Cardiologists and electrophysiologists are tasked with managing not only the challenging clinical questions regarding the management of atrial fibrillation (AF), but are also many times the focal point to making the critical decisions regarding stroke prevention. As the population ages, and the incidence and prevalence of AF only rises, and the dilemmas regarding stroke management and risk reduction become more complex. The left atrial appendage (LAA) is the focal point of stroke prevention due to atrial fibrillation. In recent years it has gone from a long ignored anatomic structure, to the subject of a wide variety of interventional procedures. While surgical ligation of the left atrial appendage was described several decades ago, it is only more recently that options of LAA exclusion have entered the percutaneous arena. Currently the only FDA-approved product is the LARIAT® Suture Delivery Device (SentreHEART, Inc.). In the future, additional device-based options will include therapies such as the WATCHMAN Device (Boston Scientific) and the AMPLATZER Amulet Occluder (St. Jude Medical).
One of the most critical aspects of AF management is establishing each patient’s specific risk of stroke, routinely performed by determining a patient’s CHADS2 or CHA2DS2-VASc score. This data allows the clinician to then gauge the need for anticoagulation compared with the patient’s risk of bleeding, typically demonstrated by the patient’s HAS-BLED score. Oftentimes there are obvious contraindications to anticoagulation such as hemorrhagic CVA, recurrent life-threatening GI bleeds, or other bleeding diatheses that preclude anticoagulation. Patients that are intolerant of anticoagulation are candidates for the LARIAT Suture Delivery System. Currently our practice is to offer this option only to patients with contraindications to anticoagulation, not as an alternative.
While no guidelines-based criteria have been set forth as of yet for the LARIAT system, current practice at our institution involves screening patients with nonvalvular AF and a CHADS2 risk score of 2 or higher. In addition, there must be an absolute or relative contraindication to long-term anticoagulation as well as no prior history of sternotomy or pericarditis. Formal consultation or documentation of the specific contraindication is obtained, as is the patient’s assessment of risk for a short course of post-procedure anticoagulation.
All patients screened for the LARIAT procedure undergo an extensive vetting process that starts with establishing eligibility. Pre-procedure imaging is one of the most critical aspects of planning and patient selection. Patients undergo CT angiography of the LAA with the same protocol that is used for EP planning of our AF ablations. The CTA findings are also reviewed by SentreHEART, who corroborate our evaluation of the LAA in terms of size, shape, orientation, and width. Nomenclature has also recently been established to describe the variants that may be encountered when reviewing the LAA; windsock, fan-shaped, or multi-lobed shapes have been described.1 Currently the first-generation LARIAT is restricted to LAA width of 40 mm, as the loop of the device must negotiate a fixed diameter as it snares the LAA. However, any appendage morphology that takes a course posterior to the pulmonary artery is contraindicated in the current LARIAT device.
LARIAT procedures at our institution are performed in the hybrid OR in order to have prompt surgical backup if necessary. The LARIAT procedure is part of the structural heart program, and is done with the collaboration of the EP, interventional cardiology, and noninvasive cardiology departments. All members of the team met the training guidelines set by SentreHEART, including didactic sessions, hands-on training, and observing live cases. Protocols and guidelines were established, and training pathways were reviewed and approved well in advance of our first case. Both interventional cardiology and EP nurses were trained as well as sonographers.
LARIAT procedures are done under general anesthesia, and start first with a transesophageal echocardiogram, performed to rule out LAA thrombus. Epicardial access is gained using standard technique with specific consideration to maintain an anterior approach, which is essential for procedural success. Our approach is to start with the AP view, targeting the needle toward the appendage guided by the CTA. We then strictly use the left lateral approach, using a 50/50 mixture of contrast as saline until pericardial staining is seen specifically with layering. Utilizing as little contrast as possible is suggested, in case multiple attempts are needed. Confirmation in orthogonal views, particularly the LAO view, is critical. Usually the wire can also be seen in the pericardium on TEE. We cannot emphasize enough the importance of obtaining access that is not only anterior but also coaxial to the LAA in order to allow the magnets to adhere successfully. After confirmation of pericardial access, a second wire is advanced to retain access, and sheaths are slowly and cautiously upsized to accommodate the 14 Fr suture delivery device sheath.
