Saturday, May 21, 2011


Even as EuroPCR draws to a close, one of the Friday papers merits comments, as it is part of everyday decision making. Dr Stephen Windecker ( University hospital, Berne, Switzerland ), and group, did a meta-analysis of three large DES trials to compare the MACE rates and stent thrombosis rates of stents with bio-erodable polymers and permanent polymers. The trials involved ( all Europeans trials ) were ISAR-Test 3, ISAR-Test 4, and LEADERS. ISAR-Test 3,4 compared their Yukon Choice PC stent with bio-erodable polymer, and the LEADERS of course was using the Biomatrix Flex stent with biolimus A9 and abluminal surface, bio-eorable polymer. There were a total of 2358 patients followed for 3 years at least. They were all compared with the then standard Cypher, which had a permanent polymer with a topcoat ( old technology ). After 3 years, they found that the MACE rates were 18.2% for the bio-erodable group, and 20.1% for the Cypher group. The stent thrombosis rates were 1.2% for the bio-erodable group and 2.1% for the Cypher group, showing that the fact that the polymer erodes away, does lower stent thrombosis and also MACE rates. It is however important to note that the differences are small, 1.2 Vs 2.1 and 18.2 Vs 20.1, so that you would need to treat thousands and millions to see the real difference.
However, one must note that they are actually comparing a first generation DES ( Cypher ), with a second generation DES. You can also call this progress for the better.
I learn 2 points. The observation by the Berne-Rotterdam interventionist in 2006, Barcelona, that there is a problem of late stent thrombosis with the first generation DES is correct, but not as dramatic as they put it out to be. This has somewhat been addressed by inductry with second generation DES which have bio-erodable polymers. However, I also note that the big four stent companies are still bring out stents that have permanent polymers. This puzzles me. I would have thought that all DES now would have bio-erodable polymers, even as we move towards bio-degradable stent?
Incidentally ( not in EuroPCR ), I have just seen a paper on Biotronik's BIO DISOLVE DES. It is only a 6 months result. Looks promising. Obviously more work needs to be done. At least, if results are sustained, it will provide an alternative to the ABSORB DES from Abbott Vascular.

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