May 16th, 2012

Robert Hauser, ICD Watchdog, Offers Viewpoint On Riata Controversy At HRS

The St. Jude Riata ICD lead controversy took center stage at last week’s Heart Rhythm Scientific Sessions in Boston, as previously reported here.  Near the end of the meeting a leading figure in the field, Dr. Robert Hauser, of the Minneapolis Heart Institute, summarized the current state of the Riata crisis and discussed its broader implications. Hauser has played key roles in the Riata and several other similar, highly disturbing cases, including those involving the Sprint Fidelis ICD leads and the Prizm 2 DR ICD device malfunction.

In a troubling revelation near the end of his talk, Hauser suggested that St. Jude’s problems may not end with the now discontinued Riata leads, and that the company’s Durata leads may have failure mechanisms not previously reported.

Hauser first discussed an abstract from Steinberg and associates from Quebec.  These investigators used chest x-rays rather than fluoroscopy to detect Riata externalizations:

They, like others, found a far higher incidence of externalized conductors than what has been reported by St. Jude Medical.  And frankly, this and other reports presented at this meeting raise serious questions about the accuracy of the data that the manufacturer has communicated to us.  What we learned today is that this externalized cable process is time dependent.  It seems to be occurring more frequently in the 1580 leads, particularly in the 8 French, and that with time we are going to see progression.  The fact that these investigators were able to use special chest radiographs to identify externalized conductors is interesting and deserves further study by comparing the sensitivity and specificity of their technique to high-resolution cine-flouroscopy

Hauser then discussed the Riata extraction experience from Royal Victoria Hospital in Belfast, and then offered some practical advice:

[these investigators] stunned us all last summer at the European Society of Cardiology in Paris with their report of a 15% incidence of Riata externalized cables.  Previously we saw them in isolated case reports.  We are certainly in their debt for this important communication.  Today, Dr. Rebecca Noad and colleagues reported their excellent results with extracting Riata and Riata ST leads with and without insulation breaches.  There was one complication, and that was a tear in the superior vena cava.  Everyone should take note that this patient survived that complication because the procedure was performed in the operating room with a surgeon immediately on standby.  Veteran extractors have emphasized the difficulties encountered in extracting Riata leads, particularly with externalized cables, with frequent need for 16 French sheaths, which we know increase procedural risk.  Importantly, these investigators point out that it may not be possible to pass a locking stylet beyond the insulation breach to the lead tip.  And we saw that the stylet actually provoked externalization of the cable.  Perhaps we should all be passing a stylet down a Riata lead at the time of PG change, even if the externalized cables are not visible on fluoroscopy.

Next up was the Danish Pacemaker Registry experience presented by Dr. Jens Johansen confirming, as have others, the inferior long term performance of ICD leads with small diameters (including Medtronic Sprint Fidelis and St. Jude Riata):

This finding raises the question:  can a small diameter lead be sufficiently robust to perform reliably over years of biologic exposure and mechanical stress in the human body?  Hopefully, small diameter leads like Riata ST Optim and Durata are up to the challenge and will do well.

Amplifying this theme was the experience from Dr. Rordorf and coworkers from Pavia, Italy again showing poor performance of thin ICD leads.  Hauser’s compelling conclusions followed:

Again this study poses the provocative question:  is it possible to produce a small diameter lead that is durable.  Presently we do not know the answer.  Perhaps we have pushed lead design to the limits of what can be accomplished with current designs and materials.  Maybe it is time for us to stick with what works.  We have defined acceptable lead performance as a lead that has a failure rate of 0.5% per year over 10 years.  Available leads appear capable of achieving this level of reliability.  Not perfect, but leads will never be perfect.  But is it good enough?  I say yes.  For the time being at least, until a new technology is proven in long-term clinical trials to be superior to the leads we are implanting today, we should stick with what we have.  This field needs to put the era of lead and pulse generator problems behind us.  Industry should stop innovating to gain market share, and innovate and focus on product reliability and longevity.  Remember the saying “the enemy of good enough is better.”

Hauser then summarized a talk by Dr. Mark Carlson, the Chief Medical Officer of St. Jude Medical, who presented the last study in the place of Dr. Steven Greenberg:

Unfortunately, Dr. Greenberg was unable to attend today, but St. Jude’s Dr. Carlson stood bravely in the breach (no pun intended) to describe the performance of St. Jude’s 3500+ Durata leads in its OPTIMUM registry.  Follow up was 2.4 years, and my only comment is that 2.4 years in my view is an early experience, not a mid-term experience.  The event free survival was >99%.  Excluding dislodgments and perforations, which may be operator dependent, there were only 5 lead mechanical problems, namely conductor fractures, in over 8400 implant years.   Now this is truly spectacular.  There were no inside-out insulation abrasions and no all-cause abrasions.  But I have to say, that the Durata leads that I have been looking at in the FDA’s MAUDE database must not have been included in this study. 

Although only hinted in the presentation quoted above, Hauser confirmed in the post session question and answer that he has submitted a manuscript for peer review on Durata failures in the MAUDE database.  He could not confirm the publication date, but implied that the paper would challenge St. Jude’s assertions about the reliability of the Durata lead. Wrapping up the session, Hauser circled back to challenge the cardiac device community to improve post market surveillance and prioritize safety:

A few closing comments:  We need good data for all life-saving and life-sustaining medical devices.  I believe that every pulse generator, every ICD pulse generator, and every lead should be registered and followed, at least annually.  We need to apply sophisticated techniques to these registries to uncover potentially defective devices before they are implanted in a large number of patients.  It is a goal we the caregivers should accept and drive toward.  Lastly, and perhaps most importantly, patient safety should become the overarching goal of this society.  Thank you.

Photo of Durata promotional truck at HRS courtesy of Dr. Wes


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