Association of catheter ablation for atrial fibrillation with mortality and stroke: A systematic review and meta-analysis

Highlights

• Catheter ablation of AF may reduce mortality compared with medical treatment alone.

• Data does not lend unequivocal support to the theory of stroke reduction with ablation.

• Mortality and stroke rates in real-world patients significantly exceed those seen in randomized studies.

Abstract

Background

Maintenance of sinus rhythm has been associated with lower mortality, but whether atrial fibrillation (AF) ablation per se benefits hard outcomes such as mortality and stroke is still debated.

Objective

To determine whether AF ablation is associated with a reduction in all-cause mortality and stroke compared with medical therapy alone.

Methods

Literature search looking for both randomized and observational studies comparing AF catheter ablation vs. medical management. Data pooled using random-effects. Risk ratios (RR) with 95% confidence intervals (CI) used as a measure of treatment effect. The primary and secondary outcomes were all-cause mortality and occurrence of cerebrovascular events during follow-up, respectively.

Results

Thirty studies were eligible for inclusion, comprising 78,966 patients (25,129 receiving AF ablation and 53,837 on medical treatment) and 233,990 patient-years of follow-up. The pooled data of studies revealed that ablation was associated with lower risk of all-cause mortality: 5.7% vs. 17.9%; RR = 0.44, 95% CI 0.32–0.62, p < 0.001. In a sensitivity analysis by study design, a survival benefit of AF ablation was seen in randomized studies, with no heterogeneity (mortality risk 4.2% vs. 8.9%; RR = 0.55, 95% CI 0.39–0.79, p = 0.001, I² = 0%), and also in observational studies, but with marked heterogeneity (6.1% vs. 18.3%; RR = 0.39, 95% CI 0.26–0.59, p < 0.001, I² = 95%). The mortality benefit in randomized studies was mainly driven by trials performed in patients with left ventricular (LV) dysfunction and heart failure.

The pooled risk of a cerebrovascular event was lower in patients receiving AF ablation (2.3% vs. 5.5%; RR = 0.57, 95% CI 0.46–0.70, p < 0.001, I² = 62%), but no difference was seen in randomized trials (2.2% vs. 2.1%; RR = 0.94, 95% CI 0.46–1.94, p = 0.87, I² = 0%).

Conclusions

Ablation of atrial fibrillation associates with a survival benefit compared with medical treatment alone, although evidence is restricted to the setting of heart failure and LV systolic dysfunction.

Introduction

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and its prevalence is on the rise worldwide due to aging of the population and the increased survival from conditions often associated with AF [1]. Approximately 1% of the general population is estimated to have AF, with a prevalence of up to 10% among elderly patients [2]. Atrial fibrillation is a major cause of stroke and is associated with increased cardiovascular and overall mortality [3].

In randomized trials, catheter ablation has been shown to effectively reduce AF recurrence and burden and improve quality of life when compared with antiarrhythmic therapy [4,5], and therefore it has become a widely accepted treatment to restore and help maintain sinus rhythm in symptomatic patients who have failed antiarrhythmic therapy (class I, level of evidence A) [3]. In the AFFIRM trial, which did not include patients undergoing catheter ablation, patients remaining in sinus rhythm for longer durations had reduced mortality [6]. However, the overall comparison of rhythm-control vs. patients receiving rate control alone in this study failed to show any significant survival benefit or reduction in the risk of stroke which was attributed to the adverse effects of antiarrhythmic drugs [7]. Therefore, if AF catheter ablation can maintain sinus rhythm with higher efficacy and lower rate of complications than antiarrhythmic drugs, it has the potential to improve patient outcomes with respect to stroke and cardiovascular mortality. Thus far, results in this regard from different observational and randomized trials [[8], [9], [10], [11], [12], [13], [14], [15]] have been inconclusive and somewhat contradictory.

We therefore conducted an up-to-date systematic review and meta-analysis of randomized and observational studies aiming to assess the impact of catheter ablation on the risk of mortality and cerebrovascular events (stroke/transient ischaemic attacks).