title: Transvenous cryoablation reduces platelet activation during pulmonary vein ablation compared with radiofrequency energy in patients with atrial fibrillation.
abstract: BACKGROUND
  Radiofrequency (RF) ablation procedures for atrial fibrillation (AF) are associated with potential risks of thromboembolism, which may be minimized by the use of cryoablation that preserves the integrity of endocardium. The objective of this study was to compare the thrombogenic potential of transvenous cryoablation versus RF ablation during pulmonary vein (PV) isolation.
  
  
  RESULTS
  Thirty consecutive patients with paroxysmal AF were randomized to undergo segmental PV isolation procedure using 4-mm tip RF ablation (n = 15) or cryoablation (CryoCor, San Diego, CA, USA) (n = 15). Blood samples were drawn after sheath insertion (baseline), after transseptal puncture, before ablation (after heparin administration), and after isolation of a superior PV. Activation of coagulation was measured with plasma levels of prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin III complex (TAT), and platelets by plasma level of beta-thromboglobulin (beta-TG) and flow cytometric enumerating of P-selectin (CD62)-positive platelets. In both groups, the plasma level of beta-TG, F1 + 2, and TAT were elevated after sheath insertion. The percentage changes in plasma level of beta-TG, F1 + 2, and TAT and CD41/62-positive platelets from baseline after transseptal puncture and before ablation were similar (P > 0.05). However, the percentage changes in CD62-positive platelets from baseline were significantly higher in patients treated with RF ablation (82 +/- 20%) than with cryoablation (22 +/- 14%, P = 0.02), although their plasma levels of beta-TG, F1 + 2, and TAT were not different (P > 0.05).
  
  
  CONCLUSIONS
  Significant platelet and coagulation activations were observed during PV ablation procedures, and heparin administration only prevented activation of coagulation but not platelets. Persistent platelets activation was observed during RF energy application, but not during cryoablation.
authors.affiliation: Department of Medicine, Queen Mary Hospital, The University of Hong Kong. hftse@hkucc.hku.hk
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Yok-Lam
authors.initials: YL
authors.lastname: Kwong
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
mesh_terms: D000990:Antithrombin III; D001281:Atrial Fibrillation / Q000097:blood / Q000503:physiopathology / Q000601:surgery*; D015415:Biomarkers / Q000097:blood; D001777:Blood Coagulation; D017115:Catheter Ablation; D003452:Cryosurgery / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010447:Peptide Hydrolases / Q000097:blood; D015539:Platelet Activation; D011516:Prothrombin; D011667:Pulmonary Veins / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D001620:beta-Thromboglobulin / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019007:P-Selectin; D010446:Peptide Fragments; C046193:antithrombin III-protease complex; D001620:beta-Thromboglobulin; C045879:prothrombin fragment 1.2; D000990:Antithrombin III; D011516:Prothrombin; D010447:Peptide Hydrolases