Comparing LAA Closure Devices: Amulet vs. Watchman
May 24, 2023
If you’ve been diagnosed with atrial fibrillation / Afib, you’ve probably been told you have a significantly increased risk of stroke – a five-fold increase in risk. Managing this stroke risk is the primary goal we, as electrophysiologists, have when treating Afib. While our minimal invasive cardiac catheter ablation procedures are very effective at treating paroxysmal and certain persistent cases of Afib, they cannot reverse the existing risk of stroke because that ultimately comes from a small outpouching of the heart known as the left atrial appendage for LAA. This feature of the heart, whose existence we don’t fully understand, causes outsized effects on the risk of stroke.
What’s So Bad About the LAA?
When the heart beats normally, there is minimal risk from the LAA. Blood flows in and out of this area predictably and reliably. However, the irregular heartbeat associated with Afib often causes blood to pool within the pouch. This pooled blood eventually coagulates, and if a small piece of blood dislodges, it can travel to the brain, where it can block a small blood vessel and cause what is known as an ischemic stroke. While it’s difficult to accurately predict this stroke risk without intervention, we stratify Afib patients based on their CHA₂DS₂-VASc score.
This score, from zero to nine, evaluates various criteria that increase the risk of stroke. Based on that, we can best understand the necessary treatment options. While cardiac catheter ablation has proven superior in most cases over medication for the long-term treatment of Afib, medication wins the day when it comes to stroke risk. Anticoagulant medications, colloquially known as blood thinners (though they do not thin the blood), are the first and best line of defense against this increased risk of stroke. These medications target blood clotting properties, making it far less likely for a stroke to occur. With that said, some patients may not be good candidates for anticoagulant medication therapy due to side effects or reactions; others may have bleeding or clotting disorders or a heightened fall risk, which would be dangerous when combined with anticoagulant medication. As such, the mechanical closure of the LAA is needed and comes in the form of two devices – the Amulet from Abbott and the Watchman FLX from Boston Scientific. To fully understand and compare these devices, it’s important first to point out their similarities.
- The FDA approved the Amulet and the Watchman to help patients with heightened stroke risk that cannot take anticoagulants.
- Both devices are placed using minimally invasive cardiac catheter technology in an electrophysiology lab. This means a tiny incision is made in the groin area, and a spaghetti-like catheter system is threaded through the blood vessel and up to the heart.
- Once in place, the devices work in a very similar way. They are deployed from the tip of the catheter and placed at the opening of the LAA to occlude or close it off from the rest of the heart, thus helping prevent the movement of clotted blood out of the pouch.
- In both cases, patients can often leave the hospital within a day of the procedure.
- Both devices also offer a very similar long-term risk profile.
And Now, the Differences Between These Two Procedures
The Amulet has eight different-sized implants allowing it to fit a broader range of heart anatomies than the Watchman FLX. While this is theoretically a significant difference between the two, in practice, most patients will find an appropriately sized implant regardless of the device used. That said, a small number of patients have LAA anomalies that require the flexibility of the Amulet. As such, Dr. Tordini will use the most appropriate device for each patient.
The Amulet also has a dual seal design to reduce the possibility of leakage after the procedure. This was shown in a 2021 clinical trial¹ here in the United States, with the amulet having a slight advantage over Watchman in the amount of occlusion it provides.
As for peri-procedural risks (complications during the procedure), there has been some variance in the literature. A European study showed that the Amulet has a significantly greater complication risk during the procedure.² In contrast, an American study showed a far more negligible difference, and both showed peridevice leakage is more likely with the Amulet.
Lastly, and importantly for many patients, the Amulet does not require anticoagulant therapy after the procedure. On the other hand, Watchman patients must continue anticoagulants for 45 days after the procedure or antiplatelet medication for up to six months.
Doctor Tordini’s Take
As a user of both devices, there are clear benefits and risks to each, as there would be for any interventional procedure. Complications are well-managed regardless of the device, and outcomes are generally excellent. We strongly believe that patient selection is critical to reducing the risk of any procedure, and these are no different. As such, we keep an open mind about which method to use and base that decision on the individual patient and their medical circumstance. Finally, for most patients that qualify for the Watchman or Amulet, the procedure’s risks are far outweighed by the benefits they will receive.
Most importantly, don’t ignore arrhythmia, as the consequences of increased stroke risk, heart attack, and congestive heart failure risk are significant. We have the tools to manage arrhythmias and their follow-on problems, and it’s simply up to our patients to understand that they may be at risk and get appropriate treatment. If you have any questions about your risk of stroke or if you currently experience a cardiac arrhythmia, it’s vital that you see your electrophysiologist. If you are in Tampa, please visit us at one of our three convenient locations.
Also, remember that heart palpitations are not exclusive to cardiac arrhythmia and could be something more serious, so if you believe you have a heart attack, do not delay seeking emergency care by dialing 911 or visiting your nearest emergency room.
References:
- Lakkireddy D, Thaler D, Ellis CR, Swarup V, Sondergaard L, Carroll J, Gold MR, Hermiller J, Diener HC, Schmidt B, MacDonald L, Mansour M, Maini B, O’Brien L, Windecker S. Amplatzer Amulet Left Atrial Appendage Occluder Versus Watchman Device for Stroke Prophylaxis (Amulet IDE): A Randomized, Controlled Trial. Circulation. 2021 Nov 9;144(19):1543-1552. doi: 10.1161/CIRCULATIONAHA.121.057063. Epub 2021 Aug 30. PMID: 34459659; PMCID: PMC8570346.
- Galea R, De Marco F, Meneveau N, Aminian A, Anselme F, Gräni C, Huber AT, Teiger E, Iriart X, Babongo Bosombo F, Heg D, Franzone A, Vranckx P, Fischer U, Pedrazzini G, Bedogni F, Räber L, Valgimigli M. Amulet or Watchman Device for Percutaneous Left Atrial Appendage Closure: Primary Results of the SWISS-APERO Randomized Clinical Trial. Circulation. 2022 Mar 8;145(10):724-738. doi: 10.1161/CIRCULATIONAHA.121.057859. Epub 2021 Nov 6. PMID: 34747186.