Executive summarySoluble ST2 is a novel cardiac biomarker that reflects cardiac injury and the response to treatment. Previous studies showed that ST2 has less confounding and more specific than NT-proBNP. ACCF/AHA has proposed 2013 Guidelines for the Management of Heart Failure that includes ST2 in the recommendations. In the research proposal, we will assess the clinical role of serum ST2 level in cardiac non-coronary valve surgical patients.We will recruit 70 patients who undergo cardiac non-coronary valve operations. Serum levels of ST2 and NT-proBNP and troponin-T will be measured at preoperative baseline, postoperative 24 hours, and postoperative 5 to 10 days in the routine blood sampling. The endpoints include hospital mortality, all-cause mortality, unexpected ICU return, MACE, time to extubation, and total length of stay. We will also collect various preoperative, operative, and postoperative variables, such as EuroScore-II. Their relationships will be analyzed.We expect to demonstrate the superior role of ST2 to NT-proBNP and other variables in risk stratification and outcome prediction and assessment in our cohort. ‡, §