Are biodegradable stents the future?
Stents are tiny tubular scaffolds and they have overtaken bypass graft surgery in terms of popularity for treating clogged arteries. About four stent procedures are done for every bypass. The latter procedure is invasive, but some surgeons argue that it is better for many patients.
There have been big improvements in the success of stents over the years. Angioplasty, where a balloon is inserted to clear a clogged artery, needed repeating in about 35% of cases. Bare metal stents, which prop open the artery, came in the 1990s and brought failure rates down to 15%. More recently, stents which release drugs to prevent the artery from narrowing reduced the rate of recurrence to around 5%.
The figures above come from Professor Tony Gershlick. A cardiologist, he inserted the new biodegradable stent in a patient at Glenfield Hospital in Leicester.
This is not the first dissolving stent - there've been trials of a biodegradable magnesium scaffold and while successful, it did not show huge benefits over existing devices.
Abbott's "bioresorbable vascular scaffold" is a drug-eluting (drug releasing) stent. It's actually four years since the first patient - in New Zealand - had one fitted, and there is trial data on a small group of patients over three years. The results seem promising, and it might appear an obvious advantage to have a device which disappears from the body when you no longer need it.
Interestingly, although Abbott's product was developed in the United States it is not being trialled there. I'm told this is because the Food and Drug Administration has tighter regulations on new medical devices. Abbott, which has its headquarters in Chicago, has preferred to do trials in Australia, New Zealand and Europe.
But it is far too early to know whether this product represents the next phase in treating clogged arteries. Professor Peter Weissberg from the British Heart Foundation feels that biodegradable stents are likely to be an incremental advance rather than a dramatic improvement.
Professor Gershlick is also cautious; stressing it's too early to say anything definitive about the dissolving stent. But he is much more optimistic and believes scaffolds that disappear from the body will be the future.
The trial at Glenfield hospital, which is likely to be extended to King's College Hospital in London, will involve only limited numbers of patients. And it could be five years before the results are known of an international trial. Until then, the dissolving stent remains an experimental treatment. As with all new drugs, devices and treatments, a highly cautious and careful approach is essential long before anyone can deem them a success.
As for the first patient in Britain to have the Abbott device, he's doing fine, two weeks after it was inserted. Shabbir Makda was back at his bus station in Leicester this morning, where he's a driver. He'll have to have some refresher training but should be back behind the wheel in a few weeks, and - he promises - doing more to look after his heart.