For Clinicians

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Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease, caused by amyloid-beta protein accumulation in the walls of leptomeningeal and cortical blood vessels. Clinically, it is associated with intracerebral hemorrhage or acute convexity subarachnoid hemorrhage, and therefore is frequently encountered by stroke clinicians. CAA can also present with transient focal neurological episodes (TFNE, or ‘amyloid spells’; see for further reading CAA is associated with certain hemorrhagic imaging features on MRI (cortical superficial siderosis, cerebral microbleeds) and these can sometimes be incidentally identified on brain imaging performed for other reasons. Usually CAA is age-related, but there are other, rarer forms of CAA, including: inherited forms of CAA, CAA-related inflammation, and Iatrogenic CAA.

The diagnosis of probable CAA can be made during life using the MRI-based Boston criteria: Alternatively, one can use the CT-based Edinburgh criteria, which require knowledge of a patient’s ApoE genotype:

At present there are no disease modifying treatments for CAA. The International CAA Association advises against the use of anti-amyloid-beta antibody Aducanumab (Aduhelmtm) as a treatment for CAA: In all cases, a decision should be made on an individual basis. Potential considerations include:

  • Blood pressure management: the PROGRESS study demonstrated that blood pressure reduction as secondary prevention reduced the risk of further intracerebral hemorrhage:
  • Anti-platelet therapy: the RESTART trial demonstrated that the benefits of anti-platelet therapy for the prevention of occlusive vascular disease are likely to outweigh the risk of recurrent intracerebral hemorrhage in those with CAA:
  • Anticoagulant therapy: there is no high-quality evidence to guide practice at present. Clinical trials evaluating whether people with CAA and atrial fibrillation should be anticoagulated to avoid ischemic stroke (including SoSTART, APACHE-AF and ENRICH-AF) are underway. Consideration of approaches that limit the use of anti-coagulation (for example, left atrial appendage closure) can be considered in appropriate patients.
  • See for more information the 2022 guideline for the management of patients with spontaneous intracerebral hemorrhage from the American Heart Association:

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General clinical overviews of CAA: and

Transient focal neurological episodes (“amyloid spells”) in CAA:

The relationship between Alzheimer’s disease and CAA:

Resourcesd on Dutch-type CAA (formerly known as HCHWA-D):