Heparin is then infused, and transseptal puncture is performed aiming for a mid-septal approach. The standard transseptal sheath we use for LARIAT procedures is an SL1 (St. Jude Medical). An atriogram is then performed in the LAO and RAO caudal views to further identify the LAA anatomy. A balloon occlusion device allows for further delineation of LAA anatomy and the closure line for the suture. The balloon is seen both on TEE and fluoroscopy. Utilizing a unique 0.025” magnetic tip FindrWIRZ® Guide Wire System (SentreHEART, Inc.), a wire is advanced endocardially via the transseptal sheath and positioned in the LAA. A second 0.035” FindrWIRZ is back-loaded into the LARIAT system and advanced epicardially. The magnetic tip on each wire will allow for the wires to meet. Positioning the endocardial wire in the most anterior lobe of the LAA will allow for best alignment. Once wires are determined to be coaxial, the LARIAT snare is advanced over the wire via the epicardial sheath. Re-inflation of the balloon confirms closure and that the suture is deployed; confirmation of LAA closure is determined via repeat LA atriogram and TEE color flow Doppler. A TenSURE™ Suture Tightener (SentreHEART, Inc.) is used to ensure that knots are delivered a consistent strength. A final atriogram is performed, and a confirmation that there is no leak is determined via TEE.
A pigtail drain is then directed posteriorly, and the pericardial space is monitored for an adequate waiting period before extubation.
As tissue necrosis ensues to the ligated LAA, patients have exhibited a wide variety of pericardial symptoms. Consequently, all patients maintain drains for 12-24 hours, even if minimal serous drainage is seen in the immediate post-operative period. Additionally, high-dose colchicine is used to prevent recurrent pericarditis. The use of intrapericardial steroids has not been recommended, although no published data are available to help guide management. Our patients are admitted to the cardiothoracic ICU overnight, and then transferred to telemetry if they are not discharged the following day. Patient length of stay has ranged from two to five days. Longer stays have been due to pain management. Transthoracic echocardiograms were performed in all patients prior to discharge. Follow-up TEE is performed in all patients at 30 days to ensure complete ligation.
The initial experience published by Bartus et al2 demonstrated acute closure in 82/85 (96%), and at one year, approximately 98% also demonstrated long-term closure. Additional single-center experiences have mirrored this data with high initial closure rates.
Known adverse events that have been reported with the LARIAT procedure most commonly include complications related to epicardial access, including RV perforation. However, the current published data do not cite any device-related complications.
A case report has noted that as soon as three months after complete LAA closure, thrombus formation was demonstrated at the closure site.3 In this case, a patient was noted to have RA thrombi as well, which resolved with restarting anticoagulation. Additionally, LAA perforation has been described, most commonly occurring when the Lasso apparatus is in an unusual orientation coming out of the epicardial sheath. Maneuvering the snare while it has already snared the appendage has also been associated with tearing of the LAA. Regardless of the mechanism, the treatment of choice for left atrial appendage perforation is prompt closure of the LAA. This has been demonstrated to be an effective therapy.4
The space of left atrial appendage ligation is in its infancy. The LARIAT procedure introduces a novel mechanism by which the left atrial appendage can be excluded in the absence of an implantable device, but with strict criteria excluding patients with previous sternotomy or pericarditis. There are several questions that are still unanswered, not only for the LARIAT procedure, but also for LAA ligation in general. First, what is the long-term durability of the closure, and what is the clinical significance of leaks that are demonstrated? Second, will the LARIAT procedure carry data to support its use as noninferior to warfarin, as has been demonstrated in the clinical trials with the WATCHMAN device? Currently the device is only indicated for patients intolerant to anticoagulation. Finally, what role, if any, will LAA ligation have in the field of rhythm control management and hybrid procedures involving AF ablation and LAA closure? As is the rule for most interventional procedures, each approach will need to be tailored to every patient. We eagerly anticipate additional data that will ultimately assist in guiding us to best treat our patients. n
- Blendea D, Heist EK, Danik SB, et al. Analysis of the left atrial appendage morphology by intracardiac echocardiography in patients with atrial fibrillation. J Interv Card Electrophysiol. 2011;31:191-196.
- Bartus K, Han FT, Bednarek J, et al. Percutaneous left atrial appendage suture ligation using the LARIAT device in patients with atrial fibrillation: initial clinical experience. J Am Coll Cardiol. 2013;62:108-118.
- Giedrimas E, Lin AC, Knight BP. Left Atrial Thrombus After Appendage Closure Using LARIAT. Circ Arrhythm Electrophysiol. 2013;6:e52-53.
- Shetty R, Leitner JP, Zhang M. Percutaneous Catheter-Based Left Atrial Appendage Ligation and Management of Periprocedural Left Atrial Appendage Perforation With the LARIAT Suture Delivery System. J Invasive Cardiol. 2012;24:E289-293.
Disclosure: The authors have no conflicts of interest to report regarding the content herein. Outside the submitted work, Dr. Patel reports honoraria to his institution and travel/accommodations expenses covered or reimbursed to his institution from St. Jude Medical.