HOUSTON (October 15, 2013)

A clinical trial evaluating a cardiac plug for the prevention of stroke in patients with atrial fibrillation has been launched by cardiology researchers at The University of Texas Health Science Center at Houston (UTHealth) Medical School.

In September, UTHealth cardiologists implanted the state’s first AMPLATZER™ Cardiac Plug (ACP) in a patient at the Memorial Hermann Heart & Vascular Institute-Texas Medical Center. The study will determine if the transcatheter device is safe and effective in preventing blood clots from migrating out of the left atrial appendage in patients with non-valvular atrial fibrillation who are at high risk for stroke.

“Atrial fibrillation is a common problem and patients need blood thinners to help prevent stroke,” said Pranav Loyalka, MD, co-principal investigator of the Houston study, associate professor in the Program of Advanced Heart Failure at the UTHealth Medical School and associate chief of the medical division at the Center for Advanced Heart Failure at HVI.

“AMPLATZER™ is one of the devices being studied that could give patients the ability to not take blood thinners.”

Atrial fibrillation is the most common type of arrhythmia, a problem with the rate or rhythm of the heartbeat caused by dysfunctional electrical activity. The heart can beat too fast, too slow or irregularly. It causes blood to pool in the atria, the heart’s upper two chambers, causing an inadequate supply of blood to pump into the ventricles, the lower chambers.

“When the blood pools in the atria, blood clots can form in the left atrial appendage, the site of 90 percent of blood clots associated with atrial fibrillation,” said Ramesh Hariharan, MD, co-principal investigator and medical director of the Complex Arrhythmia Center and a professor at the UTHealth Medical School.

An estimated 2.7 million Americans suffer from atrial fibrillation, which causes 20 percent of all ischemic strokes, the most common form of stroke. A person with atrial fibrillation is five times more likely to have a stroke.

“Symptoms of atrial fibrillation can include a racing heart and shortness of breath,” said Biswajit Kar, MD, co-investigator, professor in the Program of Advanced Heart Failure at UTHealth and chief of the medical division at the Center for Advanced Heart Failure at The Institute. “Over time, it can lead to heart failure.”

The most common blood thinners prescribed for atrial fibrillation are warfarin and dabigatran.

“The biggest drawback of warfarin is that patients need regular blood tests to check levels of the drug, which typically keep changing, causing cardiologists to adjust the dosage to prevent dangerous bleeding,” said Richard Smalling, M.D., co-investigator, professor and the Jay Brent Sterling Professor of Cardiovascular Medicine and James D. Woods Distinguished Chair of Cardiovascular Medicine at the UTHealth Medical School and interventional cardiologist affiliated with The Institute.

“Dabigatran remains at more consistent levels in the body but there is no reversal agent for it, so if a person is in an automobile or other accident, there is a risk for excessive bleeding,” said Saumya Sharma, MD, co-investigator, assistant professor in the Complex Arrhythmia Center at UTHealth and an affiliated cardiologist at The Institute.

The AMPLATZER™ plug is a self-expanding device made from nitinol mesh to seal the left atrial appendage, minimizing the chance of blood clots migrating into bloodstream. Patients usually have a one-night hospital stay.

“It’s like a windsock,” Loyalka said. “It plugs it so that nothing can get through and we believe this can help prevent stroke.”

The multiple-site study will enroll between 400 and 3,000 patients. It is randomized with two patients receiving the device and one patient receiving traditional medical treatment using long-term, blood-thinning medication.