Periprocedural Safety Data From EWOLUTION Registry Supports Boston Scientific's Watchman LAA Closure Device

November 13, 2015—Preliminary data from the EWOLUTION registry of left atrial appendage (LAA) occlusion with the Watchman device (Boston Scientific Corporation) were presented at the 2015 American Heart Association (AHA) scientific sessions, which were held November 7–11 in Orlando, Florida.

Lucas Boersma, MD, et al are conducting the prospective, multicenter EWOLUTION registry to obtain real-world clinical data on procedural success and complications, as well as long-term patient outcomes, including bleeding and incidence of stroke and transient ischemic attacks. Patients will be followed for 2 years according to the schedule and standard practice at the enrolling centers. LAA occlusion with the Watchman device has been found to be effective and noninferior to oral anticoagulation in randomized trials and prospective registries in patients with atrial fibrillation, noted the investigators in the background to the study.

As summarized in the AHA abstract, the EWOLUTION investigators prospectively enrolled 1,025 patients who were scheduled for a Watchman implant at 47 centers in 13 countries during a period of 19 months. Current European Society of Cardiology guidelines recommend LAA closure for patients with a (relative) contraindication for oral anticoagulation and increased risk of stroke.

At the AHA sessions, the EWOLUTION investigators reported on periprocedural safety in this high-risk population.

The baseline data showed that the population presented with higher CHADS2 (2.8 ± 1.3), CHADsVASc (4.5 ± 1.6), and HAS-BLED (2.3 ± 1.2) scores compared to previous randomized clinical trials, such as PROTECT-AF and PREVAIL (CHADS2 score, 2.2 ± 1.2 and 2.6 ± 1.0, respectively).

In EWOLUTION, 59.9% of patients were male with mean age of 73.5 ± 8.9 years; 34.3% had congestive heart failure; 55.9% were New York Heart Association class II and 31.3% were class III; 15.6% had abnormal renal function; 10.6% had a history of transient ischemic attack; 19.8% had a history of ischemic stroke; 14.8% had previous hemorrhagic stroke; and 31.3% had a history of major bleeding. Additionally, 60.9% of the patients were deemed to be relatively contraindicated for oral anticoagulation.

The investigators reported that 99.3% of procedures were successful in closing the LAA with no/minimal (< 5 mm) leakage assessed by periprocedural transesophageal echocardiography. Despite the high-risk population, 93.1% of patients were free from any adverse event within the first 30 days of the implant procedure. Most notably, pericardial effusion occurred in only 0.9% of the procedures. Device embolization was observed in only two cases (0.2%).

The investigators concluded that LAA closure with the Watchman device has a high initial success rate in complete LAA closure with minimal periprocedural risk when performed by appropriately trained operators, even in patients with multiple comorbidities. Improvements in implantation techniques and operator experience may further improve the net clinical benefit of the procedure, advised the EWOLUTION investigators.