Left atrial appendage closure (Percutaneous left atrial appendage occlusion (LAAO))
A catheter-based procedure that seals off a small pouch on the heart (the left atrial appendage) to lower the risk of stroke in atrial fibrillation, mainly for people who cannot safely take blood-thinning medicines long term.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- Left atrial appendage closure seals off a small pouch on the heart where clots tend to form in atrial fibrillation, to lower stroke risk.
- It is mainly for people who cannot safely take blood-thinning medicines long term, and is chosen by a specialist heart team.
- It is not a cure for atrial fibrillation, does not fix the heart rhythm, and does not remove every cause of stroke.
- It carries real procedure risks — including bleeding around the heart, the device moving, a clot on the device, and stroke — which must be weighed against your bleeding and stroke risk.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Targets the main site where clots form in atrial fibrillation, to lower stroke risk
You can safely take anticoagulant medicine long term, where medicine is usually the standard treatment.
You are monitored closely, especially your heart rhythm and the groin access site. You usually keep the leg still for a while to protect the access point.
A clear, written plan of which blood thinners or antiplatelets to take and when to stop them.
You are monitored closely, especially your heart rhythm and the groin access site. You usually keep the leg still...
Most people get up and about and go home within a day or two, once the heart rhythm and access site are stable.
Take it easy and avoid heavy lifting and straining while the access site heals. Continue any blood thinner or...
A follow-up scan (often through the gullet or a CT) usually checks the device is sealing the pouch and that no...
What is left atrial appendage closure?
Atrial fibrillation (AF) is an irregular heart rhythm that lets blood pool and form clots, mostly in a small pouch off the heart's left upper chamber called the left atrial appendage. If a clot escapes, it can travel to the brain and cause a stroke. The usual way to prevent this is a blood-thinning (anticoagulant) medicine taken every day.
Left atrial appendage closure seals off this pouch so clots are much less likely to form there and escape. A thin tube (catheter) is passed through a vein in the groin and across to the left side of the heart, and a small device is placed in the mouth of the pouch to block it off. Over the following weeks, a thin layer of the heart's own lining grows over the device.
It is used mainly for people with AF who are at high risk of stroke but cannot safely take anticoagulants long term — for example because of serious bleeding or a high bleeding risk. It is not a cure for atrial fibrillation, does not control the heart rhythm, and does not remove every cause of stroke.
It is less invasive than open surgery, but it is still a serious heart procedure with real risks, including bleeding around the heart, the device moving, a clot forming on the device, and stroke.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Appendage closure vs lifelong anticoagulant medicine
| Point | Appendage closure | Anticoagulant medicine |
|---|---|---|
| What it is | One-off procedure to seal the pouch | A tablet taken every day |
| Best for | People who cannot safely take anticoagulants | Most people with AF at stroke risk |
| Bleeding risk | Aims to reduce long-term bleeding risk | Ongoing bleeding risk while taking it |
| Stroke cover | Targets the main clot site only | Reduces clot risk throughout the body |
| Reversibility | Permanent device in the heart | Can be stopped or changed |
Anticoagulant medicine is the standard treatment for most people. Closure is mainly for those who cannot take it safely. A specialist heart team weighs your stroke risk and bleeding risk with you.
Preparing for your procedure
- Be assessed by a specialist heart team, who weigh your stroke risk against your bleeding risk and decide whether closure is right for you.
- Expect detailed imaging, especially an echocardiogram through the gullet or a CT scan, to size the pouch and check for any existing clot.
- Tell the team about all your medicines and supplements, and discuss exactly which blood thinners or antiplatelets you will take before and after.
- Mention any allergy to contrast dye and any kidney problems, as dye is used during the procedure.
- Have a dental check if advised, as treating dental infection first lowers the risk of a device or heart infection.
- Arrange someone to take you home and help for the first day or two, as you should not drive straight away.
- Ask whether you will have a general anaesthetic or local anaesthetic with sedation.
What happens
The procedure is done in a specialist catheter lab by a heart team, often under general anaesthetic so that detailed ultrasound from inside the gullet can guide it; some centres use local anaesthetic with sedation.
