New cardiac stent shows promise in lowering complications

Heart disease patients requiring intervention for blocked arteries may soon have another option for treatment. This week, a new cardiac stent, the Absorb, made of biodegradable material that gradually dissolves after restoring blood flow to the heart, completed a one-year trial and performed as well as drug-elutingstent devices.

The Absorb works by holding the artery open long enough for it to heal, said Dean Kereiakes, a cardiologist at Christ Heart and Vascular Center in Cincinnati. Unlike metal stents, when the Absorb dissolves in one to two years’ time, it leaves no trace in the artery.

“It can return the artery to its normal, natural structure and function,” Kereiakes said.

Traditionally doctors treat a blocked coronary artery by inserting an inflated balloon into the narrowed area and placing an appropriately sized metal stent to keep the blood vessel open. Once the damage starts to resolve, the vessels typically resume a normal size, leaving gaps between the stent and vessel wall. Blood clots and plaque can accumulate in the gaps, causing more blockages. While these types of complications have decreased with the introduction of new drug-eluding stents and specialized blood thinners, long-term safety and efficacy remain a concern. And 20 to 30 percent of patients have recurrent angina during the first year after implantation of a drug-eluting stent.

Some physicians hypothesize that by dissolving over time, bioresorbable stents like the Absorb could reduce the frequency of many of these complications. While the notion of a new stent performing only as well as current stent devices may seem slightly underwhelming, many physicians believe the benefits of the Absorb as well as other biodegradable devices will become evident in longer-range studies.

“Dissolvable stents may be a future game-changer for the way we treat coronary artery disease and heart attack in the United States,” said Samin Sharma, director of clinical and interventional cardiology at Mount Sinai Medical Center in New York.

But the device is not without its critics.

“Although the concept of self-degrading stents is intuitively attractive, promise alone is not enough to make us unconditionally embrace this technology,”wrote Robert A. Byrne, a cardiologist at the German Heart Centre in Munich, Germany. Byrne also noted the larger, less flexible device proved more challenging to deploy in narrower vessels.

Others express concern over the cost-risk benefits.

“Unless Absorb offers some tangible evidence of benefit in terms of cost, convenience, or complications, including stent thrombosis, why would I bother putting it in my patients?” asked Sanjiv Kaul, head of cardiovascular medicine at Oregon Health and Science University.

The current cost of coronary stenting for the more than 850,000 U.S. patients who receive them each year ranges from $11,000 to $41,000or more, depending on the type of stent and length of hospital stay. The research firm EvaluateMedTech predicts the United States will contribute a third of the $3.82 billion stent market. Abbott, the maker of Absorb, would not disclose the cost of its stent, since it is pending approval from the Food and Drug Administration.

Researchers presented their results on the Absorb at the annual Transcatheter Cardiovascular Therapeutics conference and published their findings in the New England Journal of Medicine. A five-year study currently underway hopes to demonstrate the device’s potential to reduce long-term complications.

Absorb is already available in more than 100 countries worldwide and has been used to treat more than 125,000 people. Some physicians who have been using the device for several years are impressed.

“As the body of data and real-world experience increases for Absorb, we are seeing compelling evidence that a temporary scaffold that dissolves completely after doing its job represents the future of interventional cardiology,” said Patrick Serruys, professor of interventional cardiology at the Thoraxcentre, Erasmaus University Hospital in the Netherlands.

The U.S. now has at least 15 bioresorbable stent program studies in progress, with five in advanced stages.

The Associated Press contributed to this report.