What is the Left Atrial Appendage (LAA) and why is it relevant to me?

Atrial fibrillation (AF or AFib), the most common heart rhythm disorder, is present when the heart’s two upper chambers, the left and right atria, beat in a fast and irregular manner. The left atrial appendage (LAA) is a small sac or pouch which opens into the left atrium.

AF is present in 1-2% (ie, one or two in a hundred people) of the Irish population and is more common if other forms of heart and vascular disease are present (eg, coronary artery disease, heart valve disease and hypertension). AF is also more common in older people. As a rule, people with chronic (or long-term) AF will have a five times greater risk of stroke and a two times greater risk of dying, as compared to similar people without AF. As a result of AF, blood flow within the atria becomes sluggish and this may result in the development of blood clot within the atria, particularly within the LAA.

As a result of this potential for blood to clot, drugs to “thin” one’s blood, known as anticoagulants (ie, anti-clotting agents), are one of the most commonly prescribed treatments for patients with AF.

Although Warfarin is still the most commonly prescribed anticoagulant, available for more than 50 years, other anticoagulant agents have become available in recent years (eg, Dabigatran, Rivaroxaban and Apixaban). All of these agents, when taken regularly, reduce the risk of blood clot formation and stroke.

As with any drug, anticoagulant medication is associated with various risks, benefits and downsides. The main risks relate to frequent minor and less frequent serious bleeding. Downsides sometimes include the need to modify one’s diet and/or alcohol intake as well as the need for life-long supervision in an Anticoagulant Clinic in some cases.

In some patients, the risks or consequences of bleeding with anticoagulant medication are so great that it is simply not possible to prescribe such agents and antiplatelet drugs (ie, Aspirin and/or Clopidogrel) are used instead. The combination of Aspirin and Clopidogrel, whilst not as effective as the anticoagulant agents in terms of AF stroke prevention, does offer some measure of protection with a lower risk of bleeding.

The procedure of LAA closure is intended to reduce one’s risk of stroke without the medium to long-term need for anticoagulant or antiplatelet therapy thereby reducing the potential for serious bleeding which would otherwise be associated with such agents.

Two devices to close the LAA are now available and we propose to use either the Watchman device or the Amplatzer Cardiac Plug (ACP) depending on the size and shape of your heart’s LAA.

Recent clinical studies comparing transcatheter LAA closure with the Watchman device against conventional treatment with Warfarin have shown that the Watchman device is at least as good as taking Warfarin, thus giving patients and doctors an alternative to Warfarin therapy when it comes to reducing the risk of stroke.

The Amplatzer Cardiac Plug device performs the same function as the Watchman and is implanted in the same way. It is used when the size and shape of the LAA does not accommodate the Watchman device. Less evidence is available for the Amplatzer Cardiac Plug as compared with the Watchman device, although like Watchman it has all the necessary European regulatory approvals in place.

How is the procedure carried out?

Transcatheter closure of the LAA is carried out in the cardiac catheterisation laboratory. A small cut (or incision) is made in your groin and, through this cut, a small plastic tube (known as a catheter) is inserted into a vein in your leg. This catheter contains the compressed umbrella shaped device, which is used to close the opening of the left atrial appendage.

Using X-rays and ultrasound images, this catheter is guided into your heart. The umbrella-like Watchman or Amplatzer Cardiac Plug device, is passed through the catheter and into position within the LAA. As the compressed device is pushed from the end of the catheter tip it expands thereby blocking the mouth of the left atrial appendage.

A Watchman device in position within the LAA, resulting in its closure (shown below).

The Watchman occlusion device (shown below) is an umbrella shaped device made of Nitinol with a PET [polyethylene] fabric covering. Five sizes are available, ranging from 21-33 mm.

An Amplatzer Cardiac Plug device in position, with the LAA resulting in occlusion (shown below).

The Amplatzer Cardiac Plug is also a Nitinol device consisting of disc and plug components with an internal PET fabric mesh (shown below).

Which device is suitable for me?

Following your previous assessments, your doctor may recommended that you consider and potentially proceed with LAA closure. The Watchman device is usually the “first choice” since research has shown that it works as well as Warfarin. However, in some cases the size and shape of one’s LAA is not suitable for the Watchman device and in these circumstances it may be possible to use the Amplatzer Cardiac Plug as a potential “second choice”, as this device is newer and there is less research evidence regarding its benefit as compared with anticoagulant therapy.

It is possible that you will be asked to undergo a heart CT scan in advance of your LAA closure procedure so as to help determine whether your LAA is more suited for either the Watchman device or the Amplatzer Cardiac Plug.

