Biodegradable stents in human arteries for the first time

July 23, 2000

DALLAS, July 25 -- A biodegradable arterial stent, a tube that is inserted into clogged blood vessels to restore proper blood flow, has been successfully tested in human patients for the first time researchers report in today's Circulation: Journal of the American Heart Association.

The new stents could revolutionize coronary angioplasty, a procedure to re-open narrowed blood vessels that is performed thousands of times each day, says lead researcher Hideo Tamai, M.D., of the department of cardiology at Shiga Medical Center, Japan.

A traditional stent is a tube -- usually a cage of surgical-grade stainless steel somewhat resembling chicken wire -- that props open an artery that has become partially closed from the fatty build-up of atherosclerosis.

The Japanese study is the first to demonstrate the feasibility and safety of biodegradable stents in humans, Tamai says. He notes that no deaths, heart attacks, or bypass surgeries were recorded among the 15 study participants during a six-month monitoring period. Tamai says that one patient underwent a second angioplasty during the monitoring period.

A multi-center randomized U.S. study of biodegradable stents is now being planned as a follow-up to the Japanese research, according to Tamai. "If this study supports our findings about the efficacy of biodegradable stents, and if the FDA approves them, they could be in general use in America within a few years," he says.

"This study represents the first move toward a new concept of coronary stenting," says Antonio Colombo, M.D., of the Centro Cuore Columbus in Milan, Italy, author of an editorial accompanying the Circulation report. "It is a fresh departure from the traditional idea of stents as permanent replacements for a part of the body."

Because the new stents are fully absorbed and disappear within two years after implant, they allow medical science to "fulfill its mission and step away," rather than leave a permanently intrusive object behind, Colombo adds.

In the Japanese study, 25 biodegradable stents were implanted in 15 individuals undergoing angioplasty. Because there is a high risk of restenosis during the three to six months following coronary angioplasty, the participants' conditions were monitored for six months. Tamai says his results were "highly encouraging."

Although this number of patients is considered too small to draw definitive conclusions, researchers say the rate of restenosis, or re-narrowing of the arteries, was generally lower than that seen with metallic stents.

"Since metal is a foreign material for humans, traditional stents sometimes cause inflammatory reactions in patients, and there are many long-term safety concerns associated with metallic stents," says Tamai. The metal stent may also injure the artery wall when inserted, which would cause an inflammatory response.

During an inflammatory response the body's immune defenses are activated, causing immune cells to "pile up" at the site of the stent. This activity can cause restenosis, Tamai says.

"What is unique about the stent these researchers invented, compared with prior investigators, is the change in stent design from a knitted pattern to a zigzag coil design," says Colombo. He says the new design may be less traumatic to the artery wall, therefore reducing the chance of restenosis.

In addition, Tamai says that no one really knows the effects of metallic stents after 10 or more years of use. "Those that remain in place for long periods may become obstacles to additional treatments, such as repeat angioplasty or bypass grafting," he says.

Another advantage of the biodegradable stent is that it can self-expand gradually for at least three months, says Tamai. This allows stented sections of arteries to fully expand, which may be responsible for the low stenosis rate.

Colombo notes that a biodegradable stent may have an additional advantage as a vehicle for administering drug or gene therapy at the site where the stent is inserted.
Co-authors include Keiji Igaki, M.D.; Eisho Kyo, M.D.; Kunihiko Kosuga, M.D.; Akiyoshi Kawashima, M.D.; Shigeo Matsui, M.D.; Hidenori Komori, M.D.; Takafumi Tsuji, M.D.; Seiichiro Motohara, M.D.; and Hiromu Uehata, M.D. Editorial co-author is Evangelia Karvouni, M.D.

For journal copies only, please call: (214) 706-1173
For other information, call:
Carole Bullock: (214) 706-1279
Maggie Francis: (214) 706-1397

Media Advisory: Dr. Tamai can be reached by phone at 81 77 582 5031; or by fax at 81 77 582 5426; Dr. Colombo can be reached by phone at 39 02 481 2920; or by email at (Please do not publish numbers.)

American Heart Association

Related Angioplasty Articles from Brightsurf:

Ticagrelor was not superior to clopidogrel to reduce heart attack risk during angioplasty
A new study found the rate of heart attack and severe complications before, during or soon after elective surgery to open a blocked artery was similar between patients treated with clopidogrel and those who received the more potent antiplatelet medication ticagrelor.

Study finds significant variability in doctors' angioplasty death rates
Some doctors have higher or lower than expected death rates from coronary angioplasty procedures, also known as percutaneous coronary intervention (PCI); however, doctors should not be judged solely on the rate of patients who die from the procedure.

Beta-blockers following angioplasty show little benefit for some older patients
Following coronary angioplasty, beta-blockers did not significantly improve mortality rates or reduce the number of future cardiovascular incidents for older patients with stable angina but no history of heart attack or heart failure, according to a study published today in the JACC: Cardiovascular Interventions.

Sleep disorders may predict heart events after angioplasty
People who have had procedures to open blocked heart arteries after acute coronary syndrome (ACS) may have a higher risk of death, heart failure, heart attack and stroke if they have sleep disorders, such as sleep apnea, compared to those who don't.

Reasons for hospital-level variations in bleeding post-angioplasty are unclear
The use of bleeding avoidance strategies has only a modest effect on the variation in bleeding rates post-angioplasty among hospitals performing this procedure, leaving about 70 percent of the causes for this variation unexplained, according to a study published today in JACC: Cardiovascular Interventions.

US prediction models for kidney injury following angioplasty hold up in Japan
Models developed by the American College of Cardiology NCDR CathPCI Registry to predict the likelihood of angioplasty patients developing acute kidney injury and acute kidney injury requiring dialysis have proven to be effective among patients in Japan.

IV beta blockers before angioplasty are safe, but offer no clinical benefit
Giving intravenous beta blockers before performing a coronary angioplasty in patients who had experienced the deadliest form of heart attack -- ST-segment elevation myocardial infarction (STEMI) -- was safe but did not reduce heart attack severity or improve blood flow from the heart's main pumping chamber, according to research presented at the American College of Cardiology's 65th Annual Scientific Session.

Life-threatening bowel ischemia can often be treated by balloon angioplasty
Acute mesenteric ischemia (AMI) can be successfully treated with endovascular therapy such as balloon angioplasty, according to research from the University of Eastern Finland.

Radial access used less than femoral approach for emergency angioplasty
Although using the radial artery as the access point for angioplasty has been linked to reduced bleeding compared to use of the femoral artery, only a small number of high-risk heart attack patients who undergo rescue angioplasty -- emergency procedures following failed therapy with clot-busting drugs -- are treated by radial access, according to a study published today in the Journal of the American College of Cardiology: Cardiovascular Interventions.

Use of rarely appropriate angioplasty procedures declined sharply
The number of angioplasty procedures classified as rarely appropriate declined sharply between 2010 and 2014, as did the number of those performed on patients with non-acute conditions, according to a study published today in the Journal of the American Medical Association and simultaneously presented at a meeting of the American Heart Association in Orlando.

Read More: Angioplasty News and Angioplasty Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to