P1784 Atrial function as a stratification tool in cryptogenic stroke
Authors: Stassen J , Herbots L , Timmermans P JR , Scherrenberg M , Verwerft J , Vijgen J , Stroobants D 
Published: January 2020

Abstract

Introduction

In a large proportion of patients with ischemic stroke, no identifiable cause is found. Paroxysmal atrial fibrillation (AF) plays an important role in the pathogenesis of this kind of stroke. Improved stratification of patients with cryptogenic stroke (CS) would be helpful, because these patients with paroxysmal, often silent, AF may benefit from increased monitoring or targeted therapy.

Purpose
This study aims to identify parameters of left atrial (LA) function that could be used as an imaging biomarker to predict AF in patients with recent CS.

Methods
We retrospectively examined echocardiographic measurements of LA size and function in 58 patients who received an implantable loop recorder (ILR) for CS from January 2010 till October 2018. Only patients in whom the echocardiography was performed within a week after CS were included. Patients with poor imaging quality for atrial strain measurements were excluded. Differences among groups of continuous variables were determined by the student t-test. Categorical variables were compared by χ2 analysis. ROC curves were constructed to assess the sensitivity and specificity. The optimal ROC-derived cut-off levels were determined using the Youden’s J statistic.

Results
17 of the 58 patients (29.3%) developed AF, detected by ILR. The mean time for diagnosis after implantation was 144.29 ± 182.20 days. There was no statistical difference in age (64,8 ± 12,7 vs 62,9 ± 11,9 yrs, p 0,606), gender (76,5 vs 53,7% female, p 0,106) or CHA2DS2-VASc score (5,0 ± 1,3 vs 4,3 ± 1,4, p 0,855) between the AF group and non-AF group. LA volume was significant higher in the patients who developed AF (29,1 ± 10,8 vs 43,6 ± 17,8 ml/m2, p 0.005). Reservoir strain (ƐR; 28,7 ± 5,6 vs 18,1 ± 5,2%, p &lt;0.001), conduit strain (ƐCd; 13,0 ± 4,3 vs 10,3 ± 4,3%, p 0.038) and contractile strain (ƐCt; 15,6 ± 4,1 vs 7,8 ± 2,9%, p &lt;0.001) were all significant lower in the AF group, as were peak early and peak late negative strain rate (SRe; 1,3 ± 0,6 vs 0,9 ± 0,4 1/s, p 0.011 and SRa; 1,9 ± 0,6 vs 1,0 ± 0,4 1/s, p &lt;0.001 respectively). Also, color TDI septal a’ and lateral a’velocity (7,4 ± 1,5 vs 5,4 ± 1,4 cm/s, p &lt;0,001 and 7,2 ± 2,0 vs 5,0 ± 1,6 cm/s, p &lt;0,001 respectively) were lower in the AF group. Total atrial conduction time (PA-TDI interval) was longer in the AF group (130 ± 25,7 vs 152 ± 30,4 ms, p 0,027). Finally, LAVI/ ƐR ratio was found to be higher in the AF group (3,2 ± 3,4 vs 1,1 ± 0,7, p &lt;0,001). The optimal ROC derived cut-off value of LAVI/ ƐR ratio was 1,3 with a sensitivity of 93,8% and a specificity of 73,7% (AUC 0,9).

Conclusions
Novel LA parameters have an additive value to current risk-prediction models for predicting AF following CS. LAVI/ƐR ratio is a strong imaging parameter to predict AF in this cohort. Further studies are necessary to investigate if this parameter could have an implication for the decision making of implanting an ILR or for starting early, empiric anticoagulation.