St. Jude Issues "Dear Colleague" Letter Regarding Older Pacemakers During Surgery

On 29 January 2014, St. Jude Medical issued a "Dear Colleague" letter regarding their review of incident reports on older-model pacemakers (Affinity, Entity, Integrity, Identity, Sustain, Frontier, Victory and Zephyr models) that occasionally dropped their output voltage during surgical electrocautery. (Here's a publication describing two such cases.)

Several issues regarding this advisory letter are troubling.

First of all, according to the St. Jude letter: "Placing a magnet over the device or programming to an asynchronous pacing mode will not prevent this temporary reduction in pacing output." Consequently, St. Jude advises that pacemaker-dependent patients with these older pacemakers consider undergoing surgery without the use of electrocautery or to "employ appropriate precautions to ensure that the heart rate will be supported in the presence of electrocautery. Consideration of placing a temporary transvenous pacemaker is appropriate. (Emphasis mine)"

Typically, placing a magnet over pacemakers causes them to pace at a default "magnet rate" and pace at the programmed output voltage. This is such a common feature among pacemakers that it formed one of the cornerstones of the 2011 guidelines for peri-operative pacemaker management. While electromagenetic interference on older pacemaker models has been seen due to the device being reset, it is unusual for pacemaker output voltage to drop briefly. Furthermore, the recommendation to place a temporary pacing wire before surgery where electrocautery use is anticipated in pacemaker-dependent patients suggests there is no programmable "work-around" for this problem.

Secondly, while it seems an effort has been made to notify physicians about this problem with certain older St. Jude pacemaker models, it is concerning that I could not find the notice on St. Jude's Healthcare Professional website at the time of this writing, nearly three weeks after date of the original notification letter. Furthermore, it is concerning that such an unusual (and potentially fatal) failure mode of these older models of pacemakers has not been made more public to patients with these older St. Jude pacemakers so they can serve as their own advocates when surgery is in its planning stages.

-Wes

Boston Scientific Issues Alert Regarding Their New Subcutaneous ICD

From Massdevice.com:

The company has received reports of 4 instances in which a fuse inside the subcutaneous ICD was activated inappropriately, which could cause the devices to fail. No adverse events have yet been reported, according to Boston Scientific.


"The company is issuing a software update that takes less than a minute to complete using a programmer in the physician's office," Boston Scientific senior VP of global corporate communications Denise Kaigler told us today. "We recommend patients with recently implanted S-ICDs meet with their doctors for a follow-up visit to receive the software update."

-Wes

The Riata ICD Lead Recall: Two Perspectives

Robert Hauser, MD published a perspective piece in the New England Journal of Medicine today entitled "Here We Go Again — Another Failure of Postmarketing Device Surveillance." In the piece, he offers these suggestions on how to detect these failures earlier:

Opportunities have emerged for automated tools to prospectively monitor multicenter device databases for early, low-frequency adverse events and to compare suspect devices with established products that have been shown to be reliable.(4) The goal is a postmarketing surveillance system that not only detects device problems early but also accumulates the data needed to guide patient care. Until such a system exists, St. Jude Medical should initiate a study with these attributes for recalled Riata and Riata ST leads and for the currently marketed Durata leads. Indeed, all manufacturers should conduct postmarketing studies of this type for marketed class III devices that sustain or support life.

It has been 3 years since the FDA launched the Sentinel Initiative, as Congress, in 2007, directed it to do.(5) The intent of this new system is to supplement the current passive adverse-event reporting with an active, real-time network capable of identifying any safety or efficacy issues soon after a new drug or device is marketed and then communicating the information in a timely manner to health care providers and the public. Creating such a system is an ambitious undertaking, and the initiative aims to gather electronic health data from 100 million people by the end of 2012. Formidable challenges lie ahead, such as setting priorities, developing analytic tools, and deciding when and how to alert the public if a safety signal is detected. Thus, we are years away from a fully operational Sentinel Network.

Jay Schloss, MD offers another thoughtful perspective on this issue in his guest post over on Cardiobrief:

It is worth noting that all high impact device failures in the cardiac rhythm device industry have occurred well after device approval. In most cases, failures have been rare events occurring many years after these devices became clinically available. The industry is littered with high profile device failures, some of which serve now as footnotes or memories from the more gray haired members of the EP community: Medtronic polyurethane pacing leads, Ventitex Cadence ICDs, and Telectronics Accufix pacing leads were all devices that failed well after they had been introduced to the market. It was through case reports from concerned doctors – not the FDA — that these problems were brought to light.

