Extraction of lumenless leads:
Extraction of chronically implanted lumenless leads poses other
challenges but are mitigated due to a smaller surface area compared to
standard leads. Several series have described extraction of these
leads[14, 15] . There are several differences in the design that
impact extraction. First, the fixation helix is designed to straighten
with modest force[11] . The rationale for the design of the fixation
helix that straightens out is that torque transmission to the tip may
vary depending on lead dwell time and patient response, potentially not
allowing to unscrew these leads. Attempts to unscrew chronically
implanted lumenless leads are likely to complicate extraction attempts
as the lead tip stays in place and torque may lead to bending or
intravascular loops.
Second, the central cable has considerable tensile strength, and it does
not elongate with traction as compared to traditional leads prepared
with locking stylets that can slip with high traction force. However,
caution needs to be taken when applying traction not to exceed the
tensile capability of the inner cable. If the conductor cable detaches
from the lead tip, the lumenless lead loses its tensile strength and the
coiled outer conductor will unravel[11]. This can make complete
system extraction difficult and require the use of femoral tools to
complete the extraction. Fortunately, in our experience, extraction
tools are generally not needed for removal of these leads unless they
have developed calcification. If calcification is present, or the lead
cannot be removed with gentle traction, the use of small diameter
cutting tools(laser or mechanical) is needed. Therefore, proper lead
preparation ensuring adequate engagement of the inner cable is required
to provide appropriate rail strength for extraction. If extraction tools
should be used, we cut the lead and expose the inner cable. After
folding the cable onto itself, a lead extender such as a BulldogĀ® device
(Cook Medical, Bloomington, IN ) can be applied. Alternatively, the lead
can be left intact and the silicone around the pin and ring can be
shaved off to allow an up-sized cutting sheath to pass over the intact
lead. However, this requires quite a miss-match between the 4.1 French
lead diameter and a 14 French extraction sheath. We feel that the lowest
risk approach is to use a smaller sheath and the traction device.
Clever techniques have been used with standard leads to maintain venous
access at the time of lead removal when the lead requiring modification
remains mobile, such as placing a wire under the outer insulation and
advancing the lead and wire into the vasculature[16]. This technique
will not work with the lumenless leads due to lack of a stylet to allow
for lead advancement. A method that has been successful for us is to
free the lumenless lead from the endocardium but letting it remain in
the heart. A snare is then advanced from the femoral vein and the lead
is grasped firmly. The lead (with the snare attached) is then removed
from the access site, externalizing the snare delivery catheter. The
lead can then be released, and the snare removed from its catheter,
which is now left entering the femoral vein and exiting the CIED venous
entry site. A stiff guidewire is then advanced through the catheter,
which is then removed, and the operator is left with a guidewire in
place for placement of a new lead. Due to the possibility of venous
stenosis along the course of prior leads we typically use a stiff
guidewire for this technique such as the Supra CoreĀ® wire (Abbott
Medical, Chicago, IL).