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Cardiovascular Anesthesiology: Echo Rounds

Real-Time Transesophageal Echocardiography for Left Atrial Appendage Ligation Using the LARIAT Snare Device

Lasala, Javier D. MD*; Tolpin, Daniel A. MD; Collard, Charles D. MD; Pan, Wei MD

Author Information
doi: 10.1213/ANE.0000000000000648

A 79-year-old woman with a history of refractory atrial fibrillation (AF) presented for elective closed-chest percutaneous left atrial appendage (LAA) ligation using the LARIAT snare device and EndoCATH balloon (SentreHEART, Inc., Palo Alto, CA) monitored with real-time transesophageal echocardiography (TEE). This approach uses a percutaneous approach for LAA ligation via the femoral vein and the epicardial space. After induction of general anesthesia, a TEE examination was performed and absence of LAA thrombus was confirmed.

A femoral vein sheath was inserted by an interventional cardiologist for transseptal puncture of the atrial septum, for placement of the EndoCATH balloon catheter (SentreHEART, Inc.). An endocardial balloon catheter with a magnet-tipped guidewire was directed to the apex of the LAA using TEE and fluoroscopic guidance (Figs. 1 and 2A; Video 1, Subsequently, a second magnet-tipped wire was introduced into the epicardial space from a subxiphoid approach and positioned to make magnetic contact with the tip of the endocardial wire located in the apex of the LAA. The magnetic connection facilitated stabilization of the LAA (Fig. 2B). At this point in time, using real-time TEE guidance and fluoroscopy, it was confirmed that the EndoCATH’s inflated balloon was positioned in the proximal LAA, just past the ostium. Once this was confirmed, an over-the-wire approach was used to guide the LARIAT snare device over the LAA to allow closure and suture ligation of the LAA, once no evidence of color Doppler flow from the left atrium (LA) to the LAA was present (Video 2, Intraoperative TEE and LA angiography were used to confirm closure of the LAA (Video 3, Patient consent for publication of this case report was obtained.

Figure 1
Figure 1:
Midesophageal 2-chamber view as imaged with xPlane mode; the scan on the left demonstrates the left atrium (LA) and left atrial appendage (LAA) at a scan angle of 115°; the wire can be seen in the LAA. The scan on the right shows the LA and LAA with the wire in place at a scan angle of 38°.
Figure 2
Figure 2:
A, Labeled illustration demonstrating transseptal sheath, catheter, balloon, and magnet-tipped endocardial wire; in relation to relevant cardiac anatomy. Please note how the balloon is inflated in the proximal left atrial appendage (LAA), just past the ostium of the LAA. Published with permission from The University of Texas MD Anderson Cancer Center. B, Labeled illustration, a magnetic-tipped pericardial wire has been inserted and contacts the wire in the left atrial appendage (LAA) thereby facilitating delivery of the snaring loop. Published with permission from The University of Texas MD Anderson Cancer Center.


The alternative to anticoagulation in patients with AF is surgical exclusion of the LAA. Because approximately 90% of emboli in nonvalvular AF arise from the LAA, new nonsurgical interventions like the LARIAT snare device are being tested as minimally invasive alternatives to surgery.1 The LARIAT is one of the several new nonsurgical interventions available for LAA exclusion. In a trial of 13 patients using the LARIAT snare device for LAA ligation, acute and complete closure was accomplished in all patients with the use of fluoroscopy and TEE.2 An observational study of 89 patients undergoing LAA exclusion with the LARIAT snare device concluded that closure can be performed effectively with acceptably low access complications and periprocedural adverse events. The results revealed that 96% of patients in this study had successful LAA ligation and after 1 year 98% had complete LAA closure.3 A limitation to this approach is the inability to access the LAA if there are pericardial adhesions, for example, a patient with a previous sternotomy or history of pericarditis.

Closed-chest percutaneous LAA ligation is performed in an interventional hybrid suite, with an interventional cardiologist inserting the LARIAT snare device into the epicardium percutaneously (similar to performing a pericardiocentesis) in addition to accessing a femoral vein for endocardial catheter placement. A transseptal 8.5-Fr sheath is placed under fluoroscopic and intraoperative TEE guidance via femoral vein access. The trans-Fseptal sheath is used for placement of the endocardial guidewire, which has a built-in 20-mm occlusion balloon for deployment in the LAA, the EndoCATH (SentreHEART, Inc.). After this step, a magnet-tipped wire is inserted through the 14-Fr soft-tipped pericardial cannula and attached to the endocardial magnet-tipped guidewire. The LARIAT snare device is advanced over the epicardial magnet-tipped wire and positioned around the LAA. Once proper positioning is confirmed, the snare is closed. In the presence of a multilobed LAA, the snare is placed over both lobes or if this is not feasible, the procedure can be repeated over each lobe individually. Absence of flow from the LA to the LAA is confirmed by color Doppler TEE (Fig. 3) and LA angiography. At this point, the suture is tightened, the device removed, and a suture cutter advanced. The 14-Fr soft-tipped epicardial guide cannula is removed and exchanged for a pericardial drain.

