What is the role of biomarker measurement after cardiac surgery?

Measurements of cardiac troponin (cTn) and natriuretic peptides can predict outcomes after cardiac surgery and may thus assist in decision making about diagnostic and therapeutic steps in this setting. Not every cardiac surgical procedure is associated with the same degree of cTn or natriuretic peptide elevation; the factors known to affect concentrations of these markers include the severity of preoperative coronary artery disease as well as presenting syndrome, while forms of cardioprotection and anesthesia may affect postoperative concentrations of biomarkers. Release of cTn appears to represent irreversibly damaged myocardium; however, clinicians are cautioned when measuring cTn in post-cardiac surgery venues not to assume an elevated concentration is equivalent to regional acute myocardial infarction; indeed, more often than not, excessive values of cTnT or cTnI more typically represent diffuse myocardial injury. Natriuretic peptide release may occur through both states of irreversible dysfunction as well as more reversible states, such as postoperative shock. Indeed, both cTn and natriuretic peptides are unequivocally prognostic for delayed recovery, intensive care unit utilization, as well as short- and longer-term mortalities following cardiac surgery.