Pulsed Field Ablation–Related Hemolysis: Comparison Between Technologies

BACKGROUND: Hemolysis is a recognized side effect of pulsed field ablation (PFA). Severe hemolysis can lead to acute kidney injury, affecting the morbidity of patients undergoing PFA for atrial fibrillation. Here, we aimed to characterize the degree of hemolysis across different PFA technologies. METHODS: This is a retrospective cohort study of 552 PFA procedures performed in our center, where Hp (haptoglobin) was measured both at baseline and on postoperative day 1. The PFA catheters used were Farawave (59%), Sphere-9 (19%), Pulseselect (16%), and Varipulse (5.8%). RESULTS: Hemolysis (ie, reduction in Hp >10 mg/dL) was observed in the majority of cases (95%), with the lowest incidence observed in patients undergoing PFA with Sphere-9 (88%) compared with Farawave (97%), Varipulse (97%), and Pulseselect (100%). Significant and severe hemolysis (ie, Hp–postoperative day 1 ≤25 mg/mL and Hp–postoperative day 1 ≤10 mg/mL) occurred in 34% and 13%, with a different distribution across catheter types: Farawave 46% and 21%, Varipulse 29% and 9.7%, Pulseselect 23% and 1.2%, and Sphere-9 5.5% and 0%. Hp decreased by a mean of 76±40 mg/dL from baseline, with a significantly greater degree of reduction seen with Farawave (94±40 mg/dL) and Varipulse (85±32 mg/dL) compared with Pulseselect (62±25 mg/dL) or Sphere-9 (39±23 mg/dL). There is a linear relationship between Hp reduction and number of PFA applications, with a decrease of Hp per application of 0.47 mg/dL (95% CI, 0.22–0.71 mg/dL) for Farawave, 0.40 mg/dL (95% CI, 0.09–0.73 mg/dL) for Pulseselect, and 0.10 mg/dL (95% CI, 0.02–0.19 mg/dL) for Sphere-9. CONCLUSIONS: PFA-induced hemolysis is common, with different PFA technologies exhibiting variable degrees of hemolysis, lower with the focal PFA catheter Sphere-9 when compared with single-shot PFA catheters.