A thin tube is passed through a vein in the groin and guided up to the heart, then across the wall between the upper chambers through a tiny controlled puncture, so the team can reach the left atrial appendage. Guided by X-ray and ultrasound, they measure the pouch, position a closure device in its mouth, and check it is stable and fully sealing the opening before releasing it. The tubes are then removed.
The procedure often takes around one to two hours. Afterwards you are monitored closely, especially the groin access site and your heart rhythm, and many people stay overnight. You will usually take a blood thinner or antiplatelet for a period afterwards while the device heals over, then have a scan to confirm the pouch is sealed.
Is this procedure right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- You can safely take anticoagulant medicine long term, where medicine is usually the standard treatment.
- There is already a clot in the appendage, which usually needs treating or clearing first.
- The appendage shape or size is unsuitable for a device to seal it safely.
- Active infection or another condition makes the procedure unsafe right now.
Delay or rearrange if…
- You have an active infection, including a dental infection, that should be treated first.
- A clot is found in the appendage and needs anticoagulation or clearing before the device can be placed.
- Important imaging is missing, such as echocardiography through the gullet or a CT to size the pouch.
- Your kidney function needs review before contrast dye is used.
- Your medicines need safe adjustment, or your bleeding source needs controlling, first.
Alternatives to discuss
- Anticoagulant medicine (the standard treatment for most people at stroke risk).
- Treating a reversible cause of bleeding so that anticoagulants can be used.
- Treatment of the atrial fibrillation itself, such as rhythm control or ablation, where appropriate.
- Surgical closure of the appendage if you are already having heart surgery.
- A second opinion or heart-team review before deciding.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Comfort, sedation or contrast choices
If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.
Benefits
- Targets the main site where clots form in atrial fibrillation, to lower stroke risk
- An option for people who cannot safely take blood-thinning medicines long term
- May allow some people to come off, or reduce, anticoagulant medicine over time, as advised by the team
- Usually a quicker recovery and shorter hospital stay than open surgery
- A one-off procedure rather than a daily tablet
- Can reduce the long-term risk of serious bleeding linked to anticoagulants in suitable people
Risks & complications
- Bruising, bleeding or swelling where the catheter went in (usually the groin)
- A sore throat from the ultrasound probe or breathing tube
- Feeling tired or washed out for a few days
- A short-lived irregular heartbeat around the procedure
- A collection of blood around the heart, sometimes needing drainage
- A clot forming on the device, which may need extra blood-thinning treatment
- A small leak around the edge of the device, sometimes needing monitoring
- Damage to the blood vessel used for access, occasionally needing repair
- Stroke during or soon after the procedure
- The device moving or coming loose, occasionally needing retrieval or surgery
- Infection of the device or heart lining
- Death — uncommon, but a real risk, higher in frailer or higher-risk patients
The main specific concerns are bleeding around the heart, a clot forming on the device, the device moving, and stroke. Because this procedure is usually chosen for people with a high bleeding risk, the trade-off between bleeding and stroke risk is central. Ask the heart team why closure rather than medicine is recommended, your own estimated stroke and bleeding risks, and exactly which blood thinners you will take afterwards and for how long.
Published figures to discuss
Risks depend on your anatomy, frailty and bleeding risk, and the procedure is used mainly in higher-risk people, so a single figure can mislead. Complication rates have fallen as techniques have matured. The ranges below come from device registries and systematic reviews (mostly Watchman data); your personal risks should be estimated by the heart team, and this procedure does not remove every cause of stroke.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Fluid or blood around the heart (pericardial effusion) | Around 3% in pooled Watchman data | A proportion of these need drainage; it is one of the more common periprocedural complications. | Left atrial appendage closure for stroke prevention in AF — European Heart Journalacademic.oup.comPublished figure |
| Clot forming on the device (device-related thrombus) | Roughly 3–4% over follow-up in trial data | Reported around 3.7% over follow-up in pooled trial data; may need extra blood-thinning treatment and is checked for on the follow-up scan. | Left atrial appendage closure for stroke prevention in AF — European Heart Journalacademic.oup.comPublished figure |
| Device moving or embolising | Uncommon (well under 1% in modern series) | Occasionally needs the device to be retrieved or, rarely, surgery. | Left atrial appendage closure for stroke prevention in AF — European Heart Journalacademic.oup.comPublished figure |
| Stroke around the procedure | Roughly 1–2% in published series | A recognised but uncommon periprocedural risk; closure also does not remove every long-term cause of stroke. | Left atrial appendage closure for stroke prevention in AF — European Heart Journalacademic.oup.comPublished figure |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
Recovery is usually quicker than after open surgery because there is no chest wound — only a small access point in the groin. Many people go home within a day or two, though it can take a week or two to feel fully back to normal.
