Atrial fibrillation (A-Fib), an irregular cardiac rhythm that causes the heart’s two atria to quiver, ineffectively
contracting up to 300 to 400 beats per minute, is a nuisance to some, with side effects including fatigue and
dizziness. But A-Fib can also lead to stroke and death in others since blood can stagnate and form clots in an
area of the heart called the left atrial appendage.
Compared to people with normal heart rhythm, patients who have A-Fib—they number more than five million
in the United States—have a five-fold increased risk of suffering a clot-related stroke.
It’s estimated that 90% of clots in A-Fib patients are found in the left atrial appendage, a thumb-sized pouch
attached on top of the left side of the heart. Although this appendage can be removed surgically—like the appendix, it serves little useful purpose—as part of a procedure to stave off future clot formation, surgery is not always an option.
Primary A-Fib treatment includes daily doses of the anticoagulant warfarin (Coumadin), which is used to thin the
blood that can pool in the heart. Warfarin, unfortunately, has one major drawback: It is a tricky medication to use,
especially with frail and elderly patients. Warfarin dosages need to be monitored regularly (for some, this could be several times a week), since illness, diet, physical activity, and medication can easily affect the drug’s effectiveness.
It’s a delicate balance with warfarin: Too little of the drug leaves the patient vulnerable to stroke, while too much
can cause fatal bleeding.
In the past, new drugs have been sought to replace long-term warfarin therapy, but none have succeeded. In late April, however, an FDA advisory panel voted 7 to 4 in favor of approving a totally new device alternative to long-term warfarin use that can prevent clots from developing in patients with A-Fib. A second device is undergoing testing, with FDA approval expected in early 2010.
During a 90-minute minimally-invasive procedure with one device, a tiny polyester-covered umbrella-shaped mesh device is snaked up via a catheter through a blood vessel in the groin into the right atrium of the heart and implanted permanently just behind or at the opening of the left atrial appendage. The body soon begins to form tissue over the implant, permanently closing off the appendage and eliminating the risk of forming blood clots there.
The second device is a clip that is placed over the left atrial appendage, either during surgery or a minimally-invasive procedure. A catheter-based procedure is under development.
Overall, the new devices show great promise: Most patients implanted with the devices are able to discontinue warfarin use. Samir Kapadia, MD, an interventional cardiologist at Cleveland Clinic states, “Our hope is that this device will allow people who suffer from A-Fib to enjoy a better quality of life, free from the very real risks that come with the use of warfarin, while minimizing or eliminating the risk of stroke due to atrial fibrillation.”
Where Are They Now
Compared to people with normal heart rhythm, patients with atrial fibrillation (AF) have a five-fold increased risk of suffering a clot-related stroke and thus have to take anticoagulant medications, such as warfarin, to manage their AF-related stroke risk. However, warfarin is a problematic medication to use and the drug dosage needs to be monitored regularly. By implanting a left atrial appendage occlusion device, which is specially designed to prevent the formation of blood clot, patients may now discontinue warfarin use.
A new device was approved in 2015 as a left atrial appendage closure device to reduce the risk of stroke. However, the US still does not include use of these devices in their recommendations for people with atrial fibrillation and high risk of stroke despite multiple, large scale studies where it was tested over standard warfarin treatment. In a study published in 2016, results were similar to 2015 studies where there were both promising trials and trials that diverged leaving inconclusive results. Study results released in 2017 follow the pattern of ambiguity. However, the FDA has granted limited device registration for patients deemed fit by their physician and have appropriate reasoning for seeking a nonpharmacological alternative.