Interventions:
The selection of the comparators was appropriate as they appear to have been the relevant procedures for patients with atrioventricular nodal re-entrant tachycardia. A description of the two surgical procedures was given.
Effectiveness/benefits:
The clinical evidence came from the review of a prospective database and a major weakness was the lack of randomisation to allocate patients to treatment arms. The reasons for deciding to perform either procedure and who made this choice were unclear. The two groups were comparable at baseline, but selection bias cannot be ruled out. The size of the sample was not formally justified. The evidence was from a single institution and might not be generalisable to other patient populations, but the study is likely to have represented the usual clinical practice. The benefit measure was disease specific and clearly of importance for clinicians, but possibly not the most appropriate outcome for decision makers. Especially given that radiofrequency ablation was associated with a higher success rate, but also with the occurrence of the only major complication.
Costs:
The economic viewpoint was not explicitly stated, but those costs relevant to the hospital appear to have been included. The unit costs and quantities of resources used were not reported and neither was a list of cost items. All the economic data were from a single institution, which might not be representative of other medical centres. The cost estimates were treated deterministically and the impact of variations in them was not reported. The price year was not reported, which will hinder reflation exercises.
Analysis and results:
Average cost-effectiveness ratios were calculated to synthesise the costs and benefits of the two approaches, but an incremental analysis would have been more appropriate given the dominance of radiofrequency ablation over cryoablation, when comparing their success rates. The results were clearly presented. The issue of uncertainty was not investigated. The authors stated that the main limitation of their analysis was the use of a non-randomised observational study for the clinical data.
Concluding remarks:
The study had some methodological limitations that might affect the validity of the authors’ conclusions.