Plasma p‐tau217 detects Alzheimer's disease co‐pathology in cerebral amyloid angiopathy: Comparison to CSF biomarkers in the ANGMAR cohort
Aida Fernández‐Lebrero, Joan Jiménez‐Balado, Greta García‐Escobar, José Contador, Isabel Estraguès‐Gázquez, Laia Peraferrer‐Montesinos, Rosa María Manero‐Borràs, Laura Ludovica Gramegna, Marc Viles, Ana Rodríguez Campello, Paula Ortiz‐Romero, Marina de Diego, Marta del Campo, Javier Torres‐Torronteras, Esther Jiménez‐Moyano, Helena Blasco‐Forniés, Marc Suárez‐Calvet, Angel Ois, Albert Puig‐Pijoan, Irene Navalpotro‐GómezAbstract
INTRODUCTION
Cerebral amyloid angiopathy (CAA) frequently co‐occurs with Alzheimer's disease (AD), generating mixed vascular–neurodegenerative phenotypes. Plasma phosphorylated tau (p‐tau)217 is a robust biomarker of AD, but its performance in CAA remains unclear.
METHODS
We studied 231 participants, including 50 patients with CAA (Boston v2.0), 154 with AD, and 27 cognitively unimpaired controls. Plasma p‐tau217 was measured on an automated platform and compared to cerebrospinal fluid (CSF)–defined AD status. Associations with magnetic resonance imaging (MRI) markers of CAA burden were evaluated.
RESULTS
Among CAA participants, 29 met CSF criteria for AD co‐pathology. Plasma p‐tau217 discriminated CAA patients with and without AD co‐pathology (area under the curve = 0.920) and showed no association with MRI markers of CAA burden. Predefined cut‐offs (≥ 0.27 pg/mL and ≥ 0.34 pg/mL) yielded high accuracy for identifying AD co‐pathology within CAA.
CONCLUSIONS
Plasma p‐tau217 shows high diagnostic accuracy for identifying AD co‐pathology in CAA and is not associated with MRI markers of CAA burden, supporting its specificity for AD‐related pathology.