Page 82 - ADD-ON ABLATION SURGERY IN PATIENTS WITH ATRIAL FIBRILLATION

Chapter 9
contrast, age >75 years (p=0.01) and type of AF > paroxysmal (p=0.01) played a significant role in the decision-making process for OAC use at inclusion.
Finally, in our study complications during follow-up were present in 6% of the patients.We could not demonstrate that these adverse events played a role in the decision-making of OAC prescription, although some studies suggest that complications might influence the employment or avoidance of OAC in AF patients64. In this study over-treatment or under-treatment did not show any significant differences in stroke or bleeding risk, and, in addition, we failed to show any correlation between OAC-related complications and guideline adherence, over-treatment or undert-reatment.This finding is in contrast with Nieuwlaat et al58 who showed that especially high-risk patients who are under-treated are at great risk of developing stroke.This aspect requires further investigation and it will be the subject of an ongoing study.
Add-on surgery:The importance of lesion sets
The multicentre study in Chapter 7 analysed the long-term follow-up outcomes of patients undergoing add-on radiofrequency (RF) ablation. Our main objective was to assess the impact of lesion set and surgical technique on long-term recurrence of AF.
Briefly, this study showed favourable long-term results following RF add-on surgical AF ablation with a percentage of patients in NSR and off-antiarrhythmic drugs (AAD) of 62.3% at a median follow-up of 49.8 months (Inter Quartile Range [IQR] 27.0. - 86.5).
Data from transcatheter ablation65, 66 and AF surgery67 have demonstrated that clinical outcome is strongly influenced by completeness, transmurality and continuity and of the lesion set. Continuity and transmurality of the lesions are strongly related to the ablation tool employed and different studies have confirmed that bipolar RF clamps are reliable and effective in creating transmural scars68. Our findings confirm the superiority of the bipolar source. Indeed, the complete bipolar RF lesion set resulted to be the technique with the highest number of patients in NSR-off antiarrhythmic drugs (AAD) at follow-up (p<0.001 vs. unipolar, p=0.001 vs. combined bipolar/unipolar lesions). Furthermore, at multivariate analysis using competing risk regression the use of unipolar RF (SHR 7.41, p<0.001) or combined unipolar/bipolar ablation (sub-hazard ratios [SHR] 3.93, p=0.003) were independent predictors of AF recurrence.
In addition to the uncertainty of transmurality of the lesions of unipolar sources69,
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