Novel LAA Closure Device ‘Promising’

PHOENIX — A novel transcatheter device that twists the left atrial appendage (LAA) closed from the inside appeared safe in first-in-human results.

Among 15 atrial fibrillation patients who received the Laminar device, all had successful implantation and LAA closure without any device-related thrombus or safety events out to 12 months.

Two of the 15 had a less than 3-mm leak of blood through to the LAA, which persisted from day 7 to 12 months, reported Jason H. Rogers, MD, of the University of California Davis Medical Center, at the annual Transcatheter Valve Therapeutics (TVT) conference hosted by the Cardiovascular Research Foundation.

The findings also appeared in JACC: Cardiovascular Interventions.

The results hit many of the goals for LAA closure — no major complications, covering all anatomies, complete seal without any leak, rapid and complete endothelialization, and elimination of device-related thrombus while minimizing post-procedural anticoagulation — that were noted by another session speaker, William Gray, MD, of the Lankenau Heart Institute in Wynnewood, Pennsylvania.

Session panelist Saurabh Sanon, MD, of HCA Florida Heart Institute in Largo, highlighted the promising safety findings so far. “This is an elective procedure in mostly younger people,” he said. “I think that there’s no room for any complications here. But a lot of our current devices are very safe. So, for me, the biggest issues are, can you do this in a way that we can achieve no DRT [device-related thrombus] and no peridevice leaks? This technology will allow us to do that. … I think this is going to play a big role in the future of LAA [closure].”

The Laminar device is dubbed LAA exclusion, in contrast to LAA occlusion with transcatheter LAA closure devices on the market like the the Amplatzer and Watchman. After punching through the septum, a self-expanding nitinol “ball” is advanced into the LAA, where nubs engage the tissue and the device is rotated until the LAA twists closed. The ball is then locked in place from the outside with a small, six-petal “flower” that excludes and eliminates the LAA pouch from the left atrium.

“That’s the future not only of LAA closure but of interventional cardiology — to leave nothing behind,” said session moderator Horst Sievert, MD, of the Cardiovascular Center Frankfurt in Germany.

Without depending on a plug, the device can cover the “snowflake” variety in distal LAA anatomies and a wide range of ostial diameters, Rogers noted.

“Moreover, the implant has a low device left atrial surface area, which may minimize the risk for device-related thrombosis,” according to an accompanying editorial by Apostolos Tzikas, MD, PhD, of the European Interbalkan Medical Center in Thessaloniki, Greece, who said the “initial human results seem promising.”

In the canine model studied before the attempt in humans, there was a completely smooth appearance of the endocardial surface with the lock completely covered over by tissue, while the residual LAA outside shrank and involuted. “And we have some early data also to suggest that this is electrically isolated from the rest of the left atrium due to the involution of the tissue,” Rogers told attendees.

While some on the panel speculated about a potential advantage in reducing atrial fibrillation drivers from the LAA, Gray cautioned that the aMAZE trial did not show any advantage to LAA ligation in reducing recurrent atrial arrhythmias.

The patients in the first-in-human experience will continue to be followed out to 5 years post-implantation, Rogers noted. The early feasibility trial is now enrolling.

Questions that remain to be answered are whether tissue folding will lead to long-term thrombogenicity from the formation of pleats and how well an average operator can avoid complications in thin-walled, fragile anatomies, Tzikas wrote.

“More experience and data are needed to understand possible limitations of the device design, its use by an average operator, LAA anatomical characteristics, and long-term tissue remodeling and healing,” he wrote. “It is conceivable that proper patient selection, careful preprocedural planning with advanced cardiovascular imaging, and adequate device surveillance will be the key factors for success.”

Proving stroke reduction with the device long-term will be key, said Sameer Gafoor, MD, of the Swedish Medical Group and Providence St. Joseph Health in Seattle. “I want the Mandrola’s of the world to be convinced.”