First fully biodegradable coronary artery stent appears safe for long-term treatment of coronary artery disease, says study published in Circulation.
Stents are mesh tubes inserted into coronary arteries to help prop them open and allow for blood flow to the heart muscle.
The biodegradable Igaki-Tamai stent is used in nine European Union countries and Turkey but not in the United States to treat peripheral artery disease (PAD), the disorder which results from fatty deposits that narrow leg arteries. However, no countries have approved the Igaki-Tamai stent for treating clogged heart arteries.
"We have needed this long-term clinical data to clarify the coronary safety of the stent," said Kunihiko Kosuga, M.D., Ph.D., co-author of the study and director of cardiology at Shiga Medical Center for Adults in Moriyama City, Japan. "Our findings will pave the way for the entry of coronary stents made of biodegradable polymers into the real world of interventional cardiology."
Metal stents, sometimes coated with drugs, remain in the body and can reclog. This biodegradable stent is made of poly-l-lactic acid, a cornstarch-based material, which dissolves into the artery wall. This leaves no foreign material in an artery permanently and reduces the occurrence of an in-stent blood clot.
In the study, researchers tracked 50 Japanese patients (44 men, average age 61 years old) who received 84 Igaki-Tamai stents between September 1998 and April 2000. The stents weren't coated with drugs. After an average 10 years, researchers found:
- The survival rate was 98 percent free from cardiac death and 87 percent free from death from all causes.
- Fifty percent of patients experienced no major cardiac complication.
- Acceptable major event complication rates were similar to those for bare metal stents.
Although researchers expected stent degradation to take six months, the study indicated the stent was totally absorbed in three years.
"Fully biodegradable stents may hold an important position as the next generation of coronary devices," Kosuga said.