Apolipoprotein E polymorphism: survival and neurological outcome after cardiopulmonary resuscitation

The apolipoprotein E 3/3 (apoE 3/3) genotype is associated with a reduced risk of developing Alzheimer's disease and with a favorable neurological outcome after traumatic head injury. In vitro studies suggest that the most common genotype, apoE 3/3, may be involved in neuroprotective and neuroregenerative mechanisms. The aim of this study was to determine whether the apoE 3/3 genotype has an impact on survival and neurological outcome after cardiopulmonary resuscitation.

Eighty patients with cardiac arrest were investigated prospectively for their apoE genotype. Epidemiological data were assessed according to recommended guidelines. Patients were divided into 2 groups, ie, with the apoE 3/3 genotype present or absent, and tested for differences in survival and neurological outcome. Further statistical analysis with respect to survival and neurological outcome was performed by using a stepwise logistic regression analysis.

Patients with the apoE 3/3 genotype had a significantly higher survival rate (64% versus 33%, P:=0.007) and more often a favorable neurological outcome (55% versus 27%, P:=0. 013) compared with patients with other apoE genotypes. The apoE 3/3 genotype was shown to be a substantial predictive factor for a favorable neurological outcome (odds ratio 3.2) and was, apart from other essential factors, predictive for survival (odds ratio 4.4) after cardiopulmonary resuscitation.

These data give evidence that patients with the apoE 3/3 genotype have a better chance of recovery after cardiopulmonary resuscitation than do patients with apoE genotypes other than 3/3.