Elevated troponin I and its prognostic significance in acute liver failure

INTRODUCTION Acute liver failure (ALF) is a life-threatening multisystem illness complicated by multiple organ failure (MOF) and haemodynamic disturbances. Morbidity and mortality remains high and various prognostic and scoring models are in use to predict outcome. A recent observation in a large cohort of ALF patients suggested a prognostic value of troponin I (cTnI) and its role as a marker of subclinical myocardial injury and outcome. METHODS Data from consecutive ALF patients over a four-year period from January 2007 to March 2011 were included. The aim of this study was to correlate any relationship that may exist between cTnI, mortality, severity of illness and non-hepatic organ failure. RESULTS A total of 218 subjects (age 36 (16 to 90) years, M:F 103:115) were studied, of which 136 had an elevated cTnI > 0.05 μg/L. Higher organ failure scores were found with positive cTnI: APACHE II (19.5 (3 to 51) vs 14 (2 to 51), P = 0.001), APACHE III (81 (15 to 148) vs 59 (8 to 172), P = < 0.001) SOFA (15 (4 to 20) vs 13 (2 to 21), P = 0.027) and SAPS (48 (12 to 96) vs 34 (12 to 97), P = 0.001). Patients with positive cTnI had higher serum creatinine (192 μmol/l (38 to 550) vs 117 μmol/l (46 to 929), P < 0.001), arterial lactate (0.25, P < 0.001) and a lower pH (-0.21, P = 0.002). Also a higher proportion required renal replacement therapy (78% vs 60%, P = 0.006). Patients with elevated cTnI more frequently required vasopressors-norepinephrine (73% vs 50%, P = 0.008). Elevated cTnI did not predict outcome as effectively as other models (AUROC 0.61 (95% CI 0.52 to 0.68)). CONCLUSIONS More than 60% of ALF patients in this study demonstrated elevated cTnI. Despite a close correlation with organ failure severity, cTnI was a poor independent predictor of outcome. cTnI may not represent true myocardial injury and may be better viewed as a marker of metabolic stress.