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St. Jude Medical Inc. Message Board

  • espitzer01 espitzer01 Dec 16, 2011 8:32 AM Flag

    Durata will save lives

    Not to worry. Optim is a formula of Kevlar, kryptonite and carbon nano tubes. It will not fare the same inside out abrasion of the Riata.

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    • Sorry, but I dont think you get the engineering behind what is going on with these leads. Read Hauser's recent abstract.

      These leads (Riata / Durata) have a design issue. The conductors (small wires within the lead) are placed in air pockets within the lead body insulation (silicone). As the lead moves with every heart beat (on average you have 100,000 heart beats a day), those conductors move within that air pocket, and the moving conductor slowly saws through the silicone. This is an "inside out abrasion", and leads have failed solely because of this mechanism. The conductor is insulated in ETFE, and if the ETFE erodes away as the conductors works its way through the silicone, the conductor fails in it's mission to pace, or shock.

      If the conductor erodes all the way through the insulation, and then becomes visible outside the lead (using fluoro or x-ray), this is titled an "externalized conductor".

      Keep in mind that "inside out abrasion" and "externalized conductor" observations are not the problem, these are the symptoms. The cause is that the conductors are in the air pockets and move as the lead moves with every heart beat. Think of it like having a winter cold. Congestion is the symptom, the cause is the viral infection you picked up because the guy who touched the door handle right before you at Subway didn't wash his hands after blowing his nose... Sorry, I digress. But, it is important to note that only STJ tachy leads place thier conductors in air pockets. All other tachy lead conductors are insulated in ETFE (or something very similar), and immediately wrapped / surrounded by the silicone lead body insulation. Why did STJ design thier lead different? That is a question for them.

      Now, the Durata (which has this kevlar / kryotonite coating you are hopeful about) still has the same ETFE insulated conductors housed in the same air pockets in the same silicone lead body insulation as every Riata out there. The difference is this Optim (call it kevlar if you like) coating / wrap. This wrap is 0.08 mm thick. Hmmm...

      Will the kevlar eliminate, or reduce, the rate of externalized conductor observations? Probably, kevlar is tuff stuff. Will the kevlar have any effect on inside out abrasions? No way, no chance! Again, the conductors are inside the lead body, the kevlar is the outer 0.08 mm of the lead. Think of it as Saran wrap around a pencil. The HUGE dilemma is that the kevlar could increase the incidence of failing leads because as an inside out abrasion would have become an externalized conductor on a Riata lead, that conductor will now be up against kevlar, rubbing on it 100,000 times a day. So, think of this stage as Optim vs ETFE. Which is stronger? We dont know. We do know that these conductors were not designed for this contact. If the Optim wins and the ETFE loses, this is very bad for electrical performance. This will most frequently be caught on clinical follow-up (at which time implanters will lose confidence in the lead). If the Optim loses this will become an externalized conductor and this is very easy to see under x-ray / fluoro. If implanters start seeing externalized conductors on Durata, then they will know that STJ was just lying to them when the company line was "Durata will be fine, trust us!" I will admit that in my opinion it will be 2-4 years before we really know on the Durata because so far it hasn't been out long enough.

      Lastly, as Hauser points out, about 25% of the Riata failures in his abstract were documented as "under the shocking coils". Why does this matter? Because on a Durata lead there is no Optim under the shocking coils. Said another way, there is ZERO engineering difference between a Riata and Durata lead!

      If Optim is kryptonite, we better find out who is Superman...

      • 3 Replies to whirly01
      • Very good post Whirly!

        You know it's bad try to hide your problems and a physician has to call a Summit to address your issue because you won't. This is easily translated in many different languages as "KISS OF DEATH".

        Many Durata failures are being identified DAILY. They are just on the leading edge on implant time to fail. In the words of a very famous EP, "how can you not link the two?". (Riata and Durata) I am looking forward to the feedback that will put the situation into perspective and help manage these effected patients at the Hauser Riata Summit Meeting on January 20th.

      • Yea, I know. I was being sarcastic. Same story w/ durata. Terrible thing is that docs continue to implant due to payola

    • Good. I hope we see a a stock price reversal with this, and soon!!

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