What is WATCHMAN?
WATCHMAN LAA Device is FDA approved, an alternative to taking warfarin lifelong, for patients who are suffering from atrial fibrillation that is not due to heart valve problems, also known as non-valvular Afib.
It is a permanent implant that is done via a minimally invasive procedure, which can reduce the risk of stroke, without the risk of bleeding that can come with the long-term use of warfarin. It was found that left atrial appendage closure with WATCHMAN is as effective as warfarin in preventing strokes in patients with atrial fibrillation, and strokes in Watchman recipients are 55% less likely to be disabling, according to a meta-analysis of 5-year outcomes in the PREVAIL and PROTECT AF randomized trials.
This device therapy has addtional benefits over warfarin, such as significantly reduced risks of mortality, non–procedure-related major bleeding, and hemorrhagic stroke, Saibal Kar, MD, reported in presenting the results of the meta-analysis at the Transcatheter Cardiovascular Therapeutics annual educational meeting (TCT) in 2017.
How does WATCHMAN LAA Closure Device prevent Stroke?
In atrial fibrillation, the heart pumps irregularly and there is a tendency for blood to pool in a part of the heart chamber, called the left atrial appendage (LAA). As the blood pools, a clot may form, and when it escapes from the LAA and travel to the rest of the body, it can cut off the blood supply to the brain, resulting in a stroke. In patients with non-valvular Afib, more than 90% of stroke-causing clots that come from the heart are formed in the LAA.
The WATCHMAN LAA device fits right into the LAA, permanently closing it so as to prevent blood clots from escaping, thus reducing the risk of stroke.
How is the WATMAN LAA Device Implanted?
The device is implanted into the heart via a minimally invasive procedure. The doctor cuts a small hole in the leg vein and inserts a narrow tube, similar to the angioplasty when a stent is required. Using transesophageal echocardiography and Xray, the doctor guides the WATCHMAN into the left atrial appendage (LAA). The procedure is done under general anesthesia and takes about an hour. Patients commonly stay in the hospital overnight and leave the next day.
What to expect after the procedure?
After the procedure, the patients will require to continue their warfarin until the LAA is permanently closed off. Heart tissue will grow over the implant, which blocks out the blood clots, and to verify that this has happened, transesopheal echocardiography tests will be performed.
After than the patient will still require blood thinners, but those of a lower bleeding risk than warfarin.
Studies on WATCHMAN LAA Device Closure
“This is not a first-line therapy. But we know there is a large number of patients who cannot tolerate long-term anticoagulation. And this is the ideal therapy for stroke prophylaxis in that group of patients,” according to Dr. Kar, director of interventional cardiac research at Cedars-Sinai Medical Center in Los Angeles.
The patient-level meta-analysis of 5-year outcomes included 1,114 patients with atrial fibrillation who were randomized 2:1 to the Watchman device or warfarin, with 4,343 patient-years of follow-up. This was a fairly high–stroke risk population, with CHA2DS2-VASc scores in the 3.6-3.9 range, and 40% of patients aged 75 years or more. At baseline, 23% of subjects had a history of stroke or transient ischemic attack.
At 5 years’ follow-up, the composite endpoint of all stroke or systemic embolism was the same in the two study arms. However, the rate of hemorrhagic stroke was 80% lower in the Watchman group, the risk of disabling or fatal stroke was reduced by 55%, the rate of cardiovascular or unexplained death was 41% lower, all-cause mortality was reduced by 27%, and postprocedure major bleeding was 52% less frequent in the device therapy group. All of these differences achieved statistical significance, the cardiologist reported at the meeting sponsored by the Cardiovascular Research Foundation.
In the PREVAIL trial, 92% of patients were able to stop taking warfarin just 45 days after the procedure, while 99% of patients were able to stop taking warfarin within 1 year after the procedure.
Please watch the following videos from Boston Scientific, to learn more about the WATCHMAN LAA device closure.
Holmes DR Jr, Kar S, Price MJ, et al. Prospective randomized evaluation of the Watchman Left Atrial Appendage Closure device in patients with atrial fibrillation versus long-term warfarin therapy: the PREVAIL trial. J Am Coll Cardiol. 2014;64(1):1-12.