Periprocedural 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). OBJECTIVES: This study sought to compare the potential for hemolysis during PVI with PFA vs radiofrequency ablation (RFA). METHODS: In consecutive patients, PVI was performed with PFA or RFA. Blood samples were drawn at baseline, immediately postablation, and 24 hours postablation. Using flow cytometry, the concentration of red blood cell microparticles (RBCµ) (fragments of damaged erythrocytes) in blood was assessed. Lactate dehydrogenase (LDH), haptoglobin, and indirect bilirubin were measured at baseline and 24 hours. RESULTS: Seventy patients (age: 64.7 ± 10.2 years; 47% women; 36 [51.4%] paroxysmal atrial fibrillation) were enrolled: 47 patients were in the PFA group (22 PVI-only and 36.4 ± 5.5 PFA applications; 25 PVI-plus, 67.3 ± 12.4 pulsed field energy applications), and 23 patients underwent RFA. Compared to baseline, the RBCµ concentration increased ∼12-fold postablation and returned to baseline by 24 hours in the PFA group (median: 70.8 [Q1-Q3: 51.8-102.5] vs 846.6 [Q1-Q3: 639.2-1,215.5] vs 59.3 [Q1-Q3: 42.9-86.5] RBCµ/µL, respectively; 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, periprocedural increase in RBCµ with RFA (77.7 [Q1-Q3: 39.2-92.0] vs 149.6 [Q1-Q3: 106.6-180.8] vs 89.0 [Q1-Q3: 61.2-123.4] RBCµ/µL, respectively; P < 0.001). At 24 hours with PFA, the concentration of LDH and indirect bilirubin increased, whereas 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. CONCLUSIONS: PFA was associated with significant periprocedural hemolysis. With a number of 70 PFA lesions, the likelihood of significant renal injury is uncommon.

Atrial fibrillation therapy and stroke prevention in hemodialysis patients.

The prevalence of atrial fibrillation (AF) in patients with chronic kidney disease (CKD), especially on hemodialysis (HD) is higher compared to the general population without CKD and reaches ~20%. The risk of ischemic stroke in CKD patients is also significantly increased. However, since the risk of bleeding is also significantly increased in CKD patients and the number of bleeding events exceeds the number of thrombotic events, there are great concerns regarding the routine use of anticoagulation in this patient population. No randomized studies were performed to compare anticoagulation with placebo in patients with advanced CKD and AF. This lack of knowledge is reflected in international guidelines which refrain from clear recommendations. The use of anticoagulation for stroke prevention in HD patients with AF should be strictly individualized for each patient. Anticoagulation for stroke prevention in HD patients with AF seems justified only in selected patients with high stroke and low bleeding risk. Reduced-dose direct oral anticoagulants (especially apixaban) may prove beneficial. In patients with high thrombotic and bleeding risk, left atrial appendage closure could be considered. In this article, the results of the most relevant observational studies with anticoagulation in CKD/HD patients with AF have been presented and discussed. Furthermore, results of randomized studies comparing vitamin K antagonists with non-vitamin K antagonists in CKD patients have been discussed in detail. Finally, ongoing randomized studies with reduced doses of apixaban, factor XI inhibitors, and left atrial appendage closure in CKD patients are mentioned. A brief summary of rhythm control strategies in AF is given.