Comparison of a guidewire with an uninsulated tip versus dedicated radiofrequency wire with discrete electrode for energy-based transseptal puncture: a pre-clinical study.

Background: Dedicated radiofrequency (RF) needles and wires for transseptal puncture (TSP) achieve better outcomes vs. electrified open-ended needles and guidewires due to optimized electrode design and energy delivery. This study benchmarked TSP performance between the dedicated VersaCross wire system (VC; Boston Scientific) and an electrified guidewire with an alternative electrode configuration similar to commercially available devices.

Methods: A 0.025″ guidewire (Cordis) was modified to mimic the 15 cm 0.025″ distal uninsulated wire length of the HOTWIRE (Atraverse) device and electrified using a ValleyLab generator (EG; 30-50 W, 1 s and 300 ms). EG was extended 0-3.5 mm from the dilator tip to mimic clinical use. RF puncture using VC and EG was performed on ex vivo porcine septa (n = 18) and in vivo swine heart (n = 3), to compare TSP performance, thermal damage and energy output measured using an oscilloscope.

Results: Ex vivo, VC had 100% TSP success with 1 attempt using 1 s (constant) and 300 ms (pulse) modes; EG demonstrated higher failure rates and less consistency at 30 W (78%) and 40 W (88%), requiring more RF applications, longer duration and energy output. EG crossings ex vivo and in vivo showed thermal damage on septa and device charring along the uninsulated distal end, unlike VC. Successful TSP with EG (1 s, 30-50 W) in vivo demonstrated wire charring and thrombus along the uninsulated wire length within the dilator.

Conclusion: Manual protrusion of a wire with a long uninsulated length can be difficult to control in a clinical setting, thus, introducing variability, excess energy, and risk of thermal injury and thrombus formation. A purpose-built electrode and dedicated generator optimize RF delivery for efficient and safe TSP.