Left Atrial Reservoir Strain is a Superior Discriminator of Cardioembolism in Ischemic Stroke

Echocardiographic measures of left heart size and function have long been associated with cardioembolic mechanisms of stroke development, however the diagnostic performance and comparison of measures of atrial function in this context has not been well studied. We sought to evaluate the diagnostic performance of LA reservoir strain (LASr) in identification of cardioembolism in the ischemic stroke population relative to traditional measures of left heart size and function. Consecutive patients admitted to our institution with ischemic stroke or transient ischemic attack were recruited and underwent comprehensive transthoracic echocardiography. Strokes were classified by etiology with comparison undertaken between cardioembolic and non-cardioembolic types. 418 consecutive stroke patients with a cardioembolic (n = 229) or non-cardioembolic (n = 189) stroke etiology were analyzed. LASr was impaired in cardioembolic compared to non-cardioembolic strokes (16.7 ± 8.2% vs 26.0 ± 5.5%, p < 0.01) and provided greatest discrimination [area under the curve (AUC) 0.813, 95%CI 0.773 to 0.858] in differentiating stroke subtypes when compared to LVEF (AUC difference 0.150, p < 0.01), LAVI (AUC difference 0.083, p < 0.01) and E/e’ (AUC difference 0.163, p < 0.01). Inclusion of LASr in a model with conventional left heart echocardiographic factors improved model performance with a net reclassification improvement of 1.083 (95%CI 0.945 to 1.220, p < 0.01). Further, a proposed user-defined model-based clinical algorithm with LASr demonstrated improved diagnostic accuracy of identification of cardioembolic stroke subtypes which was best appreciated in patients without atrial fibrillation. LASr may provide enhanced diagnostic accuracy beyond conventional echocardiographic measures to discriminate cardioembolic from non-cardioembolic stroke mechanisms, in particular amongst those without comorbid atrial fibrillation.