of MAU-positive group and negative group were 8 cases (28.57%) and 14 cases (38.89%) respectively; two-vessel lesions were 9 cases (32.14%) and 12 cases (33.33%) respectively; three-vessel lesion were 11 cases (39.29%) and 10 cases (27.78%) respectively; there were no significant statistical differences (P>0.05).④Self controlled study: postoperative cTnI, CK-MB and MYO values of MAU-positive and MAU-negative group patients were higher than preoperative levels [(1.47±0.70)ng/mL vs (0.17±0.10) ng/mL; (0.93±0.49)ng/mL vs (0.19±0.12)ng/mL; (9.37±4.15)ng/mL vs (3.42±1.11)ng/mL; (6.64±3.11)ng/mL vs (3.88±0.78)ng/mL; (38.43±16.04)ng/mL vs (19.75±87.52)ng/mL; (31.98±10.83)ng/mL vs (20.64±8.00)ng/mL], the differences had statistical significance (P0.05). Postoperative cTnI value of MAU-positive was significantly higher than negative group [(1.47±0.70)ng/mL vs (0.93±0.49)ng/mL, (P0.05). Postoperative CK-MB value of MAU-positive was significantly higher than negative group [(9.37±4.15)ng/mL vs (6.64±3.11)ng/mL, (P0.05).Conclusion: Postoperative cTnI, CK-MB and MYO values of two groups were higher than preoperative levels, the differences had statistical significance, suggested that Percutaneous Coronary Intervention caused myocardial injury; postoperative cTnI and CK-MB values of MAU-positive were significantly higher than negative group, suggested that widespread vascular endothelial dysfunction may be one of the causes of why MAU-positive patients with coronary heart disease were more susceptible to myocardial injury. Preoperative MAU being positive had significantly predicted effect on myocardial injury after coronary intervention. therefore, interventional physicians should pay attention to the preoperative level of MAU who will be performed PCI.