Evaluation of cardiac troponin I as a predictor of death in critically ill cats

Abstract Background Abnormally high serum cardiac troponin I (cTnI) concentration, reflecting leakage from or necrosis of cardiomyocytes, is a negative prognosticator for death in dogs. Objectives To investigate in critically ill cats whether serum cTnI concentration is abnormally high, identify conditions associated with abnormally high cTnI concentrations, and evaluate cTnI as an independent prognosticator for death and a potential coprognosticator to the acute patient physiologic and laboratory evaluation (APPLE) score in cats. Animals One hundred nineteen cats admitted to intensive care units (ICU) and 13 healthy cats at 2 university teaching hospitals. Methods Prospective study. Clinical examinations were performed, APPLE scores calculated, and serum cTnI and serum amyloid A (SAA) measured within 24 hours after admission. Outcome was defined as death/euthanasia or survival to discharge, 28 and 90 days after ICU‐admission. Prognostic capacity of cTnI, APPLE scores and models combining cTnI and scores were evaluated by receiver‐operator‐characteristic analyses. Results Median (IQR) serum cTnI concentration was higher in ill (0.63 [0.18‐2.65] ng/mL) compared to healthy (0.015 [0.005‐0.041] ng/mL) cats (P < .001) and higher in subgroups with structural cardiac disease (2.05 [0.54‐16.59] ng/mL; P < .001) or SAA >5 mg/L (0.84 [0.23‐2.81] ng/mL; P = .009) than in cats without these characteristics (0.45 [0.12‐1.70] and 0.35 [0.015‐0.96] ng/mL). The in‐hospital case fatality rate was 29%. Neither serum cTnI concentration for all critically ill cats (area‐under‐the‐curve 0.567 [95% CI 0.454‐0.680], n = 119) or subgroups (0.625 [0.387‐0.863], n = 27; 0.506 [0.360‐0.652], n = 86), nor APPLE scores (fast 0.568 [0.453‐0.682], full 0.585 [0.470‐0.699], n = 100), were significant prognosticators for death. Conclusions and Clinical Importance Abnormally high serum cTnI concentration was common in critically ill cats. Unlike in dogs, cTnI did not confer prognostic information regarding death.