- Bruising, tenderness or a small lump where the catheter went in
- A sore throat for a day or two after the ultrasound probe and breathing tube
- Feeling tired or a little washed out for several days
- Taking a blood thinner or antiplatelet for a period while the device heals over
- A planned scan after several weeks to check the device
Aftercare
- Take any blood thinner or antiplatelet exactly as prescribed, and do not stop it without your team's advice.
- Look after the groin access site and watch for bruising, swelling, bleeding or pain.
- Avoid heavy lifting and straining for a week or two while the access site heals.
- Attend the follow-up scan that checks the device is sealing the pouch and that no clot has formed.
- Tell any dentist or doctor you have a heart device, as you may need antibiotics for some procedures.
- Keep managing your other stroke risk factors, such as blood pressure.
- Do not drive until your team advises it is safe, and check the current driving rules for where you live — the DVLA in England, Scotland and Wales, or the DVA in Northern Ireland.
- Someone to take you home and help for the first day or two
- A clear written plan of which blood thinners or antiplatelets to take, and for how long
- Loose, comfortable clothing that does not press on the groin site
- The follow-up scan appointment (often at around 6–12 weeks) noted
- An alert card or note that you have a heart device
- Clinic and out-of-hours contact numbers saved
Scars and how they heal
There is no chest wound. You will usually have only a small puncture where the catheter entered the vein, most often in the groin, which leaves a small mark and may bruise for a couple of weeks.
⚠ Get urgent help if…
- Signs of stroke — face drooping, arm weakness or slurred speech — call 999 immediately
- Sudden breathlessness, chest pain or fainting
- Bleeding, a rapidly swelling lump, severe pain, or a cold, pale or numb leg at the access site
- Fever, chills or feeling generally unwell, which can signal infection
- A fast or very irregular heartbeat with dizziness
- Any new bleeding (such as black stools or blood in urine) while taking a blood thinner
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A successful left atrial appendage closure seals off the main pouch where clots form in atrial fibrillation, so the risk of a clot escaping and causing a stroke is lower. A scan a few weeks later usually confirms the pouch is sealed, and in suitable people this can allow blood-thinning medicine to be reduced or stopped, lowering the long-term risk of serious bleeding.
Closure does not cure atrial fibrillation, does not control the heart rhythm, and does not remove every cause of stroke — clots can occasionally still form elsewhere, or on the device itself. Your team should be clear about how much it is expected to reduce your risk, and that managing your other risk factors and any remaining medicines still matters.
The device is permanent, and once the heart's own lining has grown over it the pouch should stay sealed. For carefully selected patients, the protection against appendage clots is intended to be long term. However, this does not stop atrial fibrillation, so your rhythm and other stroke risk factors still need managing, and a small leak around the device or a clot on the device can occasionally develop and need monitoring or treatment. Long-term outcomes depend on careful patient selection and follow-up.
Related tests, treatments or support
Appendage closure is sometimes done at the same time as another catheter procedure for atrial fibrillation, such as an ablation to control the rhythm, in selected patients. Surgical closure of the appendage is usually only done when you are already having heart surgery for another reason. Closure does not replace treatment of the rhythm itself, nor management of other heart conditions.
Follow-up & long-term care
You will be monitored for a day or two after the procedure, particularly the access site and your heart rhythm. You will usually take a blood thinner or antiplatelet for a set period, then have a scan (often through the gullet or a CT) at around six to twelve weeks to confirm the pouch is sealed and that no clot has formed, before any change to your medicines. Tell your team promptly about any stroke symptoms, new bleeding or fever.
