Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Study finds new stent improves ability to keep vessels open for dialysis patients

University of Maryland research published in New England Journal of Medicine

Kidney dialysis patients often need repeated procedures, such as balloon angioplasty, to open blood vessels that become blocked or narrowed at the point where dialysis machines connect to the body. These blockages can impact the effectiveness of hemodialysis, a life-saving treatment to remove toxins from the blood when the kidneys are unable to do so.

But a new FDA-approved stent graft can keep these access points open longer, reducing the number of procedures these patients may need, according to research from the University of Maryland published in the February 11, 2010, edition of the New England Journal of Medicine.

"This is the first large-scale randomized study to find a therapy to be superior to the gold standard of balloon angioplasty. We found that using this new stent for dialysis patients whose access grafts have become narrowed improves graft function. It also clearly reduces the need for repeated invasive procedures and interruption of dialysis," explains lead author Ziv Haskal, M.D., chief of vascular and interventional radiology at the University of Maryland Medical Center. Dr. Haskal is also professor of diagnostic radiology and nuclear medicine, and surgery at the University of Maryland School of Medicine.

The prospective multi-center study took place at 13 sites across the country and enrolled nearly 200 patients. Ninety-seven patients received angioplasty with the new stent, which is a small metal scaffold inserted in the patient's arm, compared to 93 who received angioplasty alone.

In the study, patients with the stent graft were more than twice as likely to have open vessels compared to the angioplasty only group after six months. The recurrence of vessel narrowing, restenosis, was nearly three times lower with the stent group, (27.6 percent vs. 77.6 percent). In later follow-up, some patients still had functioning grafts two years after the stent graft was first implanted.

"Results of this research should change the way we treat hemodialysis patients. In this study, patients who received angioplasty alone were twice as likely to need additional procedures compared to those who had the stent in addition to angioplasty," adds Dr. Haskal. "That can translate into cost savings and improved quality of life for these patients, who already spend about nine to 12 hours a week in dialysis. We can now start considering grafts as something that may last for years in dialysis patients, instead of months."

According to the researchers, the cost to treat dialysis access failure amounts to about $1 billion per year, and the number of patients needing hemodialysis is expected to continue to grow substantially over the next decade.

Kidney failure patients often have a synthetic portal, known as an access graft, embedded into their arm before they begin hemodialysis. The access graft works like an artificial blood vessel, allowing needles to be inserted repeatedly, so the blood can be circulated out of the body, filtered in a machine and then returned to the patient's circulatory system. Patients must undergo dialysis several times a week. (Another less commonly used form of dialysis, peritoneal dialysis, filters waste by using the peritoneal membrane inside the abdomen. Patients inject a special solution into the body, which is later drained from the abdomen after the toxins are filtered. Peritoneal dialysis can be done at home, but must be done every day.)

For hemodialysis, scar tissue naturally forms at the edges of the access grafts. That scarring can impede blood flow, requiring doctors to perform angioplasty to open the vessels. In that outpatient procedure, doctors insert a balloon into the blood vessel and inflate the balloon to open the narrowed artery or vein. Following angioplasty, vessel narrowing frequently recurs, requiring repeated procedures, up to several times a year. If scarring becomes too severe and repeated angioplasties do not work, the patient may need another procedure put in an access graft at a different site on the arm. Other therapies have been compared to balloon angioplasty, but, until now, none has shown benefit in a prospective randomized study.

"More than 350,000 Americans are currently receiving dialysis. These patients need those access grafts to be as durable as possible because they only have so much space on their arms for the surgical creation of new access grafts. Our research has shown that using this stent graft to treat failing accesses keeps them open longer that the existing gold standard; it offers a real, longer-term solution for patients, reducing the need for repeated surgeries. This research suggests that physicians may need to make a fundamental change in their approach to treating hemodialysis patients," says Dr. Haskal. This self-expanding metal stent graft creates a scaffold to keep the blood vessel open. It is encapsulated by polytetrafluoroethylene, the same material from which most dialysis grafts are made. The device allows the physician to mimic the effect of surgery at the scarred area without actually performing surgery.

"This study offers strong evidence of the benefit of using this new stent therapy for hemodialysis patients. It represents the type of important clinical research with direct patient benefit undertaken by physicians at the University of Maryland School of Medicine," says E. Albert Reece, M.D., Ph.D., M.B.A, vice president for medical affairs, University of Maryland, and dean, University of Maryland School of Medicine.

Dr. Haskal is leading another large study that is currently enrolling patients to assess the benefits of the device over a longer period of time. The other sites participating in this study were the Hospital of the University of Pennsylvania; University of Texas, Southwestern Medical Center; Oregon Surgical Consultants, Portland, OR; Open Access Vascular Access Center, Miami, FL; Vascular Access Center, Augusta, GA; Tucson Vascular Surgery; Indiana University School of Medicine; Bamberg County Hospital and Nursing Center, Bamberg, SC; and Vascular Access Center of Frontenac Grove, Frontenac, MO. This study was funded by Bard Peripheral Vascular, Inc., manufacturer of the Flair Endovascular stent graft.

Sharon Boston | EurekAlert!
Further information:

More articles from Medical Engineering:

nachricht Gentle sensors for diagnosing brain disorders
29.09.2016 | King Abdullah University of Science and Technology

nachricht New imaging technique in Alzheimer’s disease - opens up possibilities for new drug development
28.09.2016 | Lund University

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>