Relationship Between Troponin Levels and Clinical Outcomes Among Critically Ill Patients With Suspected Cardiovascular Injury

Background: Cardiac troponin is a sensitive biomarker of myocardial injury and is frequently elevated in critically ill patients, even without acute coronary syndrome. Elevated concentrations have been linked to greater disease severity, prolonged intensive care unit (ICU) stay, organ dysfunction, and higher mortality. To assess the relationship between serum troponin levels and clinical outcomes among critically ill patients with suspected cardiovascular injury. Methods: Previously published observational studies of critically ill adults admitted to ICUs were reviewed. Patients were grouped by normal or elevated troponin, and reported outcomes (ICU mortality, hospital mortality, ICU stay, mechanical ventilation, organ dysfunction) were examined. Results: Elevated troponin-I was found in 81% of patients in one large medical-surgical ICU study, and hospital mortality rose from 23.4% in the lowest troponin category to 57.4% in the highest. Another study found myocardial injury in 32% of patients, with mortality of 51% versus 16% in those without injury. Elevated troponin was also associated with longer ICU stay, mechanical ventilation, vasopressor requirement, and multiple-organ dysfunction. In adjusted analyses, elevated troponin was independently associated with hospital mortality (pooled adjusted OR 2.5, 95% CI 1.9–3.4, in one meta-analysis). Conclusion: Elevated troponin is associated with poorer outcomes in critically ill patients and serves as a marker of myocardial injury and overall illness severity. Because elevation also occurs in sepsis, renal failure, and other critical illness without myocardial infarction, interpretation must take the full clinical picture into account.