- Taking any prescribed blood thinner or antiplatelet exactly as advised, and not stopping it without guidance
- Attending the follow-up scan that checks the device is sealing and clot-free
- Good dental care and telling clinicians you have a heart device, to reduce infection risk
- Continuing to manage other stroke risk factors, such as blood pressure
- Prompt review for stroke symptoms, new bleeding or signs of infection
Repeat, follow-on and what comes next
- A clot can form on the device and may need a period of extra blood-thinning treatment.
- A small leak around the device may be found on the follow-up scan and is usually monitored.
- Rarely the device moves or embolises and needs retrieval or surgery.
- Closure does not treat the atrial fibrillation, so rhythm and other risk factors still need managing.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear, written plan of which blood thinners or antiplatelets to take and when to stop them.
- A planned follow-up scan to confirm the pouch is sealed and check for a device clot or leak.
- A named contact and clear out-of-hours route for stroke symptoms, new bleeding or fever.
- Advice on dental care and antibiotic cover to reduce device-infection risk.
- Continued management of atrial fibrillation and other stroke risk factors, such as blood pressure.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The operator's and team's fees, and the specialist heart-team assessment
- The closure device used (different devices have different costs)
- Catheter-lab time, and whether a general anaesthetic and detailed ultrasound guidance are used
- Pre-procedure imaging, including echocardiography through the gullet or CT, and contrast dye
- Length of stay and level of monitoring needed afterwards
- The follow-up scan to confirm the pouch is sealed, and any treatment of a complication
- Follow-up appointments and any change to medicines
- The operator's and heart-team fees
- The device cost and which device is included
- Catheter-lab, anaesthetic and imaging charges
- Pre-procedure imaging and assessments
- Expected length of stay and monitoring, and the cost of extra days
- The follow-up scan to confirm sealing, and follow-up appointments
- What happens, and who pays, if you need drainage, device retrieval, surgery or readmission
On the NHS? Left atrial appendage closure is available on the NHS for selected patients, chosen by a specialist heart team, mainly when anticoagulant medicine cannot be used safely; private care may be considered for timing, but suitability is still decided clinically.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not being told anticoagulant medicine is the standard treatment for most people at stroke risk.
- No clear plan for exactly which blood thinners to take after the procedure, and for how long.
- The risks of bleeding around the heart, device clot and device movement not spelled out.
- Implying it removes all stroke risk, when clots can still form elsewhere or on the device.
- No written aftercare and warning-signs plan, including stroke and bleeding symptoms, before discharge.
Marketing red flags
- Promising it 'ends the need for blood thinners' from day one, or removes all stroke risk.
- Describing it as a cure for atrial fibrillation.
- Calling it a quick or without risks fix, without mentioning bleeding, device clot or stroke.
- Skipping the role of a specialist heart team and careful weighing of stroke versus bleeding risk.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Why do you recommend closure rather than blood-thinning medicine for me?
- What are my estimated stroke and bleeding risks, with and without this procedure?
- Exactly which blood thinners or antiplatelets will I take afterwards, and for how long?
- What is my personal risk of bleeding around the heart, a clot on the device, or stroke?
- When will the follow-up scan be, and what happens if it shows a leak or a clot?
- Do I still need treatment for the atrial fibrillation itself?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my procedure, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this procedure not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Will I be able to stop my blood thinners after this?
Does this cure my atrial fibrillation?
Will I be asleep during the procedure?
Who is this procedure mainly for?
What is the main thing that can go wrong?
Is it available on the NHS?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NICE HTG222 (formerly IPG349) — Percutaneous occlusion of the left atrial appendage in non-valvular AF NICE IPG349 — Guidance: left atrial appendage occlusion British Heart Foundation — Atrial fibrillation Left atrial appendage closure for stroke prevention in AF — European Heart Journal Percutaneous left atrial appendage closure with the Watchman device: systematic review — PubMed Device-related thrombus after left atrial appendage closure — PMC DVLA — assessing fitness to drive DVA Northern Ireland — telling DVA about a medical condition
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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