Authors' objectives:

The aim of this review was to assess the safety and efficacy of intraoperative surgical ablation techniques for the treatment of atrial fibrillation (AF) compared to other surgical procedures, including cardiac surgery (CS) alone, or the Maze-III procedure, the current gold standard surgical treatment for AF.

Authors' results and conclusions: A total of 69 studies using intraoperative ablation were identified, plus 15 studies with Maze-III surgery as a benchmark. There were 30 studies using cryotherapy ablation (CA): 14 non-randomised comparative studies (four CA versus CS, five CA versus Maze-III, four studies with internal comparisons and one questionnaire study) and 16 case series. A total of 29 studies used radiofrequency ablation (RFA): one RCT comparing biatrial RFA versus CS, nine non-randomised comparative studies (five RFA versus CS, one RFA versus cardioversion, one RFA versus Maze-III and two biatrial versus left atrial RFA) and 19 case series. One RCT compared left atrial microwave ablation (MWA) versus CS, two non-randomised comparative studies compared left atrial MWA versus CS, and five case series used MWA. Finally, one case series used laser ablation and one nonrandomised comparative study compared RFA versus MWA. No studies comparing intraoperative ablation with medical management were located. Evidence was mostly limited by the many variations of energy sources and ablation patterns used in the included studies. The primary efficacy outcome was conversion to normal sinus rhythm (SR), which was greater with CA, RFA and MWA versus CS alone. In the RCTs, the relative risk (RR) of patients being in SR at 12 months followup after RFA compared with MV surgery alone was 3.82 (95% CI: 1.35 to 10.81, p=0.01) in Khargi et al. (2001), while at three months follow-up in Schuetz et al. (2003) the RR was 3.24 (95% CI: 1.09 to 9.65, p=0.03). Conversion to SR was at least 68% for all the different energy sources and lesion sets. There were no consistent differences in efficacy between CA versus Maze-III, and insufficient evidence for this comparison using other energy sources. In the one study comparing different energy sources, there were no significant differences in efficacy between RFA versus MWA. Addition of ablation significantly increased CPB and cross clamping times versus CS alone. Left atrial versus biatrial CA or RFA generally appeared to decrease CPB and cross clamping times without influencing efficacy. Atrial function results were difficult to interpret due to the varying criteria used to assess effective atrial contraction. There were no consistent differences in mortality when ablation was compared to CS or Maze-III surgery, and there did not appear to be any greater risk of bleeding with CA or RFA versus CS. Not enough evidence was presented to make any conclusions about stroke incidence. Small numbers of oesophageal perforation and circumflex artery stenosis, both of which may be lethal, were reported, mostly in case reports. All of the oesophageal perforations were associated with unipolar non-irrigated RFA.

Authors' recommendations: On the basis of the evidence presented in this systematic review, The ASERNIP-S Review Group agreed on the following classifications and recommendations concerning the safety and efficacy of intraoperative ablation for the treatment of AF: Classification: Evidence rating - The available evidence was assessed as being poor. Safety - There was insufficient evidence to determine if intraoperative ablation was more or less safe than cardiac surgery alone, or the Maze-III procedure. Associated risks relating to longer bypass times, plus the possibility of oesophageal perforation and circumflex artery injuries, are potential concerns. There were no studies comparing intraoperative ablation with medical management of AF, therefore safety could not be evaluated. Efficacy - Intraoperative ablation is at least as efficacious as cardiac surgery alone, or the Maze-III procedure. There were no studies comparing intraoperative ablation with medical management of AF, therefore efficacy could not be evaluated.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.surgeons.org/media/5513/AFreview0704.pdf

Year Published: 2004

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Australia

Organisation Name: Australian Safety and Efficacy Register of New Interventional Procedures-Surgical

Contact Address: ASERNIP-S 24 King William Street, Kent Town SA 5067 Australia Tel: +61 8 8219 0900

Contact Name: racs.asernip@surgeons.org

Contact Email: racs.asernip@surgeons.org

Copyright: Australian Safety and Efficacy Register of New Interventional Procedures - Surgical