Information for patients undergoing Mechanical Clot Retrieval for Ischaemic Stroke

What has happened?

You have had an ischaemic stroke. It happens when an artery (blood vessel) is blocked by a clot, cutting off blood flow to part of the brain. Without a blood supply, brain cells can be damaged or destroyed because they may not receive enough oxygen. Symptoms may include numbness or weakness on one side of the body and problems with balance, speech and swallowing.

Ischemic stroke image

What is Thrombolysis?

Thrombolysis is a drug treatment which is given within 4 hours of an ischaemic stroke to dissolve the blood clot. It is a treatment that is not suitable for everyone and is less effective than mechanical thrombectomy when the clot is large.

What is Mechanical Clot Retrieval?

Mechanical clot retrieval for treating acute ischaemic stroke aims to remove the obstructing blood clot or other material from arteries with in the brain, restoring blood flow to the brain and minimising brain tissue damage.

The procedure is only suitable for some patients, a healthcare team experienced in managing acute ischaemic stroke will decide if you are suitable for this procedure.

What are the benefits and risks of Mechanical Clot Retrieval?

If used within the first twelve hours of symptoms beginning to show and alongside other specialist medical treatment and care – the procedure has been shown in clinical trials to significantly improve disability free survival and quality of life by restoring blood flow and therefore limiting brain damage. The National Institute of Health and Care Excellence (NICE) recommend this procedure for certain patients up to 24 hours however there are some risks and it is only suitable for some patients.

Risks include bleeding in the brain and a possibility of making the stroke worse, occasionally with a fatal outcome (NICE).

What does the procedure involve?

Mechanical clot retrieval aims to restore normal blood flow, using a device to remove the blood clot from the artery. You will first have cerebral angiography (a procedure using dye and X-rays that shows how blood flows through the arteries in your neck and brain) to see where the blood clot is.

The procedure is normally done under general anaesthetic and you will be asleep. In some case a local anaesthetic may be used so that you are awake with mild sedation. An anaesthetist will be present during the procedure.

A thin tube called a catheter is inserted into your artery, usually in the groin, and moved towards the site of the clot. The clot retrieval device is inserted through the catheter. Different devices and methods have been used to remove blood clots. The most commonly used device is called a stent retriever, which traps and removes the clot. The aim is to remove the clot as soon as possible, within a few hours of the stroke.

Thrombectomy image

Stent retrieval of a clot

Picture of stent retrieval of a clot

A clot that has been removed

Picture of a clot that has been removed

Who will perform the procedure?

An experienced consultant neuro-radiologist and his/her team will perform the procedure in the radiology department. Normally you will have a general anaesthetic so that you are comfortable and can keep completely still during the procedure.

One of our specialist stroke nurse practitioners will accompany you throughout the procedure and will keep your family updated.

What happens following the procedure?

If you have had a general anaesthetic you will go to the recovery area prior to transfer to ward 34b, which is a hyperacute stroke area. You will have close monitoring and observations, which will include heart monitoring, frequent measurements of your blood pressure, heart rate and oxygen saturation levels. We will also test how you can move your arms and legs, talk and what you can remember. Any signs of bleeding or neurological deficit will be detected quickly and treated as necessary. You will be kept in this hyper-acute area for 24 -48 hours or when the consultant decides you are stable to step down to a side-room.

How long will I be in hospital?

1. If you came from another hospital then you will stay with us until you are stable to be repatriated back to your own hospital. This is normally 24-48 hours.

2. It will depend on the type and severity of your stroke.

3. It will depend how well you are recovering.

4. Whether you need rehabilitation.

No two people are ever affected in the same way and recovery from stroke depends on many factors, such as where the stroke occurred in the brain, the severity of the stroke, the age of the patient and their medical history.

Where can I get further information?

If you have any questions about the procedure or care following the procedure, do not hesitate to speak to any of our Stroke team. This leaflet is only a starting point for discussion and our doctors and nurses can answer any of your queries during your stay.

You can also speak to one of our Stroke Nurse Practitioners at any time. They can be contacted on 0117 414 9092

References and further information

The Stroke Association

Tel:0303 303 3100


Bristol Area Stroke Foundation

Tel: 0117 964 7657




NHS Choices


Stroke association Thrombectomy patient information leaflet:

How to contact us:

Stroke Nurse Practitioners

Tel:0117 414 9092

© North Bristol NHS Trust. This edition published March 2019. Review due March 2021. NBT003017

Information for patients undergoing Mechanical Clot Retrieval for Ischaemic Stroke