Trying to absolutely prevent the failure of medical devices through the FDA approval process would be challenging to say the least. This would require an anticipation of the potential failure mechanism before the fact to design a study that would detect said defect. Moreover, the number of patients and length of study for these trials would be daunting, impractical and quite likely prohibitively expensive.

Hauser’s call to enforce a robust active postmarket surveillance system would allow ongoing innovation and appropriately timed approval of new technology. With the ability to carefully monitor a large population of approved devices “in the field,” sentinel failures could be detected and acted upon as they occur. With public reporting of these events, doctors could draw their own conclusion of whether to keep implanting these devices and prospective studies could then be designed promptly to determine the scope of the problem. That would be a system that protects patients while still allowing innovation.

Neither author mentions how their approaches might be funded. Nor is there a clear consensus on how to determine a threshold for sounding a recall (or "advisory"). Should it be announced before a root cause of the problem is known or suspected, or after? Pulling a recall trigger too early before a root cause of the defect is identified leaves doctors and patients completely in the dark about how to manage these complicated situations. These issues are still debated today.

What is clear, though, is that the efforts to prevent such widespread recalls continue and doctors (as shown by these two perspectives) remain eager to participate in the process.

-Wes

More Troubles for St. Jude's Riata Defibrillator Leads?

From the Minneapolis Star Tribune:

Researchers in Ireland have discovered a possible problem with a heart defibrillator component made by St. Jude Medical Inc. in which wires that run from the device to the heart may poke through the outer coating of their cable.

The study looked at 212 patients in Ireland who received St. Jude's Riata defibrillator lead and found that 15 percent had suffered such an "insulation breach," which could interfere with the device's life-saving therapy. Normal screening of the device or even X-rays may not pick up the breach, and patients would have no outward clue that their lead wire may be compromised.

It should be noted that the "study" referenced in this artice was actually an abstract published in the European Heart Journal's September supplement edition. I could not find it online yet, but a copy of the source abstract can be found on CafePharma, the medical device / pharmaceutical industry representative's anonymous messaging board.

-Wes

Bristol-Myers Squibb Issues 5 mg Coumadin Tablet Recall

From the FDA today:

Bristol-Myers Squibb initiated a voluntary recall of one lot of 1,000-count bottles of Coumadin (warfarin sodium) Crystalline 5 mg tablets. Company testing of tablets from a returned bottle found a tablet to be higher in potency than expected. The lot number affected in the U.S. is 9H49374A with an expiry date of September 30, 2012. A decrease of active ingredient may increase the risk of clots which could lead to heart attack or stroke, and if there is too much active ingredient, there is an increased risk of bleeding.

So what should patients who take 5 mg tablets of Coumadin do?

Here's the FDA's recommendation from the same notice:

Patients who may have 5 mg tablets should not interrupt their therapy but should seek advice from their pharmacist to see if they have tablets originating from the affected lot and if so, should consult their physician for appropriate medical advice.

In short: call your pharmacist first. If the pharmacist where you picked up your 5 mg Coumadin tablets did not fill your prescription from the affected lot, no change in management is required.

But this is where this FDA advisory stops short. What are doctors going to recommend to patients who are taking 5mg Coumadin tablets from this lot?

If it were me, I would probably advise my patients to exchange tablets at their pharmacy for tablets from a non-affected lot and have a blood thinning level (prothrombin time or INR) checked to make sure their blood is not excessively thinned.

But, hey, that's just me.

-Wes

St. Jude Withdraws Riata Defibrillator Leads

St. Jude Medical announced they are withdrawing a portion of their thinner 7Fr Riata defibrillator lead line despite earlier glowing company reports because of a higher degree of insulation failures in the earlier design of the leads made with silicone insulation material:

The Riata and Riata ST family of silicone defibrillation leads have exhibited an insulation abrasion rate of 0.47% over 9 years of use. Silicone rubber, while representing the industry’s most commonly used defibrillation lead insulation material over the past 20 years, has been observed to be vulnerable to abrasion. Abrasion of silicone defibrillation leads is acknowledged within the clinical community as a well known clinical risk and is well documented in the literature as the number one cause of lead failure across the industry with reported failure rates ranging from 3 to 10 %. Lead insulation damage and its possible effects are also described as a potential adverse event in all silicone defibrillation lead user’s manuals, including Riata User’s manuals.

Later St. Jude lead designs with their newer "Optim" polymer insulation appear to not be affected by this action. St. Jude had hoped their Riata line of defibrillator leads could replace the niche left by Medtronic's earlier withdrawl of their downsized Sprint Fidelis defibrillator leads after Medtronic's line of 7Fr defibrillator leads experienced higher-than-expected fracture rates.

