Coronary surgery – keeping the way clear

This medical device keeps the coronary artery open while controlling the dose of medication and preventing blockage and excessive scaring. Coating the stent in biodegradable polymer containing the exact dose of medication ensures its total release and avoids potentially toxic drug retention. With heart disease and blocked coronary arteries among the major killers in the western world, this project hopes to pave the way for more precise drug delivery and increase success levels in heart surgery.

Ensuring blood supply to the heart, through the coronary artery, is essential to keep it working. However, the coronary artery is particularly prone to narrowing, causing a restricted blood flow and leading to angina or heart attacks. By inserting a wire mesh tube collapsed to a narrow diameter (the stent) into the narrow part of the artery, and inflating a balloon catheter inside, the artery is successfully held open. This procedure often causes damage to the artery wall; scar tissue forms around the stent and blocks the artery. The current technology consists in coating the stent with a biodegradable polymer bound with a drug to control this unwanted cell growth.

Less drug needed

The major problem with current drug eluting stents is that 85% of the drug, which is very toxic, remains in the coronary vessel for the rest of the patient’s life because it is bound in the polymer. To remedy this problem, the participants in the project developed a bio-absorbable polymer which is completely absorbed after about three weeks. This means it is possible to use a much smaller dose of drug, allowing for complete assimilation and leaving none unused in the stent. Blue Medical, a project participant from the Netherlands, has developed the optimum biopolymer and two drugs which will regulate excessive cell growth with much lower toxicity than is currently needed. Extensive testing has led to creating a uniform, reproducible and accurate biopolymer coating for the metal stent.

Blue Medical Devices focused on the drugs development, their interaction with the polymer and designing and validating the dosage as well as the elution rates and determining the effect of bio-absorption. Their partner, Creganna Medical Devices from Ireland, developed the process of applying the biodegradable polymer to the metal surface of the stent, with or without a drug component.

Both partners foresee a strong future for the product, which should be available in mid-2007. The projected market could reach 30% of the total stent market outside the US; worth €800m. Blue Medical has increased its workforce from 30 to 50 in two years and expects to employ 150 people by 2008. “As well as substantial financial benefit, participating in a EUREKA project has given the project a much higher profile and status, enabling strong international working relationships to be developed,” believes Ronald Horvers, project coordinator at Blue Medical Devices.