Anticoagulation After Catheter Ablation of Atrial Fibrillation: An Unnecessary Evil?

A Systematic Review and Meta-analysis

Riccardo Proietti MD, PhD; Ahmed AlTurki MD; Luigi Di Biase MD, PhD; Paolo China MD; Giovanni Forleo MD; Andrea Corrado MD; Elena Marras MD; Andrea Natale MD; Sakis Themistoclakis MD

Disclosures

J Cardiovasc Electrophysiol. 2019;30(4):468-478. 

In This Article

Methods

Search Strategy

Studies were identified by searching electronic databases (Medline via OvidSP, Emabase via OvidSP, Medline via PubMed, Biosis Previews via OvidSP, web of Science, and Scopus) from their inception to July 31, 2018. The literature search used text words and relevant indexing to capture data on OAC management after ablation. The search structure was used in Medline and translated into the other databases as appropriate: (AF [Title/Abstract]) AND (ablation [Title/Abstract]) AND (OAC [Title/Abstract]) OR (oral anticoagulants [Title/Abstract]). No restriction on study type or language was applied. Hand searching, with cross-references of retrieved publications, review articles, and guidelines, was also performed to ensure that all relevant studies were included.

Study Selection

Studies were included if they reported data on OAC management after ablation. Review articles, editorial, case reports, case series, and conference abstracts were excluded. The selection was limited to English-language articles.

The first screening was performed independently by two authors (RP and AA) on the basis of title and abstract. The full text of the article was then examined to ensure that they met the following criteria: (1) included patients who underwent AF ablation; (2) compared two different strategies of treatment after ablation: off-OAC vs on-OAC; and (3) reported outcomes (CVE) and complications (major bleeding) in both groups. From the studies selected, the same authors independently extracted the data. Information was extracted on: (1) baseline characteristics of the study participants, year, and country where the study was performed; (2) primary outcome: number of CVE (including TIA and stroke) after ablation in both groups: on and off OAC; (3) secondary outcome: major bleeding (including both intracranial hemorrhages and clinically significant bleeding requiring transfusion) in both groups; and (4) confounding variables, CHADS2 and CHA2DS2-VASc score of the population. Disagreements were resolved by discussion. If no agreement was reached, a third author (ST) made the final decision.

Statistical Analysis

From the numbers of events documented in the two groups (off and on OAC) and their respective populations, the number of nonevents in both groups was calculated. The risk ratio (RR) was the primary measurement of treatment effect or side effect. The RRs were then pooled by means of a DerSimonian and Laird random-effects model.[16] Since one study included zero events in both groups, the analysis of this study was repeated on considering the difference in risk as effect size risk difference (RD), to include it in the analysis. A subanalysis stratified by CHADS2 and CHA2DS2-VASc score was performed that included the studies that contained this information.

Heterogeneity was assessed by means of the I-squared statistic (I 2). The I 2 statistic indicated the percentage of variability due to between-study (or inter-study) variability, as opposed to within-study (or intra-study) variability. An I 2 greater than 50% was classified as indicating the substantial presence of heterogeneity. A meta-regression was carried out for four variables to control for clinical covariates.

Quality Assessment

Publication bias was assessed visually by means of a funnel plot and quantified by means of Egger's test for small study effects.[17] For every study included, the risk of bias was assessed by means of the National Institute of Health quality assessment tool for observational cohort and cross-sectional studies. On the basis of the 14-point scale and overall assessment, studies were rated as good, fair, or poor. In addition, the Newcastle-Ottawa scale[18] was used to evaluate observational studies from three broad perspectives: selection of the study groups, comparability of the groups, and the ascertainment of exposure and outcome of interest.

The study was approved by the institutional review board of Azienda ULSS 3 Serenissima in Mestre-Venice, Italy.

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