Antiphospholipid Syndrome (APS) and Stroke

Understanding Antiphospholipid Syndrome (APS) and Its Link to Stroke

APS Support UK

We would like to extend our sincere thanks to Professor Anisur Rahman from APS UK – the only UK charity dedicated to supporting anyone affected by Antiphospholipid Syndrome (APS). This blog is based on a video interview with Professor Rahman where he kindly shared his expert insights into APS.

Did you know that up to a third of strokes in people under 50 could be due to Antiphospholipid Syndrome (APS)? Despite being a major cause of stroke in younger adults, APS remains underdiagnosed and poorly understood.

APS is a rare autoimmune condition that increases the risk of blood clotting, leading to strokes, deep vein thrombosis (DVT), pregnancy complications, and other serious health issues. Different Strokes recently hosted a webinar featuring Professor Anisur Rahman on behalf of APS Support UK, highlighting the importance of raising awareness and ensuring early diagnosis.

In this blog, we explore what APS is, how it’s connected to stroke, and what stroke survivors should know about testing, treatment, and long-term management.

What is Antiphospholipid Syndrome (APS)?

APS is an autoimmune disorder, meaning the immune system mistakenly attacks the body. In APS, the body produces antiphospholipid antibodies that cause excessive blood clotting. These abnormal clots can block blood flow, increasing the risk of serious conditions, including:

Strokes – APS-related strokes occur when clots obstruct blood supply to the brain.
Transient Ischaemic Attacks (TIAs) – Often called mini-strokes, these are warning signs of a possible major stroke.
Deep vein thrombosis (DVT) – Clots in the legs, which can become life-threatening if they travel to the lungs (pulmonary embolism).
Recurrent pregnancy loss – APS is a leading cause of recurrent miscarriage due to placental blood clots.
Heart attacks and organ damage – Clots can also affect the heart, kidneys, and other organs.

APS can develop on its own (primary APS) or alongside another autoimmune disease, such as systemic lupus erythematosus (SLE).

The Connection Between APS and Stroke

Although strokes are more common in older adults, APS is a major cause of stroke in younger people, often without traditional risk factors like high blood pressure or diabetes. It’s estimated that one-third of strokes in people under 50 may be linked to APS, making it crucial to consider this condition when diagnosing younger stroke survivors.

APS-related strokes tend to be ischaemic strokes, meaning they occur due to a blood clot blocking an artery in the brain rather than a bleed. These strokes can happen suddenly, with symptoms including:

Weakness or paralysis on one side of the body
Slurred speech or difficulty understanding language
Vision disturbances or sudden blindness in one eye
Severe headaches and dizziness

Because APS can cause repeated clotting events, survivors of APS-related strokes may be at higher risk of multiple strokes if the condition is not diagnosed and treated effectively.

Diagnosing APS in Stroke Survivors

One of the biggest challenges with APS is that many people do not know they have it until they experience a major clotting event, such as a stroke. APS cannot be diagnosed based on symptoms alone, so specific blood tests are required.

To confirm APS, doctors will check for the presence of three key antiphospholipid antibodies:

Anticardiolipin antibodies
Anti-beta-2 glycoprotein 1 antibodies
Lupus anticoagulant

A positive test must be repeated after 12 weeks to confirm a persistent presence of these antibodies. Some people may test positive once but not have APS, so retesting is essential.

If you’ve had a stroke at a young age without clear risk factors, talk to your doctor about APS testing.

How is APS Treated?

Although there is no cure for APS, treatment focuses on preventing further blood clots and reducing stroke risk. This typically includes:

Blood Thinners (Anticoagulants)

Most APS patients who have had a stroke require lifelong anticoagulation therapy.
Warfarin is the most commonly used anticoagulant, as it is more effective than newer blood thinners for APS.
Aspirin may be used for lower-risk patients, particularly those with APS who have not had a clot.

Lifestyle Changes

Controlling blood pressure and cholesterol to reduce overall stroke risk.
Regular movement and exercise to help circulation (as long as approved by a doctor).
Avoiding smoking and reducing alcohol intake, as both can worsen clotting.

Pregnancy Management

For women with APS who wish to have children, specialist care is essential. Treatment may include:

Low-dose aspirin and heparin to prevent pregnancy complications.
Close monitoring throughout pregnancy to reduce the risk of miscarriage or pre-eclampsia.

Raising Awareness and Advocating for Change

One of the key messages from APS Support UK is that early diagnosis saves lives. APS is now included in the UK’s National Stroke Guidelines, meaning more stroke survivors should be screened for this condition.

However, awareness remains low, even among medical professionals. Some stroke survivors may never be tested for APS unless they actively request it. This is why APS Support UK is dedicated to:

Funding research into better diagnosis and treatment.
Supporting individuals affected by APS.
Raising awareness so more people receive the right care.

To learn more, visit aps-support.org.uk.

Why This Matters for Stroke Survivors

If APS is the underlying cause of a stroke, getting the right diagnosis and treatment could prevent another one. Many stroke survivors never find out why their stroke happened, but in younger adults, APS is a significant possibility.

By increasing awareness, testing, and proper treatment, we can help reduce the number of APS-related strokes and support those already affected.

If you’ve had a stroke, especially at a young age, consider speaking to your doctor about APS testing. Taking control of your health starts with knowledge—and knowing about APS could be lifesaving.