Elevated serum cardiac troponin I levels may be used as an independent marker to predict adverse outcomes after cardiac surgery, including risk of death and postoperative myocardial infarction, researchers report.

Cardiac surgery is often associated with high morbidity and mortality, and the ability to identify individuals at risk in a timely manner could greatly improve prognosis. Although several biomarkers have been evaluated to identify postoperative myocardial injury, they either lack sensitivity and specificity or are elevated over a short period of time. However, supplementing postoperative troponin I preoperative risk scores, such as creatinine kinase- MB and cardiac troponin T, allows for better detection of postoperative complications and therefore a better prognosis.

In a literature review, Ahmed and colleagues analyzed data from 13 studies (12 prospective studies) with a total of 12,483 participants (77.8% men) that were conducted in May 2022 and evaluated the role of cardiac troponin I in predicting postoperative mortality, MI and ICU, and length of stay in adults undergoing CABG and valve replacement. Cohort size ranged from 41 to 7918; mean age ranged from 54 to 73 years, and 864 participants reported prior myocardial infarction.

The study results were published in the Journal of Cardiac Surgery.

Eleven of the 13 studies mentioned postoperative troponin I levels, and two studies represented them graphically; all of these were measured in various time frames, from the end of extracorporeal circulation to 72 hours postoperatively. eight of the 13 studies assessed mortality from hospitalization to 5 years. Four studies proposed cardiac troponin I as an independent predictor of mortality; the remaining studies reported that troponin I was superior to EuroSCORE and CK-MB as predictors of event-free survival or that EuroSCORE was superior to troponin I.

Six studies evaluating postoperative myocardial infarction,reported myocardial infarction after surgery in patients with elevated troponin levels. Three of the six studies that suggested troponin I was an independent predictor; the remaining studies noted that the marker was more sensitive and specific than CK-MB, which was the threshold for excluding postoperative MI or lacking any significant correlation.

Three studies evaluated ICU length of stay and all reported a significant correlation between postoperative cardiac troponin I elevation and prolonged length of stay. Similarly, longer hospital stays were significantly associated with elevated cardiac troponin I levels in all three assessments, the researchers wrote.

Although cardiac troponin I has great potential to influence the outcome of cardiac surgery, there is a lack of standardization in the studies conducted Future studies must follow a standardized protocol, including the use of uniformly measured interval troponin level measurements. Finally, standardized threshold values for (cardiac troponin I) elevation over selective intervals need to be determined to provide the best prognostic value and comprehensive guidelines published to help improve surgeon adherence.