Significance of troponin elevation after severe traumatic brain injury.

INTRODUCTION: Elevation of serum troponin (cTnI) after nontraumatic cerebral insult has been associated with an adverse prognosis. This association has not been well documented in traumatic brain injury (TBI).

OBJECTIVE: To evaluate the association and prognostic significance of cTnI elevation in severe TBI. To evaluate the role of beta-blocker (BB) therapy in TBI patients with elevated cTnI.

METHODS: Retrospective review of all blunt trauma patients with severe TBI (head Abbreviated Injury Scale score [AIS] >/=3) admitted to the intensive care unit (ICU) with serial TnI measurements at a Level I trauma center from January 1998 to December 2005. Patients with AIS score >/=3 to other body regions were excluded. Univariate and multivariate logistic regression was performed to determine prognostic significance of TnI elevation.

RESULTS: There were 420 severe blunt TBI patients who had serial cTnI measurements during the study period. One hundred twenty-five (29.8%) had an elevated admission cTnI. TBI patients with an elevated cTnI had a lower admission Glasgow Coma Scale (GCS) score (7.5 vs. 8.7, p < 0.05), higher Injury Severity Score (27.4 vs. 24.8, p < 0.01), and increased hospital mortality (44% vs. 29%, p < 0.05), compared with TBI patients with a normal cTnI. Increasing severity of head injury was associated with an increasing cTnI (TnI level 0.8 mug/L for head AIS score = 3 vs. TnI Level I 0.3 mug/L for head AIS score = 4, 5, p = 0.09). After adjusting for injury severity, elevated cTnI was an independent predictor for mortality (Odds ratio [OR[: 8.5; 95% confidence interval [CI]: 3.46, 22.15, p < 0.0001). BB therapy was associated with a significant survival advantage (OR: 0.38; 95% CI: 0.15, 0.87, p = 0.03) in TBI patients with any elevation of cTnI.

CONCLUSION: Elevated TnI is frequently observed after severe TBI. The level of TnI correlates with the severity of head injury and is an independent predictor of adverse outcomes. BB therapy is associated with a survival advantage in TBI patients with elevated cTnI.