After Years of Scrutiny, Watchman Ready for Prime Time

With the recent approval of the Watchman device as an alternative to warfarin, US clinicians finally have another option for preventing stroke in selected patients with A-fib.

On March 13, 2015, the FDA gave the nod to the Watchman (Boston Scientific) left atrial appendage closure device for the reduction of thromboembolism in high-risk patients with nonvalvular A-fib. The labeling states that patients must:

• Be at increased risk for stroke and systemic embolism based on CHADS₂ or CHA₂DS₂-VASc scores and be recommended for anticoagulation therapy
• Be deemed by their physicians as suitable for warfarin
• Have an appropriate rationale to seek a nonpharmacologic alternative to warfarin, taking into account the safety and effectiveness of the device compared to warfarin

The road to approval has not been an easy one.

In an interview with TCTMD, David E. Kandzari, MD, of Piedmont Heart Institute (Atlanta, GA), who was a member of the Circulatory System Devices Panel that reviewed the Watchman data, said that to his knowledge, it is the only technology that has come before the FDA panel 3 separate times for data review. For Watchman, the first time was in 2009, the second in 2013, and the third in October 2014.

At the third meeting, which focused on updated datasets from the PREVAIL and PROTECT AF trials, the panel voted unanimously that the device was safe, but its members were evenly split on the question of efficacy. They voted 6-5 in favor regarding risks vs benefits, with 1 member abstaining. At the time, Dr. Kandzari said the panel was troubled by a numerical excess of ischemic stroke that emerged in the device arm of PREVAIL between the second and third FDA panel meetings. Panel members, he noted in an October 2014 interview with TCTMD, had begun to feel that “we were moving further away from the expected benefit with the Watchman device.”

Now that it has been approved, however, and incremental improvements have been made in procedural safety, “ultimately, I think this is a welcome technology for patients who are at high risk for bleeding complications [with] warfarin,” he said.

Similar Technologies in the Wings

In an email with TCTMD this week, Robert J. Sommer, MD, of Columbia University Medical Center (New York, NY), noted that as with any procedure, there are some potential complications with Watchman. “[B]ut with increased use and familiarity with the device implant procedure,” he added, “the risks are very small.”

Despite the bumpy road to approval, Dr. Sommer said, Watchman is “definitely relevant” and is the first of many such technologies expected to be introduced.

Both St. Jude Medical, which manufacturers the Amplatzer Cardiac Plug, and Coherex, which makes Wavecrest, “were waiting for the approval so they [could] run their pivotal trials in the US head-to-head against the approved device,” he said.

A primary concern throughout the FDA panel meetings for Watchman was which patients would benefit most from the device. While the labeling limits its use to those who are eligible for warfarin, both Drs. Kandzari and Sommer said off-label use is anticipated.

“There is no question that warfarin-ineligible patients, who are most likely to benefit from the device, will be a prime target audience,” Dr. Sommer said. “I suspect that there will be ongoing registries and other data collection to compare the outcomes in this group with the warfarin-eligible folks.”

Dr. Kandzari agreed. “We intuitively might think it would be very useful in patients who cannot take warfarin anticoagulation, [so] how that leads to product labeling and reimbursement will be a very interesting topic,” he said.

Dr. Sommer said the Watchman is a welcome addition to clinicians’ armamentarium considering that medical therapy for stroke prevention carries “a significant risk of bleeding complications— including the potential for life-threatening bleeding—especially in the older patient population.”

He added that the trial data demonstrate that “over a period of 4-5 years [Watchman] becomes statistically superior to the blood thinners with a 50% reduction in stroke and a 60% reduction in overall mortality compared to staying on the blood thinner.”