There is clearly a need for a nonpharmacological alternative to prevent stroke in high-risk patients with atrial fibrillation (AF), and it is logical to assume that removal or occlusion of the left atrial appendage (LAA) would be a valid approach. However, the development of a safe way to take out the LAA has been challenging. The WATCHMAN LAA closure device, under development now by Boston Scientific Inc., was subjected to a third panel review by the Food and Drug Administration (FDA) in October 2014, and won approval by a very narrow margin. After many years and two large randomized trials, it remains unclear when the WATCHMAN device will be commercially available in the U.S. and how restrictive the labeling will be. 

Because LAA occlusion devices remain investigational in the U.S., some patients with AF are being offered LAA ligation, either surgically or percutaneously. The LARIAT Suture Delivery Device is a suture-snare based ligation system manufactured by SentreHEART, Inc. It requires both transseptal catheterization and epicardial access to snare and strangle the base of the LAA using two magnetic wires that create a rail. Although the snare is not specifically approved for stroke prevention and is not an option for patients with prior cardiac surgery or variant LAA shapes and positions, it is FDA approved for soft tissue closure and is currently being used at many U.S. hospitals. The procedure is very smooth when all goes well, leaving no endocardial device behind that could embolize, and results in impressive, acute obliteration of the LAA. It is a less invasive alternative to surgical removal or clipping, and most patients are discharged the following day.

One challenge of the LARIAT procedure, however, has been safety. Despite early reports of impressive results, there have been anecdotal reports of occasional catastrophic outcomes during LARIAT procedures. Two recently published case series by high volume, experienced operators (Price et al in the Journal of the American College of Cardiology¹ and Miller et al in Heart Rhythm²), further quantify the risks and outcomes of the LARIAT procedure. The table below summarizes the findings of each study and provides a total rate of each outcome. Although the reports used different definitions of successful closure and various complications, the data from almost 200 cases reveal a relatively high complication rate. The rate of successful closure was 93%, but the rate of acute tamponade was 7% and the rate of emergency cardiac surgery was 2%. Fortunately, there were no deaths.

These data regarding the LARIAT procedure are important to consider. Is it worth a 7% risk of tamponade to prevent stroke in a patient with AF? The answer to that question depends on how accurate the data are and how high the individual stroke risk is for the patient. It is likely that these reports represent the early experience with the LARIAT procedure, and that the current rate of complications after more experience is significantly lower. The techniques used during the procedure have also evolved and should improve the safety of the procedure. These techniques include the use of a micropuncture needle to gain pericardial access and double wiring of the pericardial space to allow for a pericardial drain to be placed at the same time that the LARIAT is deployed. In addition, recent developments that include a larger snare and a more torquability sheath will probably improve the success of the procedure. For now, however, it seems that the LARIAT procedure should be limited to patients who have a very high risk of stroke and cannot tolerate oral anticoagulation, and should be performed by operators with a lot of experience in transseptal catheterization and pericardial access. It appears that there is still a need for better and safer ways to prevent strokes from LAA clots in patients with AF.

References

1. Price MJ, Gibson DN, Yakubov SJ, et al. Early safety and efficacy of percutaneous left atrial appendage suture ligation. Results from the U.S. Transcatheter LAA Ligation Consortium. J Am Coll Cardiol. 2014;64:565-572. 
2. Miller MA, Gangireddy SR, Doshi SK, et al. Multicenter study on acute and long-term safety and efficacy of percutaneous left atrial appendage closure using an epicardial suture snaring device. Heart Rhythm. 2014;11:1853-1859.