Younger age at death, APOE ε2 carriage, and vascular remodeling CAA were identified as independent predictors of intracerebral hemorrhage in a multivariate analysis of 205 autopsy-confirmed cerebral amyloid angiopathy brains, supporting a complex interaction among APOE genotype, vascular amyloid pathology, and concomitant AD changes in shaping the hemorrhagic phenotype.
Younger age at death was an independent predictor of intracerebral hemorrhage in autopsy-confirmed CAA.
APOE ε2 carriage was an independent predictor of intracerebral hemorrhage in CAA.
Vascular remodeling CAA was an independent predictor of intracerebral hemorrhage.
The APOE ε2/ε4 genotype showed the highest frequency of intracerebral hemorrhage among all APOE genotype combinations.
Severity of CAA was most strongly associated with intracerebral hemorrhage in the presence of concomitant Alzheimer's disease neuropathologic changes.
The study analyzed 205 autopsy brains with CAA from two Spanish cohorts using standardized neuropathological grading.
This research suggests that the risk of brain bleeding (intracerebral hemorrhage) in people with cerebral amyloid angiopathy (CAA) — a condition where amyloid protein builds up in brain blood vessel walls and is a major cause of stroke in older adults — is shaped by a combination of genetic, pathological, and demographic factors. By examining 205 donated brain samples from two Spanish groups, researchers found that dying at a younger age, carrying a specific version of the APOE gene called ε2, and having a particular type of blood vessel damage called vascular remodeling CAA each independently increased the likelihood that a person had experienced a brain bleed. Notably, the ε2/ε4 combination of the APOE gene was linked to the highest rates of hemorrhage. The study also found that the presence of Alzheimer's disease-related brain changes alongside CAA made the link between CAA severity and bleeding even stronger. Interestingly, the APOE ε2 gene variant appeared to increase bleeding risk through a mechanism separate from the vascular remodeling it did not cause, suggesting it promotes hemorrhage in a different way. These findings help clarify why some people with CAA develop brain bleeds while others do not — a question that was previously not well understood. This research matters because CAA is increasingly recognized as a major contributor to stroke and dementia in elderly populations, and understanding who is at greatest risk of bleeding could eventually help guide clinical decisions about treatments — such as blood thinners — and monitoring strategies. The interaction between genetic makeup (especially APOE genotype), the type and severity of amyloid damage in blood vessels, and co-existing Alzheimer's pathology appears to collectively determine a person's hemorrhagic risk profile in CAA.
Chaachou-Charradi A, Burgueño-García I, Camacho-Soriano J, Moliné-Marimón T, Zagrean N, Ramón Y Cajal-Agüeras S, et al.. (2026). Factors associated with intracerebral hemorrhage in confirmed cerebral amyloid angiopathy.. Alzheimer's & dementia : the journal of the Alzheimer's Association. https://doi.org/10.1002/alz.71786