Characterization of successful transseptal access with an electrified guidewire: An ex vivo ovine study
S Pattu Valappil, D Chapman, A Puvrez, A Pina, J Ariyaratnam, A Elliott, E Shahmohamadi, S J Tu, N Weerasooriya, P Sanders, A Ganesan, C X WongAbstract
Background
The determinants of successful transeptal puncture (TSP) using an electrified guidewire (ETSP) have not been studied.
Purpose
We used an ex-vivo ovine model to identify the determinants for successful ETSP.
Methods
Twenty-five fresh ex-vivo ovine hearts were dissected, and lateral right atrial/appendage tissue was excised to create an interatrial septum (IAS) model. The sheath and guidewire were fixed to a custom-made jig which allowed linear displacement to model clinical catheter manipulation (displacement) of the IAS model. We observed TSP at different amounts of IAS-displacement (0mm, 5mm, 10mm, 15mm) using differing degrees of guidewire tip protrusion (1mm, 3mm, 5mm). Electrocautery was applied to the proximal end of the guidewire at 15W in the ‘Coag’ mode for 2 seconds to attempt ETSP. The thermal profiles of the various configurations during electrification were studied using thermal imaging. Finally, thermal assessment of ETSP was studied comparing two common waveforms (‘Coag’ and ‘Cut’) at 15W.
Results
A total of 58 ETSP runs were performed. The model with 1mm of wire protrusion and IAS-displacement of 10mm yielded a probability of 100% to achieve TSP. Extended guidewire protrusion (3mm & 5mm) and no IAS displacement resulted in unsuccessful puncture and increased the risk of high tissue temperatures and larger thermal lesions. The ‘Coag’ waveform produced lower peak temperature (34.36±3.17℃ vs 68.6±3.7℃ , p<0.0001) and smaller thermal footprint (2.9±0.2mm vs 5.1±0.2mm , p<0.0001) while maintaining perforation success compared to the ‘Cut’ waveform.
Conclusion
Displacement of the IAS is required for successful ETSP.Guidewire protrusion beyond 1mm resulted in inconsistent perforation and increased tissue temperature.Graphical abstractPredicted Probabaility of TSP success