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August 2005
Archives: What is Deliverability? Imagine snaking a long cable through a wall and trying to steer it so it comes out in the right place. The shape of the tip, the stiffness of the wire, the "lubricity" or smoothness of the shaft -- all these things meld together to form a very complex set of physical dynamics that determine the chances of success for getting that beautiful and expensive polymer-coated drug-eluting stent to exactly the right place in the patient's anatomy. Thus, "deliverability"! And some cardiologists will say that the Boston Scientific Taxus stent is more "deliverable" than its rival Cypher. You, of course, would rather not spend 30 minutes trying to get a stent around a sharp curve in the artery only to find that a different stent would go through easily and with less trauma to the artery lining. But other cardiologists will say that there really is no difference between the two and that they've never encountered a situation where they couldn't place the Cypher stent where they wanted. But I'll put forth that "deliverability" may also mean something else, as in "Did the right size stent get 'delivered' by Fedex this morning?". One of the early, and not yet completely resolved, complaints about the Johnson & Johnson / Cordis stent was that doctors couldn't get a good supply in a wide range of sizes. This was definitely an advantage that the Taxus had, at least until now. Correct sizing of the stent to the artery is a critical measure (kind of like getting the right shoe size -- you mean you don't carry it in a size 7? Well, I'll go somewhere else!). All recommendations to cardiologists emphasize NOT stretching the stent to fit a larger-sized artery. So the success of one stent over the other depends on "deliverability" -- of the stent from the introducing sheath to the lesion...and of the stent from the factory to the hospital. Speaking of deliverability, I will be delivering myself across the U.S. in the coming weeks and will return in September. Happy August! « send comment » « back to top »
Who's on First? -- Cypher vs. Taxus Rehash Both articles point to the fact that the sirolimus-coated stents (Cypher) showed greater reduction in angiographic restenosis than the paclitaxel (Taxus) especially in patient populations who are at the highest risk for restenosis (diabetics primarily). So this would mean everyone should be using the Cypher, right? Wrong. The same issues discussed in March still exist. The actual differences in the restenosis rate or in a related measure, called TLR (Total Lesion Revascularization, long-hand for "redo") are significant, but not massive -- somewhere in the area of 4%. Several cardiologists have stated that there still isn't that much difference, except maybe in high-risk-of-restenosis cases they would go with the Cypher. But "deliverability" and ease-of-use still seem to be phrases that crop up in favor of the Taxus. Interestingly enough, none of the studies so far presented show the Taxus as superior to the Cypher, but a number show the opposite. If this is confusing, add to the mix a comment (from theheart.org article) by well-known interventional cardiologist Ron Waksman, MD of the Washington Hospital Center:
'Nuff said. |