Early Stroke: A Dynamic Process

Mechanisms involved in progression of stroke are little understood. Studies in animals have shown an association between neuronal death mediated by excitatory aminoacids and deterioration in focal cerebral ischaemia. We looked for an association between concentrations of glutamate and glycine in plasma and cerebrospinal fluid (CSF) and early progression in a prospective study of 128 patients with acute ischaemic stroke. Of 556 consecutive admissions to our emergency unit, 128 eligible patients with ischaemic stroke were included in our study. Blood and CSF samples were taken within the first 24 h from stroke onset when cerebral oedema had been excluded on a previous cranial computed tomography. Ischaemic stroke was judged to be in progression if the Canadian stroke scale score (1.5 = maximum neurological deficit, 10 = no deficit) fell by 1 or more points during the first 48 h after inclusion. Glutamate and glycine concentrations in plasma and CSF were measured by high-performance liquid chromatography. The effect of plasma and CSF glutamate concentrations on progression was analysed by logistic regression. 43 (33.6%) patients had progressing ischaemic stroke. Concentrations of glutamate and glycine in plasma and CSF were higher in patients with progressing stroke than in those with stable cerebral infarcts (p < 0.0001). There was a significant linear correlation between CSF and plasma concentrations of glutamate (r = 0.79, p < 0.001). The positive predictive value of a plasma glutamate concentration of more than 200 mumol/L for progression of ischaemic stroke was 97% (95% CI 85-100). Glutamate concentrations of more than 200 mumol/L in plasma and of more than 8.2 mumol/L in CSF were independently and significantly associated with progression of neurological deficit (26.1 [6.9-98.6] and 40.9 [7.6-220], respectively). Early neurological progression of acute ischaemic stroke is associated with high concentrations of glutamate in blood and CSF. Measurement of plasma glutamate may be useful for the early detection of those patients with acute stroke who will deteriorate during 48 h after onset.

To assess whether a raised serum troponin T concentration would be an independent predictor of death in patients with an acute ischaemic stroke. Observational study. Auckland Hospital, Auckland, New Zealand. All 181 patients with an acute ischaemic stroke admitted over nine months in 1997-8, from a total of 8057 patients admitted to the acute medical service. Blood samples for measuring troponin T concentration were collected 12-72 hours after admission; other variables previously associated with severity of stroke were also recorded and assessed as independent predictors of inpatient mortality. Troponin T concentration was raised (>0.1 microgram/l) in 17% (30) of patients admitted with an acute ischaemic stroke. Thirty one patients died in hospital (12/30 (40%) patients with a raised troponin T concentration v 19/151 (13%) patients with a normal concentration (relative risk 3.2 (95% confidence 1.7 to 5. 8; P=0.0025)). Of 17 possible predictors of death, assessed in a multivariate stepwise model, only a raised troponin T concentration (P=0.0002), age (P=0.0008), and an altered level of consciousness at presentation (P=0.0074) independently predicted an adverse outcome. Serum troponin T concentration at hospital admission is a powerful predictor of mortality in patients admitted with an acute ischaemic stroke.