AuthorisedTherapeutic use (Phase IV)Interventional

Weight-loss Effects aNd absorption of Direct oral anticoagulants in roux-en-Y gastric bypass patients: a prospective study (WENDY)

This study, called WENDY, is looking at people who are having a type of stomach surgery called Roux-en-Y gastric bypass to help them lose weight. We want to understand how this surgery and the resulting weight loss affect a common blood thinning medicine called apixaban. This medicine is used to prevent blood clots. Researchers will check the levels of apixaban in your blood at different times: before the surgery, and then a few weeks and a few months afterwards. They will also keep track of your weight, and check if you experience any serious bleeding or develop any blood clots like DVT (deep vein thrombosis) or pulmonary embolism. The aim is to make sure we give people the right dose of blood thinners after this type of surgery.

At a glance

Status

Authorised

Phase

Therapeutic use (Phase IV)

Sponsor

Amsterdam UMC Stichting

Enrolment target

Start

26 May 2025

Roux-en-Y gastric bypass

What is this study about?

When people have a type of weight-loss surgery called Roux-en-Y gastric bypass, their digestive system changes significantly. This can affect how medicines are absorbed into their body. Many patients undergoing this surgery also need to take blood thinning medicines, like apixaban, to prevent serious blood clots. However, we don't fully understand how effective these medications are after such surgery when the body handles them differently.

This study, named WENDY, aims to find out exactly how the levels of blood thinning medication (specifically apixaban) change in the body after Roux-en-Y gastric bypass surgery. Researchers will measure how much of the medicine is in the blood at different points in time: just before the surgery, and then again a few weeks and a few months later. By doing this, they hope to get a clear picture of how the surgery and weight loss impact the medicine's work.

Understanding these changes is very important. It will help doctors make sure that patients who have had this surgery are prescribed the correct dose of blood thinning medication. This can help prevent potentially dangerous blood clots while also avoiding problems with too much bleeding, ultimately leading to safer and more effective care for patients.

Key takeaways

The study looks at how weight-loss surgery affects blood thinning medicine.
It aims to understand apixaban levels in the blood before and after surgery.
Researchers will also track weight, bleeding, and blood clot events.
The goal is to help doctors choose the correct medicine doses for patients.
This is an 'observational' study, meaning no new drugs are being tested.
Participation involves blood tests and follow-up over roughly three months.

Who may be eligible?

This study is looking for adults aged 18 years and older. There is no upper age limit for taking part.

Both men and women are welcome to join this study.

The main requirement is that you are planning to have a specific type of weight-loss surgery called Roux-en-Y gastric bypass. You will need to be taking or be prescribed apixaban, which is a blood thinning medicine.

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?
Are you planning to have Roux-en-Y gastric bypass surgery?
Will you be taking apixaban (a blood thinner) around the time of your surgery?
Are you comfortable with attending follow-up visits and having blood tests?

Answer every question to see your result.

What does participation involve?

If you decide to take part in this study, you would attend several appointments. Before your surgery, you will have a visit for some baseline measurements. After your Roux-en-Y gastric bypass surgery, you will have follow-up visits. One visit will be between 17 and 60 days after your surgery, and another around 3 months after surgery. At these visits, doctors will take blood samples to measure the levels of the blood thinning medicine in your body. They will also measure your weight and height to calculate your body mass index (BMI). You will also be asked about any bleeding problems or if you have had any blood clots. The total duration of your participation in the study will be approximately 3 months after your surgery.

Potential risks and benefits

Taking part in this study may help us understand more about how blood thinning medicines work after weight-loss surgery, which could benefit future patients. The main procedures involve blood tests, which carry minimal risks like bruising or discomfort. There are no new medications being tested in this study; it observes how existing medicines work in a new situation. You are free 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.

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Unverified
Netherlands

Common questions

What is Roux-en-Y gastric bypass surgery?

It's a type of weight-loss surgery where a small stomach pouch is created and connected directly to the small intestine, changing how your body digests food.

What is apixaban?

Apixaban is a common medicine used to thin the blood and prevent dangerous blood clots.

Why is this study important?

It will help doctors understand how best to give blood thinning medication after weight-loss surgery, making treatment safer and more effective for patients.

Do I have to take any new medicines for this study?

No, this study is about observing how a medicine you already take (apixaban) works after surgery; you won't be given any new trial medications.

How long will I be involved in the study?

Your participation will last for about 3 months after your gastric bypass surgery, with a few visits during that time.