Cardiology Societies Provide Direction on Future of LAA Closure in Clinical Practice

July 10, 2015

WASHINGTON, DC — Three major cardiology societies have copublished a review paper on the use of left atrial appendage (LAA) occlusion devices for stroke prevention in patients with atrial fibrillation (AF) in an attempt to address key questions influencing percutaneous LAA occlusion technologies in clinical practice[1].

Published June 29, 2015 in Heart Rhythm, the statement, coauthored by the American College of Cardiology, Heart Rhythm Society, and Society for Cardiovascular Angiography and Interventions (ACC/HRS/SCAI), takes a close look at the existing data, as well as their shortfalls, and several key issues regarding the uptake of percutaneous LAA occlusion-device technologies, including who should be performing the procedures and in what setting.

Importantly, the experts call for better surveillance through the establishment of a nationwide registry in order to understand who is getting the devices and how well they fare after undergoing the percutaneous procedure. The establishment of a registry, not unlike the national registry created for transcatheter-valve therapies, would benefit the "still-nascent field," they say, especially since only one LAA device is supported by randomized, controlled clinical-trial data.

Speaking with heartwire from Medscape, chair of the writing committee Dr Frederick Masoudi (University of Colorado, Denver) said the position statement was developed, in part, because LAA occlusion is a "potentially impactful and important technology on the one hand, but on the other there really is a paucity of data, particularly for some devices more than others." The ACC, HRS, and SCAI, he added, want to see the technology rolled out in a manner that ensures optimal outcomes for patients and enhances physician understanding of how patients fare when they receive one of the technologies.

"It's absolutely critical to understand a number of aspects around the diffusion of a new technology, including the patients who are selected for the technology and the extent they conform to the populations from randomized trials and the clinical guidelines where they exist," said Masoudi. "Understanding who gets selected for the procedure is important, and understanding the longitudinal outcomes of patients after they receive these therapies is also important."

US Guidelines: No Mention of Percutaneous LAA Closure

Currently, the US clinical guidelines for the management of patients with AF do not include recommendations for the use of LAA closure devices for stroke prevention, mainly because only one device has been approved by the US Food and Drug Administration (FDA). The Watchman (Boston Scientific) is the only LAA closure device to undergo testing against the gold-standard warfarin in multiple randomized controlled trials and was approved by the FDA only in March 2015.

In Europe, the 2012 Focused Update to the European Society of Cardiology (ESC) for the management of patients with AF gives a relatively weak recommendation for LAA closure/occlusion/excision with percutaneous technologies and recommends the procedure for patients at high risk for stroke unable to take long-term oral anticoagulation (class IIb, level of evidence B).

Recently, some experts have been critical about the absence of data concerning LAA occlusion and the off-label use of Amplatzer devices (St Jude Medical) and the Lariat (SentreHEART) snare device. For example, the Lariat LAA occlusion device received class II (intermediate-risk) clearance by the FDA via the 510(k) protocol and was approved for suture placement and knot tying in surgical procedures where soft tissue is approximated and/or ligated. It did not require the more rigorous premarket-approval (PMA) pathway that all class I (high-risk) devices undergo and is not approved in the US for LAA occlusion or stroke prevention despite its widespread off-label use.

As reported by heartwire in May 2015, a review highlighted a number of adverse events with the Lariat device, with researchers calling for formal, randomized clinical trials to test the device specifically for this indication.

For its part, SentreHEART, the maker of the Lariat, which is officially known a "suture-delivery device," has received an investigational device exemption (IDE) from the FDA to begin enrolling patients in the AMAZE trial[2]. In AMAZE, researchers will evaluate the Lariat device for the closure of the LAA as an adjunct to ablation in approximately 600 patients with AF.

In addition to the Lariat, there are at least four Amplatzer devices that have been used off-label for LAA closure. These include atrial and ventricular septal defect occluders, the cardiac plug, and the Amulet (a second-generation cardiac plug). The atrial septal occluder had a high rate of embolization when it was first adopted for LAA closure, although it has been modified for LAA closure. A trial testing the Amplatzer cardiac plug against optimal medical therapy with dabigatran or warfarin is currently on hold. As the ACC/HRS/SCAI experts point out, the only published reports of the Amplatzer devices in LAA occlusion are retrospective, nonrandomized case series.

To heartwire , Masoudi said it would be optimal for LAA closure devices on the market to have the type of data that supported the approval of the Watchman.

"Obviously, the way the Lariat came to the market was a little bit unusual, being approved by means of the 510(k) process for approximating soft tissue," he said. "The data on the Lariat comprise a few uncontrolled case series of patients. The device is being used in the absence of any data about whether it actually reduces the risk of stroke and whether or not the complications for this fairly invasive procedure are offset by the benefit that might be obtained by it."

Masoudi said the ACC/HRS/SCAI position statement is intended to emphasize the importance of reporting and collecting clinical, procedural, and device data to better understand the outcomes of patients. With greater surveillance, physicians and researchers will be able to better understand the risk of procedural complications, the risk of stroke, and the risk of other adverse outcomes, as well as the extent to which patients are using different types of medications after the procedure, particularly antiplatelet and anticoagulant therapy.

The collection of data through registries, however, would not preclude randomized, controlled trials, which are paramount for emerging technologies, added Masoudi.

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