Peri-Procedural Intravascular Hemolysis during Atrial Fibrillation Ablation: A Comparison of Pulsed Field with Radiofrequency Ablation

Background Hemolysis-related renal failure has been described after pulmonary vein isolation (PVI) with pulsed field ablation (PFA). Objective To compare the potential for hemolysis during PVI with PFA versus radiofrequency ablation (RFA). Methods In consecutive patients, PVI was performed with PFA or RFA. Blood samples were drawn at baseline, immediately post-ablation, and 24 hours post-ablation. Using flow cytometry, the concentration of red blood cell microparticles (RBCμ, fragments of damaged erythrocytes) in blood was also assessed. Lactate-dehydrogenase (LDH), haptoglobin and indirect bilirubin were measured at baseline and 24 hours. Results Seventy patients (age 64.7+10.2, 47% women, 36 [51.4%] paroxysmal atrial fibrillation) were enrolled, 47 patients in the PFA group (22 PVI-only, 36.4+5.5 PF applications and 25 PVI-plus, 67.3+12.4 PF applications), and 23 patients underwent RFA. Compared to baseline, the RBCμ concentration increased ∼12-fold post-ablation, and returned to baseline by 24 h in the PFA group (median and interquartile range: 70.8 [51.8-102.5] vs. 846.6 [639.2-1,215.5] vs. 59.3 [42.9-86.5] RBCμ/μL, p<0.001); this increase was greater with PVI-plus compared to PVI-only (p=0.007). There was also a significant, albeit substantially smaller, peri-procedural increase in RBCμ with RFA (77.7 [39.2-92.0] vs. 149.6 [106.6-180.8] vs. 89.0 [61.2-123.4] RBCμ/μL, p<0.001). At 24 h with PFA, the concentration of LDH and indirect bilirubin increased, while haptoglobin decreased significantly (all p<0.001). In contrast, with RFA, there were only smaller changes in LDH and haptoglobin concentrations (p=0.03), and no change in bilirubin. Conclusion PFA was associated with significant peri-procedural hemolysis. With a number of 70 PFA lesions, the likelihood of significant renal injury is uncommon