The Use of Leadless Pacemakers in Infected Patients:
The authors present an interesting report of the use of a leadless pacemaker in patients who have a need for continued pacing support and have had an extraction due to infection. While this concept has been previously described by others [2-4], this report provides further data to support the efficacy of this approach and provides for longer duration follow-up. The studied patient group is diverse with some patients having simple device pocket infections and others having complex lead-associated endocarditis. Likewise, the patients were treated differently with respect to the timing of leadless pacemaker implantation. Just under half were implanted as part of the extraction procedure and the rest were implanted soon thereafter. In follow-up there were no device related infections. [3-5]
Growing evidence supports the use of leadless pacemaker implantation in patients with high risk of infection recurrence. In addition to eliminating the device pocket, a leadless pacemaker has several inherent design features that make it resistant to infection. First, the intravascular surface area of the device is quite small as compared to a traditional transvenous pacemaker. In fact, most of the time the current Medtronic leadless pacemaker is buried deeply in the trabecula with very little device exposure to the blood pool. Secondly, it seems obvious that in many cases the course of the lead may be involved in the infection. This may include cardiac valves, as well as the fibrous tissue tract along the lead body. If that is the case, any new device, be it permanent or temporary, will be in contact with this potentially infected tissue. Thirdly, the Medtronic leadless pacemaker described in this report is almost entirely covered by parylene, a material that has been demonstrated to inhibit biofilm formation and should reduce device-associated infections[6].
In the more than 2500 patients enrolled in the Micra Transcatheter Pacemaker System pivotal and post approval studies [7, 8], there were no device-associated infection reports and no leadless pacemakers required extraction due to a reported infection. The post-approval study included a subset of patients considered at high risk for infection, including patients in whom transvenous device implantation was precluded due to previous infection, need for dialysis or cancer (22.4%). Rare case reports have been reported in the literature documenting Micra device removal for infection; however, the infection rate remains orders of magnitude lower than traditional transvenous systems. While utilization of a leadless pacemaker provides an attractive alternative to a transvenous system in patients with a recent CIED infection, only retrospective data on a limited sample size are descried evaluating Micra implantation concomitant with CIED extraction.