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EWOLUTION: Left atrial appendage closure device safe, effective at 1 year
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CHICAGO — A left atrial appendage closure device successfully reduced stroke and had a high implant success rate at 1 year among patients with nonvalvular atrial fibrillation, including those who were contraindicated for oral anticoagulation, according to data from the EWOLUTION registry presented at the Heart Rhythm Annual Scientific Sessions.
In the prospective, single-arm, multicenter EWOLUTION registry, 1,025 patients consented to study participation and 1,005 patients were successfully implanted with a left atrial appendage (LAA) closure device (Watchman, Boston Scientific). Anticoagulation regimens were not dictated by study protocol and were prescribed according to standard clinical practice at the participating centers.
“Outside of randomized clinical trials, especially in Europe, the guidelines tell us to use this therapy for patients who cannot tolerate warfarin — to use the device when there is no other alternative — but there are little data to support this because it hasn’t been tested widely in that population,” Lucas V.A. Boersma, MD, PhD, principal study investigator and electrophysiologist at St. Antonius Hospital in the Netherlands, told Cardiology Today.
At baseline, 39% of patients had prior major bleeding or predisposition to bleeding, 49% had a CHA2DS2-VASc score 5, 40% had a HAS-BLED score 3, and 73% were deemed ineligible for long-term use of anticoagulants.
From 3 months to 6 months, oral anticoagulant use dropped from 27% to 8% and dual antiplatelet therapy use dropped from 60% to 28%, whereas single antiplatelet use increased from 7% to 55% and use of no anticoagulants increased from 6% to 9%.
At 1 year, the implant success rate was 98.5%; 99.8% of patients had complete seal or jet size of 5 mm or less at implant; and the rate of 7-day procedure- or device-related serious adverse events was 2.8%, according to the data.
Most operators (78%) had less than 2 years of experience with the device but performed 75% of the procedures in the study.
Also at 1 year, the annual stroke rate decreased by 84%, from an expected stroke rate of 7.2% based on CHA2DS2-VASc score to 1.1% with the device. The annual rate of ischemic stroke, transient ischemic attack or systemic embolism also decreased by 85%, from an expected rate of 10.1% to 1.5%.
Additionally, the annual rate of major bleeding also dropped by 48%, from an expected 5% based on HAS-BLED score to 2.6%. The rate of major bleeding excluding procedural bleeding also decreased by 54%, from an expected rate of 5% to 2.3%, the researchers found.
Similarly, among patients eligible for warfarin, the annual stroke rate decreased by 83%, from an expected 6.4% to 1.1%, and the rate of major bleeding decreased by 65%, from an expected rate of 4.7% to 1.7% with use of the LAA closure device.
The rate of device thrombus was only 3.7%, which was unrelated to use of antithrombotic agents, Boersma noted. He also said there was no strong correlation with strokes, with only one patient who experienced a thrombus on the device having a stroke.
“Although we are using lower anticoagulation during follow-up, the stroke rate remains low, the bleeding rate remains low, the thrombus rate remains the same with the device, and we don’t see more strokes in these patients,” Boersma said. “These data are encouraging, specifically for this patient population that has no alternative.”
The trial is intended to follow these patients for 2 years, and final follow-up data will be available next year, Boersma said. – by Melissa Foster
Reference:
Boersma LV, et al. LBCT02-03. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 10-13, 2017; Chicago.
Disclosure: The study was funded by Boston Scientific. Boersma reports consulting for Boston Scientific.