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Meta-Analysis
. 2017 Sep;40(9):641-647.
doi: 10.1002/clc.22701. Epub 2017 May 4.

Thromboembolic risk and effect of oral anticoagulation according to atrial fibrillation patterns: A systematic review and meta-analysis

Alessio Lilli  1 , Andrea Di Cori  2 , Valerio Zacà  3
Affiliations
Meta-Analysis

Thromboembolic risk and effect of oral anticoagulation according to atrial fibrillation patterns: A systematic review and meta-analysis

Alessio Lilli et al. Clin Cardiol. 2017 Sep.

Abstract

Oral anticoagulation (OAC) is recommended in both paroxysmal atrial fibrillation (pxAF) and nonparoxysmal AF (non-pxAF), but disagreement exists in classes of recommendation. Data on incidence/rate of stroke in pxAF are conflicting, and OAC is often underused in this population. The objectives of the meta-analysis were to investigate different impact on outcomes of pxAF and non-pxAF, with and without OAC. Two reviewers searched for prospective studies on risk of stroke and systemic embolism (SE) in pxAF and non-pxAF, with and without OAC. Quality of evidence was assessed according to GRADE approach. Stroke combined with SE was the main outcome. Meta-regression was performed to evaluate OAC effect on stroke and SE incidence rate. We identified 18 studies. For a total of 239 528 patient-years of follow-up. The incidence rate of stroke/SE was 1.6% (95% confidence interval [CI]: 1.3%-2.0%) in pxAF and 2.3% (95% CI: 2.0%-2.7%) in non-pxAF. Paroxysmal AF was associated with a lower risk of overall thromboembolic (TE) events (risk ratio: 0.72, 95% CI: 0.65-0.80, P < 0.00001) compared with non-pxAF. In both groups, the annual rate of TE events decreased as proportion of patients treated with OAC increased. Non-pxAF showed a reduction from 3.7% to 1.7% and pxAF from 2.5% to 1.2%. Major bleeding rates did not differ among groups. Stroke/SE risk is significantly lower, although clinically meaningful, in pxAF. OAC consistently reduces TE event rates across any AF pattern. As a whole, these data provide the evidence to warrant OAC irrespective of the AF pattern in most (virtually all) patients.

Keywords: Oral Anticoagulants; Paroxysmal Atrial Fibrillation; Stroke; Systemic Embolism.

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Conflict of interest statement

The authors declare no potential conflicts of interest.

Figures

Figure 1
Figure 1
Stroke and SE by AF pattern, forest plot. Abbreviations: AF, atrial fibrillation; CI, confidence interval; df, degrees of freedom; M‐H, Mantel‐Haenszel; non‐PxAF, non‐paroxysmal AF; pts, patients; PxAF, paroxysmal AF; SE, systemic embolism.
Figure 2
Figure 2
Stroke and SE by AF pattern in studies with definition of paroxysmal according to current guidelines; forest plot. Abbreviations: AF, atrial fibrillation; CI, confidence interval; df, degrees of freedom; M‐H, Mantel‐Haenszel; non‐PxAF, non‐paroxysmal AF; PxAF, paroxysmal AF; SE, systemic embolism.
Figure 3
Figure 3
Meta‐regression analysis. Pooled incidence rate (y‐axis) and according to OAC proportion within studies (x‐axis) in paroxysmal (Panel A) and non‐paroxysmal (Panel B) AF. Abbreviations: OAC, oral anticoagulation; non‐PxAF, non‐paroxysmal AF; PxAF, paroxysmal AF.
See this image and copyright information in PMC

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