The implantation procedure is the same for both devices, but in many instances it may not be possible to tell if the Watchman device may be used until after you have been anaesthetised. Thus, it is important for your doctor to know your decision regarding Watchman versus Amplatzer Cardiac Plug versus leaving you untreated if the Watchman device cannot be used allowing you to remain on long-term anticoagulant therapy, if appropriate.

With these options in mind, the doctor obtaining your consent for LAA closure will ask you specifically if you consent to: (a) the Watchman device or the Amplatzer Cardiac Plug device; or (b) if unsuitable for the Watchman device you would prefer to simply continue with Warfarin [or other anticoagulant/antiplatelet] therapy.

Local and general anaesthesia

The procedure is usually carried out using both local anaesthesia (an injection to numb the area of your groin where the catheter is inserted) and general anaesthesia (so that you will be asleep during the procedure).

During the procedure, a cardiac ultrasound (or echo) examination is undertaken (to obtain clear pictures of your heart) by placing an echo probe in your gullet (also known as the oesophagus). In addition, you will be given a drug called Heparin via an intravenous injection which further reduces the risk of blood clot forming whilst the device is being inserted.

General anaesthesia will be given by a Consultant Anaesthetist.

On the ward

An anaesthetist will visit you on the ward before the operation to discuss your anaesthetic. The anaesthetist will enquire about your general health, previous experiences of anaesthesia, any medicines you are taking and any allergies you might have. You must tell the anaesthetist if you have had any problems with swallowing or food getting stuck; this is important because a special ultrasound probe will be passed down your gullet (oesophagus) during the procedure, which could cause an injury especially if you have had previous problems with swallowing or surgery to your oesophagus.

If you have caps or crowns on your teeth, please tell the anaesthetist at this time as these can very occasionally be damaged during anaesthesia. This is a good time to talk about any previous experiences you have had with injections or hospitals, or any particular concerns you have.

Occasionally, your anaesthetist may discover something about your general health that could increase the risks of your anaesthetic or operation. It might then be better to delay your operation until the problem has been reviewed. This could happen if you have a cold, rash or infection.

Eating and drinking

It is important that your stomach is as empty as possible before the anaesthetic Usually you must not eat anything at all for six hours before you go to the catheterisation laboratory but you may drink clear fluids (eg; water) up until 2 hours before the procedure. The nurse looking after you on the ward will tell you when you need to stop eating and drinking.

Before the procedure

The anaesthetist may prescribe a sedative (pre-medication) to be given by the nurses before you go to the operating theatre. Pre-medication or “pre-med” is given to you to help you to relax ahead of a procedure. It will usually be given to you in the form of a tablet.

The procedure

You will then be taken to the cardiac catheterisation laboratory. One of the nurses from the ward will come and remain with you until you are transferred into the care of the anaesthetist. When you arrive in the catheterisation lab, the anaesthetic assistant will check your details. You will be transferred onto the operating table and moved into the anaesthetic room where, the anaesthetic assistant will attach you to a heart monitor and place a pulse and oxygen monitor on your finger.

The anaesthetist will then put a needle into a vein in your hand or arm, through which the anaesthetic can be given to send you to sleep. You may also be aware of him/her injecting some local anaesthetic into your wrist in order to place a small tube into an artery. After this, you will receive some oxygen from a mask and the anaesthetist will start to give you the anaesthetic medication.

Once asleep the anaesthetist will monitor your condition carefully throughout the procedure and give you fluids and medication as necessary. An ultrasound probe (used to obtain a view of your heart) will be passed down your throat, helping us to perform LAA occlusion and generally monitor how well your heart is working during the procedure.

Once the device is positioned and the procedure completed you will be woken from the anaesthetic and taken to the recovery area where you will be monitored closely until you are fully awake. Then you will be taken back to the ward where you will be cared for until discharge the following day.

What are the benefits of this procedure?

The main benefit of this procedure is that it potentially eliminates your need to take Warfarin for the rest of your life. You are unlikely to feel any different once the anaesthetic wears off and you return to normal. In the majority of patients Warfarin (or other anticoagulant therapy) is continued for a minimum period of 6-8 weeks post procedure so as to allow time for the implanted device to “bed in”. You will also usually be advised to take low-dose Aspirin alongside Warfarin from the time of your procedure. During the initial 3-5 week period following device implantation your body will form a new layer of natural tissue over the device sealing it into place.

Are there any alternatives to this procedure?

If you choose not to have your LAA closed with either the Watchman device or Amplatzer Cardiac Plug you will be advised to simply continue with Warfarin (or other anticoagulant therapy), unless there is a specific reason why you should not take such treatment. In selected circumstances, you may be offered an alternative approach to LAA closure, for example using a surgical approach.

Are there any risks?

No medical procedure is entirely without risk. It is important to remember that your doctor would not have recommended this procedure if he / she did not believe the potential risks were outweighed by the likely benefits to your health.

