As the population ages, GKT137831 increasing numbers of high-risk cardiovascular patients will undergo surgery and sustain PMI��s. However, at present, as there are no obvious symptoms in sedated patients, it is difficult to diagnose PMI in the early postoperative period. In addition, ECG signs may also be unreliable because abnormal findings may be absent or may be non-specific. Traditionally, PMI is often recognized late, resulting in high mortality. Currently, although monitoring of the increase of cardiac troponin I level has helped to improve the diagnosis of PMI at 24 to 48 hours of surgery, an earlier diagnosis that potentially further reduces the mortality rate is still desirable. MicroRNAs are a class of conserved, single-stranded non-coding RNAs consisting of 19�C25 nucleotides that regulate a variety of biological cell behaviors of proliferation, differentiation, and development. It seems clear that some miRNAs are present in a tissue or cell-specific manner, although the biological functions of miRNAs are only partly understood. Recent studies have Topiramate demonstrated that miRNAs are also present in various body fluids, including plasma or serum, and circulating miRNA levels have emerged as novel biomarkers linked to various diseases. Recent reports suggest that the plasma levels of heart-expressed miRNAs respond to cardiac injury similarly to cardiac enzymes, and several groups have reported circulating miRNA levels are increased in patients with acute myocardial infarctions, indicating that plasma miRNAs are potentially new and sensitive biomarkers. With the emerging role of circulating miRNAs in the diagnosis of various diseases and their early appearance in circulation, the objective of the present work was to examine the release patterns of heart-specific miRNAs and analyse whether miRNAs can provide early prediction of PMIs after cardiac surgery. A two-step study was conducted on CABG patients. In step I, we selected cardiac-specific miRs as candidates for the present study, tested their release patterns and relevance to myocardial injury, and compared miRs release between on-pump group and off-pump group.