Stroke endovascular Mechanical Thrombectomy (MT): Clot removal procedure for Acute Ischemic Stroke (AIS) with Large Vessel Occlusion (LVO)
Information for patients from the Stroke Service
This leaflet is for patients and their relatives who have suffered an acute Ischaemic Stroke with large blood vessel blockage in the brain, requiring an Endovascular Mechanical Thrombectomy procedure.
Read this leaflet carefully before you / your relative decide whether to have this procedure.
This leaflet will explain the following.
What a mechanical thrombectomy is.
Why you need a mechanical thrombectomy. What the alternatives are.
Who will carry out the procedure and where.
How a mechanical thrombectomy is performed.
If you need a general anaesthetic.
What the benefits of having a mechanical thrombectomy are.
What the risks of having a mechanical thrombectomy are.
Consenting for mechanical thrombectomy.
What happens immediately after the procedure.
When you can leave the recovery area.
Recovery after a mechanical thrombectomy and hyperacute stroke care.
How long you will need to stay in hospital.
What to do if you have any questions or concerns.
We hope this leaflet answers some of the questions you may have. If you have any further questions or concerns, please speak to a member of your healthcare team.
What is a mechanical thrombectomy (MT)?
Mechanical thrombectomy is an emergency surgical procedure. It physically removes a blood clot from a blocked brain artery, using image guidance (an x-ray). After an acute ischemic stroke, this procedure restores blood flow and minimises brain damage.
Why do I need a mechanical thrombectomy? Are there alternatives?
Ischaemic stroke is the most common type of stroke. It is caused by a blood clot cutting off blood flow to part of the brain. When this happens, the brain does not receive the oxygen and nutrients it needs. It can become irreversibly damaged over a time. Therefore, we need to remove the blockage without delay, to restore the blood flow. This is done with an MT.
We may try to dissolve the clot before we try a mechanical thrombectomy. We do this by giving patients a clot-busting medication in the vein or an artery. This procedure is called Thrombolysis. Thrombolysis is a less invasive treatment compared to mechanical thrombectomy. However, the clot-busting drug may not dissolve the clot in all patients. Also, some patients may not be eligible to receive these drugs.
If a clot-busting drug does not work or you are not eligible to have it, we will use MT to:
physically remove the blood clot; and
help return the blood flow to your brain.
Who will carry out the procedure and where?
A multidisciplinary team of health professionals will be involved in the decision making for MT. The health professionals who perform the procedure are called:
interventional radiologists
interventional neuroradiology operators, or
interventional neuroradiology doctors.
You / your relative will be taken to an Angiography suite at the Mechanical Thrombectomy Centre.
The interventional radiology doctor / operator is supported by a team, including:
a stroke consultant
an anaesthetist
radiographers
radiology nurses, and
other operating department practitioners.
The team will make sure you / your relative are safe and comfortable during the procedure.
How is a mechanical thrombectomy performed?
A small cut / puncture is made in the groin or wrist. A thin plastic tube (called a catheter) is carefully inserted and guided up to the blocked blood vessel in the brain.
The operator will inject a contrast (dye) into the blood vessel. The dye allows them to see clearer pictures of the blood vessel, and guides the catheter through using an x-ray. Once the blood clot is reached, the operator will use a clot-removal device passed through this catheter to the clot.
At this point, the operator may use two types of device to remove the clot.
A stent retriever (a tiny wire-mesh) is used to trap the clot. It is pulled out as the operator withdraws the catheter.
An aspiration catheter is a tiny suction device, used to suck out the clot.
During the procedure, we will take angiogram scans. The scans allow us to view the blood flow in the affected site.
An MT opens the artery in about 7 in every 10 cases. There are some cases where the operator may need to use a stent during the procedure. This needs to be done if retrieval or aspiration fails to reopen the blocked blood vessel.
Will I have a general anaesthetic?
Before the procedure begins, the anaesthetist will give you either a:
general anaesthetic, where you are asleep for the procedure; or
local anaesthetic with sedation, which is where the area is numb but you are awake for the procedure.
The multidisciplinary team will decide which anaesthesia you will have. The decision is based on your medical condition. If you have any questions or concerns about the anaesthesia, please speak to the doctor.
What are the benefits of having an MT?
About 4 to 5 in every 10 people who have an MT recover better than those who do not.
