Big benefits from a small heart implant, with less need for blood thinners
A small device with the big job of preventing strokes just got an upgrade, and Cape Cod Healthcare cardiac experts say that means more patients with a dangerous type of heart arrhythmia may be able to stop taking blood thinners.
The Watchman FLX™ is an implant device about the size of a quarter. Doctors insert it in the heart to keep blood clots from forming in an area called the left atrial appendage (LAAC).
The Watchman™, manufactured by Boston Scientific, was first approved by the U.S. Food and Drug Administration in March 2015 for patients who met certain risk criteria and could show a compelling reason for not taking anticoagulants long-term. Cape Cod Healthcare Interventional Cardiologist and chief of Inpatient Cardiology Richard Zelman, MD, FACC, said the Cape team has implanted 173 LAAC devices, 16 of which have been the Watchman FLX.
The U.S. Food and Drug Administration approved the second generation, the Watchman FLX™, in July 2020. It comes in different sizes, allowing doctors to use it in more patients, Dr. Zelman said. And, because of improved configuration and flexibility, it’s even safer, he said. About a dozen of the new models have been implanted at Cape Cod Hospital.
“It’s always been a safe procedure,” he said. “But now it can be implanted successfully about 99 percent of the time, and about 95 percent of these patients can stop their blood thinners.”
The LAA, a ½-to-2-inch pouch off the heart’s left atrium, is a common site for blood to collect and form clots, which can travel to the brain and cause a stroke. About 90 percent of strokes that are not related to a valve problem are related to the LAA, according to Peter Friedman MD, PhD, FACC, FHRS, a Cape Cod Healthcare cardiac-electrophysiologist and member of the team that inserted the first Watchman at Cape Cod Healthcare’s Heart and Vascular Institute in 2018.
In a normally functioning heart, the sinus node acts as the pacemaker, sending off electrical impulses through the atria (the heart’s upper chambers) into the ventricles (the lower chambers), telling them to contract and pump blood throughout the body. AFib occurs when the electrical impulses fire independently of each other, causing a chaotic heart rhythm. When the heart’s rhythm is off, it can cause the heart to quiver instead of contract, allowing the blood to pool in nooks and crannies, particularly in the LAA, and form clots.
Until the Watchman™, the most common solution for patients with AFib was blood anticoagulants, like warfarin (the generic name of Coumadin). Ablation, in which doctors use radiofrequency or very intense cold to destroy the abnormal cells causing the arrhythmia, was another option. But even patients undergoing ablation may still require anticoagulants, which have their own issues such as bruising, nosebleeds, gastrointestinal bleeds and stroke if incorrectly dosed. They can also be expensive or require blood tests that may not always be reimbursable by insurance, according to Dr. Friedman.
Instead, the Watchman™ implant seals off the atria from the LAA so blood can’t pool in the pouch. The process usually takes less than an hour under general anesthesia. Doctors use a catheter to travel through an incision in the upper leg, through the vascular system, into the left atrium.
The Watchman™ is then detached from the tip of the catheter and opens like an umbrella, creating a dam to block blood from passing into the LAA. Eventually, heart tissue grows over the device, permanently sealing off the LAA, according to a video on the Watchman website.
Currently, patients spend a night in the hospital, Dr. Zelman said, although he hopes that within a few months, the Watchman FLX™ implant will be an outpatient procedure, allowing many patients to go home the same day. Patients are off blood thinners in about six weeks, he said, although for a few months, they take aspirin and a drug called clopidogrel, which prevents platelets (a type of blood cell) from collecting and forming clots.
“It’s a safer device,” Dr. Zelman said about the updated Watchman FLX™. “It’s able to be utilized in a larger percentage of the population of patients with atrial fibrillation. It’s more effective.”