Pacemaker Lead Recall
April 1, 2012 4 minutes read
Pacemaker Lead Recall
Abstract & Commentary
By John P. DiMarco, MD, PhD, Professor of Medicine, Division of Cardiology, University of Virginia, Charlottesville. Dr. DiMarco does research for Medtronic, is a consultant for Medtronic, Novartis, and St. Jude, and is a speaker for Boston Scientific.
Source: Birnie DH, et al. Clinical predictors of fidelis lead fracture: A report from the Canadian Heart Rhythm Society device committee. Circulation 2012;125:1217-1225.
This report from a consortium of Canadian implantable cardioverter-defibrillator (ICD) implantation centers analyzed predictors of failure of the Medtronic Sprint Fidelis lead. The Canadian Heart Rhythm Society Device Committee collected data from 23 adult Canadian ICD implant centers. For this report, the failure rate for the Medtronic Sprint Fidelis lead was calculated for each center and data from the median center and five low and high failure rate centers were analyzed. These data included clinical and device interrogation data from the ICD databases at each site and from local clinical records. Items analyzed included demographics, lead model, failure mechanisms, and potential clinical predictors of failure including age, number of additional leads, prior device procedures, implant vein, ejection fraction, and type of underlying heart disease. Lead failure was defined as an abrupt rise in chronic pacing or defibrillation impedance or signal noise on the rate sensing circuit electrogram. Cases of failure not related to lead malfunction were not included. The clinical predictors of lead failure were assessed using a Cox Proportional Hazard model.
There were 3169 Fidelis leads included in this survey. The largest group was dual coil active fixation leads (model 6949) but smaller numbers of other Fidelity leads were also included. The median follow-up duration was 3.4 years. The patient group was 82% male with a mean age of 62.8 years. During follow-up, 16.5% of the patients died, 6.4% of the leads were electively replaced, and 2.2% were removed from service for reasons other than failure (cardiac transplantation or systemic infection). A total of 251 Fidelis lead failures were observed. The failure rates at 1-, 2-, 3-, 4-, and 5-year time points were 0.2%, 2.1%, 5.3%, 10.6%, and 16.8%, respectively. Most failures (92%) were in the rate/sense circuit with 8% in the high voltage circuit. The highest failure rate was seen with single coil active fixation lead (model 6931) and the lowest failure rate was seen with model 6948 dual coil passive fixation leads. Analysis of the lead survival curves showed that the failure rate increased significantly with time. Patients with ICDs that had been uploaded with a lead integrity alert system were less likely to receive inappropriate shocks but among those with inappropriate shocks, the number of shocks was not changed. In addition to lead type, three other independent predictors of failure were identified: female gender, access vein, and center. The hazard ratio for females was 1.51. Access using a site other than the cephalic vein resulted in hazard ratios of 1.94 for the axillary vein and 1.63 for the cephalic vein. An additional risk factor for failure was if the Fidelis lead was inserted as a replacement lead as opposed to an initial implant. The hazard ratio for these leads was 3.12. If the failure rate continues as predicted by the survival curves, the authors estimate that 23% of leads with normal function 5 years post implant will fail over the next 5 years.
The authors conclude that lead replacement should be strongly considered at the time of their next elective generator change in patients with Fidelis leads in place.
Commentary
It is now well recognized that there is a substantial risk for complications associated with repeat device procedures. When lead failure rates are low, most authorities recommend a conservative lead management approach with lead extraction and/or replacement only when electrical problems are confirmed. However, when the pocket must be reopened for a generator change, the risk:benefit equation for changing the lead may shift toward benefit if the risk for lead failure is high. The data presented here suggest that doctors should strongly consider replacing Fidelis leads at the time of elective generator changes if the change can be accomplished without markedly increasing the procedure risk.
The current recommendations on the Medtronic Fidelis site are listed below.
In the event of a device change out or upgrade procedure, with no manifestation of lead fracture, consider the patient age and lead model data above, as well as patient life expectancy, comorbidities, ease of extraction related to implant time, patient preference, etc., for the following options:
Leave a properly performing lead intact.
Implant a new ICD lead without extraction of the existing lead.
Carefully consider all factors before prophylactic placement of a pace- sense lead given the data in Table 1, which shows an increased risk of high voltage conductor fracture if a pace-sense conductor fracture has previously occurred.
Individual patient circumstances may warrant extracting and implanting a new ICD lead. If warranted, Medtronic's Independent Physician Quality Panel recommends the lead extraction procedure be performed by a physician with extensive lead extraction experience.1
Thus, the weight of evidence may be tilting toward a more aggressive approach to lead replacement.
Reference
1. Medtronic Dear Doctor Letter. Sprint Fidelis® Lead Patient Management Recommendations Update Models 6949, 6948, 6931, 6930. April 2011. www.medtronic.com/product-advisories/physician/sprint-fidelis/PHYSLETTER-2011-04. Accessed March 12, 2012.
This report from a consortium of Canadian implantable cardioverter-defibrillator (ICD) implantation centers analyzed predictors of failure of the Medtronic Sprint Fidelis lead.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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