Friday, April 23, 2010


I have just seen a copy of the presentation given by Dr John Ormiston at the March 2010 ACC annual scientific meeting. He was updating us on his work in bioabsorbable stents, the latest generation.
I first met John, back in the late nineties when we were involved in a interventional conference. He was working in Greenlane Hospital, Auckland as an interventional cardiologist. However, their system in New Zealand is so good that he could also do a lot of research in the laboratory, with engineers and lab animals. He was one of the first to produce a model of what happens at the coronary artery bifurcation when we implant all our stents, the crushed stent model, the coulette stent model, the T stent model and the single stent model. It looks like after the 2006 Barcelona interventional cardiology fiasco when European researchers frigthtened us with the " stent thrombosis " hype, much research has gone into developing the bioabsorbable stent. Many felt that keeping stainless steel in the artery wall was not helpful in the long term and may even be harmful. I had seen some of the earlier work by the late Dr Tamai ( the Tamai bioabsorbable stent ) and also the Biotronik Magnesium bioabsirbable stent. The results were scary. The restenosis rates were worse then bare metal stents.
Therefore, when I saw the presentation of Dr Ormiston in ACC, March 2010, I was very impressed. He showed results, varified by OCT ( Optical Coherence Tomography ). OCT is a very sensitive ( also very costly ) way of studying the inside of the vessel wall. Supposedly better then intra-vascular ultrasound. Dr Ormiston showed his first generation bioabsorbable stent, on the Abbott multi-link platform with the everolimus drug, which at 6 months and two years, was as good as the Taxus and Endeavor stent ( the late loss, I mean ). Not satisfied with this result, he went on to work with a second generation multi-link stent which had closer struts and thinner. Also with the everolimus drug. At 6 months, there was no more stent and the late loss was better. I recond that in 3 years ( at the current pace of development ), we will see a bioabsorbable stent ( probably from Abbott ), CE mark approved for clinical use. This is certainly promising.
My only worry is that, I am not certain if late loss as measured by OCT is the best way to assess the bioabsorbable stent? The there also the question of stent thrombosis, especially late and very late stent thrombosis. Does a bioabsorbable stent solve that issue. I could not get that information from Dr Ormiston's presentation. I rather suspect that we do not know. In the first place, that was the 2006 september, Barcelona issue.
Be that as it may, we can look forward to a small revolution in PCI, the commercial use of the bioabsorbable stent. We can tell our patients that after 6 months, there will not be metal in the artery anymore. Only time will tell, if this is true. And as always, there is the issue of cost. Are we willing to pay two to three times the current DES cost, for a bioabsorbable stent, just to have no more metal in your artery wall, all else being equal.

1 comment:

XYZ said...

My brother 32, got a heart Attack. He got angiography done and has a blocked artery (100%). His angioplasty is due in 15 days, as the cardialogist suggested. My question is that are these bio-absorable stents available in the market? if no (:()by how much time are they expected to arrive in market. We want the best treatment available now a days. If they aint, what do you recommend?
Please your reply is very eagerly awaited.
Qadir Nawaz
(Concerned Brother)