Just as with the Medtronic Sprint Fidelis defibrillator lead withdrawl, St. Jude does not recommend the affected leads be extracted. I would suspect that doctors will weigh the risks vs. benefits of placing a new defibrillator lead at the time of device battery changes.

In November 2007, the Riata line of defibrillator leads were plagued by concerns of a higher-than-average rate cardiac perforation, but these were quickly disputed by the company.

-Wes

More on Biotronik's Exploding ('Venting'?) ICD

According to MedPageToday, it appears an earlier case report that was mysteriously withdrawn from the peer-reviewed journal Europace will soon be republished:

A controversial article about problems with an implanted cardiac device -- published by and then withdrawn from the journal Europace -- has been resubmitted and is under review, according to the journal's editor.

"I expect that a decision on publication will be made very shortly," John Camm, MD, of St. George's University of London, told MedPage Today in an e-mail.

Hopefully, the journal will explain why they failed to notify their readers about the withdrawl as well. To withdraw an article of such signficance to their readership without explanation should not be tolerated by the scientific community.

Several other issues:

1. Perhaps even more concerning this whole ordeal has been the FDA's management of the device report made to them in May. It seems public reporting of Biotronik's filing did not appear on the MAUDE database until after my blog post was published in October.
   
   If this is their policy to withhold reports in patients that are injured for this length of time irrespective of "cause," there are bigger concerns with the government's policies that should be immediately addressed.
2. I should also explain my rationale for my "defensive blogging" earlier, too.
   
   The Fair Use Act of US Copyright law has been a favorite place for malicious lawyers to attack bloggers who republish content in their blogs. Irrespective of whether or not one could defend their actions in the court of law on the consitutional basis of "free speech."
   
   But when challenged, as soon as a lawyer gets involved, thanks to the large costs involved, you've "lost" your case even before going to trial. I did not need that expense at the time, so I caved and withdrew the pictures I had published (note: they have since been republished on the blog Cardiobrief.org, courtesy of Google cache, but have included a pdf of my copy of the entire case report in this blog post).

-Wes

Yet Another Boston Scientific Defibrillator Advisory

With their stock struggling to survive, the latest Boston Scientific defibrillator advisory could not come at a worse time:

Boston Scientific Corp. warned physicians that three of its implantable defibrillators have a defect that can prevent them from working properly, in the latest problem for the company's heart devices.

A magnetic switch on the implantable cardiac defibrillators can get stuck, stopping the devices from delivering an electric shock to the hearts of patients who need the therapy, the company said in a letter to doctors.

The Contak Renewal 3, Contak Renewal 4 and Vitality HE ICDs were made in 2006 and 2007, and about 34,000 remain implanted in patients, according to the Natick, Mass., company, which said on Thursday that it had issued the advisory.

It is unclear how Boston Scientific learned about the problem, and why it issued the advisory now. A company spokeswoman didn't immediately respond to requests for comment.

Boston Scientific said in its product advisory that the risk of harm was remote, and it hasn't received any reports of deaths or injuries. Doctors have replaced some of the devices, according to the advisory, but the company recommends against it.

The original physician communication, dated today, can be found in pdf format here.

-Wes

Addendum:
08:20AM 23 Jul 2010: The Boston Scientific 'Dear Doctor' letter (pdf) regarding the advisory.

Software Glitch Found in Medtronic's Latest Defibrillator Line

From 7thSpace:

(Hong Kong) The Department of Health (DH) today (May 5) received notification from Medtronic International Limited (MIL), the local branch of a multi-national medical device manufacturer, that software problems in six of its implantable cardiac devices may risk life-threatening though rare malfunctioning. A DH spokesman said, the affected models are Consulta CRT-D (D234TRK), Secura DR/VR (D234DRG, D234VRC), Maximo II CRT-D (D284TRK) and Maximo II DR/VR (D284DRC, D284VRC).All except Maximo II VR (D284VRC) are distributed in Hong Kong. As of April 19 this year, the manufacturer has received five confirmed reports of defect out of approximately 144 000 devices sold worldwide.However, it is reassuring that no patient injury or death arising from the affected devices has been reported thus far.

I called Medtronic technical support and they confirmed the issue. It appears they are not recommending any additional action on the part of patients be undertaken at this time since the problem is only caused if a rare sequence of events takes place. They are awaiting for FDA approval of a software fix for the problem can be upload during patients' next routine device follow-up to avoid the issue.

More details as they become available...

