EXPERT ANALYSIS FROM THE CARDIOVASCULAR CONFERENCE AT SNOWMASS

SNOWMASS, COLO. (FRONTLINE MEDICAL NEWS) – The goal is finally in sight following an odyssey to develop the Watchman left atrial appendage closure device as a safe and effective alternative to oral anticoagulation for stroke prevention in patients with nonvalvular atrial fibrillation, Dr. David R. Holmes Jr. said at the Annual Cardiovascular Conference at Snowmass.

It’s all coming together: The Watchman, a small percutaneously delivered parachute-like device, has received FDA marketing approval as the sole authorized left atrial appendage closure device in this country on the strength of two compellingly positive randomized controlled trials. A recent meta-analysis of those trials showed significantly fewer hemorrhagic strokes, fewer cardiovascular or unexplained deaths, and fewer nonprocedural bleeding events in Watchman recipients than in patients randomized to warfarin. And a cost-effectiveness analysis has concluded that after 8 years, the Watchman becomes “the dominant strategy” – meaning more effective and less costly for stroke prevention in patients with atrial fibrillation (AF) having a contraindication to warfarin – compared with the novel oral anticoagulant apixaban ( J Am Coll Cardiol. 2015 Dec 22;66[24]:2728-39 ).

Moreover, the final pieces required for the Watchman to become a mainstream reimbursable therapy are falling into place. The Society for Cardiovascular Angiography and Interventions (SCAI), the American College of Cardiology, and the Heart Rhythm Society (HRS) have jointly issued institutional and operator requirements for left atrial appendage occlusion programs ( J Am Coll Cardiol. 2015 Dec 8. pii: S0735-1097[15]07550-6 ). The ACC’s National Cardiovascular Data Registry has set up a new left atrial occlusion registry. And most important of all from a reimbursement standpoint, the Centers for Medicare and Medicaid Services has released a preliminary National Coverage Determination for left atrial appendage occlusion.

“This will affect your patients and your lives,” noted Dr. Holmes of the Mayo Clinic in Rochester, Minn. He and the Mayo Clinic share a financial interest in the Watchman technology, which has been licensed to Boston Scientific.

The CMS will cover the Watchman only when the catheter procedure is performed by an experienced interventional cardiologist or electrophysiologist in an experienced center as defined by the SCAI/ACC/HRS standards, and only in patients enrolled in the national prospective registry. The registry will monitor operator and device-related complications, stroke and systemic embolism rates, deaths, and major bleeding rates for 5 years post-procedure.

“If you want to be in this field, you will be in that registry because reimbursement will depend on that,” Dr. Holmes explained. “This registry will be incredibly important. It will tell us how we’re doing, what we should be doing, and what we could potentially be doing in the future.”

One hitch is that the preliminary National Coverage Determination states that coverage will be limited to AF patients with high stroke-risk and HAS-BLED scores as well as a contraindication to warfarin, whereas the FDA-approved indication says patients must be deemed by their physician to be suitable for warfarin.

“In this particular case, CMS was not talking with FDA. We don’t know how that will get sorted out,” according to the cardiologist. “But as soon as CMS comes through with their final regulatory coverage determination, I think we will finally be there. We’ll then be able to offer this as a treatment strategy for stroke prevention in selected patients with atrial fibrillation, realizing that with this device there’s a 40% reduction in the composite endpoint of cardiovascular or unexplained death, stroke, and systemic embolism compared to warfarin.”

That figure of a 40% relative risk reduction comes from the 46-month follow-up data in the randomized PROTECT AF trial ( JAMA. 2014 Nov 19;312[19]:1988-98 ).

More recently, Dr. Holmes and his coinvestigators published a patient-level meta-analysis of data from PROTECT AF and PREVAIL, the other randomized trial of the Watchman versus warfarin. They reported that Watchman recipients had a 78% reduction in hemorrhagic strokes, a 52% reduction in cardiovascular or unexplained deaths, and a 49% lower rate of nonprocedural bleeding, compared with patients assigned to warfarin ( J Am Coll Cardiol. 2015 Jun 23;65[24]:2614-23 ).

There have been no randomized trials comparing the Watchman to novel oral anticoagulants.

Dr. Holmes said the worldwide experience to date has been that roughly 95% of AF patients are able to safely go off warfarin or a novel oral anticoagulant 12 months after Watchman placement.

“So instead of taking eight drugs when you’re 75 years old, you can take seven. Most patients think that’s a pretty good deal,” the cardiologist observed.

Session moderator Dr. Samuel J. Asirvatham posed a question: Since recurrence of AF following catheter ablation is common and it’s now thought that up to 20% of AF arises from foci located in the left atrial appendage, what about combining standard catheter ablation of AF via pulmonary vein isolation with placement of the Watchman in a single procedure?

If such a combined procedure can be done efficiently, it should enable recipients of AF catheter ablation to safely go off oral anticoagulation, noted Dr. Asirvatham, an electrophysiologist who is professor of medicine and pediatrics at the Mayo Clinic, Rochester, Minn.

Dr. Holmes said several small studies of patients who have received combined AF ablation and Watchman implantation have been published.

“It’s uncertain whether left atrial appendage closure will affect AF recurrence rates post ablation, but it should reduce stroke risk. It’s a terribly important field of exploration that will be pursued in registries both in Europe and the United States,” he said.

bjancin@frontlinemedcom.com

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