An Exploratory Study of Relationships Between Arginine Vasopressin and Cerebral Edema: Usefulness of Postmortem Serum and Cerebrospinal Fluid

Background: The present exploratory study aimed to investigate the relationship between arginine vasopressin (AVP) secretion and cerebral edema and evaluate its usefulness as an index for assessing severity of cerebral edema. Methods: Forensic autopsy was performed within 96 h after death in 143 cases, and samples of right heart blood and cerebrospinal fluid (CSF) were collected. Serum AVP levels and CSF were then measured and relationships with brain weight (BW) and normalized BW were investigated. Results: No relationships between serum AVP levels or CSF and age, sex, survival, or postmortem period were identified. A comparison in regard to cause of death revealed lower CSF AVP concentrations in cases of blunt head injury and cerebrovascular disease. In addition, a correlation was observed between serum AVP levels and non-normalized or normalized BW with blunt head injury or asphyxia. Receiver operating characteristic analysis revealed that neither serum nor CSF AVP concentrations yielded cutoff values readily applicable to the diagnosis of cerebral edema. Conclusions: The present findings suggest that postmortem AVP concentrations remain relatively stable and may be involved in the formation of cerebral edema. The findings also highlighted issues such as the influence of confounding factors associated with individual pathologies and the verification of AVP stability in postmortem samples. Thus, the usefulness of AVP as an indicator of cerebral edema in forensic evaluation remains unclear.