Left atrial appendage occlusion
Left atrial appendage occlusion | |
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ICD-9-CM | 37.36 |
Left atrial appendage occlusion (LAAO), also referred to as left atrial appendage closure (LAAC), is a
Rationale
The left atrial appendage is a pouch-like structure located in the upper part of the left atrium.[1] Left atrial appendage occlusion (LAAO) is an alternative therapy to oral anticoagulation in a certain subset of patients with atrial fibrillation. Atrial fibrillation is characterized by an irregular and uncoordinated pumping function of the atria. This chaotic pattern of contraction can lead to reduced pumping efficiency and subsequent formation of blood clots, most notably in the left atrial appendage.[1] Over 90% of stroke-causing clots that originate in the heart in patients with non-valvular AF are formed in the left atrial appendage.[2] LAAO does not completely eliminate the risk of stroke in patients with AF but it does reduce the risk of stroke from emboli that originate in the left atrial appendage.[3] The left atrial appendage can be purposefully occluded (i.e. closed) to help prevent the formation of clots in one of two ways.
- The Lariat procedure is a surgical procedure that can be performed to ligate the left atrial appendage from outside the heart.
- Endovascular implant is a catheter-based procedure used to place an occlusion device inside the orifice of the left atrial appendage.
Indications
The most common treatment aimed at alleviating the burden of stroke in the setting of AF includes anticoagulation (blood-thinners), which are used to reduce the chance of blood clot formation. These medications, specifically direct oral anticoagulants (i.e. dabigatran, apixaban, rivaroxaban, edoxaban) and vitamin K antagonists (i.e. warfarin), are very effective in lowering the risk of stroke in AF patients. Most patients can tolerate anticoagulation for years (and even decades) without serious side effects. However, there are certain subsets of individuals who are unable to tolerate anticoagulation, and may be subject to increased bleeding or hematological risks. These patients may be good candidates for LAAO:[4]
- Patients with poor anticoagulation therapy compliance (approximately 45% of patients who are eligible for warfarin are not being treated, due to tolerance or adherence issues)[5]
- Patients with intolerable side effects to anticoagulation therapy
- Patients with chronic thrombocytopenia (low platelets) or a known coagulation defect associated with bleeding
- Patients with a prior history of severe bleeding (e.g., intracranial hemorrhage, major gastrointestinal bleeding)
- Patients with a high risk of falling or a history of prior falls that resulted in injury
- Patients with AF that are already undergoing cardiac surgery for other indications
Devices and alternatives
Surgical procedure
Lariat procedure
Occlusion of the left atrial appendage can be achieved from outside the heart (the Lariat device) or from inside the heart (endovascular) with a blood-exposed implant (the Watchman and Amulet devices). The first method is a form of ligation that eliminates perfusion of the LAA. While effective in preventing many embolic strokes, it also negates the endocrine contribution (atrial natriuretic peptide) of the LAA. The second approach has many hazards as well but preserves the cardiac endocrine properties of the LAA. Further evaluation of both approaches is merited.
Over-sewing
The LAA can also be surgically removed simultaneously with other cardiac procedures such as the maze procedure or during mitral valve surgery; specifically, it can be occluded or excluded by over-sewing, excision and resection, ligation, stapling with or without amputation of the LAA or application of a clip system [6][7][8] Finally, the left atrial appendage has been closed in a limited number of patients using a chest keyhole surgery approach.[9][10]
Clip devices
LAA can also be occluded by the placement of clips such as the AtriClip or Penditure devices.
Catheter-based LAAC implant procedure
Watchman device
On March 13, 2015, the
The Watchman is a one-time implant typically performed under
The patient continues taking warfarin with aspirin for 45 days post implantation at which point in time they return for a
Another device termed PLAATO (percutaneous left atrial appendage transcatheter occlusion) was the first LAA occlusion device,[17][18] although it is no longer being developed by its manufacturer (Appriva Medical, Inc. from Sunnyvale, California). In 210 patients receiving the PLAATO device, there was an estimated 61% reduction in the calculated stroke risk.[19]
Amplatzer Amulet device
The Amplatzer device from St. Jude Medical, used to close atrial septal defects, has also been used to occlude the left atrial appendage.[20][21] This can be performed without general anaesthesia and without echocardiographic guidance. Transcatheter patch obliteration of the LAA has also been reported.[14] The Amulet device is inserted very similarly to the Watchman LAAC implant. A catheter is introduced into the groin and travels up to the heart where it crosses from the right atrium into the left atrium via a hole in the septum. The device is then discharged into the LAA. Eventually tissue grows over the Amulet device and completely occludes the LAA.[22]
The ULTRASEAL LAA device, from Cardia, is a percutaneous, transcatheter device intended to prevent thrombus embolization from the left atrial appendage in patients who have non-valvular atrial fibrillation. As with all Cardia devices (such as: Atrial Septal Defect Closure Device or Patent Foramen Ovale Closure Device), the Ultraseal is fully retrievable and repositionable in the Cardia Delivery System used for deployment. The device can be retrieved and redeployed multiple times in a single procedure without replacing the device or delivery sheath.
Other devices exist to occlude the
Adverse events
The main adverse events related to these procedures include pericardial effusion, incomplete LAA closure, dislodgement of the device, blood clot formation on the device requiring prolonged oral anticoagulation, and the general risks of catheter-based techniques (such as air embolism).[25] The left atrium anatomy can also preclude use of the device in some patients.[26]
Theoretical concerns surround the role of the LAA in
Preserving the right atrial appendage might attenuate this effect.[29]Footnotes
- ^ a b "Left Atrial Appendage Closure Procedures". www.hopkinsmedicine.org. 2023-03-15. Retrieved 2023-11-05.
- PMID 8572814.
- PMC 4659748.
- ^ "UpToDate". www.uptodate.com. Retrieved 2023-11-05.
- ^ Jani, et al. (April 2014). "Uptake of Novel Oral Anticoagulants in Patients with Non-Valvular and Valvular Atrial Fibrillation: Results from the NCDR-Pinnacle Registry", J Am Coll Cardiol 63 (12). Table 1.
- PMID 12514671.
- PMID 16086933.
- PMID 10856866.
- PMID 14522490.
- US Food and Drug Administration), April 2015.
- PMID 25332785.
- ^ a b c Watchman Left Atrial Appendage Closure Device with Delivery System Archived 2015-06-24 at the Wayback Machine. 14 (Boston Scientific), March 2015.
- ^ PMID 17261703.
- ^ Schmidt H, Hammerstingl C, von der Recke G, Hardung D, Omran H (2006). "Long-term follow-up in patients with percutaneous left atrial appendage transcatheter occlusion system (PLAATO): risk of thrombus formation and development of pulmonary venous obstruction after percutaneous left atrial appendage occlusion". J. Am. Coll. Cardiol. 47: 36A.[permanent dead link]
- PMID 24998121.
- PMID 11997272.
- PMID 15992628.
- S2CID 54365763.
- S2CID 2978865.
- S2CID 1895296.
- ^ Health, Center for Devices and Radiological (2021-10-04). "Amplatzer Amulet Left Atrial Appendage Occluder – P200049". FDA.
- .
- PMID 23062528.
- PMID 17397680.
- PMID 16996847.
- PMID 7455689.
- PMID 9699572.
- PMID 1830916.