CardioBrief

Updated with remarks from William Maisel and a statement from Boston Scientific– A case of a weakened bond between the header and case of a subcutaneously implanted Cognis CRT-D is raising new concerns about the Boston Scientific Cognis and Teligen ICDs. Last December Boston Scientific issued a product advisory based on two cases of a weakened header bond in ICDs that had been implanted subpectorally. Subpectoral implants account for approximately 5% of procedures, according to the company. Now, with the report of a weakened header bond in a Cognis ICD that had been implanted subcutaneously, concerns are being raised about a much larger number of devices that have already been implanted.

In the manuscript for an article that has been accepted for publication in Heart Rhythm (but has not yet been edited), JJ Germano, an electrophysiologist at Winthrop-University Hospital in Mineola, NY, Alicia Darge (RPA-C), and William Maisel (Beth Israel Deaconess Medical Center) report the case of a patient with a subcutaneously implanted Cognis CRT-D who “experienced a weakened bond between the device header and case resulting in noise and inappropriate therapies.” The patient eventually had his device replaced.

Wells Fargo analyst Larry Biegelsen observed that these cases may be the tip of a larger iceberg, since the Cognis and Teligen are new devices launched in 2008 that won’t be replaced for several years, and because the publicity for the case may lead to the identification of additional cases. He also noted that the issue “could negatively impact” the company’s reputation because it “represents the third issue with Cognis and Teligen (set screws, respiratory sensor, header bond).”

Boston Scientific said it has improved its manufacturing process of the devices. The company said it will provide CardioBrief with a statement later in the day. (Look for an update of this story later today.) CardioBrief has also requested comments from Germano and Maisel.

Electrophysiologist Westby Fisher (author of the Dr Wes blog) reminded CardioBrief that “a single case does not a recall make,” but agreed that the issue “warrants careful follow-up and might affect implant choice going forward.”

3:20 PM Update:

William Maisel told CardioBrief that he has learned that “Boston Scientific has received reports of at least two other header problems in patients located in a subcutaneous location” and that the company has submitted an application to the FDA for changes to the header.

3:40 PM Update:

Boston Scientific sent the following statement to CardioBrief:

Boston Scientific statement in response to Cognis article in HeartRhythm

February 8, 2010

We are disappointed the manuscript was accepted without any detailed engineering analysis of the explanted device. Boston Scientific’s laboratory analysis found that while the bond between the header and the case was weakened, the explanted device functioned appropriately. We have concluded that the weakened header bond was not the cause of the abnormal sensing and pacing impedance observed in this patient.

X-ray analysis and electrical testing verified that the header wires were neither fractured nor otherwise damaged. The medical adhesive seal between the header and the titanium case was secure with no evidence of body fluid under the device header. With no damage to feedthrough wires and no conductive fluid pathway between the wires and body tissue, there is no mechanism to link the noise observations to the weakened header bond.

Noise observations during the initial implant were lead-specific, indicating that the noise was lead-related rather than header-related.  In fact, the authors state: “It is possible that the initial noise observed on the RV pace/sense channel was due to an RV lead abnormality and not to the header abnormality.”  They acknowledge that: “Without lead extraction and analysis, we cannot completely exclude lead fracture as the cause of oversensing.”  None of the leads implanted in the patient were manufactured by Boston Scientific.

We are committed to rigorous monitoring and transparent communication of product performance through the publication of our quarterly Product Performance Reports. Two previous weakened header bond events within the subcutaneous population are included in our Product Performance Report scheduled for publication this week, and they were previously reviewed with our independent patient safety advisory board and discussed with the FDA.  The most recent case will be published in next quarter’s report.  Including this most recent case, three instances of weakened header bonds have been observed in a context of more than 90,000 COGNIS and TELIGEN devices implanted subcutaneously. While Boston Scientific carefully considers every adverse event, the overall rate of events for this device family compares favorably to the performance of similar devices.

The Company has implemented manufacturing process improvements to strengthen the header bond on these devices, allowing physicians to position devices in a subpectoral or subcutaneous position.  We have received approval from U.S. and European regulatory authorities for the devices with the strengthened header bond and expect to complete the transition to these devices in both markets by next month.

6:45 PM Update:

William Maisel sent the following statement in response to the above statement from Boston Scientific:

As noted in the article, this patient had an ICD with a weakened header bond confirmed by the manufacturer. The clinical abnormalities disappeared as soon as the ICD was replaced and have not recurred. Clearly there was a problem with the Boston Scientific device. Boston Scientific’s bench testing failed to detect weakened header bonds in the first place. Their subsequent testing failed to explain the observed device abnormalities suggesting their test methodology may be insensitive.

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