Two medical devices approved by the FDA within the past year – a miniaturized pacemaker that doesn't have any wires and a coronary stent that gradually dissolves in the body – are showing promise as effective treatments for people with certain heart and vascular problems.
The new pacemaker, called the Micra Transcatheter Pacing System, is just an inch long, about one-tenth the size of traditional devices, and is the first "leadless" pacemaker to be approved for use in the United States.
Conventional pacemakers, surgically implanted devices that generate electrical impulses to treat irregular or stalled heartbeats, are placed under the skin near the collarbone and connected to the heart by lead wires that run through a vein. The Micra's smaller size, however, allows it to be implanted directly in the heart's right ventricle chamber. This eliminates the lead wires and the problems associated with them, which can include infection and interference with other medical treatments such as chemotherapy and diagnostic tests such as MRIs.
At Wake Forest Baptist Medical Center, the new pacemaker has been employed to treat bradycardia, an abnormally slow heart rate that can cause dizziness and fainting spells and lead to heart failure.
"Slow heartbeat is increasingly common as people age, and it can be compounded by medications used to treat other problems," said Patrick Whalen, M.D., director of electrophysiology at Wake Forest Baptist. "The Micra and devices like it will change how we treat patients with slow heartbeats in the future."
Doctors at Wake Forest Baptist also have begun to use a newly approved stent. The device, called the Absorb GT1 Bioresorbable Vascular Scaffold System, is the first fully absorbable stent for the treatment of coronary artery disease, the most common type of heart disease. Coronary artery disease is frequently treated with the insertion of a stent – a tiny mesh tube – into an artery clogged by plaque to hold it open and restore the free flow of blood. Many stents are coated with drugs that help keep the artery from re-closing.
Most stents are made of metal and remain in the body permanently, which can produce negative side effects in some people. The Absorb scaffold, on the other hand, is made of a biodegradable polymer that is gradually absorbed by the body and completely dissolves after about three years. The device also releases a drug to prevent the artery from narrowing again.