Thrombogenicity of radiofrequency ablation procedures: what factors influence thrombin generation?

Aims Thromboembolic complications have been reported after radiofrequency a blation but the low incidence of overt clinical events has been a limitatio n to the study of factors affecting thrombogenic risk. The aim of this stud y was to determine whether radiofrequency ablation has a procoagulant effec t and to examine variables that affect thrombin generation. Methods and Results Thirty-seven consecutive patients who underwent radiofr equency ablation were studied prospectively. Blood samples were assayed for thrombin-antithrombin III (TAT) and d-dimer (DD) at five different time po ints: (1)baseline; (2) after sheath insertion; (3) after electrophysiologic al study but before radiofrequency ablation; (4) at completion of the proce dure; and (5) 24 h post-procedure. TAT levels were within the normal range at baseline and increased significa ntly after sheath insertion From 2(.)1 +/- 1(.)2 mug 1(-1) to 13(.)3 +/- 16 (.)0 mug 1(-1) (P <0(.)01). Levels increased further to 24(.)0 +/- 19(.)9 m ug 1(-1) (P <0(.)01) after electrophysiological study but did not increase after radiofrequency ablation. TAT normalized at 24 h. DD increased signifi cantly from baseline values (230(.)2 +/- 176(.)8 ng ml(-1)) to 285(.)4 +/- 237(.)4 ng ml(-1) (P=0(.)019) after sheath insertion. There was a further s ignificant increase after electrophysiological study to 423(.)4 +/- 324(.)3 ng ml(-1) (P <0(.)01), and a slight but non-significant increase to 464(.) 4 +/- 307(.)4 ng ml(-1) after radiofrequency ablation (P=0(.)159). DD remai ned elevated at 24 h. Procedure duration was the only variable that correla ted with the relative increase in TAT and DD. The patients with the longest procedure durations had more catheters inserted, more radiofrequency appli cations and largely consisted of accessory bypass tract-mediated tachycardi as. Heparin administration significantly blunted the relative increase in T AT after radiofrequency ablation (p=0(.)005). Conclusion Radiofrequency ablation procedures confer an increased risk of t hrombosis. Catheterization and diagnostic study contribute largely to the t hrombogenic stimulus. Thrombogenicity is increased in prolonged, complex pr ocedures and is decreased in patients who have been administered heparin du ring the procedure. (C) 2000 The European Society of Cardiology.