Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Biodegradable Magnesium Stents For Coronary Arteries

01.06.2007
Biodegradable magnesium stents have been developed to treat blockages in coronary arteries which can degrade within four months and achieve the same results as conventional stents, conclude authors of an Article published in this week’s edition of The Lancet.

But both the Article and an accompanying Comment warn longer term follow-up of the patients fitted with biodegradable stents is needed.

Coronary stents improve immediate and late results of balloon angioplasty by closing up dissections and preventing collapse of the arterial walls.

Professor Raimund Erbel, Department of Cardiology, West German Heart Centre Essen, Germany, and colleagues successfully implanted 71 of the biodegradable magnesium stents in 63 patients in their study – the PROGRESS-AMS clinical trial.

The researchers found that after 12 months, the stents were safe, with no incidence of stent thrombosis (clotting within the stent), heart attack or death in any of the patients. They found that the diameter of the blood vessel within the stent (in-stent acute gain) increased by an average of 1.41mm. Whilst the stent struts disappear over time, ultrasound confirms they remain present but have been absorbed into the vessel walls, with the space left behind “filled in.”

The magnesium is eventually replaced by calcium and phosphorous through the body’s natural processes.

However the trial also showed that angiographic restenosis (re-blocking of the artery) occurred in 47.5% of patients who received the biodegradable stents, and 27% needed target lesion vascularisation within 12 months due to recurrent ischaemia (lack of blood flow to the tissues).

The authors say: “This study showed that absorbable magnesium stents can be delivered and expanded at high pressure in artherosclerotic coronary arteries, providing good mechanical scaffolding and achieving a lumen enlargement similar to the immediate lumen gain obtained with conventional metallic stents.”

The Article says the new biodegradable stents overcome the limitations of conventional permanent stents – namely that they can cause thrombosis many months after implantation – and thus regular dual antiplatelet drug treatment such as aspirin and clopidogrel are required to prevent this occurring in patients with conventional stents fitted.

And drug-eluting stents have limitations because despite being able to achieve significant decreases in angiographic restenosis, they can cause hypersensitivity reactions and late-stent thrombosis, possibly because the drugs eluted hinder re-endothelialisation (re-lining of the inside wall of the artery) of stent struts. Biodegradable stents avoid this problem.

The authors caution that studies with more patients and longer term follow-up are required to confirm the safety of biodegradable magnesium stents.

They say: “For a new product such as absorbable metal stents, four months of angiographical study and 12 months clinical follow-up might be insufficient to capture all the potential late events and complications.”

They conclude: “This study shows that biodegradable magnesium stents can achieve an immediate angiographic result similar to the result of other metal stents and can be safely degraded after four months. Modifications of stent characteristics with prolonged degradation and drug elution are currently in development.”

In an accompanying comment, Dr John Ormiston and Dr Mark Webster, Mercy Angiography and Auckland City Hospital, Auckland, New Zealand, say: “Bioabsorbable stents are in an early stage of development but hold considerable promise for overcoming many of the limitations of permanent metallic implants.”

They add: “The initial patients treated with these devices will need to be followed up closely and for a long time. Whether bioabsorbable stents signal the threshold of a new era for percutaneous coronary intervention is yet to unfold.”

Tony Kirby | alfa
Further information:
http://www.thelancet.com
http://www.thelancet.com/webfiles/images/clusters/thelancet/press_office/Scaffolding.pdf

More articles from Medical Engineering:

nachricht Visualizing gene expression with MRI
23.12.2016 | California Institute of Technology

nachricht Illuminating cancer: Researchers invent a pH threshold sensor to improve cancer surgery
21.12.2016 | UT Southwestern Medical Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>