Cerebrospinal Fluid p-Tau181/Amyloid Beta 42 Ratio Identifies Lymphatic-Venous Anastomosis Patients Who Respond to and Benefit from the Surgery for Relief of Cognitive Impairment with a Diagnostic Accuracy of 0.744

Responders (R) and Non-Responders (NR) to lymphatic-venous anastomosis (LVA) surgery for relief of cognitive impairment show significant difference in their p-tau181/Aβ42 ratios via enzyme-linked immunosorbent assay (ELISA) of their cerebrospinal fluid (CSF). LVA involves the conjugation of a lymph vessel to a small vein in the neck to facilitate lymph flow. The R and NR groups were classified using five standard cognitive assessment tools: Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog), Activities of Daily Living (ADL) and Clinical Dementia Rating (CDR), and augmented by clinical assessments. ELISA results for 43 patients were available. Welch's t test and Mann-Whitney U-test revealed significant difference between R and NR's p-tau181 value and p-tau181/Aβ42 ratio. Using a p-tau181/Aβ42 cutpoint of 0.0923 allows patient selection for LVA with a specificity of 0.800, sensitivity of 0.667, positive predictive value (PPV) of 0.706, and negative predictive value (NPV) of 0.769. The diagnostic accuracy is 0.744. The receiver operating characteristic (ROC) curve gives an area under the curve (AUC) of 0.793, which compares well with those of biomarker tests currently in use: prostate specific antigen (PSA), Straticyte and Oncotype DX. The p-tau181/Aβ42 ratio could serve to predict LVA's effectiveness in alleviating AD patients' symptoms and to rule-in patients for LVA, once validation from a larger patient cohort is available.