1 in every 2.6 people treated with MT were less disabled than those who were not treated.
1 in every 5 people achieved independence.
The faster the treatment happens, the better the chance of recovery. Removing the blood clot like this can:
reduce brain damage
improve recovery, and
help you regain independence.
However, there is no guarantee that everyone will completely recover after this treatment. The severity of the damage depends on several factors, but mainly on how long the clot blocked the blood supply in the brain.
What are the risks of having an MT?
As with any surgical procedure, there are risks related to thrombectomy. For most people, the benefits outweigh the risks. Having this treatment may save your own life or your relative’s life.
The risks include the following.
Bruising, swelling, infection or bleeding at the puncture site, where the catheter is inserted (groin). Rarely, surgery may be needed to repair the artery.
There is a small chance the procedure can:
temporarily affect kidney function; or
lead to an allergic reaction to the contrast (dye) used.
Around 2 to 10 in every 100 patients may suffer a bleeding in the brain.
Around 4 to 6 in every 100 patients may suffer a further stroke.
Very rarely, the procedure may cause
a tearing of the artery; or
perforation of a blood vessel. If this happens, further treatment may be needed and / or it may lead to disability or death.
There may be some chance of brain swelling, which may need further surgery. Especially when stroke damage was significant before the procedure and / or because of complications.
Consenting for mechanical thrombectomy
It is important that you / your relatives are involved in decisions about your care. Before we can go ahead with the procedure, we will explain:
why we think you need the procedure; and
what the benefits and risks are.
During this time-critical live-saving emergency situation, you may be too unwell and / or unable to give consent. If this happens, the senior multidisciplinary team can make a best interest decision for the procedure to be carried out.
Why do I need to sign a consent form?
All patients must give permission before they receive any type of:
medical treatment
test, or
examination.
Consent is usually obtained when you sign the consent form before your treatment. However, we may ask you to give your consent verbally (spoken rather than written consent).
You must give your consent voluntarily.
The hospital must give you all the information you need for deciding about your treatment. This is so you can give us informed consent. Please speak to staff if:
staff have not given you this information; or
they have but you still have questions.
You must be capable of giving consent. This means you understand the information given to you, and can make an informed decision.
When we ask you to give consent, please use this time to ask any questions you may still have. For more information, please go to the NHS Consent for Treatment web page. Remember, you can withdraw your consent for treatment at any time.
What happens immediately after the procedure?
Once the procedure is complete, you will have a repeat CT head scan in the Angiography suite. This is to make sure there were no complications related to the procedure.
We will then move you / your relative to the post-operative Recovery Area for continued observation.
You / your relative will need to stay in bed for around 4 hours, or as advised by your doctor.
In the Recovery Area, the nurses will monitor your observations, including your:
blood pressure
heart rate
oxygen levels
conscious levels (are you awake)
the puncture site in you groin or wrist, and
the pulses in your feet.
When will I leave the Recovery Area?
Once it is safe, you / your relative will be moved to the:
Hyperacute Stroke Unit (HASU);or
an Intensive Care Unit (ITU), if continued closer monitoring is needed.
You / your relative may move to your local hospital as soon as it is safe (if you / your relative are not local to the area).
Post-MT recovery and hyperacute stroke care
The Stroke team will take over you / your relatives’ care, as soon as the MT procedure is complete.
You will have another CT head scan at 24 hours. This is done to:
rule out any possibility of complications after the procedure; and
to start other stroke treatments, such as blood thinners.
You / your relative will receive ongoing stroke care during your hospital stay. Ongoing stroke care includes rehabilitation.
How long will I need to stay in hospital after an MT?
Stroke affects patients differently. Recovery from stroke depends on many factors. This may include:
the size, location and severity of the stroke damage; and
your age and overall health.
You / your relative will receive ongoing stroke care until you are discharged from hospital. You / your relative will have a follow-up with the stroke doctors around 3 months after you are discharged.
What if I have any concerns or worries?
If you or your relative have any questions, please contact the Hyper Acute Stroke Unit.
Hyper Acute Stroke Unit, Harbledown Ward, Kent and Canterbury Hospital, Canterbury
Telephone: 01227 766877 extension 722 3180
References
[Web sites last accessed 29 April 2026]
Ask 3 Questions
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