In May, the CMS began a National Coverage Analysis for Watchman prompted by a request from the device’s manufacturer, Boston Scientific. The appeal for Medicare coverage received support in a June letter written by the presidents of the American College of Cardiology, the Heart Rhythm Society, and the Society for Cardiovascular Angiography and Interventions.
A national coverage determination by the CMS in favor of paying for Medicare patients who undergo Watchman placement “would be a huge benefit,” said Dr. Holmes, who predicted that private insurers would then follow the CMS’ lead and cover the procedure as well. The CMS set Nov. 21, 2015, as the deadline for its decision.
Patients with anticoagulant contraindications will take more time
Even if the CMS decides in favor of reimbursing Watchman placement, the request that it received from Boston Scientific specified coverage for the FDA-approved indication, which stipulates placement in patients able to undergo warfarin treatment. That means for patients who are unable to receive anticoagulant treatment, placement constitutes off-label use that will likely remain unreimbursed, yet these are the very patients that experts agree form an obvious target for Watchman intervention. Currently, these AF patients generally rely on chronic aspirin treatment as their only protection against ischemic stroke.
The only formal, reported experience using Watchman in AF patients who did not also receive warfarin during the first 6 weeks following placement came in a 150-patient, uncontrolled feasibility study, ASAP(ASA Plavix Feasibility Study With WATCHMAN Left Atrial Appendage Closure Technology) run at four centers in Europe (J Am Coll Cardiol. 2013 June 25;61[25]:2551-6). All of the enrolled patients were ineligible to receive warfarin, and instead following Watchman placement these patients received either clopidogrel or ticlopidine for 6 months and chronic treatment with aspirin (dual antiplatelet therapy [DAPT]). Follow-up averaged 14 months, and based on the patients’ average CHA2DS2-VASc score at entry the expected annualized rate of ischemic stroke in these patients was roughly 7%.
However, their observed rate was just 1.7%, and their rate of periprocedural and postprocedural complications roughly matched the rates seen in the first Watchman randomized trial. The researchers who ran the study concluded that the results showed that “Watchman can be safely implanted without a warfarin transition.”
Dr. Dhanunjaya R. Lakkireddy
Although the ASAP results showed “Watchman is very effective for stroke prevention” without early anticoagulation following placement, “I’m not sure how one could use Watchman for patients contraindicated for oral anticoagulation,” said Dr. Lakkireddy. “This is a controversial area, and one has to be cautious about cavalier off-label use of the device.”
“I think we need to know more about the [ASAP] data before we’d feel comfortable offering the Watchman device” to patients contraindicated for oral anticoagulation, said Dr. Weiss.
Patients with a total contraindication against treatment with warfarin or a NOAC have the greatest need, said Dr. Reddy. “The problem is, we don’t have much safety data” for these patients, and while the results from the ASAP trial showed the device can be safely placed just using DAPT, the numbers were small and the device is not approved” for use in this setting, said Dr. Reddy, the lead investigator for the ASAP study.
The solution to the dilemma posed by this patient group may lie in the ASAP 2 study, a large, multicenter trial that will enroll AF patients with a contraindication to oral anticoagulation and will compare Watchman placement followed by several months of antiplatelet treatment with DAPT head-to-head with patients randomized to today’s standard treatment of aspirin only. The trial will be sponsored by Boston Scientific, and should start by the end of this year, Dr. Reddy said. He envisions enrolling many of the AF patients he sees with an absolute contraindication to oral anticoagulant treatment in the trial once it starts, though it will mean that only half the enrolled patients will receive a Watchman device.
Dr. Holmes sees registry data as another possible route for eventually expanding the labeled indication for Watchman to patients who can’t receive warfarin or another anticoagulant. He cited the precedent of the FDA broadening the labeled indication for transcatheter aortic-valve replacement in 2013 based in part on U.S. registry data as well as on data collected in Europe.
One potential source of U.S. patients who could wind up receiving only brief warfarin treatment after Watchman placement would be those who develop a major bleed soon after starting on anticoagulation, an event that would prompt most physicians to discontinue and not restart warfarin, Dr. Holmes said. He suggested that in these circumstances patients receive DAPT for 6 months using aspirin and clopidogrel, following the protocol tested in ASAP.