Management and clinical outcome of patients with atrial fibrillation stratified by the 4S-AF scheme for structured characterization of atrial fibrillation: data from CODE-AF registry
Authors: Lee S.R , Park K.M , Joung B , Choi E.K ,   CODE-AF investigators
Published: October 2021

Abstract

Background
Recently, 4S-AF scheme consisting of four essential domains requiring for integrated management of atrial fibrillation (AF), including stroke prevention, symptom severity, severity of AF burden, and substrate for AF, has been proposed for the structured characterization of AF.

Purpose
To classify patients with AF applying 4S-AF scheme, evaluate how rhythm control and stroke prevention strategies were applied according to the 4S-AF scheme, and analyze the association between 4S-AF scheme score and the risk of clinical outcome, composite of stroke and admission for heart failure in patients with AF.

Methods
Using the data from the COmparison study of Drugs for symptom control and complication prEvention of Atrial Fibrillation (CODE-AF) registry from June 2015 to October 2020, we identified patients with AF who had information about 4S. The 4S-AF scheme score was calculated by stroke risk (truly low risk patients = 0; otherwise = 1), symptom severity (no symptom = 1; presence of symptom = 1), severity of AF burden (paroxysmal = 0, persistent = 1, and long-persistent to permanent = 2), substrate for AF (add 1 if &gt;75 years; no comorbidity=1, 1 comorbidity = 1, 2 or more comorbidities = 2; left atrial anteroposterior diameter &lt;40mm = 0, 40 to &lt;50mm = 1, and ≥50mm = 2). Treatment strategies, including rhythm control and anticoagulation, were analyzed according to the 4S-AF scheme score. The risk for a composite of stroke and admission for heart failure was evaluated according to the 4S-AF scheme score during follow-up.

Results
Among 8199 patients with AF, the 4S-AF scheme scores of 0, 1, 2, 3, 4, 5, and ≥6 were 2.5%, 5.6%, 9%, 17.1%, 20.1%, 17.6%, and 28%, respectively. Patients with higher scores were tended to be older, had higher CHA2DS2-VASc score, included less proportion of paroxysmal AF, and showed larger left atrial size (Table). According to 4S-AF scheme, physicians preferred to apply a rhythm control strategy through both performing catheter ablation and prescribing antiarrhythmic agents in patients with lower 4S-AF scheme score (Figure). Oral anticoagulation rates were higher in patients with higher 4S-AF scheme score owing to higher CHA2DS2-VASc scores of these patients (Figure). The incidence rates of composite clinical outcomes were increased with increasing in 4S-AF scheme score (Figure). When grouping 4S-AF scheme score 0 and 1 as group A, 2 to 4 as group B, 5 as group C, and 6 as group D, group B, C, and D were associated with a higher risk of the composite clinical outcomes by 3.4, 7.9 and 11.5-fold compared to group A, respectively (Figure).

Conclusions
The 4S-AF scheme score was well-associated with the risk of stroke and admission for heart failure in patients with AF. Although the 4S-AF scheme might be already reflected in clinical practice when physicians determined the rhythm control and stroke prevention strategies for their AF patients, more systematic approach should be utilized for better clinical outcomes in patients with AF.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported by a research grant from the Korean Healthcare Technology R&D project funded by the Ministry of Health & Welfare (HI15C1200, HC19C0130).