-Wes

Addendum 7 May 2010 17:27PM: The Dear Doctor letter from Medtronic, posted today.

When Doctors Decide Damages

In an interesting twist to the ongoing saga of device recalls, the Minneapolis Startribune reported that the two doctors, Robert Hauser, MD and Barry Maron, MD who first brought the Prism II ICD device malfunction to public attention by releasing their story to the New York Times in 2005, wrote a letter to the judge reviewing the plea bargain agreement and told him:

We are physicians who cared for Joshua Okrup (eds note: should be "Oukrop"), a 21 year-old college student, who died when his Guidant Prizm 2 implantable cardioverter-defibrillator (ICD) short-circuited and failed to deliver a life-saving shock. His unnecessary death was caused by a product defect that Guidant Inc. had known about for years and failed to inform patients, physicians, and the U.S. Food and Drug Administration. Accordingly, we are extremely dismayed by the U.S. Attorney General’s decision to enter into a plea agreement with Guidant LLC, rather than prosecute the company and the individuals responsible for this egregious act. On behalf of the patients who died or suffered pain and mental anguish as the direct result of Guidant’s illegal and unethical behavior, we urge you not to accept the plea agreement.

An out-of-court $296 million plea agreement is not enough it seems.

While these doctors have every right to express their opinions on the case (and certainly the actions of the company were egregious), their letter opens an interesting precedent for physicians advocating on behalf of their patients: deciding what is "just" concerning damage awards in legal matters on their behalf.

Should this be the purview of physicians?

I wonder.

What I do know is an incredible amount of good has come to the medical device industry since this story broke. Companies do a much better job of reporting problems with their devices now as evidenced by excellent product performance reports. Companies also raise flags regarding their devices MUCH earlier, perhaps even notifying patients of every advisory condition imaginable (like cosmic radiation could interact with their device memory chips) - suddenly nothing was too small to report. We have also seen the profession have a greater understanding of the need to quantify the incidence of device problems by returning all devices - normally functioning or not - to companies for ongoing quantification of device reliability to better appreciate the level of device performance we should accept as "standard." Device registries now are used routinely to track and better understand the myriad of variables that influence device performance in the real world.

Litigation is always expensive and time-consuming. I am left to wonder if ongoing court litigation versus a hefty out-of-court settlement will really provide additional benefit to to the loved ones who lost their children or, as these doctors suggest in their letter, future patients. I worry that ongoing litigation might just drag this process on for years so that future patients will have to bear the costs in the form of even higher device prices.

I admit that I do not know how much money the plaintiffs would receive with the anticipated settlement and whether that will be enough compensation for all that has happened, but irrespective of the judge's decision in this matter, I hope we can continue to move past this unfortunate incident and continue working with industry and regulators to make sure this never happens again.

-Wes

Boston Scientific Issues New ICD Advisory and Halts Sales of All ICDs

Despite the excitement of the American College of Cardiology meeting in Atlanta, Boston Scientific issued a self-reported advisory about all of their high-voltage defibrillators (pacers are not affected) stopping sales until "administrative issues" regarding a change in manufacturing processes and changes of their IS-4 lead connector. This advisory does NOT affect existing implanted devices, but rather halts the sales of further devices:

The Company has determined that some manufacturing process changes were not submitted for approval to the U.S. Food and Drug Administration (FDA). At this time, the company has identified two instances of changes that, while successfully validated, were not submitted to the FDA. Boston Scientific has informed the FDA and plans to work closely with the agency to resolve this situation as soon as possible.

The Company has no indication that the manufacturing process changes pose any risk to patient safety, and it is not recommending explantation of the devices.

Product families included in this advisory include: COGNIS®, CONFIENT™, LIVIAN™, PRIZM™, RENEWAL®, TELIGEN® and VITALITY™. The Company's pacemakers and other products are not affected by this advisory.

But the interesting part of this news is who knew first. According to theheart.org:

Analyst reports were among the first to trumpet the news, even before Boston Scientific issued its alert. Larry Biegelsen of Wells Fargo Securities predicted early this morning that the news will mean "reputational damage" for the company, despite the fact that the problem appears to be "administrative."

And here I thought the big news of the day was going to be at the meeting.

-Wes

Boston Scientific Issues 'Soft' Defibrillator Advisory

Boston Scientific recently issued a new device advisory for their current line of Teligen ICD and Cognis CRT-D automatic defibrillator devices. The advisory affects only those devices that are implanted beneath the breast muscle (subpectorally) on the chest wall. It seems two (2) devices implanted (of 77,000 total devices implanted worldwide) in this location experienced weakening of a header bond caused by significant forces applied to the header by the pectoralis muscle to the rib. This resulted in altered lead impedances and the introduction of noise to the defibrillator sensing lead that might inhibit pacing or result in inappropriate tachycardia therapies (shocks).