The overall risk of suffering any complication from this procedure is in the range of 2-4% (in other words, between 2 and 4 people out of every 100 who undergo this procedure experience a complication of some sort). Some complications are minor such as bruising whilst others may be serious, such as bleeding around the heart. These are listed below.

The risk of dying as a result of the procedure itself is estimated to be less than 1 in 500 (ie, less than 0.2%). No deaths have been reported to have occurred directly as a result of the procedure itself in the patients who have received these devices to date.

To put this into perspective, the risk associated with supervised Warfarin use amounts to an annual risk of any form of bleeding of between 4-15% (ie, 4 to 15 out of every 100 people taking Warfarin experience bleeding problems). The risk of life-threatening bleeding is in the range of 1-3% per year (ie, 1-3 people in every 100 treated).

The most common complications from this procedure include:

Bleeding or bruising in the area of the groin where the catheter was inserted: This is the most common complication from the procedure and is not normally serious. You will be asked to keep your leg straight for a few hours after the procedure to minimise the risk of bleeding. When you leave hospital, you will be advised to avoid any strenuous physical activity or heavy lifting for at least one week. In some patients a single skin suture (or stitch) will be used to reduce bleeding at the end of the procedure; if so, this stitch will need to be removed by a practice or district nurse 3-5 days post procedure.

Stroke: This is an uncommon complication (occurring in approximately 1% of patients receiving the device) and may occur during the procedure if a small blood clot or air bubble passes to the brain. As mentioned above, you will be given Heparin during the procedure to reduce the risk of blood clots.

Device malposition or embolisation:

* Sometimes the device does not sit properly within the heart even though it closes the hole. If this happens, we may need to remove the device and insert another one.

* In some cases, the LAA is too big and the implanted device cannot be correctly positioned and so it must be removed and the LAA left untreated.

* Rarely, the device may move after being released or fall out of position into left-sided heart chambers; this complication occurs in approximately 1 in 300 patients and if this happens, we will try to remove the device by a similar catheter-based technique. If this is not possible, open heart surgery may be required to remove the device.

* You will have a chest X-ray and/or an echocardiogram (an ultrasound of the heart) on the day after the procedure to make sure that the device remains in the correct position.

Bleeding around the heart: Sometimes the catheter used to insert the device can make a small hole in the heart during the procedure and cause bleeding. This can usually be drained under local anaesthetic with a needle but occasionally surgery is required. This complication occurs in approximately 1-3% (ie, one to three out of every 100) of people having this procedure.

Infection: Infection in the heart or of the heart valves (known as “endocarditis”) has not been reported with the Watchman device, but is recognised as a rare complication following other types of heart defect device closure.

Oesophageal damage: During the procedure an ultrasound probe will be passed down your gullet (oesophagus) to assist in positioning the device. Rarely (less than 1 in 2000) this can cause damage to the gullet, which requires major surgery to repair.

What happens after the procedure?

As mentioned above, you will have a chest X-ray assessment and/or an echocardiogram (an ultrasound scan of the heart) on the day after your procedure to make sure the device remains in the correct place and, if all is well you will be discharged home.

You will be given a follow-up appointment for about six to eight weeks after your discharge. During this appointment you will undergo a further transoesophageal echocardiogram to make sure that the device is working properly and that there are no “gaps” around the device.

By this time between 85-90% of patients will have no significant “gap” and be able to safely discontinue their Warfarin (or other anticoagulant / antiplatelet therapy). The remaining group of patients may take a little longer and approximately 5% (ie, 1 in 20 patients) may be advised not to discontinue their anticoagulant/antiplatelet therapy long term.

The majority of patients treated with the Watchman device in our hospital have been able to discontinue Warfarin within 2 months of having the procedure performed.

Most people feel completely well and back to normal within two or three days of their procedure. If, for whatever reason, you do not feel well at any time after your procedure, please make telephone contact with the nursing and/or medical staff on the ward where you were treated, even if this happens to be days or weeks following your procedure.

What medication will I need to take?

After this procedure, you will usually need to take Warfarin for at least 6-12 weeks, and possibly longer until the LAA is fully sealed. Some patients who cannot take Warfarin at all will be given Aspirin and Clopidogrel for a period of 3-6 months. If you are on a different anticoagulant specific advice will be given to you prior to discharge.

These medications help to prevent any blood clots forming on the device and so it is very important you take them as prescribed. Dr Lyne will discuss this with you and adjust any other medication as necessary according to your condition.

It is important you understand the information provided here, the risks and benefits of the procedure that has been recommended to you and the choice you are being asked to make.

 

If you have any further questions please ask and we will be happy to discuss these with you.