Impact of pulsed-field ablation on kidney function

Abstract Introduction Real world evidence shows that heme mediated acute kidney injury (AKI) is a potential complication of pulsed-field ablation (PFA) for atrial fibrillation (AF) through associated hemolysis. Purpose The degree and timing of changes in kidney function following PFA in routine clinical practice with peri-procedural hydration is not established. We therefore conducted an observational study to prove renal safety of PF with peri-procedural hydration. Methods AF patients indicated for PFA were enrolled. Patients received peri-procedural hydration per institutional protocol. Blood sampling and urinalysis was performed at baseline, 24h and 48h (and later, if indicated) after the procedure. Serum creatinine, cystatin c and urinary erythrocyte concentrations were analyzed. Results Samples at baseline and 24h were obtained from 76 patients (26 [34%] women, mean age 64 ± 9.6 years, 42 [55.3%] paroxysmal AF). Creatinine samples at 48h were available in 45 [59.2%] patients. The median number of PF pulses was 64 (IQR: 40-76). At 24 hours, median urinary erythrocyte concentrations increased significantly (4 [IQR 2-9] erythrocytes/µL vs. 11.5 [IQR: 4-50.5] erythrocytes/µL; p=0.001). There was no significant change in the median concentrations of cystatin C (0.98 [IQR: 0.85-1.16] mg/L vs. 0.98 [IQR: 0.86-1.11] mg/L). The median serum concentration of creatinine decreased significantly at 24h (86.5 [IQR: 73-100] µmol/L vs. 83.5 [IQR: 66-95] µmol/L; p=0.001), the change from baseline to 48h was not significant (87.0 [IQR: 72-100] µmol/L vs. 83.0 [IQR: 72-100] µmol/L; p=0.98). Significant and clinically relevant increases in serum creatinine meeting AKI criteria were present in 8 patients (10.5%); 4 of these patients met AKI criteria only 48h post-procedure. All changes in renal functions were transient and the creatinine values returned to baseline values within days after PFA without the need for hospitalization. Changes in creatinine and cystatin c values were not significantly correlated with the number of PF applications. The changes in urinary erythrocyte concentrations was not significantly correlated to changes in creatinine nor cystatin C (p>0.05). Conclusion Routine pulsed field ablation with peri-procedural hydration with an average number of 64 PF pulses in patients without significant preexisting renal disease is safe, and the chance for clinically relevant renal impairment is low. However, follow-up testing of kidney function is warranted and blood sampling at more than 24h may be reasonable. The slight decrease in serum creatinine post-procedure may be attributed to periprocedural hydration or sinus rhythm restoration. Research aimed at distinguishing patients at higher risk of periprocedural AKI is warranted.