The submuscular implantation location is an uncommon location to implant the devices. It is estimated that only 5% (3850) of the 77,000 devices implanted, were implanted in the subpectoral location.

From Boston Scientific's "Dear Doctor" letter:

Boston Scientific has determined that the bond between the header and case could be weakened by significant forces associated with a subpectoral implant procedure or when a device in a subpectoral position is pushed against a rib during contraction of the pectoralis muscle. A weakened header bond may alter lead impedance and introduce noise that may inhibit pacing therapy or initiate inappropriate tachy therapy. Additional mechanical stress applied to a weakened bond may eventually cause header connection wires to fracture, resulting in loss of therapy.

. . .

Rate of Occurrence
The implant orientation of devices is not reported to Boston Scientific, making it difficult to provide rate of occurrence and prediction information. We have received two (2) reports worldwide of subpectoral implants with weakened header bonds. We estimate that 5% of approximately 77,000 COGNIS and TELIGEN devices worldwide have been implanted in a subpectoral location.

The following factors may also impact the risk of failure if implanted in a subpectoral location:

• Exact location of the patient’s ribs relative to the device
• Body size and/or muscle mass of the patient (risk may increase for larger/muscular patients)
• Activity level and/or occupation of the patient (risk may increase for more active patients)

Recommendations

For future implants:
• Boston Scientific recommends that subpectoral implantation of affected COGNIS CRT-Ds or TELIGEN ICDs (Table 1) be avoided until improvements to header bond strength are available for devices in your geography.

For affected devices (Table 1) implanted in a subpectoral location:
• Follow patient at least once every three months as recommended in device instructions for use.
• Consider advising patients to contact their physician or clinic if they receive shocks, in order to ensure timely review of associated electrograms and other device data via in-clinic or remote interrogation.

In summary, the devices need to be followed as usual (every three months), but are not recommended for removal unless they begin to develop erratic behavior. The warranty and unreimbursed medical expenses "may" be honored in "certain geographies."

-Wes

Reference: Boston Scientific's webpage with more information as well as links to the Dear Doctor and Dear Patient letters

Boston Scientific's Ultra-Soft Device Advisory

How do you notify people gently about a device alert that doesn't involve an implanted device, but rather a monitoring device developed for the implanted device? Where does a sophisticated implanted defibrillator device end: with the part that's implanted inside a patient or does it include the peripherals that monitor the implanted device, too?

These are the issues that have surfaced with a very recent medical device advisory issued by Boston Scientific on 9 September 2009 in a "Dear Doctor" letter (pdf) I managed to find on their website, and was brought to my attention by an anonymous commenter on this blog:

Background
Boston Scientific defibrillators include a Daily Measurements feature that conducts several diagnostic tests on a daily basis to monitor the implanted defibrillator and leads. At the next in-clinic visit, test results are displayed on the programmer, with out-of-range results appropriately highlighted.

To supplement in-clinic visits, the LATITUDE Patient Management system enables clinicians to monitor the status of the implanted system remotely between clinic visits. Status information from the implanted defibrillator is transferred by an in-home communicator to the LATITUDE Website according to a schedule set by the clinician. If Daily Measurements are programmed On in the implanted defibrillator (nominally On) and the desired Alerts are configured On in LATITUDE, out-of-range Daily Measurements will generate a corresponding Red or Yellow Alert on the LATITUDE Website.

Description
Boston Scientific has determined that alert conditions for a limited subset of out-of-range Daily Measurements related to leads may not be recognized by Model 6476 (United States) or Model 6468 (Europe) LATITUDE in-home communicators. If a communicator fails to recognize a valid alert situation, notification for this or subsequent alerts for the same test will not be displayed for physician review on the LATITUDE Website. However, Daily Measurement values uploaded from the implanted defibrillator will be available from the ALL PATIENTS page after completion of the next full device interrogation, which occurs during Weekly Device Alert Interrogations and scheduled remote follow-ups.

Although a limited subset of alerts may not display on the LATITUDE Website, it is important to note that all Daily Measurement tests within the implanted defibrillator function normally, and results will be displayed as designed when the defibrillator is interrogated with a programmer.

