Medtronic CRM Product Performance Report

Advisories

6930, 6931, 6948, 6949 Sprint Fidelis Defibrillation Leads
Original Date of Advisory: October 2007

Potential Conductor Wire Fracture

Product

All Model 6930, 6931, 6948, and 6949 implantable defibrillation leads

Advisory

There are two primary locations where chronic conductor fractures have occurred on Sprint Fidelis leads: 1) the distal portion of the lead, affecting the anode (ring electrode) and 2) near the anchoring sleeve tie-down, predominantly affecting the cathode (helix tip electrode), and occasionally the high voltage conductor. These two locations account for approximately 90% of the chronic fractures identified in Returned Product Analysis (RPA). The remaining 10% of chronic fractures occurred in the DF-1 connector leg and the proximal portion of the RV coil. High voltage conductor fractures could result in the inability to deliver defibrillation therapy. Anode or cathode conductor fractures (at either location) may present clinically as increased impedance, oversensing, increased interval counts, multiple inappropriate shocks, and/or loss of pacing output.

Patient Management Recommendations

Medtronic recommends you consider the following as part of routine follow-up for each patient:

  • To reduce the risk of inappropriate detection and therapy due to oversensing, program VF detection for initial Number of Intervals to Detect (NID) to nominal settings 8/24) or longer at physician discretion and Redetect NID to nominal settings (12/16)
     
  • Turn ON Patient Alert for RV Pacing, RV Defibrillation, and SVC Defibrillation impedance. For Concerto, Virtuoso, Consulta, Secura and Maximo II devices enrolled on the Medtronic CareLink Network, turn ON the Medtronic CareAlert Notifications for these same parameters.
     
  • To optimize effectiveness of the lead impedance alert:
    • – Review V. Pacing Lead Performance Trend to determine typical chronic impedance value for the patient (typical values for Fidelis leads should be 350-1,000 ohms)
    • – Program lead impedance alert threshold for RV Pacing to 1,000 ohms, if the typical chronic impedance for the patient is ≤ 700 ohms, or
    • – Program lead impedance alert threshold for RV Pacing to 1,500 ohms, if the typical chronic impedance for the patient is > 700 ohms
    • – Program lead impedance alert threshold for RV Defibrillation and SVC Defibrillation to 100 ohms

Status Update

Sprint Fidelis lead performance continues to be in line with the information provided in the October 2007, May 2008 and March 2009 advisory communications. In consultation with the Independent Physician Quality Panel, our patient management recommendations are as follows:

  • When a lead fracture is suspected or confirmed, we strongly recommend prompt patient attention. Patients should contact their physician without delay if they experience unexpected shocks.
  • The Lead Integrity Alert (LIA†) is expected to provide 3 days advance notice prior to inappropriate therapy to 76% of the patients with lead fractures. As a result, we strongly recommend that all Sprint Fidelis patients who have the ability to upgrade to Lead Integrity Alert do so promptly.
  • The risk of prophylactic intervention appears to be greater than the risk of serious injury resulting from lead fracture even for pacemaker dependent patients, except in select individual patient circumstances as determined by the physician
  • Special circumstances may apply to device change-out or upgrade procedures when a lead fracture has not occurred. At least four options are available, each of which carries risks and benefits that should be taken into consideration:
    • – Leave a properly performing lead intact; this is likely to be the best choice for the majority of patients
    • – Place a new ICD lead without extraction of the existing lead
    • – Place a pace sense lead without the extraction of the existing lead. This option reflects the observation that approximately 90% of Fidelis failures are related to fractures in the pace sense circuit. It is unknown what the failure rate of the high voltage conductor would be should a pace sense conductor failure occur in the existing Sprint Fidelis lead.
    • – Unusual patient circumstances may warrant extracting and implanting a new ICD lead. Factors to consider when making this decision include patient life expectancy, age, and comorbidities, number of implanted leads and duration of implant, and patient preference. Medtronic’s Independent Physician Quality Panel recommends that if a lead requires removal, the procedure be performed by a physician with extensive lead extraction experience. (A new HRS consensus document on lead extraction is expected to be available in May 2009.)

Out of the initial implant population of 204,000 in the United States, approximately 150,100 remain implanted. According to System Longevity Study results, lead survival is estimated to be 93.6% (+2.1/ -3.1) at 48 months. As the implanted population ages and the sample size increases for each time interval, the accuracy of the estimated survival probability will increase as shown by tighter confidence intervals.

As part of our commitment to keep you informed about Sprint Fidelis lead performance, Medtronic publishes the quarterly System Longevity Study’s all-cause lead survival curve and the CareLink dataset lead survival curve for the Model 6949 lead at www.medtronic.com/fidelis. Semi-annual updates will also continue to be provided in the Product Performance Report. Additional information about the Sprint Fidelis lead is available at www.medtronic.com/fidelis.

Lead Integrity Alert†

Medtronic has released Lead Integrity Alert (LIA) software. LIA was designed to provide patients more advance notice via an audible sound of a potential lead fracture that could result in an unnecessary shock.

Data show that with LIA, approximately 76% of the patients with Sprint Fidelis leads are expected to receive 3 or more days advance warning of a potential lead fracture that could result in an unnecessary shock.

Upon hearing the alert, patients should contact their physician without delay.

LIA can be downloaded into nearly all Medtronic implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy defibrillators (CRT-Ds) implanted worldwide.

† LIA software released September 2008