Figure 3
Figure 3:
Midesophageal 2-chamber view; after ligation of the left atrial appendage (LAA) with the LARIAT snare device. The small area of color flow seen on this image is the circumflex artery. There is no evidence of Doppler flow from the LAA indicating successful closure.

Previously, intraoperative TEE has been used during open, surgical exclusion of the LAA describing real-time 3-dimensional LAA ligation.4 The use of TEE during the percutaneous approach is used for excluding thrombus, confirming proper transseptal puncture and wire placement into the LAA, verifying balloon position to guide the placement of the LARIAT device, confirming closure with continuous color flow Doppler, and diagnosing any complications such as a pericardial effusion.5 The use of 3-dimensional TEE to assess closure of the appendage is helpful, although not necessary for this procedure.

When using TEE, the LAA should be visualized in 2 views. The midesophageal aortic valve short-axis view allows visualization of the aortic valve, LAA, and LA. The midesophageal 2-chamber view with the probe multiplaned to 90° and slightly rotated to the left allows identification of the left ventricle, LA, LAA, and the left upper pulmonary vein. Both views should be obtained before start of the procedure and color Doppler flow images obtained for comparison after LARIAT occlusion, which relies on the presence of no color Doppler flow for the ligation to be deemed successful by the interventional cardiology team. The aliasing velocity scale for color Doppler flow should be lower because velocities in the LAA can be low in patients with AF, hence improving the chance of identifying residual flow; although if they are too low, artifacts might appear. In addition to this, a midesophageal 4-chamber view and short-axis transgastric view are important to exclude the presence of pericardial effusions before and during the procedure (Table 1).

Table 1
Table 1:
TEE Goals During Deployment Phases

In conclusion, we describe a case using a minimally invasive technique for LAA ligation for the prevention of stroke in patients with AF. This procedure is performed in the cardiology interventional suite or in a hybrid operating room under general anesthesia. Intraoperative TEE is required to image the LAA, assist the interventionist in placement of the device, and verify successful deployment and exclude potential complications.

Clinician’s Key Teaching Points

By Kent H. Rehfeldt, MD, Roman M. Sniecinski, MD, and Martin J. London, MD

  • The LARIAT percutaneous left atrial appendage (LAA) closure system uses a magnet-tipped, endocardial guidewire that is inserted into the LAA via the femoral vein and transseptal puncture. A second guidewire is placed into the pericardial space where it makes magnetic contact with the endocardial wire at the tip of the LAA. The LAA is then expanded using a balloon from the endocardial wire and snared with a lasso from the epicardial wire.
  • Transesophageal echocardiography (TEE) imaging is critical for the evaluation of LAA morphology, as well as assuring it is free of thrombus. The LAA can be completely imaged by withdrawing the probe from a midesophageal 4-chamber view, turning the probe counterclockwise, and adding a small degree of flexion. Viewing the LAA at 0°, 45°, 90°, and 135° using the omniplane provides optimal visualization. If more than 1 lobe is identified, multiple snares may be required.
  • In this case, TEE was used during the procedure to help guide the transseptal puncture and visualize placement of the endocardial wire into the LAA. After snaring of the LAA, the LAA was interrogated with color flow Doppler imaging to verify there was no flow into it.
  • A potential complication of the procedure is the creation of a pericardial effusion. This can also be assessed with TEE using the midesophageal 4-chamber or transgastric short-axis views.


Name: Javier D. Lasala, MD.

Contribution: This author helped prepare the manuscript.

Attestation: Javier D. Lasala attests to having approved the final manuscript.

Name: Daniel A. Tolpin, MD.

Contribution: This author helped prepare the manuscript.

Attestation: Daniel A. Tolpin attests to having approved the final manuscript.

Name: Charles D. Collard, MD.

Contribution: This author helped prepare the manuscript.

Attestation: Charles D. Collard attests to having approved the final manuscript.

Name: Wei Pan, MD.

Contribution: This author helped prepare the manuscript.

Attestation: Wei Pan attests to having approved the final manuscript.

This manuscript was handled by: Martin J. London, MD.


The authors thank William E. Cohn, MD, FACS, FACCP, FAHA, Director, Center for Technology and Innovation; Associate Director, Laboratory Surgery Research, Center for Cardiac Support; Texas Heart Institute at St. Luke’s Medical Center; Associate Professor of Surgery, Baylor College of Medicine; Adjunct Professor of Bioengineering, University of Houston, for his guidance in developing an illustration (Relevant disclosure: Developer of the SentreHEART® LARIAT® Suture Delivery Device). In addition, the authors thank the medical graphics and photography department at the University of Texas MD Anderson Cancer Center for developing labeled high resolution illustrations of the LARIAT procedure.


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