Boston Scientific and Abbott this week both put forward separate studies supporting their respective implants for sealing off the heart’s left atrial appendage—the pocket within the cardiac muscle wall that can potentially increase the risk of stroke among people who have the irregular heartbeat known as atrial fibrillation.
Boston Scientific presented three-year data on its Watchman FLX to see whether the device could be safer than first-line oral anticoagulation medications while delivering the same protection against future strokes. Abbott, meanwhile, announced five-year outcomes from a head-to-head study comparing its Amplatzer Amulet to an earlier incarnation of the Watchman device.
Both studies were presented as late-breaking trials at the annual scientific sessions of the American Heart Association, being held in Chicago.
The randomized, controlled OPTION trial examined 1,600 patients at a moderate to high risk of stroke, with half receiving Watchman FLX. Nearly 40% of the participants had the device placed concomitantly during a cardiac ablation to address their afib. The other 60% received the implant three to six months after undergoing a radiofrequency or cryoablation procedure.
According to Boston Scientific, current treatment guidelines recommend that people with multiple risk factors for stroke stay on a long-term blood thinner regimen after an ablation, which carries its own risks of bleeding.
The OPTION study showed that Watchman FLX patients had fewer cases of major bleeding within three years compared to the medication arm, at a rate of 8.5% versus 18.1%—with most of those participants being prescribed direct oral anticoagulants and about 5% receiving warfarin.
The trial also recorded similar composite rates that accounted for all-cause deaths, strokes or systemic embolism, with Watchman FLX’s 5.4% being described as noninferior to the control group’s 5.8%.
“Notably, we found high rates of procedural success in patients who had a Watchman FLX implant after an ablation, and of patient adherence to their prescribed medication regimen following the procedures, which likely reinforced positive outcomes such as the low rates of ischemic and hemorrhagic stroke within the trial population,” the study’s principal investigator, Oussama Wazni, M.D., vice chairman of cardiovascular medicine at the Cleveland Clinic, said in a statement. The trial’s results were also published in The New England Journal of Medicine.
“With this data, we see potential to both expand the indication for the Watchman FLX platform and ultimately elevate it to become a frontline therapy for patients receiving cardiac ablation for atrial fibrillation to reduce their risk of stroke,” added Brad Sutton, M.D., Boston Scientific’s chief medical officer for afib solutions.
Abbott’s Amulet IDE trial put its left atrial appendage closure device up against the Watchman 2.5, which was approved by the FDA in 2015. The company described the randomized study as the largest of its kind to date, with nearly 1,900 patients enrolled.
After five years, Abbott said fewer patients who received the Amplatzer Amulet implant required blood thinners compared to the Watchman 2.5, with 94% of participants dropping their medications versus 90.9%.
“Because blood thinners may cause excessive bleeding and side effects like nausea or dizziness, we as physicians want to avoid these medications for our patients following an LAA closure procedure,” said the study’s principal investigator, Dhanunjaya Lakkireddy, M.D., executive medical director of the Kansas City Heart Rhythm Institute at HCA Midwest Health.
The study, which was published in the Journal of the American College of Cardiology, also showed similar clinical outcomes between the two devices—including in a composite rate of cardiovascular death, stroke and systemic embolism, at 20.3% and 20.7%, and in annualized ischemic stroke rates, with each at 1.6% per year.
“For years, doctors and their patients only had one minimally invasive option to close the LAA,” said Sandra Lesenfants, senior vice president of Abbott's structural heart business. “The Amplatzer Amulet redefined LAA closure by offering dual-seal technology that completely and immediately seals the LAA without requiring blood-thinning medication following the procedure. These data reinforce that the Amulet device is safe and effective, and also, importantly, that it's helping people enjoy their lives and worry less about the risk of having a stroke.”