α-Synuclein pathology is related to postoperative delirium in patients undergoing gastrectomy

The clinical characteristics of postoperative delirium are similar to core features of α-synuclein-related cognitive disorders, such as dementia with Lewy bodies or Parkinson disease dementia. We therefore investigated the α-synuclein pathology in patients who experienced postoperative delirium after gastrectomy for stomach cancer.

Patients with and without postoperative delirium were selected among patients undergoing total gastrectomy for primary gastric cancer from 2007 to 2011 (each n = 16) at the university hospital. Immunohistochemical staining for α-synuclein of both normal and phosphorylated form was performed in the myenteric plexus. A logistic regression analysis was applied to identify independent predictors of postoperative delirium.

No significant differences were observed for age, sex, operation time, or onset of delirium after total gastrectomy between patients with and without postoperative delirium. Patients with postoperative delirium had a higher frequency of intensive care unit admissions (43.8 vs 6.3%, p = 0.037) and α-synuclein-positive pathologies of normal (56.3 vs 12.5%, p = 0.023) and phosphorylated form (43.8 vs 6.3%, p = 0.037) compared with those without postoperative delirium. A logistic regression analysis revealed that immunoreactivity for normal α-synuclein (odds ratio [OR] 9.20) and intensive care unit admission (OR 11.97) were independently associated with postoperative delirium.

These results suggest that underlying α-synuclein pathologies in the stomach are associated with postoperative delirium, implying that postoperative delirium represents a preclinical stage of α-synuclein related to cognitive disorders.