Atrial Cardiopathy Biomarkers and MRI-Based Infarct Patterns in Patients with Embolic Strokes of Undetermined Source

Review and update of the concept of embolic stroke of undetermined source

Ischaemic strokes have traditionally been classified according to the TOAST criteria, in which strokes with unclear aetiology are classified as cryptogenic strokes. However, the definition of cryptogenic stroke did not meet the operational criteria necessary to define patient populations for randomized treatment trials. To address this problem, the concept of embolic stroke of undetermined source (ESUS) was developed and published in 2014. A hypothesis that underpinned this concept was that most strokes in patients with ESUS are caused by embolic events, perhaps many cardioembolic, and that anticoagulation would prevent secondary ischaemic events. On this basis, two large randomized trials were conducted to compare the non-vitamin K antagonist oral anticoagulants (NOACs) dabigatran and rivaroxaban with aspirin. Neither NOAC was superior to aspirin in these trials, although subgroups of patients with ESUS seemed to benefit specifically from anticoagulation or antiplatelet therapy. The neutral results of the trials of anticoagulation and insights into ESUS from research conducted since the concept was introduced warrant reassessment of the ESUS construct as a research concept and a treatment target. In this Review, we discuss the evidence produced since the concept of ESUS was introduced, and propose updates to the criteria and diagnostic algorithm in light of the latest knowledge.

Prevalence of markers of atrial cardiomyopathy in embolic stroke of undetermined source: A systematic review

BACKGROUND

Emerging evidence suggests the potential role of atrial cardiomyopathy (AC) as a direct thromboembolic determinant in embolic stroke of undetermined source (ESUS).

OBJECTIVE

We aimed to quantify the prevalence of potential AC markers among ESUS, non-cardioembolic (NCE) and cardioembolic (CE) stroke patients.

METHODS

PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for publications from inception to October 2021, with duplicate data extraction and risk of bias assessment. The Newcastle-Ottawa assessment scale was used to evaluate study quality.

RESULTS

Among 398 screened studies, 11 observational studies with 2009 ESUS patients (mean age 66.5 years) fulfilled the inclusion criteria. Of electrocardiographic markers, increased P-wave terminal force in lead V1 was more prevalent in ESUS vs NCE (OR=2.26, 95%CI: 1.40-3.66). Of imaging markers, left atrial volume index (LAVI) and left atrial diameter (LAd) were higher in ESUS vs NCE (OR=1.04, 95%CI: 1.02-1.06 and OR=3.41, 95%CI: 1.35-8.61 respectively). Non-chicken wing morphology of the left atrial appendage was more frequent in ESUS compared to NCE patients in the majority of studies. Of serum biomarkers, the prevalence of NT-proBNP >250 pg/ml did not differ among ESUS vs NCE (OR=0.73, 95%CI: 0.39 -1.35).

CONCLUSIONS

Electrocardiographic, echocardiographic markers and advanced imaging modalities able to assess the morphologic characteristics of left atrial appendage and left atrial function may be important tools to discriminate AC among ESUS vs NCE stroke patients. Prospective studies exploring the association of potential AC markers with ESUS occurrence are warranted to validate their clinical utility.