Case Report: Thorascopic Delivery of the AtriClip to Prevent Strokes in Patients With Atrial Fibrillation

Introduction

Projected to impact the health of over six million individuals by 2050, atrial fibrillation (AF) is the most common arrhythmia in the United States. In addition to shortness of breath, fatigue, and impaired exercise capacity, it has been associated with both dementia and stroke.¹ Given the burden of atrial fibrillation in the United States, it is estimated that approximately 15% of cerebrovascular accidents arise from AF-associated thromboembolism. Of anatomical structures in the heart, the left atrial appendage (LAA) has been implicated as the origin of thromboembolism in upwards of 90% of strokes originating from the left atrium.² 

Data from the PROTECT-AF study has demonstrated for the first time that exclusion of the LAA from circulation reduces the composite risk of ischemic stroke, non-central nervous system (CNS) thromboembolism, and hemorrhagic stroke.² Recently, the FDA approved the WATCHMAN Left Atrial Appendage Closure Device (Boston Scientific) as the first device for reducing the risk of stroke in patients with atrial fibrillation. In addition to WATCHMAN, there are two additional methods for excluding the left atrial appendage from circulation: the LARIAT Suture Delivery Device (SentreHEART, Inc.) and AtriClip (AtriCure, Inc.), both of which are approved by the FDA via a 510(k) pathway. While data on the safety and efficacy of the LARIAT and AtriClip (Figure 1) are limited compared to the randomized clinical trials that led to the approval of WATCHMAN, there are circumstances where one of these other two methods might be preferred. Moreover, there is mounting evidence that ligation of the left atrial appendage reduces the overall burden of atrial fibrillation by debulking the left atrium.³

In our institution, we limit both the LARIAT and AtriClip to patients who are at high risk for stroke (CHA₂DS₂-VASc >3) and who are not candidates for anticoagulation due to comorbid illnesses (e.g., recurrent gastrointestinal bleeding). Here we present a recent case of LAA exclusion using thorascopic delivery of the AtriClip. 

Case Presentation

The patient was a 76-year-old man with a history of persistent atrial fibrillation, a CHA₂DS₂-VASc risk score of 5, and a HAS-BLED score of 4, who had suffered from recurrent falls secondary to Parkinsonian gait instability. In addition, he had experienced several CNS embolisms, including a stroke and a series of TIAs. Given his high risk of stroke and intolerance to oral anticoagulants, he was referred for evaluation of LAA exclusion. A CT scan was performed prior to the procedure, demonstrating his candidacy for LARIAT. Using the first-generation LARIAT, an attempt was made to ligate the appendage. However, as the entire left atrial appendage could not be captured by the device, the procedure was aborted and he was referred for a thorascopically delivered AtriClip. 

Description of Procedure

The procedure itself was performed under general anesthesia. A radial arterial line was inserted for invasive hemodynamic monitoring and a TEE probe was placed in the esophagus to provide real-time imaging of the LAA. To facilitate single-lung ventilation, a left-sided double lumen tube was placed. 

The patient was placed supine on the table with a slight bump up of the left chest. The left arm was positioned posteriorly. Intercostal blocks were placed prior to port placement. Two 8-mm ports and one 10-mm port were placed in the anterior axillary line, from the axilla inferiorly (Figure 2). The 10-mm port was the most inferior of the three. A fourth 8-mm port can be placed superiorly for pericardial retraction, which was not performed in this case. 

The lung was deflated, and CO₂ was used to improve spacing between the chest wall and pericardium. The pericardium was sharply opened with a Maryland Grasper and scissors, avoiding electrocautery on the pericardium. The pericardium was taken down superiorly to the pulmonary artery and inferiorly to expose the LAA. The entry into the pericardium is generally posterior to the phrenic nerve (Figure 3). 

An AtriClip sizer was used to measure the size of the base of the LAA. The appropriate sized AtriClip, mounted on the delivery system, was inserted through the inferior 10-mm port site. A towel clip was used to pinch the port site to maintain CO₂insufflation pressure. The clip was placed over the LAA, maintaining gentle medial pressure toward the heart. No grasping of the LAA was done, as a blunt Kittner was used to tease the LAA through the opened clip (Figure 4). 

Once the device appeared to be in good position at the base of the LAA, the device was closed, but not deployed. TEE was used to evaluate obliteration of the LAA (Figures 5A and B). When this was satisfactory, the device was deployed and the delivery system was carefully removed.

A small Blake drain was placed, and the ports were removed. The drain was left for one day, and the patient discharged on day 2.

Eight months later, the patient is doing well and has had no strokes, TIAs or non-CNS embolisms. 

Discussion

Thorascopic delivery of the AtriClip is a safe, effective, and minimally invasive approach to excluding the LAA from circulation, presumably reducing the risk of ischemic stroke, hemorrhagic stroke, and non-CNS thromboembolism. Long-term studies, however, are lacking. For patients who are candidates for LAA occlusion/exclusion, we attempt to tailor the specific method with the indication for the procedure, factoring in patient-specific risks. While the procedure can be performed quickly and with minimal complications in the hands of a skilled cardiothoracic surgeon, we have found the hospital stay is longer and pain may be greater than the other methods, given the need for a chest tube. As single-lung ventilation is required during the procedure, patients with poor cardiopulmonary reserve may not be able to tolerate the procedure. However, in contrast to the WATCHMAN and LARIAT, serious complications (e.g., right ventricular laceration, device embolization, and tamponade) are limited. Also, unlike LARIAT, the AtriClip can be performed in patients who have undergone prior sternotomy or pericardial instrumentation. Finally, in contrast to LAA “plug” therapies, ligation of the LAA with AtriClip potentially reduces the overall burden of atrial fibrillation.³ Future studies are needed to further define how AtriClip should be incorporated into the EP community’s mounting armamentarium of LAA technologies.

Disclosures: The authors have no conflicts of interest to report regarding the content herein.   

References

1. Bunch TJ, May HT, Bair TL, et al. Atrial fibrillation ablation patients have long-term stroke rates similar to patients without atrial fibrillation regardless of CHADS2 score. Heart Rhythm. 2013;10:1272-1277.
2. Reddy VY, Doshi SK, Sievert H, et al. Percutaneous left atrial appendage closure for stroke prophylaxis in patients with atrial fibrillation: 2.3-Year Follow-up of the PROTECT AF (Watchman Left Atrial Appendage System for Embolic /files/epld-nilsson-6_small.pngProtection in Patients with Atrial Fibrillation) Trial. Circulation. 2013;127:720-729.
3. Afzal MR, Kanmanthareddy A, Earnest M, et al. Impact of left atrial appendage exclusion using an epicardial ligation system (LARIAT) on atrial fibrillation burden in patients with cardiac implantable electronic devices. Heart Rhythm. 2015;12(1):52-59.