The apolipoprotein E ε4 allele and outcome in severe traumatic brain injury treated by an intracranial pressure-targeted therapy

Object. In this paper, the authors' goal was to study the influence of the apolipoprotein E epsilon 4 allele on the clinical outcome in patients treated for severe traumatic brain injury (TBI) with an intracranial pressure (ICP)-targeted therapy based on the Lund concept. Methods. The authors conducted a prospective double-blinded randomized trial in which they examined patients with severe TBI. Inclusion criteria consisted of a Glasgow Coma Scale (GCS) score <= 8 at the time of intubation and sedation, patient age between 15 and 70 years, an initial cerebral perfusion pressure > 10 mm Hg, and arrival to the hospital < 24 hours after trauma. Blood samples for the analysis of apolipoprotein E allele types were collected. Independent staff members evaluated outcomes by obtaining Glasgow Outcome Scale (GOS) scores at 3, 12, and 24 months. Results. The occurrence of the epsilon 4 allele was analyzed in 46 patients (mean age 35 +/- 2.2 years with a median GCS score of 6 [range 3-8]). The epsilon 4 allele was present in 39.1% of the patients. The ICP, cerebral perfusion pressure, and injury severity score were not statistically significantly different between the groups. The median GOS score at 3 months was 3.5, and at 12 and 24 months was 4 (range 1-5). Except for the GOS score at 3 months, which was dichotomized as favorable (GOS Score 4 or 5) and unfavorable (GOS Scores 1-3), no statistically significant differences in outcome, irrespective of GOS dichotomization used, were found between the patients with the epsilon 4 allele and those without. The presence of the epsilon 4 allele did not predict for clinical outcome, but GCS and ICP did. Conclusions. The presence of epsilon 4 is not associated with long-term clinical outcome in patients with severe TBI treated with an ICP targeted therapy, based on the Lund concept. (DOI: 10.3171/2009.8.JNS09636)