A PROSPECTIVE German cohort study has found that elevated plasma amyloid-β 1-40 levels are associated with a higher risk of postoperative delirium after cardiac surgery, offering a potential new biomarker for identifying high-risk older patients before surgery.
Researchers conducted a prospective observational cohort study, FINDERI, including patients aged 50 years or older undergoing elective cardiac surgery at a comprehensive cardiac surgery centre in Germany between February 2021 and October 2022. Preoperative plasma concentrations of amyloid-β 1-40, amyloid-β 1-42, phosphorylated tau 181, and phosphorylated tau 217 were measured using validated immunoassays.
The primary outcome was postoperative delirium, assessed daily for five days after surgery using the Confusion Assessment Method, with baseline cognitive function assessed using the Montreal Cognitive Assessment.
Of 504 enrolled patients, 491 completed delirium assessment (mean age 68.4 years; 78.4% male), of whom 106 (21.6%) developed postoperative delirium. Patients who developed delirium had higher preoperative amyloid-β 1-40, amyloid-β 1-42, and phosphorylated tau 217 levels, and lower amyloid-β 1-42/1-40 ratios. Amyloid-β 1-40 was the biomarker most strongly and independently associated with delirium (area under the receiver operating curve [AUC] 0.65, 95% CI 0.59 to 0.71, p<0.001).
Combining biomarkers with clinical factors improved risk estimation (AUC 0.74, 95% CI 0.69 to 0.79, p<0.001) compared with clinical factors alone (AUC 0.73, 95% CI 0.67 to 0.78, p<0.001), and a combined model including cognitive assessment scores achieved an AUC of 0.77 (95% CI 0.72 to 0.82, p<0.001), driven primarily by amyloid-β 1-40.
These findings have suggested that preoperative plasma amyloid-β 1-40 may serve as a modest but independent risk factor for postoperative delirium in older patients undergoing cardiac surgery. As this was an observational cohort study, causality cannot be established. The authors have suggested that amyloid-β 1-40 could contribute to future multimodal risk stratification for delirium, though further research is needed to validate these findings.
Reference
von Arnim CAF, Sadlonova M, Derad C, et al. Plasma amyloid-β 1-40 and postoperative delirium after cardiac surgery. JAMA Netw Open. 2026;9(7):e2625730.
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