Complication rate and risk factors for bleeding during atrial fibrillation ablation under lower activated clotting times

AIM To observe and analyze the risk factors for major complications and the safety of atrial fibrillation (AF) ablation under lower activated clotting times (ACTs). METHODSClinical data of 231 AF patients who underwent radiofrequency or cryoballoon ablation were collected. According to the value of averaged ACT during ablation procedure, patients were divided into three groups: average ACT <200 s, 200-250 s and ≥250 s. Embolic and bleeding complication rates of each group were analyzed. Patients were then categorized into bleeding group and non-bleeding group according to the occurrence of bleeding complications. In this case-control study, uni- and multivariate logistic regression analysis were performed to identify the predictors of bleeding complications. RESULTSComplications occurred in 13 (5.6%) patients. The total complication rates in groups of <200 s, 200-250 s and ≥250 s were 4%,3% and 13%, respectively, which was much higher in the >250 s group than in the 200-250 s group (P<0.05). Compared with the 200-250 s group, bleeding complication rate of ≥250 s group was much higher (11%:1%, P<0.01). Differences in other complications among the three groups were not significant. Multivariate logistic regression analysis indicated that the total procedural time (P<0.01, OR=1.025, 95%CI: 1.007-1.043), heparin bolus normalized for body weight (P<0.01, OR=1.067, 95%CI: 1.020-1.116) and averaged ACT (P<0.01, OR=1.065, 95%CI: 1.017-1.114) during ablation procedure were independent risk factors for bleeding complications. CONCLUSIONAF ablation is relatively safe with a target ACT of 200-250 s for patients with CHADS2 scores<2. Furthermore, total procedural time, heparin bolus normalized for body weight and average ACT during ablation procedure prove to be independent predictors of bleeding complications.