Cerebral amyloid angiopathy: the vascular pathology and complications.

Twenty-five cases with cerebral amyloid angiopathy (CAA) were studied. Senile plaques (SP) were present in all cases. In only eight cases which also displayed either SP (two cases), or both SP and Alzheimer's neurofibrillary tangles (NFT) (six cases), was there a history of dementia. In five cases, SP and NFT were observed without a history of dementia. Seven cases had significant cerebral hemorrhage, single or multiple, which could be related to CAA. Ten cases had cerebral infarcts, but only in seven of these cases could the infarcts be related to CAA. In five cases, with moderate to severe CAA and no history of dementia other distinctive vascular changes were also noted in the brain. These CAA-associated vasculopathies (CAA-AV) consisted of: clusters of multiple arteriolar lumina, the so-called "glomerular" formations, with various degrees of amyloid infiltration; aneurysmal vessels with amyloid infiltration; obliterative intimal changes; "double barreling", chronic inflammatory perivascular or transmural infiltrates; hyaline (nonamyloid) arteriolar degeneration, with or without aneurysmal dilatation; and fibrinoid necrotizing vascular change. In all five cases with CAA-AV, there were cerebral infarcts or hemorrhages which were considered to be direct complications of amyloid angiopathy, or of the vasculopathies developing secondary to the amyloid infiltration of vessel walls. It is possible that the associated vasculopathies represented secondary vascular changes that followed amyloid deposition in the blood vessel walls.