Correlation Between Serum Level of Neuron-specific Enolase and Long-term Functional Outcome After Acute Cerebral Infarction: Prospective Study

Objective: To determine the value of measuring serum levels of neuron-specific enolase in predicting extent of disease and short- and long-term functional outcome after acute cerebral infarction.

Design: Prospective study.

Setting: Neurology departments at two university teaching hospitals, Shanghai.

Patients: Thirty-eight patients who presented for acute cerebral infarction between October 1998 and October 2000 were divided into two groups: those whose infarction extended to the cerebral cortex in the carotid artery region (cortical group) and those with an infarction in the subcortical carotid artery region (subcortical group).

Main Outcome Measures: Using a solid-phase enzyme immunoassay, we measured serum levels of neuron-specific enolase on admission and on days 2, 3, and 15. Infarct volume was measured by computed tomography on day 5. The Activities of Daily Living scale was used to assess the clinical outcome at 1-, 3-, and 6-month follow-up after onset.

Results: Mean (standard deviation) serum neuron-specific enolase levels were significantly higher among patients with acute cerebral infarction than among controls (18.48 [16.61] ng/mL versus 9.00 [2.70] ng/mL; P<0.001). The neuron-specific enolase level was also higher in the cortical group than in the subcortical group (33.54 [29.71] ng/mL versus 15.97 [5.91] ng/mL; P<0.01). Levels peaked after 2.11 (0.86) days and correlated positively with the infarct volume (r=0.81; P<0.01) and negatively with clinical outcome at 1 month (r= -0.37; P<0.05), 3 months (r= -0.45; P<0.01), and 6 months (r= -0.65; P<0.001), as assessed on the Activities of Daily Living scale.

Conclusion: Serum neuron-specific enolase levels after cerebral infarction may be a useful marker to predict infarct volume and short- or long-term functional outcome.