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Literature Review

Assessment of Use vs Discontinuation of Oral Anticoagulation After Pulmonary Vein Isolation in Patients with Atrial Fibrillation

Själander S, Holmqvist F, Smith G, et al. JAMA Cardiol. 2016 Nov 23.

Reviewer: Sherif Assaad, MD; VA Healthcare System, Yale University, West Haven, CT

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia in individuals between 50 and 89 years of age. It increases the risk of morbidity and mortality and leads to impaired quality of life. Treatment options depend on the symptomatology of patients. In asymptomatic patients, oral anticoagulation is the mainstay of treatment to reduce the risk of stroke. In patients who could not tolerate long-term anticoagulation or those who are symptomatic or with drug-resistant AF, pulmonary vein isolation (PVI) could be considered as a treatment option. Current practice involves prescription of oral anticoagulation for 2- to 3-month post-PVI, or longer for high-risk patients. The aim of this study is to identify the incidence and predicting factors of stroke, intracranial hemorrhage, and death in patients with AF who had PVI +/- oral anticoagulation and stratify the risks according to their CHA2DS2-VASc score (congestive heart failure, hypertension, age > 75 years [doubled], diabetes, stroke [doubled], vascular disease, age 65–74 years, sex category [female]).

Methods

Study Design: Retrospective cohort study using the Swedish health registries from January 1, 2006, to December 31, 2012, with a mean follow-up of 2.6 years

Results

A total of 1585 patients undergoing first-time PVI who were treated with warfarin were included in this study. The mean age was 59 + 9.4 years, 73% were males, and the mean CHA2DA-VASc score was 1.5 + 1.4.

There was a tendency to discontinue warfarin in the first year in patients with a lower CHA2DS2-VASc score and to continue warfarin beyond 1 year in patients with a higher CHA2DS2-VASc score. Of those continuing warfarin beyond 1 year, the incidence of relapse of AF was > 32%.

In total, 11 out of 1585 patients (0.7%) experienced an ischemic stroke during the follow-up period. In patients with a CHA2DS2-VASc score less than 2, there was no significant difference between patients taking or discontinuing warfarin in regard to ischemic stroke, intracranial hemorrhage, or death. In patients with a CHA2DS2-VASc score of 2 or more, or those with a history of ischemic stroke, there was a significant risk of stroke in patients who discontinued warfarin.

Comment

In patients with a CHA2DS2-VASc score of 2 or more, there was a higher incidence of ischemic stroke in patients who discontinued warfarin after PVI. In patients with a CHA2DS2-VASc score less than 2, there was no difference in the incidence of ischemic stroke between patients who continued or discontinued warfarin after PVI. It also showed a higher incidence of AF, which required cardioversion or repeat of the ablation.

Reviewer's Comments

Although this study is limited by its retrospective, nonrandomized design, it showed an alarming rate of relapse of AF after PVI, requiring further interventions in the form of cardioversion or repeat PVI. It also emphasizes the fact that oral anticoagulants should be continued beyond 1 year in patients with a higher CHA2DS2-VASc score. This should be discussed with patients prior to the procedure, which will help them have realistic expectations about the outcome of this procedure, because oral anticoagulants will be continued regardless.

The retrospective nature of this study did not show whether patients who were on warfarin achieved their therapeutic goal as measured by the international normalized ratio and whether that was a contributing factor for the results. This might be overcome with the introduction of new oral anticoagulants that do not require monitoring with the international normalized ratio.