The apolipoprotein E epsilon4 allele and outcome in severe traumatic brain injury treated by an intracranial pressure-targeted therapy.

Abstract

In this paper, the authors' goal was to study the influence of the apolipoprotein E epsilon4 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. 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 < or = 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. The occurrence of the epsilon4 allele was analyzed in 46 patients (mean age 35 +/- 2.2 years with a median GCS score of 6 [range 3-8]). The epsilon4 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 epsilon4 allele and those without. The presence of the epsilon4 allele did not predict for clinical outcome, but GCS and ICP did. The presence of epsilon4 is not associated with long-term clinical outcome in patients with severe TBI treated with an ICP targeted therapy, based on the Lund concept.