NATICK, Mass.-- The Heart Rhythm Journal recently reported a case
summary of a patient who had been implanted with a COGNIS cardiac
resynchronization therapy defibrillator. This device was implanted
subcutaneously (just under the skin). The article suggested a weakened bond
between the device case and header was responsible for abnormal sensing and
pacing behavior experienced by the patient.
Boston Scientific performed thorough laboratory
analysis of the explanted device involved in this case. Analysis results and
information regarding observations made during the initial implant procedure
conclude that the weakened header bond was not the cause of the abnormal
sensing and pacing behavior observed in this case study.
- X-ray and electrical testing
confirmed that the wires connecting the device header to the device case were
not damaged. - The seal between the header and
case was secure, with no evidence of body fluid under the header. - Observations of over-sensed,
abnormal signals (or “noise”) during the initial implant procedure were
lead-specific, indicating that the noise was lead-related rather than device
header-related. The leads, however, were not extracted, and analysis results
were therefore not available.
The authors state, “It is possible that the initial
noise observed …was due to a lead abnormality and not to the header
abnormality.” They acknowledge, “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.
Boston Scientific carefully considers every adverse
event and is committed to rigorous monitoring and transparent communication of
product performance. Our quarterly Product Performance Report (PPR) is
available online at www.bostonscientific.com
and provides detailed worldwide confirmed malfunction information.
Two previous weakened header bond instances within
the subcutaneously implanted patient population are reported in our Q1 2010
PPR. These reports were previously reviewed with our independent patient
safety advisory board, and were discussed with the FDA. The most recent case
will be published in next quarter’s PPR. Including this most recent case, a
total of three (3) instances of weakened header bonds have been observed in a
context of more than 90,000 COGNIS® and TELIGEN® devices
implanted subcutaneously. The overall rate of events for this device family
compares favorably to the performance of similar devices.
We have implemented manufacturing process
improvements to strengthen the header bond on these devices, enabling
physicians to position devices in a subcutaneous or sub-pectoral (under the
chest muscle) 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.
Our Patient Advocacy & Education and Patient
Services teams are happy to support you and your organization with any
questions or concerns you may have. Patients are welcome to contact our Patient
Services team by calling 1.866.484.3268 and pressing “2” when prompted.
Boston Scientific is a worldwide developer, manufacturer and marketer
of medical devices whose products are used in a broad range of
interventional medical specialties. For more information, please
visit: www.bostonscientific.com.
SOURCE: Boston Scientific