Doctors & patients are saying about 'A-Fib.com'...
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Baltimore, MD
The Watchman Occlusion Device and Risk of Device-Related Blood Clot
The Watchman is an occlusion device that closes off the Left Atrial Appendage (LAA) to prevent clots from getting into the heart. For those with A-Fib, 90%–95% of clots and strokes come from the LAA.
The Watchman device is considered an alternative or an improvement to a lifetime of taking anticoagulants including warfarin and the NOACs. See Watchman Alternative to Coumadin and Watchman Better Than Warfarin.
2018 HRS Report: Clots Can Form on the Watchman
A new meta-analysis of clinical trials and registries of the Watchman device is believed to be the largest to date of Device-Related Thrombi (blood clot) following left atrial appendage closure.
Size comparison of the Watchman occlusion device
The study shows that in about 3.7 percent of patients a blood clot forms on a metal screw on the face of the device. The clot can form many months, even a year after installation.
“While not frequent, when present, thrombus on the face of an LAA occluder is associated with a high rate of ischemic stroke,” said study presenter Vivek Y. Reddy of Mount Sinai Hospital in New York City. (Dr. Reddy was one of the original investigators of the Watchman clinical trials.) These findings were presented at the 2018 Heart Rhythm Society meeting.
Device-related thrombi (DRTs) are troublesome because they increase the risk of ischemic stroke by over 3 fold. However, no significant association with mortality emerged.
This risk, Dr. Reddy said, calls for aggressive management of patients at risk for device-related blood clots.
The Study: Finds Device-Related Thrombi (DRTs)
To better understand the mechanism of stroke after LAA closure, Dr. Vivek Reddy and his colleagues, looked at the incidence, predictors and clinical outcomes of device-related thrombus (DRT).
Watchman device: inserted (L) and progression of proper tissue growth (R)
The meta-analysis study looked at data on 1,739 patients who were successfully implanted with the Watchman device as part of four prior clinical studies. Patient follow-ups included a transesophageal echocardiography (TEE).
Findings: Among those patients receiving a Watchman, the investigators found 65 patients (3.74%) had DRT. Most were detected after anticoagulation had been discontinued at 45 days post-insertion. Some DRTs first showed up at the 1-year TEE.
Dr. Reddy reported that despite these findings, a majority of Watchman patients with an identified DRT (74% of the 65 patients) did not have a stroke. And in Watchman patients who did have stroke, 87% occurred in the absence of a DRT.
Implications: There is a strong case for rethinking the timing of planned follow-up TEE examinations of Watchman patients. The standard protocol is a TEE at 45 days after placement, when routine anticoagulation usually stops, and then a second TEE 12 months after placement.
Dr. Reddy suggests a better schedule might be to perform the first TEE at 3-4 months after placement when oral anticoagulant therapy stops. This gives time for a potential DRT to form.
What this Means For Those Patients With a Watchman
“Prevention and management of DRT may require that each [Watchman] patient receive a tailored regimen of anticoagulation and surveillance,” said B. De Lurgio, MD, a cardiac electrophysiologist at Emory Healthcare commenting on Reddy’s report.
If you have a Watchman device, you and your EP should discuss “aggressive surveillance” to find any clots on the face of your Watchman. Usually these can be resolved by taking a course of anticoagulants.
If Closing the LAA: An Alternative Occlusion Device
Lariat placement: lasso around opening to LAA
With no metal involved, another occlusion device is the Lariat II noose-like device which is slipped around the LAA. This ‘lasso’ is then tightened, and eventually the tissue dies and shrivels up (like a grape into a raisin).
But there has been a reported problem with the Lariat, too. For more on the Lariat see my article: Alert: Patients with Lariat Device for Left Atrial Appendage Closure.
A Challenge to Install: Compared to the Watchman, the Lariat is more challenging to install and is currently used less often than the Watchman. Not all EPs install and have experience with the Lariat II. You may need to do research to find an EP experienced and good at installing the Lariat. For more about the Lariat, see Lariat II Suture to Close the Left Atrial Appendage.
Watchman Still As Effective As Warfarin
Regarding this DRT data, Dr. Reddy said he didn’t think this data takes away from the argument that the Watchman is a reasonable strategy. “It doesn’t add or detract from the previous data.”
Comparing stroke risks: In cases where no treatment was applied (neither anticoagulants nor the Watchman), the overall ischemic stroke rate is 6.0% per year.
Contrast that 6% rate to the stroke rates of 1.77% per year in people with the Watchman device and 1.71% per year for those on oral anticoagulation.
The Watchman is still a viable option against stroke risk.
