German researchers look at materials to keep stents secure

Welcome back to the Medical Technology Blog, we have a great post today provided by our medical newsletters team-leader, Lawrence Miller, Lawrence is the editor for Cardiovascular Device Business, please read on…

Researchers from the Fraunhofer Institute in Germany are working on the development of a special surface coating that keeps the stent in place.

When coronary blood vessels are constricted, cardiologists try to prevent a heart attack by widening them with stent implants that stabilise the veins and arteries, improve the flow of blood and prevent vascular obliteration. These stents can be used to treat pathological constriction of the windpipe. This kind of respiratory stenosis, which may be caused by tumours, chronic infections or congenital deformities, can be life-threatening. In such cases, the metal or plastic stents are designed to enlarge the trachea and prevent it from closing up altogether. However, the stent implant can slip out of position, closing off the windpipe altogether. Bacteria can also colonise the stents and trigger pneumonia. The reason for this is that the stents have no barrier-forming cells of the kind usually present in the respiratory system, whose task is to fend off bacteria and inhaled substances such as particulate.

Dr Martina Hampel, a scientist at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart, working with Professor Thorsten Walles, head of the department of thoracic surgery at the University Hospital of Würzburg and a visiting scientist at the IGB, participated  in the “REGiNA” project, the goal of which was to develop surface coatings that enable the stents to be incorporated in the surrounding tissue, thereby reducing the risk that they will move. REGiNA, a German acronym for Regenerative Medicine in the Neckar-Alb and Stuttgart Region, is funded by the German Federal Ministry of Education and Research (BMBF).

The scientists used stents lined with a polyurethane (PU) film, which were produced by Aachen-based Leufen Medical. In the subsequent tests, a wide variety of different coatings were applied to the PU film. In addition to synthetic polymers composed of organic acids, the researchers also tried out biological proteins such as fibronectin and type-I collagen. The coating was modified again using plasma technology, with vacuum-ionised gas being used to treat the surface. The experts used an untreated PU film for control purposes.

In order to find out which of the surface coatings was the most suitable, the researchers brought both lab-cultivated cell lines and human primary tracheal epithelial cells into contact with the films in cell culture vessels. The primary goal was for the primary respiratory cells from human tissue to attach themselves to the film. The researchers achieved their best results with the protein-coated film, on which the primary tracheal epithelial cells grew particularly well and multiplied. The team found that whilst respiratory cells proved to be more vital on bioactive films rather than on ones treated with plasma, polymer-coated film turned out to be “completely useless.”

The laboratory tests have since been completed, and animal tests are currently being prepared. If the lab results are confirmed in these tests, the next step will be to conduct clinical trials of the modified stents at the Schillerhöhe specialist lung clinic, a part of the Robert Bosch Hospital. The hope is that, within a few years, well-tolerated, cell-compatible surface coatings will be available for use in other biomedical prostheses, such as pacemaker leads, tooth implants and replacement joints.

Article Source: Cardiovascular Device Business

New report published – Cardiovascular Device Companies: Surveying the Global Competitive Landscape

This week sees the release of a new report published by Espicom Business Intelligence entitled Cardiovascular Device Companies – Surveying the global competitive landscape.

Whilst it doesn’t take a genius to conclude that the cardiovascular device market is a fast changing industry, it’s often very difficult to view these changes close up. It’s been seven years since we produced our first report focused on the Cardiovascular sector, and those changes keep on coming as we head towards 2013.

For a period of time, much of the focus was all about drug-eluting stents, and for a while at least the technology looked like fulfilling its potential. In truth, the technology has faced a perfect storm of bad news that has dogged its progress. First up, there was the pricing and cost-effective issue, then came subsequently panned EU data that suggested restenosis rates were just too high and last of all, this seemingly relentless worldwide recession came along and neatly priced potential customers out of the technology.

Last year came the unexpected news that continued declines in DES sales had persuaded Cordis to quit the industry. But it’s not all doom and gloom because the removal of a major competitor might actually reduce overcapacity in the sector. Technological improvements have come in the form of biodegradeable DESs and lessons have been learned in terms of product development and research.

The issue of reabsorbable DESs also features in the report overview section – a 14-page look at the regulatory climate in the US and in Europe. As Abbott stands poised to get marketing approval for its Absorb bioabsorbable vascular scaffold more than 18 months after European authorities gave its approval, we examine whether the FDA needs to more to bridge this gap or whether the EU system is just too quick for its own good.

