Initial Experience Using the LARIAT Device
Atrial fibrillation (AF) is the most commonly diagnosed adult arrhythmia in the U.S.1 and worldwide.2 Due to an aging population and rising incidence, the prevalence of AF in the U.S. is projected to reach 12–15 million patients by the year 2050.2-4 Because of decreased flow in the left atrial appendage (LAA) during AF and resultant thrombus formation,5,6 AF is a major risk factor for stroke, accounting for 15% of all strokes, and more than a third of strokes among patients above 80 years of age.2,7-10 AF-related strokes are more frequently fatal and disabling than non-AF-related strokes, and they carry a worse prognosis than embolic events from other causes.11-13
Current ACC/AHA/HRS guidelines stress the critical role of antithrombotic therapy for the prevention of stroke and systemic embolism, with aspirin therapy recommended only for low-risk patients.1 For many decades, the vitamin K epoxide reductase inhibitor warfarin had been the only approved antithrombotic therapy for prevention of ischemic stroke in patients with AF. However, its use can be challenging due to its variable pharmacokinetic and pharmacodynamic profile, numerous drug and dietary interactions, delayed onset of action, need for substantial laboratory monitoring and dosage titrations, and most importantly, bleeding complications. These disadvantages have engendered great interest in the development of alternative antithrombotic therapies that may overcome these limitations. Three new oral anticoagulants — dabigatran, rivaroxaban, and apixaban — have received FDA approval for the prevention of stroke and systemic embolism in patients with AF.
However, a significant number of patients with AF have absolute or relative contraindications to anticoagulation. Among such patients faced with this difficult dilemma, therapies targeting the LAA through exclusion or ligation are of great potential benefit. The LARIAT device (SentreHEART, Inc.) is a suture delivery device that is FDA approved for suture placement and knot tying in surgical applications. Although it is not FDA approved specifically for treatment of AF or for stroke reduction in AF, it has recently gained interest because of its potential use in LAA ligation, and a recent study documented promising efficacy and safety in this application.14
We describe here our recent use of this device at Englewood Hospital and Medical Center for intra-pericardial ligation of the LAA in two patients with multiple risk factors for stroke and absolute contraindications to systemic anticoagulation. Our center was the first in the state of New Jersey to perform these procedures.
In terms of patient selection, prior cardiac surgery is the principal contraindication due to the risk of pericardial adhesions. Prior to the ligation procedure, a spiral CT scan was obtained to clarify LAA size and orientation, because the LARIAT device is not suitable for an LAA width over 40 mm or cases in which the LAA is situated under a pulmonary artery. We scheduled the procedures in our hybrid operating room, as we do for our lead extractions, to allow for a quick response time in the event that emergent cardiac surgery would be required.
The procedures were performed under general anesthesia with transesophageal echocardiographic (TEE) guidance. An initial TEE ruled out LAA thrombus. Pericardial access was then achieved using a subxiphoid technique. First, fluoroscopic landmarks were examined with the needle over the xiphoid region. The general direction toward the appendage, 2 o’clock orientation, was marked with a sterile pen for subsequent visual guidance. The puncture was then performed using radiopaque contrast. The AP view was used until the needle approached the cardiac silhouette, at which time the left lateral view was used. This is of utmost importance because the LARIAT procedure necessitates a very anterior puncture site to allow for a “straight shot” toward the LAA. Failure to achieve an anterior puncture can lead to great difficulties in subsequent alignment and LAA capture. Once layering of contrast was visualized within the pericardial space, a wire was advanced, and a series of dilators were used before placement of a 13 Fr sheath within the pericardium. Of note, an extra wire was also placed within the pericardium for later insertion of a pigtail catheter. Transseptal access was then achieved using TEE guidance, and an SL1 sheath was placed in the left atrium. Heparin was administered with ACT monitoring. A contrast left atriogram was performed to clarify LAA anatomy.
The subsequent steps of the procedure were directed toward advancing two magnet-tipped wires within the pericardial space and within the left atrium. The goal was to have them meet and “click together” at the most distal part of the appendage. This was achieved easily, and the wires provided a rail over which the suture delivery apparatus could subsequently be advanced to the base of the LAA. Of note, the left atrial wire was advanced within a balloon catheter. This balloon, when inflated and deflated after magnetic union of the wires, was visualized on both TEE and fluoroscopy, confirming that its radiopaque marker at the proximal end of the balloon provided a landmark at the base of the appendage.
The LARIAT suture delivery device, which is a loop snare with preloaded and pre-tied “0” polyester suture, was then advanced over the pericardial wire to the radiopaque marker, which had previously been confirmed to be at the base of the LAA. Confirmation that the loop was in the correct place was obtained with TEE and contrast atriography with the balloon was again inflated. The balloon was deflated, and the snare was then closed. Confirmation of closure of the LAA and capture of its base was again obtained on TEE via Doppler examination of the LAA base, and with a contrast atriogram. Of note, the procedure was still reversible at this point, and the loop snare could have been repositioned if necessary. Once an acceptable location was achieved, the wires were detached from each other, and the LAA wire and balloon catheter were withdrawn back into the left atrial sheath. The knot was tightened using a calibrated tension-delivery device, with repeated applications at five-minute intervals if necessary, to allow for extrusion of interstitial fluid within the knot. TEE and contrast injections confirmed complete closure of the LAA. Of note, the first patient required a second delivery of knot tension because contrast and TEE revealed persistent flow between the LA and LAA. A suture cutter was then used, after which the snare was opened and retracted, and all other hardware was removed. A pericardial pigtail catheter was then inserted, and protamine sulfate was administered prior to sheath removal.
The main issues after the procedure were management of the pigtail catheter and pain control. The pigtail catheter should remain in the pericardium until scant fluid is produced. Pain can be significant, both due to pericarditis and also due to ongoing necrosis of the LAA. A follow-up transthoracic echocardiogram was obtained in each patient 12–24 hours after removal of the pericardial pigtail catheter to rule out significant fluid in the pericardial space.
Our first two procedures were straightforward. The first case had a skin-to-skin time of 115 minutes, and the second was 62 minutes. There were no complications. One of the patients had minimal pericardial fluid production, and the drain was pulled eight hours after the procedure. This patient was discharged home the following day. However, she developed significant pericarditic pain, which required analgesics for approximately 10 days. The second patient had significant fluid production for two days, delaying removal of the pericardial drain and of hospital discharge. However, this patient had minimal pain and required no analgesics.
Despite the fact that these were our first two LARIAT cases, and indeed the first two cases statewide, our team was impressed by the refined and straightforward nature of this technology. The LARIAT device is user-friendly, and most busy electrophysiologists possess the skills required for this procedure: transseptal and pericardial access. A single venous sheath was required. Pre-procedure CT scanning selects out the most challenging appendage anatomies and orientations. The magnetically-tipped wires, once properly aligned after an anterior pericardial puncture, provide a firm rail for capture of the LAA. For high-risk AF patients with absolute contraindications to anticoagulation, this procedure offers an option worth considering, and we anticipate an increasing volume of LARIAT cases.
Disclosure: Dr. Simons has no conflicts of interest to report.