Detection of Silent Atrial Fibrillation aFter Ischemic StrOke (SAFFO) Guided by Implantable Loop Recorder. Multicentre Italian Trial Based on Stroke Unit Network With Paired Cardio-Arrhythmology Units (Italian Neurocardiology Unit Network)

Atrial fibrillation (AF) is associated with a high risk of stroke and its prevalence increases in subjects aged ≥65 years. After an ischemic stroke, the use of standard monitoring methods may underestimate the detection rate of AF. Recent studies demonstrated a fourfold to sixfold increase in the detection of AF with prolonged ECG monitoring as compared to standard cardiac monitoring in patients with cryptogenic stroke. Hence, it is very likely that even patients having a first atherothrombotic or lacunar stroke with high burden of vascular risk factors are exposed to increased risk of developing AF in the subsequent years and AF may be the cause underlying possible recurrent strokes.

SAFFO trial has the objective to evaluate the detection of AF or atrial flutter (AFL) as first diagnosis by implantable loop recorder (ILR) in patients with first-ever atherothrombotic or lacunar stroke. Patients with recent (30-60 days after symptom onset) diagnosis of first-ever atherothrombotic or lacunar ischemic stroke who fulfill inclusion criteria will be randomized to either continuous cardiac monitoring using an ILR plus standard cardiac monitoring (intervention arm) or standard cardiac monitoring alone (control arm) with a ratio of 1:1. The hypothesis is that the detection of of AF/AFL by using ILR will be higher than that observed by using standard cardiac monitoring. Secondary and tertiary objectives of the study include exploratory analyses on the incidence of recurrent strokes and different stroke subtypes and on the reduction of stroke risk and death from all causes in all study patients, in the two randomization groups and, in particular, in patients treated with antiplatelet therapy versus those treated with oral anticoagulant (OAC) therapy, the latter being implemented and guided by the detection of clinically meaningful episodes of AF/AFL/AT using ILR compared with standard cardiac monitoring. Moreover, this study has the objective to evaluate a clinical, neuroimaging, and echocardiographic profile predictive of AF/AFL/AT first diagnosis and stroke recurrence.

SAFFO is a prospective, multicenter, randomized, controlled, open-label trial with blinded assessment of outcome measures. Diagnosis of atherothrombotic and lacunar etiology will be defined according to TOAST (trial of ORG 10172 in acute stroke treatment) / CCS (Causative Classification System for ischemic stroke) classification criteria and standard diagnostic protocols that have to be fulfilled before randomization (medical history; risk factors; symptoms; cerebral magnetic resonance [MR] and/or CT; 12-lead ECG and/or Holter ECG and/or other standard heart rhythm monitoring procedure; transthoracic and/or transoesophageal echocardiogram; intra- and extracranial vessel ultrasonography and/or CT-Angiography and/or MR- Angiography, also in order to rule out non-atherosclerotic vasculopathies; thrombophilic/hematologic screening if hypercoagulability states or other hematologic disorders are suspected).

ILR (Medtronic Reveal LINQTM- LNQ11REVEAL LinQ) implantation will be performed within 8 days after randomization and will allow a continuous monitoring by single-lead ECG registration for 3 years. Standard cardiac rhythm monitoring includes: detailed data collection on any possible patient's symptom suggestive of AF/AFL/AT, physical exam including cardiovascular examination, 12-lead ECG, and 24-hour Holter ECG performed at 3-month follow-up visit.

If positive, SAFFO trial could have important clinical implications in terms of changing the standard diagnostic protocol in patients with atherothrombotic and lacunar stroke, and of increasing the shift of secondary prevention treatment from antiplatelet to anticoagulant therapy when indicated.