Comparative hemolysis profiles between systems in pulsed-field ablation

Pulsed-field ablation (PFA) is an emerging technology for catheter ablation in atrial fibrillation. Unlike conventional thermal ablation techniques, PFA is associated with a lower risk of complications such as esophageal injury, phrenic nerve palsy and pulmonary vein stenosis.1) However, PFA-specific complications, including hemolysis, have been reported. 2)Given differences in voltage settings and device design, the degree of hemolysis may vary between PFA systems, but this variability remains unclear.

This study aimed to compare hemolysis following ablation with the Pulse Select™ (Medtronic) and FARAPULSE™ (Boston Scientific) PFA systems.

Patients with paroxysmal or persistent atrial fibrillation who underwent primary catheter ablation using either the Pulse Select™ or FARAPULSE™ PFA system at Osaka Rosai Hospital between October 2024 and January 2025 were included. Hemolysis was assessed by measuring serum haptoglobin levels preoperatively, immediately postoperatively, and on postoperative days 1 and 2. The change in haptoglobin from baseline (Δ-haptoglobin) was calculated, and comparisons between the two groups were performed at each time point.

A total of 100 patients (75 ± 9 years, 43 women) were included, with 75 undergoing ablation using Pulse Select™ and 25 using FARAPULSE™. The number of applications did not differ significantly between the two groups (FARAPULSE™: 40 ± 10 applications; Pulse Select™: 39 ± 7 applications). In both groups, Δ-haptoglobin was significantly greater (indicating a decrease) on postoperative day 1 compared to baseline (Pulse Select™, p<0.0001; FARAPULSE™, p<0.0001), with a significantly greater reduction observed in the FARAPULSE™ group (p=0.017). By postoperative day 2, haptoglobin levels had recovered. Transient acute kidney injury (AKI) corresponding to stage 1 of the KDIGO classification was observed in 10 patients, but renal function subsequently improved, with no significant difference between the groups. No cases of prolonged hospitalization due to anemia progression or worsening renal function were observed in either group.

Hemolysis, as indicated by a reduction in haptoglobin, was significantly greater on postoperative day 1 in patients treated with FARAPULSE™ compared to those treated with Pulse Select™. However, haptoglobin levels recovered by postoperative day 2, and no adverse impact on clinical outcomes was observed.

Baseline characteristics