Medtronic CRM Product Performance Report

Advisories

4012 Target Tip Ventricular Lead
Original Date of Advisory: September 26, 1991

Lead Survival Below Expectations

Product

All Model 4012 implantable pacing leads

Advisory

Lead survival probability beyond 5 years is below expectations due primarily to polyurethane insulation failure (due to ESC and/or MIO) and conductor fracture (associated with “subclavian crush”).

Patient Management Recommendations

Consider increasing frequency of monitoring (e.g., from quarterly to bimonthly or monthly). Consider the following activities as part of normal follow-up procedures:

  • Monitor for significant changes in impedance, which could be an indication of impending failure (pulse generator must have impedance telemetry capabilities)
  • Review patient ECGs carefully for indications of transient sensing and/or capture abnormalities. This can be done using transtelephonic or in-clinic monitoring and/or using ambulatory monitoring.
  • Elicit any patient complaints suggestive of lead failure and investigate thoroughly lead integrity/ performance characteristics following reports of patient complaints or symptoms using the above techniques
  • Consider whether prophylactic replacement would be appropriate in patients at high risk, such as pacemaker dependent patients
  • Evaluate carefully the integrity of the lead during routine pulse generator replacement before choosing to reuse. Specifically, Medtronic recommends placement of a new lead if:
    • – Insulation breaches are observed
    • – Lead impedance is less than 300 ohms or has decreased by more than 30% from implant values
    • – Electrical properties such as impedance and threshold vary significantly when multiple readings are taken

As always, medical judgment must be used to establish the appropriate schedule and course of care for every individual, particularly pacemaker dependent or other patients at higher risk.

Status

Patient management recommendations remain unchanged. Laboratory analysis trends and engineering conclusions remain unchanged. Out of the initial implant population of 96,800 in the United States, approximately 6,500 remain implanted. The System Longevity Study results show 62.2% lead survival at 15 years, 9 months.