How to Close the Left Atrial Appendage Using Endocardial and Epicardial Approach
Venkat Vuddanda, MD; Mohammad-Ali Jazayeri, MD; Donita Atkins, RN; Dhanunjaya Lakkireddy, MD
Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide. It imparts significant stroke risk requiring oral anticoagulation (OAC) for prevention of systemic thromboembolism in the high-risk population.1 However, for various reasons at least 20% of patients with AF are not candidates for OAC.2 Alternative treatment options for this subset of patients include surgical and percutaneous catheter–based approaches for left atrial appendage (LAA) closure. Surgical approaches (e.g., Cox Maze, “mini-Maze,” AtriClip) are beyond the scope of this book. Here we will describe a detailed step-by-step approach of percutaneous LAA closure with devices currently available in the United States (LARIAT® Suture Delivery Device, Watchman™). Later, we will briefly discuss the merits and demerits of other devices approved elsewhere in the world (AMPLATZER Cardiac Plug, WaveCrest, LAmbre, Aegis).
The LARIAT® Suture Delivery Device (SentreHEART, Inc., Redwood City, CA) utilizes a combined endocardial and epicardial approach (“hybrid approach”) to LAA closure and consists of four main components (Figure 59.1):
1. A 20-mm compliant endocardial occlusion balloon catheter (EndoCATH®)
2. A 0.025-inch endocardial and 0.035-inch epicardial magnet-tipped guidewire system (FindrWIRZ®)
3. A 12-Fr epicardial snare device that delivers a 40-mm diameter, pre-tied suture loop over the LAA
4. SureCUT™ Suture Cutter to cut the multifilament, size “0” suture through pericardial access
The LARIAT device has approval for soft-tissue approximation from the United States Food and Drug Administration (FDA). It has been used “off-label” for LAA closure to prevent stroke in patients with AF who have high stroke risk and cannot tolerate or have failed long-term oral anticoagulation (Table 59.1). This procedure requires epicardial access for delivery of a pre-tied suture over the LAA so any disease process or intervention that compromises pericardial access is a contraindication, such as prior open heart surgery, severe pericardial adhesions, and pectus excavatum.
1. Nonvalvular atrial fibrillation
2. High stroke risk
• CHADS2 ≥ 2
• CHA2DS2-VASc ≥ 3
3. OAC failed (e.g., embolic event despite OAC), or
4. OAC contraindicated in long term:
• History of bleeding
• High risk for bleeding
• Recurrent falls / syncope
• High-risk occupations
• Intracranial aneurysms
• Dual antiplatelet therapy
• HAS BLED score ≥ 3
• Underlying coagulopathy
1. Adjunct treatment with radiofrequency ablation for AF to achieve electrical isolation of LAA
2. Treatment of focal atrial tachycardia originating in the LAA
1. LAA thrombus
2. Prior open-heart surgery
3. Pericardial adhesions from any cause
4. LAA anatomy not compatible with the device
a. LAA ostium width > 40 mm
b. Posteriorly directed appendage
c. Superiorly oriented LAA with apex directed behind the pulmonary trunk
d. Bilobed or multilobed LAA where the lobes are oriented in different angles
1. History of severe pericarditis
3. Prior epicardial ablation
4. Pectus excavatum
5. Severe obesity
6. Active bloodstream infection
7. Contraindications for transseptal access (e.g., ASD/PFO closure devices)
ASD, atrial septal defect; LAA, left atrial appendage; OAC, oral anticoagulation; PFO, patent foramen ovale.
Preprocedural imaging in the form of cardiac computed tomographic angiography (CCTA) (Figure 59.2) is an absolute necessity. It helps to assess the size, morphology, and orientation of the appendage, exclude patients whose anatomy is not amenable for ligation, and provide information required for successful pericardial access and placement of a magnet-tipped guidewire system to achieve good end-to-end alignment across the LAA. Periprocedural transesophageal echocardiography (TEE) must always be performed to rule out LAA thrombus, evaluate for the presence of pericardial effusion and patent foramen ovale, and to assess LAA dimensions and choose an appropriate site of ligation. In the horizontal plane, 30° to 60° and 90° to 160° views should be chosen to investigate the entire LAA cavity. During the procedure, both a bicaval and short axis view at the level of the aortic valve are used to identify the posterior and inferior portion of the interatrial septum for successful transseptal puncture. After the procedure, color Doppler helps to ensure adequate LAA closure and rule out leaks across the LAA.
At our institution, all patients undergo LARIAT procedures in a hybrid operating room under general anesthesia in anticipation of potentially serious complications like injury to the heart and surrounding structures while performing dry pericardial access. General anesthesia has many advantages in this context, the most important of which is that it helps control respiration by eliminating deep breathing that may result in myocardial injury during pericardial access and sudden catheter movement during the procedure. A TEE probe is placed for continuous visualization during the procedure. An arterial line is often placed in the radial or femoral artery for hemodynamic monitoring.
