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Cardiology: Saying Goodbye to Blood Thinners
Only one-third of patients who have atrial fibrillation (AF)—one of the most common arrhythmias—consider it to be a serious health problem, according to a 2009 survey conducted by the American Heart Association. However, because the disorder can cause blood to stagnate and clot, it significantly elevates the risk of stroke.
To combat this possibility, those with AF are often prescribed blood thinners, but patient misconceptions about the risks associated with the condition lead many to eschew these lifesaving drugs. Other patients can’t take blood thinners at all due to inherent problems with clotting or other risk factors, such as a history of falls.
“It’s striking that of all AF patients who should be on anti-coagulation therapy, only half are actually taking blood thinners,” says Hugh Calkins, director of Johns Hopkins’ Cardiac Arrhythmia Service.
There are, however, nonpharmacologic options that can also significantly reduce an AF patient’s risk of stroke. Decades ago, cardiac surgeons found that if they closed off the left atrial appendage (LAA)—a windsock-shaped outpouching in the muscle wall of the left atrium that collects blood and drains into the heart—by stapling, tying and other means, patient stroke risk shrank to baseline.
More recently, Calkins explains, three cardiac implant devices have come on the market that offer safer and more reliable means to achieve the same goal, with each option offering distinct benefits and drawbacks. To make the best recommendations for treatment with these devices, Johns Hopkins initiated the Left Atrial Appendage Occlusion Program to help evaluate which option is optimal for each patient. Although many institutions offer at least one of these options, he adds, Johns Hopkins is one of only a few that offer all three.
The first of these implantable devices, the WATCHMAN, is the only one that’s currently FDA-approved for LAA occlusion. Shaped like a small umbrella, it’s delivered via catheter to block the opening to the LAA. However, this device is only suitable for patients whose LAA is a certain size and shape, Calkins says. In addition, patients must take blood thinners for several weeks after surgery, a disqualifier for those with clotting problems and other risks.
The second device, the AtriClip, is implanted using minimally invasive techniques. Surgeons place this bobby pin-shaped clip at the base of the LAA, preventing blood from entering. Although no blood thinners are required after the procedure, Calkins notes, the minimally invasive approach disqualifies some patients who’ve had previous cardiac surgery due to scar tissue that can hinder implantation.
The third device, the LARIAT, is a catheter-implanted suture delivery loop that ties off the LAA. Although this procedure also doesn’t require postoperative blood thinners, it’s not suitable for patients whose LAAs are very large or in certain positions.
To determine whether an AF patient is eligible for one of these devices, patients at Johns Hopkins meet with a multidisciplinary team—including imaging experts, electrophysiologists, interventional cardiologists, cardiac surgeons and others—to determine the best options. Once one of the devices is in place, Calkins notes, no permanent use of blood thinners is necessary ever again to treat the consequences of AF.