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.