Obtaining an anterior pericardial access with proper directional alignment is the most crucial step for successful delivery of the LARIAT suture over the LAA. A posterior or medial access will make it difficult to direct the LARIAT suture delivery device to go over the LAA apex. Preprocedural 3D CCTA is helpful in estimating the direction and depth of the pericardial needle advancement to achieve safe epicardial access (Figure 59.2, C, D). During the procedure, an anteroposterior fluoroscopic view is used to align the needle toward the lateral aspect of the LAA i.e., between the 12 o’clock and 2 o’clock positions, and a 90° left lateral fluoroscopic view assures that the epicardial puncture occurs on the anterior surface of the right ventricle (Figure 59.3, A, B).
Large-bore needles (LBN) (17G ~ Pajunk, Tuohy) are known to be associated with a risk of ventricular puncture, coronary artery or vein laceration, and visceral injury. Therefore, we advocate the use of a 21G long micropuncture needle (LMPN).3 In obese patients, subcutaneous tissue may cause deformation of the LMPN, so we advise use of a short LBN (18G) to support the LMPN as it traverses the subcutaneous tissue (telescoping approach).
A skin incision is made 2 cm below the xiphoid process. Using a 90° left lateral fluoroscopic view the LMPN is angled at 20° to 30° and advanced into the anterior mediastinum, aiming toward the left shoulder between the 12 o’clock and 2 o’clock positions. In obese individuals, a telescoping approach is used. Once in the anterior mediastinum, needle position is confirmed using anteroposterior and left lateral fluoroscopic views. Pericardial puncture is performed using the contrast dye technique (Figure 59.3, D, E). Once inside the anterior pericardial space, a J-tipped, floppy guidewire of 0.018-inch diameter and 60 cm in length is introduced through the needle until its tip is free within the pericardial space. Once the guidewire is inserted into the pericardial space, a left anterior oblique (LAO) fluoroscopic view is chosen to assure that the guidewire is crossing the midline and winds around the lateral border of the left ventricle (LV) (Figure 59.3F) as its absence indicates RV puncture. If inadvertent RV puncture occurs, the needle is withdrawn slightly and redirected. Once the wire is confirmed to be in the pericardial space, the micro-puncture needle is withdrawn, the dilator is advanced, and a more supportive wire such as a 0.035-inch diameter, 180-cm length wire is exchanged for the floppy guidewire. Following serial dilation with a series of dilators, a 13-Fr soft tip sheath is placed in the epicardial space, through which the LARIAT suture delivery device is deployed (Figure 59.3G). Dilation and sheath exchange should be performed with caution so as not to inadvertently cause cardiac injury, and the patient should be continuously monitored for evidence of RV compression on TEE. One can avoid injury to the epigastric artery with proper choice of access sites guided by preprocedural CCTA information.
Location of the transseptal puncture plays a critical role in success of the procedure. The LAA is oriented anteriorly with the plane of the LAA ostium lying perpendicular to it. A successful device deployment requires placement of the tip of a 0.025-inch endocardial magnet-tipped wire (“endo-wire” component of FindrWIRZ) into the LAA apex. This is achieved by following a posterior-to-anterior trajectory once inside the left atrium. A transseptal puncture that is posterior and mid to slightly inferior in position provides the most favorable sheath orientation to approach the LAA. An 8.5-Fr sheath is placed in the right femoral vein. A 0.035-inch guidewire is placed into the superior vena cava (SVC), and an 8.5-Fr SL1 transseptal sheath with introducer (St. Jude Medical, St. Paul, MN) is advanced over it. Under fluoroscopy in the 30° LAO view, using intracardiac echocardiography (ICE) or TEE guidance, the sheath is directed towards the interatrial septum at the level of the SVC. The guidewire is then removed and a Brockenbrough needle (St. Jude Medical) attached to a 50 cm3 syringe filled with contrast is introduced into the sheath making sure its tip remains inside the introducer. The SL1 sheath with introducer and transseptal needle is then pulled down the septum from the SVC to the fossa ovalis. When the tip of the introducer has reached the fossa ovalis, the TEE bicaval and short axis view at the level of aortic valve are used to identify the posterior and inferior portion of the interatrial septum (Figure 59.4). The transseptal sheath is advanced slightly to stretch the septal tissue resulting in tenting to confirm the location. Once the location is confirmed, the needle is advanced through the septum into the left atrium. The transseptal introducer and sheath are then advanced simultaneously over the needle and subsequently directed towards the LAA. Heparin should be administered during this time to maintain an activated clotting time (ACT) of approximately 300 to 350 seconds. A pigtail catheter is introduced through the transseptal sheath into the LAA and an appendagram is obtained in both the LAO and RAO caudal views.
Deployment of the LARIAT Suture
An EndoCATH occlusion balloon containing the 0.025-inch endo-wire is treated with normal saline to remove all the air inside the catheter and is advanced through the transseptal sheath into the LAA apex. The guidewire lumen of the EndoCATH is used for contrast delivery to perform another appendagram in the anteroposterior view and to confirm its placement (Figure 59.5, A, B). Once in position, it is secured by closure of the rotating hemostasis valve. Maneuvering the endo-wire anteriorly into the LAA apex is crucial for proper alignment of the endocardial and epicardial magnet-tipped guidewire. Multiple fluoroscopic views should be used to verify its placement in the LAA apex. A 30° LAO view with 20° caudal orientation and a 30° right anterior oblique (RAO) view are most helpful to visualize all the lobes of the LAA.