Months after the U.S. Food and Drug Administration (FDA) approved a device with the potential to close the source of many atrial fibrillation-related strokes, hospitals, cardiologists and patients find themselves in a holding pattern increasingly common for newly emerging therapies: They are waiting for the Centers for Medicare & Medicaid Services (CMS) to issue a national coverage determination for left atrial appendage (LAA) occlusion.
As many as 6.1 million Americans are living with atrial fibrillation (afib) and the concomitant high risk for stroke. While anticoagulant medications are a proven and viable option for reducing stroke risk faced by most of these patients, about 40 percent can’t or won’t take warfarin or one of the newer oral anticoagulants (JAMA 2014;312:1988-1998). The medications prevent blood from clotting and causing ischemic stroke, but they also raise the risk for intracranial hemorrhaging and gastrointestinal bleeding.
Factor in the potential for bleeding complications and the challenge of regular blood tests required to monitor the effects of warfarin, and the circumstances are ripe for “a technology that doesn’t require that patient to be on a blood thinner long term,” says Kevin Wheelan, MD, chief of staff at Baylor University Medical Center’s Heart and Vascular Hospital in Dallas.
Enter LAA occlusion, a treatment strategy aimed at sealing off the small sac that sits on the heart’s upper left chamber. The LAA has been found to be the source of the blood clots that cause many of the strokes suffered by afib patients.
“We know that of patients who present with a stroke and have afib, about 75 to 85 percent can be demonstrated to have a clot in the left atrial appendage,” Wheelan says.
Eliminating the source of clots is the idea behind the Watchman Left Atrial Appendage Closure Device (Boston Scientific). A physician—typically an electrophysiologist or interventional cardiologist—delivers the device percutaneously. Starting from a femoral access site, the physician delivers the device through the heart’s septum to the mouth of the LAA. Once in place, the quarter-size Watchman is unfurled and implanted snugly to close off the LAA, thereby preventing blood from entering the LAA, where it could coagulate and generate clots that embolize to the brain.
Watchman was a long time coming. It was evaluated in two clinical trials and two registries encompassing more than 2,400 patients and 6,000 patient-years. It took three FDA advisory panels before the device was approved for use in the United States. The FDA indication specifies Watchman is for afib patients who are at risk for stroke and eligible to take anticoagulants, and have a need for an alternative to anticoagulants to reduce their stroke risk. The device will enter a market where cardiologists have been using the Lariat Suture Delivery Device (SentreHeart) on an off-label basis to seal off the LAA in afib patients.
The questions in play now that Watchman has been FDA-approved, say cardiologists, are which patients should undergo LAA occlusion and how long they will have to wait.
Answers will come when CMS unveils an NCD, expected in February 2016. In the interim, hints about the NCD arrived on Nov. 10, when CMS issued a proposed decision memo suggesting the NCD might limit coverage only to patients who are at high risk for stroke and bleeding and have a “contraindication to warfarin” ( www.cms.gov, 2015). These requirements were among seven criteria outlined by CMS, with others focused on institutional and operator requirements, physician training and proctoring, registry enrollment and use of clinical decision support tools. CMS’s memo triggered a 30-day open comment period during which professional societies, physicians and others could provide feedback to help inform the final NCD.
“Remember, this is only a proposal,” says Clifford Kavinsky, MD, PhD, director of the Rush Center for Adult Structural Heart Disease at Rush University Medical Center in Chicago, and lead author of the Society for Cardiovascular Angiography and Interventions (SCAI)/American College of Cardiology (ACC)/Heart Rhythm Society (HRS) expert consensus document on institutional and operator requirements for LAA occlusion (Catheter Cardiovasc Interv online Dec 10, 2015).
“We’d like to see the NCD be much more precise and granular than what the proposal includes, specifically with regard to patient selection, the definition of ‘high risk,’ and ‘contraindication