Not yet recruitingNAINTERVENTIONAL

Mechanistic Study of Anti-Platelet Therapy in Atherosclerosis

This study explores how common anti-clotting medications, aspirin and clopidogrel, impact tiny cell clumps in the blood called monocyte platelet aggregates (MPAs). These MPAs are often found in higher levels in people with atherosclerosis, a condition where arteries harden and narrow, and they can worsen the disease and predict future heart problems. We know these medicines stop blood clots, but it's unclear if they also reduce MPAs. Researchers are giving participants either aspirin, clopidogrel, or both, to see if these treatments can lower MPA levels and other inflammation markers. This is particularly important for individuals with 'silent atherosclerosis,' who have artery hardening but no noticeable symptoms yet. The goal is to understand how these widely used drugs work beyond just preventing clots.

At a glance

Status

Not yet recruiting

Phase

Sponsor

Guy's and St Thomas' NHS Foundation Trust

Enrolment target

Start

01 Oct 2025

Estimated completion

01 Jul 2026

Peripheral Arterial Disease Silent Atherosclerosis

What is this study about?

Many people are at a higher risk of developing heart problems. This can be due to factors like being very overweight, having high blood pressure, or diabetes. Often, these heart issues are linked to a condition called atherosclerosis. This is when the arteries, which are the vital blood vessels carrying blood from your heart to the rest of your body, become stiff and inflamed. This narrowing of the arteries makes it harder for blood to flow freely.

Our bodies have a natural defence system, and inflammation is a key part of it. When you get hurt or sick, your body releases special chemicals that call in your immune system to help heal injuries or fight off infections. While usually helpful, sometimes this inflammation can go wrong. In atherosclerosis, the inflammation in your blood vessels becomes abnormal and ongoing, which can unfortunately cause damage and lead to various heart problems, and issues not directly related to your heart.

In people with atherosclerosis, tiny blood cells called platelets (which usually help stop bleeding) can stick to other immune cells called monocytes. This forms clumps, which researchers call monocyte platelet aggregates (MPAs). Studies have shown that people with atherosclerosis tend to have more of these clumps, and they can make the condition worse and even predict the risk of future heart problems. This study is investigating whether two common anti-clotting medicines, aspirin and clopidogrel – both widely used and available – can help reduce the levels of these MPAs and other signs of inflammation. We are focusing on people with 'silent atherosclerosis,' meaning they have early signs of artery hardening but aren't experiencing symptoms yet. Understanding how these drugs affect MPAs could provide new insights into how they protect heart health.

Key takeaways

Tests how aspirin and clopidogrel affect blood cell clumps in arteries.
Focuses on people with hardened arteries, especially those without symptoms.
Aims to understand how these common drugs work beyond preventing clots.
Looks at lowering levels of 'MPAs' which are linked to heart problems.
Involves taking daily medication and blood tests at clinic visits.

Who may be eligible?

This study is looking for both men and women aged 18 or older. You might be eligible if you have been diagnosed with peripheral arterial disease (PAD), which affects blood flow to your limbs, especially your legs, and it's classified as Rutherford grade 1-3. Alternatively, you might be eligible if you have been assessed by a doctor as having a risk of heart and blood vessel problems due to atherosclerosis, even if you don't have clear symptoms yet.

There are several reasons why you might not be able to join the study. If you have diabetes, or if you've taken anti-clotting medications (like other anti-platelets or blood thinners) or certain cholesterol-lowering drugs (statins) in the past two weeks, you wouldn't be able to participate. Also, if you have severe issues with your liver or other major organs, are pregnant or breastfeeding, have a history of major bleeding problems, have certain autoimmune conditions, specific blood counts (too high or too low platelets, or anaemia), or are allergic to aspirin or clopidogrel, you wouldn't be able to join.

We also can't include you if you're regularly taking certain medications that can affect how your blood clots, such as some pain relievers (NSAIDs), antihistamines, or certain antidepressants, within five days before the study starts. You also can't be part of this study if you're already involved in another clinical research study.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years old or older?
Have you been diagnosed with peripheral arterial disease, Rutherford grade 1-3, OR been assessed as having a risk of heart problems from atherosclerosis?
Have you *not* taken anti-clotting drugs (like other anti-platelets or blood thinners) or statins in the last two weeks?
Are you *not* pregnant or breastfeeding, and do you *not* have diabetes, severe organ problems, or active stomach ulcers?
Are you *not* allergic to aspirin or clopidogrel?
Are you *not* currently involved in another clinical research study?

Answer every question to see your result.

What does participation involve?

If you join this study, you will be given one of four treatments: either a low dose of aspirin (75 mg) daily, clopidogrel (75 mg) daily, both aspirin (75 mg) and clopidogrel (75 mg) daily, or a different combination of the same drugs (Clopidogrel 75mg daily + Aspirin 75mg daily). Please note that the medications are ones already widely used and available. The study will involve regular visits to the clinic where our team will take blood samples to check your monocyte platelet aggregate (MPA) levels and other signs of inflammation. We will also monitor your general health and any effects of the medication. The exact number of visits, assessments, and the full duration of your participation will be explained in detail by the study team, but typically these types of studies involve a series of appointments over several weeks or months.

Potential risks and benefits

Participating in this study might offer a potential benefit by helping us understand more about how these common medications work, which could lead to better treatments for heart conditions in the future. You will also receive careful medical monitoring during your participation. However, there are potential risks, including side effects from the medications like bleeding (a known risk with anti-clotting drugs) or allergic reactions, as well as the discomfort of blood tests. It's very important to remember that participating is entirely voluntary, and you have the right to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

Guy's and St Thomas' NHS Foundation Trust
Verified postcode
London, United Kingdom

Common questions

What is atherosclerosis?

Atherosclerosis is a condition where your arteries, which carry blood from your heart, become hard and narrowed. This can make it harder for blood to flow through.

What are anti-platelet medications?

These are medicines that help prevent blood clots from forming, such as aspirin and clopidogrel. They are often used to reduce the risk of heart attacks and strokes.

What are MPAs and why are they important?

MPAs (monocyte platelet aggregates) are tiny clumps of blood cells. Higher levels of these clumps are linked to worsening atherosclerosis and a higher risk of heart problems.

Will I know which medication I'm taking?

The study aims to compare different treatments. The study team will explain how the medication assignment process works, which may involve not knowing which specific medication you are on until after the study concludes.

What is 'silent atherosclerosis'?

This means you have atherosclerosis, but you don't have any noticeable symptoms yet, even though there's hardening of the arteries.

How to find out more

Ashish Patel

ashish.patel@kcl.ac.uk 0442071880216 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.