ARIA

GENERAL ASPECTS

What does the term ARIA mean?

ARIA is the acronym for “Amyloid-related imaging abnormalities”, i.e. neuroimaging alterations related to anti-amyloid treatments.

What are anti-amyloid treatments?

The deposition of beta-amyloid protein in the brain is one of the pathological markers that define Alzheimer’s disease. Alzheimer’s disease. In the last decade, several clinical trials have evaluated drugs whose function was to eliminate these beta-amyloid deposits for the treatment of Alzheimer’s disease. These drugs are called “anti-amyloid therapies”. Some of these drugs are: solanezumab, bapinezumab, crenezumab, gantenerumab, aducanumab, lecanemab or donanemab.

What are ARIAs?

During the development of anti-amyloid therapies some patients have experienced side effects as a consequence of the administration of the new drug. One of these adverse events consists of the appearance of alterations in neuroimaging (magnetic resonance imaging). These abnormalities are called ARIA.

What types of ARIA are there?

Two types have been described.

– ARIA-E refers to the appearance of cerebral edema.

– ARIA-H refers to the appearance of microbleeds and blood degradation products.

Both are manifestations of increased vascular fragility that some patients undergoing treatment with these therapies may experience.

What percentage of patients experience ARIA?

Although it depends on the type of anti-amyloid therapy, approximately 1 in 3 patients develop these alterations.

What symptoms do they produce?

In most cases their presence is asymptomatic, i.e. they do not produce any clinical manifestations that allow them to be detected. In these cases, they can only be detected when an MRI is performed as part of the patient’s follow-up.

Occasionally they can cause symptoms. The frequency with which they produce symptoms depends on the type of anti-amyloid drug and the type of ARIA. ARIA-H are almost always asymptomatic, whereas ARIA-E produce symptoms in 6-40% of patients who develop them.

When symptoms appear, they are usually of mild intensity. They consist of headache, visual disturbances, confusion or tremor. In a low percentage of cases, their intensity is greater and may even represent a potential life threat.

What are the risk factors?

The development of ARIA has been associated with high doses of anti-amyloid drugs and genetic factors. The most important of these is being a carrier of the E4 allele of the APOE gene. They usually appear in the first months after drug initiation.

What is your treatment?

If the appearance of ARIA is asymptomatic, it usually does not require any treatment. In those cases in which the extent of the alterations in the MRI is large, or if they are associated with some symptoms, it is necessary to temporarily or permanently suspend the anti-amyloid drug. In the most severe cases, intensive care monitoring and the use of corticosteroids are necessary.