The significance of troponin elevation for the clinical course and outcome of first-ever ischaemic stroke.

BACKGROUND: An increase in the troponin I (TnI) level is a marker of myocardial damage in acute coronary syndromes (ACS) and other conditions. According to the latest reports, an increase in the concentration of TnI in the acute phase of stroke relates to 1-34% of patients. The aim of this study was to evaluate the prevalence of elevated TnI concentration in patients with acute first-ever stroke and to examine its significance for the prediction of post-stroke disability degree and death within 30 days of stroke. An additional aim of the study was to compare the anatomic location of stroke in patients with normal and elevated TnI concentrations on the 1st day of stroke.
METHODS: Patients (M/F: 609/459; mean age 72 ± 11) with stroke numbering 1,068 were included in the prospective study. Their neurological deficit (National Institutes of Health Stroke Scale), TnI concentration (normal range ≤ 0.014 ng/ml), creatine kinase and ECG were examined on the 1st day of stroke. A follow-up and ECG were performed one day later in patients with abnormal TnI. The anatomical location of stroke (the right and left hemispheres and the brain stem) was compared in patients with normal and elevated TnI concentrations on the first day of stroke. The patients' functioning status was assessed using the by modified Rankin Scale (mRS) on the 30th day, and mortality was assessed within 30 days. The analysis was performed using a single and multi-factorial method of non-linear estimation for logistic regression in order to identify the independent factors for post-stroke disability at 4-6 points on the mRS on the 30th day following the onset and for death within 30 days of stroke in relation to the entire study group. The relative risk of a 4-6 point scoring on the mRS and of death among patients with abnormal TnI concentrations was also assessed.
RESULTS: Abnormal TnI concentration during stroke was observed in 9.73% of patients. The functioning status (mRS) of patients with elevated TnI was significantly worse 30 days post stroke as compared to patients with normal TnI concentration. Stroke was significantly more frequent in the right-hemisphere in patients with elevated TnI and no ischaemic changes in the ECG. For patients with ACS Tn+ during stroke, the mortality within 30 days after stroke was significantly more frequent than for patients without ACS Tn+. The abnormal TnI level neurological status on the 1st day of stroke and age were independent mortality factors within 30 days following stroke. Elevated TnI concentration, hypertension and neurological status on the 1st day of stroke were independent factors for post-stroke disability.
CONCLUSIONS: Elevated TnI concentration occurs in 1/10 of patients with acute ischaemic stroke. It is connected with an unfavourable course of stroke leading to a significant disability and less independence in their everyday functioning. The right hemisphere is the most common site of stroke accompanied by elevated concentration of troponin in patients with no ischaemic changes in the electrocardiogram. Troponin-positive acute coronary syndrome in the period of acute stroke increases mortality within one month. Among patients with an abnormal troponin concentration in the acute phase of stroke, poor outcome is attributed to stroke severity on admission.