Sprint Fidelis Dear Doctor Letter

Well, I don't want to seem like I'm piling on Boston Scientific. On March 21st, Medtronic issued a "Dear Doctor" letter concerning higher than expected conductor fracture rates with the Sprint Fidelis lead. The Sprint Fidelis is Medtronic's premium defibrillation lead. It is the first sub-7 french ICD to be released (St Jude Medical released the Riata ST lead approximately 18 months after the Sprint Fidelis).

The body of the letter is as follows:

Dear Doctor,

Medtronic has received reports from a limited number of implanting physicians indicating they have experienced higher than expected conductor fracture rates in their centers with Sprint Fidelis leads. While current overall Sprint Fidelis performance is consistent with other leads, Medtronic is actively investigating these reports, has reviewed them with our Independent Physician Quality Panel, and would like to share what we know at this time.

Through detailed assessment of reported fractures, we have identified two primary locations where conductor fractures have occurred: 1) distal portion of the lead and 2) near the anchoring sleeve tie down. The distal conductor fractures affect the anode (ring electrode) and fractures that occur around the anchoring sleeve affect the cathode (helix tip electrode). Fractures at both locations appear to prsenet clinically as over-sensing, increased interval counts and inappropriate shocks. Medtronic has worked closely with physicians who have experienced fractures and conducted significant bench testing in an attempt to reproduce the fractures and identify root cause. At this point, our investigation suggests that variables within the implant procedure may contribute significantly to these fractures.

For distal conductor fractures, our investigation has identified severe bending or kinking of the distal end of the lead over the lead body while passing through tortuous vasculature as a significant contributing factor. If the lead is severely bent or kinked at the distal end, the conductor may be compromised such that the conductor may fracture after implant due to chronic fatigue from natural cardiac motion. The venous structure or pathway, venous access location, length of introducer sheath and lead insertion force are all factors that may contribute to sever bending or kinking of the lead. Medtronic recommends avoiding severe bending or kinking of the lead during implantation. If you encounter excessive resistance resulting in severe bending or kinking while advancing the lead, please remove the lead and return it to Medtronic.

For conductor fractures that occur around the suture sleeve, our preliminary investigation suggests that under certain implant techniques, the lead appears to be exposed to severe bending or kinking in the pectoral area. We are still investigating and actively partnering with physicians to better understand this type of fracture. If excessive kinking or bending is observed during lead suturing and/or pocket formation, Medtronic recommends the lead be re-sutured and/or pocket reassembled per guidelines in the Medtronic lead implant manual. In addition, positioning the anchoring sleeve against or near the vein may be helpful.

Sprint Fidelis lead models 6949, 6948, 6931, and 6930 were market released in the U.S. and internationally in September and October 2004. Performance of model 6949, the Sprint Fidelis lead currently followed in our System Longevity Study, indicated survival is 98.9% at two years. Sprint Fidelis 6949 performance based upon return product analysis shows 99.86% chronic fracture-free survival at two years. Both evaluation methods suggest performance is in line with other Medtronic leads and consistent with lead performance publicly reported by other manufacturers.

This letter was sent to all implanting U.S. physicians and nowhere was there any request for confidentiality. That is why I posted it.

Well, the lead fails and they state, "variables within the implant procedure may contribute significantly to these fractures." It's the implanter's fault. Of course, that makes perfect sense. The same physician who has implanted endocardial defibrillation leads since 1992 now suddenly doesn't know how to operate one of these new-fangled leads. Are they suggesting that for patients with a tortuous anatomy a different lead should be used - possibly a Sprint Quattro Secure? I don't know. What's going to happen if physicians get nervous and every time they try to implant the lead and "excessive kinking" occurs, they abandon the lead a try a different lead? Will returns to Medtronic increase?

Another Boston Scientific Product Advisory

Well, Boston Scientific (Guidant) issued another product advisory on April 5th. This one relates to certain low-voltage capacitors on certain ICDs and CRTDs. By "certain," I mean it affects devices within every product line they currently sell - Vitality, Vitality 2, Renewal 3, and Renewal RF.

I'll start the the discussion by giving an overview of capacitors. Simply put, capacitors are used in an electrical circuit as an energy storing tool. A good discussion of capacitors is at How Stuff Works - Capacitors.

In its letter, Link Boston Scientific states that, "These capacitors may cause accelerated battery depletion and may reduce the time between elective replacement indicator (ERI) and end of life (EOL) to less than three months. Device replacement indicators continue to function normally." They go on to state that there have been, "No confirmed reports of shortened ERI to EOL time while implanted." However, Nineteen (19) of approximately 73,000 devices in this population worldwide have been confirmed to have accelerated battery depletion, which could have resulted in shortened ERI to EOL time." Finally, there have been no patient deaths.

They recommended reviewing every patient's chart to assess battery voltage. If the device hits MOL2 within 27 months (32 months for EL devices), then the patient should be followed monthly until ERI is reached.

The burden this places on physicians and clinics is tremendous. Going through every chart to ascertain battery voltage and time since implant is time consuming. Who must go through charts - the reps or staff? Additionally, asking a patient to come in every month is extremely inconvenient to the patient. What if that patient can't drive? Does a family member have to take time off to bring the patient in?

I bet the FDA will classify this advisory as a recall. Once that happens, Boston Scientific will change its tune and offer a free device to any patient that wants one. Of course other manufacturers will offer programs where they will pay unreimbursed medical expenses and offer discounts to hospitals if a physician/patient decides they don't want to replace the Boston Scientific device with another BSX device.

Product advisories are a fact of life in the medical device business. That being said, Boston Scientific has had a quite a few the past 2 years. Many at BSX believe that “the world is against them.” That their quality system is robust and Barry Meiers (New York Times) and other are simply making a mountain out of a mole hill. I disagree and think the problems may be indicative of a failure of the internal control systems. I wonder if the relentless desire to sell the company off at the highest price (in 2004-05) didn’t have an effect on the reporting of problems internally. I don’t claim to know what happened at internal meetings, but, the sheer number of advisories/recalls lends credence to this hypothesis.

I think this latest advisory may be the proverbial “straw that breaks the camels back,” as far as some customers are concerned. How often can a physician say to him/herself, “Hey, it’s just a small problem, the risks are being overblown.” At this point, I think some customers may simply decide that they will no longer use Boston Scientific.