Changes in plasma and cerebrospinal fluid biomarkers in aged patients with early postoperative cognitive dysfunction following total hip-replacement surgery

We hypothesized that different patterns of biomarkers of brain injury and inflammation exist in aged patients with postoperative cognitive dysfunction (POCD) after total hip-replacement with spinal anesthesia. Eighty-three patients older than 65 years undergoing elective total hip-replacement surgery were enrolled in this prospective observational study. The CSF levels of Tau, phosphorylated-tau (pTau), amyloid beta 1-42 (A beta 1-42), Tau/A beta 1-42, pTau/A beta 1-42, BDNF, IL-6, and IL-1 beta were measured preoperatively. Perioperative plasma levels of IL-1 beta, IL-6, brain-derived neurotrophic factor (BDNF), C-reactive protein (CRP), and malonaldehyde (MDA) as well as neurocognitive tests were determined preoperatively and seven days postoperatively. Sixty-one patients completed both the CSF and blood samples collection and the neurocognitive tests. POCD occurred in 24.6 % of patients at seven days after surgery. Patients with POCD had significantly higher IL-1 beta, Tau/A beta 1-42, pTau/A beta 1-42, and a lower level of A beta 1-42 in CSF when compared with the Non-POCD group (P < 0.05). Furthermore, POCD patients displayed significantly higher plasma levels of MDA when compared with Non-POCD patients at seven days after surgery (P < 0.05). There was no difference in preoperative CSF levels of Tau, IL-6, and pTau as well as plasma levels of IL-1 beta, IL-6, BDNF and CRP between POCD and Non-POCD groups (P > 0.05). The POCD patients were associated with higher postoperative plasma levels of MDA, and higher IL-1 beta and lower A beta 1-42 levels in preoperative CSF that might predispose the development of POCD in aged patients following total hip-replacement surgery with spinal anesthesia.