High cardiac troponin levels are commonly seen in medical intensive care (MICU) patients with renal failure and no clinical evidence of acute coronary syndrome (ACS). We looked at the incidence of elevated troponin levels in this group of patients and the impact on mortality.
We prospectively collected data on all MICU patients who met the following criteria:a) Renal failure - defined as serum creatinine > 140 μmol/L (upper limit of reference range) b) No evidence of ACS (anginal pain, acute ST or T changes on ECG). All patients who fell into the study group had a troponin T level done within the first 24 hours of ICU admission. Troponin T levels ≥ 0.1 ng/mL were considered as high. Our primary outcome was the 28-day all cause mortality. We also looked at the correlation between the troponin levels and creatinine clearance as calculated from the Cockroft-Gault equation.
Fifty one patients met the study criteria. Twenty two patients (43%)had elevated troponin T levels. Six of these 22 patients died (mortality rate 27%). The mortality rate in the 29 patients with normal troponin levels was 34%. The severity of illness was similar in both groups(using the Logistic Organ Dysfunction Score). The troponin levels poorly correlated with the levels of creatinine clearance(r2=0.005).
In the absence of ACS, elevated troponin T levels in MICU patients with renal insufficiency do not appear to confer an increased mortality.
High troponin T levels in this group of patients may not be an important risk factor for death. Larger studies are needed to validate this finding.
Vijo Poulose, None.