It’s not just DESs that are the focus of attention. Edwards Lifesciences is also enjoying the fruits of long-term research and working its way through the somewhat unpredictable FDA pathway to get commercial release of its Sapien transcatheter heart valve. And boy, is the cash rolling in for the company in the US, where it dominates the market! Last year, transcatheter heart valve sales for Edwards jumped by over 60 per cent and now total US$334 million. That technology seems to have taken an age to get to the US market and some say the delay has effectively cost thousands of lives that could have been saved. Strong criticism indeed!

A detailed review of over 60 companies

This year the report has 60 companies that span the full breadth of the cardiovascular device field, ranging from cardiac rhythm management to interventional cardiology. Interestingly, after a long period of research and product fine tuning, the market for cardiac assist devices, such as ventricular assist devices, implantable heart replacement devices and other similar devices look to be approaching the first stage in the commercial endgame. The tell-tale sign is further consolidation within the industry and the focus on building a body of data to support the longevity of respective technologies.

One cannot also forget the rising profile of the renal denervation system, which represents a non-drug treatment option for hypertension. A reduction in systolic blood pressure, a function that underpins the technology, has cut incidents of stroke, heart disease and mortality. Most of the big players – including St Jude Medical and Medtronic – are working on significant trials of the devices, but it is also being driven by much smaller companies that want a slice of the action.

So there’s a lot to read – and a lot to take in and consider – about this year in our newly updated, and ever changing Cardiovascular Device Companies – Surveying the global competitive landscape report.

For more information regarding this report visit www.espicom.com/cdev

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Last post of the week in The Medical Technology Blog comes from the Cardiovascular Device Business, Espicom’s business publication. Please read on…

Swedish researchers compare risk of stent thrombosis and restenosis in new vs old DESs

Findings from the complete Swedish Coronary Angiography and Angioplasty Registry (SCAAR) have demonstrated that percutaneous coronary intervention (PCI) with ‘new generation’ drug-eluting stents (DESs) was associated with a 38 per cent lower risk of clinically meaningful restenosis and a 50 per cent lower risk of stent thrombosis compared with ‘old generation’ DESs.

Although many trials and studies support the overall early- and mid-term safety and efficacy of first-generation DESs, there has been concern regarding their long-term safety, especially regarding the potential risk of late stent thrombosis as well as late restenosis. New drug-eluting stents (n-DESs) have been developed with the purpose of overcoming the current limitations of the older generation drug-eluting stents (o-DESs).

The purpose of this study was to evaluate the long-term outcome in all patients who underwent stent implantation with bare-metal stents (BMS), o-DESs and n-DESs in Sweden, using SCAAR, a national registry with complete consecutive enrolment. The latter holds data on consecutive patients from 29 centres that perform coronary angiography and PCI in Sweden. The registry is sponsored by the Swedish Health Authorities and is independent of commercial funding. The technology is developed and administered by the Uppsala University Clinical Research Center. All consecutive patients undergoing coronary angiography or PCI are included. Information with respect to restenosis and stent thrombosis has been registered for patients undergoing any subsequent coronary angiography for a clinical reason since the beginning of 2004.

The current study included 94,384 stent implantations in Sweden (BMS, n=64631; o-DES, n=19202; n-DES, n=10551), from November 2006 to October 2010. Follow-up was performed up to two years post-intervention. The performance up to two years of different types n-DES was evaluated in an unselected, large, real-world population – including patients with myocardial infarction, three-vessel and/or left main disease, bifurcation lesions, graft disease, restenotic lesions and chronic total occlusions. The main findings from this study are that PCI with n-DESs was associated with a 38 per cent lower risk of clinically meaningful restenosis and a 50 per cent lower risk of stent thrombosis compared with o-DESs. These findings can be useful for the management of patients with a high-risk profile that could benefit more from these new devices.

Further studies are said to be needed in order to attempt to discriminate whether one of the three components of the n-DES – the polymer, the stent alloy, the eluting-drug – is mainly involved in decreasing the incidence of stent thrombosis and restenosis. Improved stent designs with thinner struts and more biocompatible polymers may have an important impact on drug elution profiles, endothelial coverage and functional recovery.

Related articles

• Thoughts on Cordis’ withdrawal from the DES market (medical-technologyblog.com)
• Non-Surgical Treatment for Varicose Veins (medical-technologyblog.com)
• New Interactive Dashboard for Medical Market Research! (medical-technologyblog.com)