Research Seeks Better Treatments

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The U.S. Food and Drug Administration considers the AMPLATZER® Cardiac Plug to be an investigational device being tested in clinical research trials for stroke prevention in atrial fibrillation.

Like many people with an abnormal heart rhythm called atrial fibrillation, Gary Nauman of Dubuque, Iowa, used to have to take a daily dose of warfarin, watch his diet carefully for foods that interfere with his medication and frequently have his blood drawn to monitor this drug.

Warfarin has long been used to prevent clots in patients at risk of stroke. However, it can increase the risks of bleeding and requires frequent trips to doctors to manage this toxic medication.

But now, Nauman is part of a small group of patients across the country participating in a clinical trial to determine the feasibility of using a non-drug alternative in place of warfarin to prevent stroke in patients with atrial fibrillation. The therapy being tested involves implanting a small mesh plug into the heart and, if it's successful, this approach could limit or eliminate the need for warfarin in patients who need long-term protection from clot formation and those with a history of bleeding problems or at high risk of falls who cannot take warfarin.

"The major advantage of this approach is being able to avoid the use of warfarin therapy," said Phillip Horwitz, M.D., an interventional cardiologist with UI Heart and Vascular Center. "This medication can be difficult to dose, needs frequent monitoring and increases the risk of bleeding. If the new investigational device therapy is effective, patients with atrial fibrillation at risk of stroke would be able to switch to a more simple treatment option with aspirin, which is safer and does not need to be monitored."

The fact that Nauman, 61, could potentially be looking at another 20 years of daily warfarin made him a good candidate for the clinical trial, according to Amy Ollinger, a clinical research coordinator in cardiology at UI Hospitals and Clinics.

"I'm a pretty adventurous person and this seemed like a good choice for me," Nauman said.

In a patient with atrial fibrillation, blood can pool in a small cavity—known as the left atrial appendage (LAA)—in the top chamber of the heart. As the blood pools, clots can form. The new treatment involves securing a small mesh plug over the entrance to the LAA to prevent clots from leaving the cavity and traveling to other parts of the body, or, most dangerously, to the brain causing a stroke.

The plug is implanted using a catheter that is threaded through the patient’s blood vessels from a small incision in the groin up to the LAA in the heart. Horwitz, who is principal investigator of the UI site for the clinical trial, specializes in delicate, minimally invasive heart procedures including closures of different holes in the heart via an artery or veins in the leg.

"This is an important trial to treat a very common disease," Horwitz said. " The UI is one of a tiny number of sites chosen in the U.S. to participate. These types of cutting edge studies allow us to offer patients potential new therapies that they would otherwise not have access to.

"The fact that UI is chosen for such studies over many other quite prestigious centers points to the expertise that Iowans have available here—not only in research studies but in all aspects of complex cardiovascular care."

The trial, known as the AMPLATZER cardiac plug clinical trial, is funded by AGA Medical, the company that makes the investigational devices.

Clinical trials like this represent one type of heart research that's being conducted by UI Health Care researchers and physicians. The studies range from laboratory research investigating the basic cellular and genetic mechanisms that contribute to heart disease, to translational research that bridge the gap between lab discoveries and new therapies, to clinical trials like the one Nauman is participating in that test potential new therapies in patients. As an academic medical center, UI Health Care has expertise in all levels of research and provides an environment where researchers and physicians collaborate, share information and insight and improve care for heart patients everywhere.