March 29, 2020
Boston Scientific’s Watchman Device Evaluated in NCDR’s Postmarket LAAO Registry
March 29, 2020—Procedures to implant the Watchman left atrial appendage occlusion device (LAAO; Boston Scientific Corporation) had a high implant success rate and a low rate of in-hospital complications in an analysis of more than 38,000 procedures.
The American College of Cardiology (ACC) announced that the data were presented as Featured Clinical Research at the virtual conference of the ACC’s Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC). James V. Freeman, MD, et al simultaneously published the findings online in the Journal of the American College of Cardiology (2020;75:1503–1518).
The ACC press release noted that the study included data from nearly all procedures conducted in the United States between 2016 to 2018 that were captured in the National Cardiovascular Data Registry (NCDR) LAAO registry. The study offers insights into how real-world implementation of the device compares to findings from premarket clinical trials. Patients are eligible for a Watchman device if they have atrial fibrillation that is not caused by valve problems, face a moderate or high risk of stroke, and cannot take anticoagulant medications.
The LAAO national database registry is capturing data on Watchman procedures; it also serves as the FDA’s postmarketing surveillance study and meets the reimbursement requirements for the Centers for Medicare and Medicaid Services. The study was funded by the National Heart, Lung, and Blood Institute and the NCDR registry.
According to ACC, the findings revealed that procedural success and complications compared favorably with randomized trials as the use of Watchman expanded across hundreds of hospitals.
The investigators analyzed data from 38,158 patients who underwent Watchman implantation procedures performed by 1,318 physicians at 495 hospitals between 2016 and 2018 in the United States.
The average age of the patients was 76 years. On average, they were 2 to 5 years older than those who participated in the Watchman pivotal clinical trials that led to FDA approval of the device. The patients also had a higher risk of stroke (an average, a CHA2DS2-VASC score of 4.6), and 70% had previously experienced clinically relevant bleeding, putting them in a higher risk category than most patients in the premarketing trials.
Although the number of procedures performed nationally was large, the median annual number of procedures was 30 per hospital and 12 per physician. Seven percent of procedures were aborted or canceled on the day of the procedure.
Among procedures in which the Watchman device was introduced into the heart, 98.1% were implanted successfully, with little to no leakage around the device—a rate of success higher than those reported in the pivotal trials and comparable to or better than previous smaller registry studies, noted the ACC announcement.
Additionally, procedures in the registry had a lower rate of major adverse events than was seen in clinical trials. The most common complications were pericardial effusion requiring intervention (1.4% of patients) and major bleeding (1.3%). Other complications included stroke (0.2%) and death (0.2%).
In the ACC announcement, Dr. Freeman commented, “There’s clearly a lot of enthusiasm in the postmarket setting in the United States to undertake this procedure as an alternative to blood thinners for these patients, who can be stuck between a rock and a hard place because they are at risk for atrial fibrillation–related stroke but have had prior bleeding or other problems with blood thinners. Patients getting this procedure in the real world are generally older and sicker than the patients who were in clinical trials, and it is reassuring to see that the procedural safety profile looks good.”
Dr. Freeman added, “Any time you’re dealing with older and sicker patients, there’s always going to be concern, and the risk of procedures is going to be higher. We also did not see an increase in adverse events as the procedure was rolled out more widely in lower-volume hospitals. The findings were generally reassuring.”
The study was limited to assessing adverse events that occurred in the hospital; it is possible that additional complications could emerge later. Patients in the registry will be followed actively to allow for analysis of outcomes at 6 months, 1 year, and 2 years. The investigators also plan to further evaluate the relationship between procedural volume and outcomes, as well as the impact of different strategies for managing anticoagulant and antiplatelet medications around the time of surgery and during follow-up, noted the ACC.