Left atrial appendage occlusion is a generally safe and effective procedure to lower the risk of stroke in people with atrial fibrillation. It closes or blocks off the left atrial appendage of the heart.

Atrial fibrillation, or “AFib” for short, is the most common type of arrhythmia. Researchers estimate that it affects 3 to 6 million adults in the United States and predict the number will rise to 16 million by 2050.

The effects of AFib increase the risk of blood clots. Due to this, people with AFib are at a higher risk of serious complications from blood clots, such as ischemic stroke. The Centers for Disease Control and Protection (CDC) notes that AFib contributes to about 1 in 7 strokes.

Left atrial appendage occlusion (LAAO) is a procedure doctors can use to prevent blood clots that may lead to a stroke. It blocks off an area of the heart where up to 90% of blood clots form in people with AFib.

The article explores the ins and outs of LAAO, including why it’s done, what it involves, and your outlook after the procedure.

What is the function of the left atrial appendage?

The left atrial appendage is a small pouch in the wall of the upper left chamber of your heart (left atrium). It helps lower blood pressure in the left atrium if it becomes too high.

In people with AFib, blood can more easily pool in the left atrial appendage, making it a common source of blood clots.

Many people with AFib take anticoagulants (blood thinners) to reduce their stroke risk. Researchers estimate that anticoagulants decrease the risk of stroke in people with AFib by 50%. However, some may not be able to take or may choose not to take these drugs on a long-term basis.

In these scenarios, doctors may recommend LAAO. Candidates for LAAO include people with AFib who are at a high risk of stroke and are in one of the following situations:

  • cannot take anticoagulants due to other underlying health factors, including but not limited to:
  • have had a blood clot-related complication despite taking anticoagulants
  • are at a high risk of stopping or not regularly taking their anticoagulant medication
  • choose not to take anticoagulants

Previously, doctors performed LAAO using a surgical (open) procedure. In this approach, a surgeon would remove the left atrial appendage or clip it shut using a device called an AtriClip.

You may still have a surgical LAAO procedure if you have AFib and are already having heart surgery. However, catheter-based approaches to placing a device that blocks or closes off the left atrial appendage are becoming more common.

A catheter-based LAAO involves the following steps:

  1. The doctor will insert a long, flexible tube (catheter) into a vein through a small incision. Typically, they’ll use a vein near your groin area.
  2. Guided by imaging, they’ll advance the catheter through your blood vessels and to your right atrium.
  3. The doctor will make a small hole in the wall between your right and left atrium. They will then move the catheter through this hole to access your left atrium.
  4. They’ll carefully place the LAAO device to block or close off the left atrial appendage.
  5. After placing the device, they will withdraw the catheter and close the small incision.

People typically receive LAAO under general anesthesia. This means you won’t be conscious during the procedure and won’t have any pain while it’s happening.

Types of left atrial appendage occlusion (LAAO) devices

In addition to the AtriClip, which requires surgery, common LAAO devices placed via catheter include:

  • Watchman: Watchman is an expanding device shaped like a little parachute. It blocks the opening of the left atrial appendage, preventing blood clots from leaving. Newer versions have a broader size range.
  • Lariat: Lariat delivers a looped suture that looks like a small lasso. When tightened, the loop closes off the left atrial appendage.
  • Amulet: Amulet is an expanding mesh device with two discs, allowing two seals to form. It also comes in various sizes to accommodate different left atrial appendage structures.

While LAAO is generally safe, associated risks include:

  • a reaction to the anesthesia
  • excessive bleeding
  • infection
  • blood clots associated with the device or procedure that may lead to stroke
  • incomplete blockage of the left atrial appendage, which may let blood clots through
  • movement of the LAAO device outside of its intended location
  • nonclosure of the hole between your right and left atria
  • injury to the heart or blood vessels
  • pericardial effusion and cardiac tamponade, complications associated with fluid accumulation in the sac that surrounds the heart
  • cardiac arrest

Prior to your LAAO, your doctor will discuss the risks and potential complications of the procedure. During this time, be sure to raise any questions or concerns that you may have.

Before your procedure, your doctor will perform a transesophageal echocardiogram (TEE). This type of ultrasound uses a device that passes through your mouth and into your esophagus to make images of your heart.

The purpose of the TEE is to evaluate the size and location of the left atrial appendage, which can vary from person to person. This helps your doctor to plan your procedure.

Your doctor will also probably do other tests to get an idea of your overall health and if you’re fit enough for your LAAO. These may include:

As the day of your LAAO nears, your doctor will also give you preparation instructions related to your current medications, eating and drinking, and what to bring to the hospital. Be sure to follow these carefully so your LAAO can go on as planned.

Some people may be able to go home on the same day as their LAAO. Others may need to stay in the hospital overnight for monitoring.

Many people who’ve had LAAO will need to take anticoagulants during recovery. This is to help reduce the risk of blood clots associated with the device or procedure.

Your doctor will want to follow up with you about 45 days after your LAAO. They’ll do another TEE to ensure the device is in place, not leaking, and that there are no device-related blood clots.

If your doctor has no concerns after your follow-up, you may be able to stop taking anticoagulants. However, the best duration for anticoagulant treatment after LAAO is unclear, so your doctor may recommend taking them longer.

LAAO is generally safe and effective. A 2022 study with a 4-year follow-up period found that LAAO was as effective as anticoagulants in preventing major AFib complications.

A 2019 study assessed the outcomes of over 13,000 people with an average age of 78 after LAAO with an implanted device. Researchers found that:

  • Mortality (death) rates were:
    • 0.6% after 30 days
    • 1.9% after 90 days
    • 4.0% at 180 days
    • 7.5% at 365 days
  • The rate of hospital readmission within 30 days of LAAO was 9.4%.
  • Of the over 9,000 participants with 6 months of follow-up data, 1.2% were readmitted to the hospital with an ischemic stroke or transient ischemic attack (TIA) within 180 days of leaving the hospital.

A 2020 study of over 38,000 LAAO procedures with a 3-year follow-up period found that major complications were rare, occurring in 2.16% of people. The most common complication was pericardial effusion.

What is the success rate of left atrial appendage occlusion?

LAAO has a high success rate. A large 2020 study found that 98.1% of LAAO devices were implanted successfully.

A smaller 2023 study found that 97.62% of LAAO devices were implanted successfully, with a follow-up stroke rate of 0.74% per year.

There are some situations in which doctors may not recommend LAAO, such as if you have:

  • AFib with a low risk of stroke
  • left atrial appendage structure where doctors can’t safely place an LAAO device
  • heart valve disease
  • an atrial septal defect
  • a blood clot in the left atrium
  • a tumor or active infection

LAAO is a procedure that helps prevent stroke in people with AFib, the most common type of arrhythmia. Doctors may recommend LAAO for people who cannot take anticoagulants or for whom anticoagulants haven’t been effective.

An LAAO procedure often involves placing a device that blocks off or closes the left atrial appendage, where most blood clots form in people with AFib. Doctors often, but not always, perform this using a catheter-based approach.

LAAO is generally a safe and effective procedure. If a doctor recommends LAAO, they’ll inform you about the details of the procedure, associated risks and benefits, and what to expect during recovery.