Rate of Occurrence
We have identified 8 missed Red Alerts and 223 missed Yellow Alerts from approximately 19,000 patients in the United States with implanted Boston Scientific defibrillators followed with a LATITUDE Model 6476 Communicator. One missed Yellow Alert has been identified from approximately 50 patients in Europe followed with a LATITUDE Model 6468 Communicator. However, root cause analysis indicates that both communicators are subject to missed alerts at the same rate of occurrence. The observed rate for a missed Red Alert (highest priority) has been approximately 0.01% per month of monitoring. No patient deaths or injuries have been associated with this communicator behavior.

Hopefully, all patients with these Communicators have been notified, but how are device clinic nurses and physicians supposed to be notified? I checked with our device clinic nurses and they were unaware of this advisory - is it because we have no patients included in this advisory? (I'm not sure). But what I do know is that the potential to miss clinically important information when we increasingly rely on color-coding of parameters on websites to identify out-of-range parameters is something every doctor and device nurse should be made aware, especially since patients move from one location to another or might not have received notification about their communicator.

Whether a targeted letter posted on a company's website is adequate notification to electrophysiology personnel nationwide about this type of advisory, whether it affects our patients directly or not, probably is not adequate either.

After all, we're ultimately responsible to our patients.

-Wes

The Importance of Blogs and Device Advisories

Yesterday, I reported on this blog the trouble Medtronic had experienced with and earlier batch of defibrillators due to a low-voltage capacitor problem from an outside supplier back in 2005 or 2006. The problem was identified in a relatively small number of devices and has not affected their devices' functionality, but the expected battery life of these batch of devices was discovered to be shorter than they had expected. A root cause analysis was undertaken and the capacitor issue was identified. After consulting their physician advisory panel, they elected to notify all doctors who implant their devices about the issue and provided the patients' names that they were aware of to doctors to help facilitate patient notification.

Importantly, there was not a press release.

Personally, I think this was a good thing. As of this moment, I was only able to find one reference to this advisory in once major newspaper, the Wall Street Journal. No doubt, the news will spread rapidly from there.

But it will not spread like a press release would: fired instantaneously to every news organization around the globe always looking for the next tidbit to report, especially tidbits that create lots of angst. Importantly, the piece from the Wall Street Journal did not include a hyperlink where patients would look up if their device was affected.

It has been interesting to also see who has been reading my blog post on this matter. Sitemeter is handy for that. At first, it was lots of hits from medtronic.com, but not too soon thereafter came guidant.com, bostonscientific.com, and the like.

There is no question that these device manufacturers are fierce competitors. As such, let's just say they like to keep things relatively private between themselves. But these device manufacturers may also use the same outside vendors for supplies, including low-voltage capacitors in their circuitry and maybe, just maybe, by getting the information out about one manufacturer's design problem, others will check their old devices as well.

So while blogs have been controvertial for their ability to spread news, good or bad, at lightning speed, the fact that they don't appear at first on the Nightly News or front page of major newspapers might just be a good thing while effectively communicating the issues to our patients (and other interested parties) without terrorizing the masses.

-Wes

A New Medtronic Defibrillator Advisory Issued Today

Today, an announcement was issued to doctors implanting Medtronic's Concerto and Virtuoso wireless implantable cardiac defibrillator's (ICDs) that a certain lot of 5,200 devices in the US of the total 158,000 implanted worldwide have demonstrated premature battery depletion due to a faulty battery capacitor containing porous copper. A total of 230 devices returned so far have demonstrated this problem. The capacitor was manufactured by an outside vendor, and more recent models of these devices manufactured reportedly no longer have this capacitor.

The notification is not a recall and does suggest any of the devices have failed and no deaths have been reported as a result of this notification. It is recommended that physicians continue the routine follow-up of these devices every three months and the patient alert feature be programmed "ON-High" for the Low Voltage Battery alert.

You can look up specific serial numbers of Concerto biventricular defibrillators(Model C154DWK) or Virtuoso DDDR defibrillators (Model D154AWG) models that might be affected at http://CVSNList.medtronic.com.

-Wes

Medtronic Issues New Pacemaker Advisory

Today, Medtronic began notifying physicians and patients about a new advisory (pdf) on some of their Kappa and Sigma series of pacemakers manufactured between 2000 and 2002. The defect stems from certain "voids" created in the solder joint where the attachments are made with the circuit board, causing them to fail over time. This loss of connection could lead to premature battery depletion, loss of rate response, loss of telemetry, or even no output.

Although these pacemakers were one of Medtronic's most popular pacemaker lines in early 2000-2004 with over 1.7 million devices implanted worldwide, it is estimated that only 36,900 remain actively implanted in patients. There have been two reported deaths that, while it is uncertain, may have stemmed from this problem.

