New LAA closure device linked to reduced stroke risk in pilot study

A new left atrial appendage (LAA) closure device can be implanted with a high success rate and slashes the one-year risk of stroke in nonvalvular atrial fibrillation (NVAF) patients, according to the researchers of the device’s pilot trial.

The LAmbre closure system (Lifetech Scientific, Shenzhen, China) successfully occluded the LAA in 152 of 153 patients enrolled in a nonrandomized trial across 12 Chinese hospitals. During one-year of follow-up, ischemic stroke occurred in two patients—both with a prior history of stroke. No incidents of device embolization were reported.

“We have shown that LAA closure with the LAmbre device is feasible and has a high short-term procedural success rate,” lead researcher Hu Huang, MD, and colleagues wrote in JACC: Cardiovascular Interventions. “Moreover, follow-up results suggest that the LAmbre device could be associated with encouraging clinical outcomes in the prevention of stroke.”

Oral anticoagulants (OACs), particularly warfarin, are most commonly used for stroke prevention in patients with atrial fibrillation, but some patients aren’t suited for long-term OAC treatment. The NVAF patients in this trial fit that description and met at least one of the following criteria for the CHADS₂ stroke risk calculator: congestive heart failure, hypertension, age of at least 75 years old, diabetes and prior stroke or transient ischemic attack.

The average CHADS₂ score of the study population at baseline was 2.5, representing a 6.4 percent annual risk for stroke. Another predictive model (the CHA₂DS₂-VASC score) estimated a 5.2 percent annual thromboembolism risk for the study patients.

But stroke occurred in just 1.3 percent of patients, results comparable to those of other LAA closure systems—the Watchman device (Boston Scientific) and Amplatzer Cardiac Plug (Abbott)—the authors wrote.

Implanted via femoral vein access, the self-expanding LAmbre system contains a cover connected to a distal umbrella with eight claws, each with individual stabilizing hooks. Compared to the other LAA closure devices, the authors wrote, the LAmbre has more sizes (15) and is “more suitable for special morphological LAA.”

The researchers noted device embolization occurred in three patients (0.6 percent) in a trial evaluating the Watchman device and in 1.5 percent of patients in a trial evaluating the Amplatzer cardiac plug. No device embolization was present in LAmbre’s initial study, although the sample size was small.

“Three possible mechanisms may contribute to improve the stability of the LAmbre device,” Huang et al. wrote. “First, claws and hooks of the distal umbrella facilitate the anchoring to the LAA wall. Second, an oversized umbrella provides a stenting effect against the LAA wall. Last, the pectinate muscles located at the mid-to-distal portion of LAA may trap the individual claws of the umbrella.”

The researchers noted the small sample size and medium-term follow-up isn’t enough to determine the long-term safety of the device. They added larger, randomized clinical trials are necessary to further evaluate the merits of the LAmbre device in NVAF patients at high stroke risk.

But while the study’s authors suggested comparing LAmbre to OAC, two German physicians said a noninferiority trial evaluating the device against the Watchman would be more appropriate.

“One may argue about ethical concerns regarding randomization of individuals with atrial fibrillation to LAAC (LAA closure) or aspirin/no treatment in those who are at prohibitive risk of bleeding from oral anticoagulation, or perhaps, warfarin in those whose bleeding risk is low, because data have now convincingly shown a benefit with LAAC compared with warfarin,” wrote Horst Sievert, MD, and Stefan Bertog, MD, both with Cardiovascular Center Frankfurt, in a related editorial. “Hence, the next step could be a randomized noninferiority trial comparing the LAmbre device to the Watchman device, or a randomized trial comparing it to direct oral anticoagulation with prothrombin or factor Xa inhibitors.”