Good News, Bad News Week for Watchman LAA Occluder


ORLANDO, FL—There’s good news and bad this week for the Watchman left atrial appendage (LAA) occluder. On the research front, early data from the EWOLUTION European post-approval registry suggest that implant success is increasing and adverse events are decreasing, at least within the first 30 days.

Here in the United States, however, the device is getting bad press for announcements stemming from both the Centers for Medicare & Medicaid Services (CMS), regarding coverage payments for the Watchman (Boston Scientific), and from the FDA, which issued 2 recalls for the device yesterday.

Lucas Boersma MD, PhD, of St Antonius Hospital (Nieuwegein, the Netherlands), presented periprocedural outcomes from EWOLUTION at the American Heart Association 2015 Scientific Sessions on Tuesday, November 10. The registry includes data from 1021 patients enrolled between October 2013 and May 2015 at 47 hospitals in Europe, Russia, and the Middle East.

Implant success was achieved in 1004 of the 1019 patients in whom Watchman deployment was attempted, for an overall implant success rate of 98.5%. By way of comparison, implant success in PROTECT was 90.9%, increasing to 94.4% in the trial’s continued access protocol (CAP) study, and 95.1% in PREVAIL (94.8% in CAP2), a statistically significant improvement, Boersma said.

During 30 days of follow-up, 7 patients died in EWOLUTION, although only 1 death was deemed device-related. Major procedure- or device-related bleeds requiring transfusion occurred in 8 patients. Other serious adverse events were infrequent and included vascular damage at puncture site (5 cases), pericardial efussion (3 cases), and air embolism (3 cases), among others.

Overall, however, 30-day serious adverse events occurred in 2.8% of EWOLUTION patients, compared with 8.7% of patients in PREVAIL, 4.2% in PREVAIL, and 4.1% of the combined CAP studies.

“EWOLUTION shows the highest LAA closure success rate out of all Watchman studies so far,” Boersma concluded.

Real-World Answers—and More Questions

Discussing the results following Boersma’s presentation, Frederick A Masoudi, MD, of University of Colorado, Denver, highlighted the fact that EWOLUTION patients had higher baseline risks of stroke and bleeding than did patients who took part in the pivotal trials and CAP studies. Of note, patients who were ineligible for oral anticoagulant therapy made up 61% of EWOLUTION and that group ultimately had the lowest rates of serious adverse events. PROTECT AF and PREVAIL enrolled only patients eligible for anticoagulation.

That said, Masoudi continued, “with no or inadequate comparison group, there can be no conclusions drawn about even the observational effectiveness of devices when only 1 device is being studied.” There are also challenges related to understanding completeness of patient enrollment and endpoint ascertainment in these kinds of registries.

“Winston Churchill said, ‘This is not the end. It is not even the beginning of the end, but it is, perhaps, the end of the beginning,’ and I think that’s where we are with this technology.” Masoudi said. “The trials have been done. [The device] is now being employed in clinical practice, and these are exactly the kind of data we need to understand if we are doing this procedure in the right patients and doing so safely.”

Responding to a question on learning curve, Boersma noted that Watchman has already been reimbursed in Germany for 5 years so operators there are very familiar with device deployment. In other countries, however, where insurers are not covering the device, some centers had very little experience with the Watchman device—some contributing only a single patient to the registry, while others enrolled up to 80 patients. An analysis looking at outcomes by enrolling center, while underpowered, did not show any statistically significant differences between centers, he said.

CMS Issues Proposed Coverage

The issue of US reimbursement was plunged into the limelight on the same day as Boersma’s EWOLUTION presentation. That’s when the CMS released its proposed National Coverage Determination (NCD) stating that the evidence is sufficient to determine that LAA closure using an implanted device is not reasonable and necessary to diagnose or treat an illness or injury or to improve the functioning of a malformed body member. As such, the agency said, it is not covered under the relative Social Security Act. 

However, the proposed decision memo continues, coverage could be considered in order to support evidence development, in specific conditions that include physician experience/volumes and patient characteristics, most notably that the patient has a contradiction to warfarin.

That’s problematic, industry analyst Larry Biegelsen of Wells Fargo pointed out in a November 10 equity research report, since the Watchman’s indications-for-use explicitly specify that patients be “deemed by their physicians to be suitable for warfarin.”

In EWOLUTION, 27% of patients were taking no anticoagulant preprocedure and 6% postimplantation.

A 30-day public comment period now follows the proposed CMS coverage decision.

FDA Class II Recalls Reveal 10-Week-Old ‘Urgent Field Correction’

On the FDA front, the agency issued 2 Class II recalls for the Watchman November 11: one for models of the closure device with delivery system and the other for specific models of the “System Access Sheath with Dilator.” Both recalls reference an “Urgent Field Correction” letter sent by Boston Scientific dated August 25, 2015, warning of a problem with cross-threading of the hemostatis valve cross-threading that could lead to “undesired blood leakage.”

No product needs to be returned as a result of the 2 recalls. Yet recipients of the letters, which include further guidance on avoiding the problem and updated directions for use, are required to complete a form acknowledging receipt of the information and return it to the manufacturer.

The FDA defines Class II recalls as “a situation in which use of or exposure to a violative product may cause temporary or medically reversible adverse health consequences or where the probability of serious adverse health consequences is remote.”

Making Sense of It All

Commenting on all the Watchman news this week, Vivek Reddy, MD, of Mount Sinai School of Medicine (New York, NY), said he was impressed by the EWOLUTION registry data but noted that the indications for use of Watchman are slightly different in Europe, specifically related to the relative contraindications to anticoagulation. The higher stroke and bleeding risks are “not terribly surprising,” he added. What is striking, however, is that despite those higher risks, mortality is pretty much similar to what was seen in the more highly controlled trials.

As for the CMS announcement, Reddy said he is confident that the language will be changed over the course of the public comment period such that patients with a “relative contraindication” to warfarin are covered, not those in whom warfarin is strictly contraindicated. And the fact that patients would only be covered for “evidence development” was always expected, he said. Creation of a post-approval registry was discussed during the FDA advisory committee meetings and is the standard set by defibrillator and TAVR approvals.

As for the FDA Class II recall, Reddy characterized it as downright confusing, pointing out that nothing is actually being recalled. Operators are simply getting tweaked instructions for use.

“I would say the EWOLUTION news is positive for Watchman, the CMS NCD has a bit of worrisome language that needs to be clarified, and the FDA ‘recall,’ in my mind, is a nonissue, other than people may be a bit confused,” he concluded

 


Source: 
Boersma L. Implant success and safety of left atrial appendage closure with the Watchman device: Peri-procedural outcomes from the EWOLUTION registry. Presented at: American Heart Association Scientific Sessions 2015. Orlando, FL.


Disclosures:

  • Boersma reports receiving “modest” honoraria from Boston Scientific
  • Masoudi reports no relevant disclosures.
  • Reddy reports serving as a consultant and receiving grant support from Boston Scientific, St Jude Medical, and Coherex.


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