According to the advisory letter, Medtronic has observed 285 Kappa devices and 131 Sigma devices affected by this issue, representing 0.49% of all Kappa devices and 0.88% of all Sigma devices implanted. It is estimated that the failure rates of Kappa pacemakers is 1.1% and Sigma pacemakers is 4.8% over the remaining lifetime of these pacemakers (the higher failure rate in the Sigma device because of its longer estimated longevity).

Physicians and patients can find if their particular device is affected by logging on to http://www.KappaSigmaSNList.medtronic.com to look up their specific serial number to see if it's affected by this advisory.

Also according to the letter, another subset of Kappa pacemakers involving an additional 96,000 devices might be affected by this defect, but at a much lower failure rate of 0.04% of the devices.

Physicians should consider replacing devices in pacemaker-dependent patients (those dependent on the device for their heart to beat). Further recommendations and information about the advisory can be found on the advisory letter issued today.

-Wes

The Challenge of Medical Device Advisories

It was a routine pacemaker implant yesterday. No big deal, really.

But there's always one point of a surgical procedure that grabs the doctor's gonads, and for device implants, it's usually gaining access to the blood vessel where the leads for a pacemaker or defibrillator are to be implanted. You see, poke too deeply, you might hit the patient's lung. Poke a half a centimeter higher toward the patient's head, you might hit the high-pressure artery rather than the low pressure vein and bleeding will compress the target vein, making it very difficult to cannulate. Don't poke deeply enough, you never get in the vessel. That's the way these procedures go. (I've already mentioned that I cheat and use a vascular ultrasound device to find the vessel. I mean, why stress, right?)

But yesterday, I encountered a "new" challenge: not being able to advance a guidewire into the vessel after I had entered it with a needle.

"What the....?" This was certainly not something I had encountered before. And that's when the rep who was in the lab said: "I wonder if that's one of those recalled SafeSheaths."

"What recalled SafeSheaths?"

"I'm not sure, but I think there was a problem that sometimes the needle hub was not aligned properly and people couldn't pass a guidewire into the vein."

"Seriously? Well that sucks," I said.

So I had to pull out the carefully placed needle and try a new one. Fortunately, the rest of the procedure went fine. But I stopped briefly later to see what existed on the Internet about this problem, and sure enough, I found this little pdf document about the problem posted way back in September, 2008. I was unaware of this problem.

I wonder, how many other advisories am I unaware of? What responsibility to distributors of medical products have to their customers? What responsibility to the manufacturers have? What did I miss?

Because all of the FDA warnings and advisories and recalls don't mean a thing if the information is not received by the end users. Unfortunately, I suspect this will always be a challenge, irrespective of the amount of money we pour into oversight bodies. Maybe, just maybe, placing information like this in the blog-o-sphere will help out another device implanter caught unaware.

-Wes

On Sprint Fidelis Lead Extraction

The New York Times published an article in their business section (interesting location to put such an article, but I digress) about extracting the Medtronic's advisory Sprint Fidelis defibrillator "cable" recently. (Note to their editors, it's actually a "defibrillator lead" containing multiple wires, not a "cable.") The article quotes some of the best and brightest in the lead extraction field - all of whom are truly experts at the task. It is interesting to note the differences in management style that these guys display: some (Wilkoff) would re-use the lead when it comes times for generator change, while others advise removing the lead at the time of a defibrillator generator (battery) change. There is little mention about placing a new lead next to the old one. Instead, the article suggests that "leaving it in place can make it more difficult to remove later, because of in-grown tissue."

No, that is not the reason to have the lead extracted. On the contrary, that's a reason to leave the lead in place so you can avoid the potential risk of tearing one of the great vessels and bleeding to death during the extraction procedure. After 6 months most of these leads have their "ingrowth" of tissue well-established. The "ingrowth" is not like a cancer that continues to grow. It can become more dense and even calcified over time, however, and the amount of ingrowth varies patient to patient.

Most experienced explanters look for certain characteristics on any lead that needs to be extracted to determine the potential difficulties they might encounter. Leads with more shocking coils are usually more difficult to extract because the coils often become adherent to tissue. Also, leads that passivly fix to the heart by scar formation tend to be harder to extract compared to those that actively screw into the heart muscle (and can have the screw retracted before removal). These are some of the bigger factors to explain why some of these leads come out more easily than others.

