Defining Procedural MI After Cardiac Surgery Using High-sensitivity Cardiac Troponin: A Systematic Review

Background: Procedural MI (PMI) is a critical determinant of clinical outcomes after cardiac surgery. While high-sensitivity cardiac troponin (hscTn) is the most sensitive biomarker for detecting PMI, the clinical significance and optimal prognostic cut-off values for isolated hscTn elevations remain uncertain. Methods: A comprehensive literature review was conducted to evaluate the optimal cut-off levels of isolated hscTn elevation for defining prognostic PMI following cardiac surgery. Results: The review identified specific thresholds for predicting major adverse cardiovascular events (MACE). For high-sensitivity cardiac troponin T (hscTnT), a cut-off of 120 × the upper reference limit (URL) was most optimal for predicting short-term MACE, while 70 × URL was better for long-term MACE. For high-sensitivity cardiac troponin I (hscTn I), the optimal threshold was higher, at 307 × URL, for predicting short-term MACE. Conclusion: Isolated hscTn elevations after cardiac surgery have prognostic significance, with distinct optimal cut-off values for hscTnT and hscTnI. A more accurate and standardised PMI definition incorporating isolated elevations in hscTn is needed, though this is challenging due to the heterogeneous nature of cardiac surgical procedures.