Stroke rates before and after ablation of atrial fibrillation and in propensity-matched controls in the UK
Received 15 February 2017
Accepted for publication 25 April 2017
Published 29 May 2017 Volume 2017:8 Pages 107—118
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Akshita Wason
Peer reviewer comments 3
Editor who approved publication: Professor David B Price
Julian WE Jarman,1 Tina D Hunter,2 Wajid Hussain,1 Jamie L March,3 Tom Wong,1 Vias Markides1
1Cardiology & Electrophysiology, Heart Rhythm Center, NIHR Cardiovascular Research Unit, The Royal Brompton Hospital, and National Heart and Lung Institute, Imperial College London, London, UK; 2Health Outcomes Research, CTI Clinical Trial & Consulting Services Inc., Cincinnati, OH, 3Health Economics and Market Access, Biosense Webster Inc., Diamond Bar, CA, USA
Background: We sought to determine whether catheter ablation of atrial fibrillation (AF) is associated with reduced occurrence of ischemic cerebrovascular events.
Methods and results: Using routinely collected hospital data, ablation patients were matched to two control cohorts via direct and propensity score matching. A total of 4,991 ablation patients were matched 1:1 to general AF controls with no ablation, and 5,407 ablation patients were similarly matched to controls who underwent cardioversion. Yearly rates of ischemic stroke or transient ischemic attack (stroke/TIA) before and after an index date were compared between cohorts. Index date was defined as the first ablation, the first cardioversion, or the second AF event in the general AF cohort. Matched populations had very similar demographic and comorbidity profiles, including nearly identical CHA2DS2-VASc risk distribution (p-values 0.6948 and 0.8152 vs general AF and cardioversion cohorts). Statistical models of stroke/TIA risk in the preindex period showed no difference in annual event rates between cohorts (mean±standard error 0.30% ± 0.08% ablation vs 0.28% ± 0.07% general AF, p=0.8292; 0.37% ± 0.09% ablation vs 0.42% ± 0.08% cardioversion, p=0.5198). Postindex models showed significantly lower annual rates of stroke/TIA in ablation patients compared with each control group over 5 years (0.64% ± 0.11% ablation vs 1.84% ± 0.23% general AF, p<0.0001; 0.82% ± 0.15% ablation vs 1.37% ± 0.18% cardioversion, p=0.0222).
Conclusion: Matching resulted in cohorts having the same baseline risks and rates of ischemic cerebrovascular events. After the index date, there were significantly lower yearly event rates in the ablation cohort. These results suggest the divergence in outcome rates stems from variance in the treatment pathways beginning at the index date.
Keywords: atrial fibrillation, catheter ablation, cardioversion, ischemic stroke, repeated measure
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