An Ex Vivo Evaluation of Air Intrusion Into Pulsed Field Ablation Sheaths During Ablation and Mapping Catheter Insertion

Abstract

Introduction: Pulsed field ablation (PFA) is the newest ablation technology, and currently, no data exist on the amount of air intrusion into new, large bore PFA sheaths during ablation or mapping catheter insertion.

Methods: An ex vivo study was performed using various combinations of commercially available PFA ablation catheters and sheaths. Common mapping catheters and a non-PFA steerable sheath were also evaluated as a reference. The siphon principle was used to create negative pressure to simulate left atrial pressure during spontaneous inspiration. Ablation and mapping catheters were advanced to the end of the sheaths under negative pressure and then removed. Air was withdrawn from the sheaths and was measured in milliliters (mL).

Results: A total of 55 trials were performed. The average volume of air intrusion with all sheath/catheter combinations was 9.6 + 5.2 mL. The 13 Fr (inner diameter) Faradrive sheath (Boston Scientific Inc.) entrained significantly more air (16.5 + 4.1 mL) compared with the 12 Fr FlexCath Contour sheath (Medtronic Inc.) (6.1 + 2.7 mL, p < 0.01), 13 Fr Agilis NxT sheath (Abbott Inc.) (8.7 + 1.8 mL, p < 0.01), and Vizigo sheath (Johnson & Johnson MedTech Inc.) (5.8 + 2.1 mL, p < 0.01), regardless of the catheter used. There was significantly higher volume of air intrusion with the Farawave ablation catheter through the Faradrive sheath (13.6 + 2.0 mL) than through the 13 Fr Agilis (9.4 + 2.1 mL, p = 0.03) or the PulseSelect through FlexCath Contour sheath (4.0 + 2.7 mL, p < 0.01). Mapping catheters entrained significantly more air than ablation catheters in both the Faradrive (18.0 ± 4.1 mL vs. 13.6 ± 4.1 mL, p = 0.04) and the FlexCath Contour (7.1 ± 2.2 mL vs. 4.0 ± 2.7 mL, p = 0.03).

Conclusion: Using a model that simulates left atrial PFA in spontaneously breathing patients, a large volume of air intrusion was observed during insertion and removal of ablation and mapping catheters into new, large bore PFA sheaths. New sheath designs are needed to minimize air intrusion during catheter exchanges to avoid air embolism when performing PFA using left atrial delivery sheaths.

Keywords: air embolism; air intrusion; atrial fibrillation; pulsed field ablation; sheath management.

Figure 1

Illustration of experimental design. (A) The height from the water surface to the bottom of the steerable sheath, which corresponded to 272 mm to create a negative pressure of −20 mmHg. (B) A mapping or ablation catheter was inserted into the sheath, advanced to the end, and removed. Air was then withdrawn from the sidearm of the sheath. The type of catheter was changed, and the process was repeated. mm, millimeter; Hg, mercury.

Figure 2

Box plots comparing average air intrusion volumes by sheath, including all catheters tested. Each box plot represents the distribution of air intrusion volumes associated with a specific sheath, incorporating data from both mapping and ablation catheters. The highest average volume of air intrusion was seen with the Faradrive and was significantly higher than the 13 Fr Agilis NxT, FlexCath Contour, and Vizigo. Fr, French; ns, nonsignificant.

Figure 3

Box plots comparing average air intrusion volumes by PFA ablation system. A PFA ablation system includes a specific manufacturer's PFA catheter and PFA sheath combination. Each box plot represents the distribution of air intrusion volumes associated with a specific ablation system. Air intrusion was significantly higher when inserting the Farawave in the Faradrive sheath compared with inserting the Farawave in the 13 Fr Agilis NxT or the PulseSelect ablation catheter through the Medtronic FlexCath Contour. Fr, French; FW, Farawave; PS, PulseSelect.

Figure 4

Box plots showing average air intrusion in each PFA sheath comparing mapping catheter to ablation catheter insertion. (A) Boston Scientific Faradrive. (B) Abbott 13 Fr Agilis NxT. (C) Medtronic FlexCath Contour. Each box plot represents the distribution of air intrusion volumes associated with an ablation or mapping catheter inserted into a specific sheath. A significantly higher volume of air intrusion was seen with mapping catheters compared with ablation catheters in both the Boston Scientific Faradrive and Medtronic FlexCath Contour sheaths. Fr, French; ns, nonsignificant.

Figure 5

Sheath hemostatic valve opening designs. Each sheath has a unique hemostatic valve opening design that may contribute to differences in air intrusion. (A) Boston Scientific Faradrive has a cat‐eye opening. (B) Medtronic FlexCath Contour has an asterisk‐like opening. (C) Johnson & Johnson Medtech Vizigo has an asterisk‐like opening. (D) Abbott 13 Fr Agilis NxT has a round, recessed opening.