Admittedly, sometimes the lead must be extracted because the blood vessel into which the original lead was inserted became completely occluded and a new lead simply cannot be placed next to the old one without removing the old one first. Sometimes there's a desire not to implant a new device from the opposite chest area because of anatomic issues, like a prior mastectomy. Or maybe the lead has become infected, then it MUST be removed because, like a splinter festering in your foot, the infection will never resolve unless the lead is removed in its entirety. These reasons I'd buy as reasons to consider lead extraction. Also, patient preference of anxiety influences the decision to remove the lead, sometimes despite the doctor's best attempts at suggesting alternatives. There will always be a few of these.

But if it is at all possible to place a new lead at the time of battery change, that's seems like a reasonable compromise to me that avoids most future issues with the advisory lead. Certainly, Dr. Wilcoff thinks that the fracture rate is low enough that he'd just re-use it. While this conservative approach might make sense in most instances, is more difficult to justify when a patient is pacemaker-dependent and must have a normally functioning lead at all times for their heart to beat. In these cases, placement of a new lead, especially at the time of device battery change when the risk of infection is unavoidable, might warrant a more aggressive approach to avoid a potentially fatal complication should the lead later fracture. But what to do if the implant vessel is completely occluded and no room exists to place a new lead in such a pacemaker-dependent patient? This is where the toughest clinical issue lies: do you implant a whole new system from the contra-lateral side or just a pace-sense lead and then tunnel the lead to the same side as the others? Or do you extract the lead to make room for a new one? Given the risks involved with extraction, it's hard to know if the "cure" is worse than the disease.

What is certain is that patients with this lead should discuss all of these potential eventualities with their cardiologist or electrophysiololgist before any surgery takes place to develop a game plan should any of these challenges be encountered during routine device battery-change surgeries.

-Wes

Boston Scientific's New ICD's Have Glitch

Barely out of the starting block with their new model of implantable cardiac defibrillators, Boston Scientific issued an advisory (pdf) on their new line of COGNIS CRT-D and TELIGEN implantable cardiac defibrillators. TELIGEN ICD products, model numbers E102, E110, F102, F110 and COGNIS CRT-D products, model number N106, N107, N118, N119, P106, P107 are affected.

This line of ICD's has a sensor that detects the patient's respirations which can be programmed ON or OFF. This advisory only affects the devices with this respiratory sensor programmed ON. It seems at this setting, certain potential right ventricular lead complications such as chronic lead fracture and acute lead connection issues may cause additional oversensing, thereby increasing the probability of the device failing to pace appropriately or giving inappropriate shocks. The company recommends programming the sensor to OFF, thereby correcting the problem.

More information and links to Boston Scientific's physician letter can be obtained from the Heart Rhythm Society's website.

-Wes

Medtronic Updates Doctors on Sprint Fidelis Defibrillator Lead

In anticipation of an upcoming New York Times article to run this weekend, I just received my 'dear doctor' letter from Medtronic updating the status of their advisory Sprint Fidelis defibrillator lead. Reportedly, the NYT article will highlight a recently reported study published online before print from the medical journal Heart Rhythm that describes a higher-than anticipated failure rate from the lead. These data are in contrast to other published data assembled in Medtronic's 'Dear Doctor' letter.

While there is probably no larger cardiac device concern for electrophysiologists and their affected patients, Medtronic's disclosure with patient management recommendations based on Hauser's data and others before the release of the upcoming article in the New York Times is appreciated and should assist patients and doctors as they discuss their treatment options. Importantly, Medtronic points out:

"The FDA’s MAUDE database currently has 107 Medical Device Reports (MDRs) that include allegations that the Fidelis lead may have caused or contributed to a patient death. Most of these MDRs were not initiated by medical professionals; the majority were initiated by family members or attorneys with minimal supporting data. Medtronic’s Independent Physician Quality Panel has reviewed 89 of the 107 reports. It is not possible to determine cause of death with certainty. The Panel has identified 13 patient deaths in which a Sprint Fidelis lead fracture may have been a possible or likely contributing factor.

The Panel noted that four of the 13 deaths were associated with lead extraction, highlighting the risks associated with that procedure. With the exception of the appearance of deaths associated with lead extraction, no new or unexpected trends have been observed."

So we'll see that the news article says, but one thing's for sure...

...Monday should be interesting.

-Wes

Addendum:
NYT article 13 Mar 2009: "Medtronic Links Device for Heart to 13 Deaths"

Dr. Wes: Medtronic's Sprint Fidelis Performance Lead Update - May 13, 2008
Dr. Wes: Challenges With a Lead Recall - Oct 17, 2007
Dr. Wes: More on Medtronics Sprint Fidelis Advisory - Oct 15, 2007