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).