Victor J. Del Brutto, MD
Ntaios G, Pearce LA, Meseguer E, Endres M, Amarenco P, Ozturk S, et al. Aortic Arch Atherosclerosis in Patients With Embolic Stroke of Undetermined Source: An Exploratory Analysis of the NAVIGATE ESUS Trial. Stroke. 2019
When it comes to establishing the mechanism of injury in a stroke victim, the label “unknown/undetermined” deprives the patient of receiving the appropriate prognosis and strategy for secondary prevention. One-fourth of ischemic strokes are identified as cryptogenic without a definite understanding of the cause, and a sizable proportion of them will fit into the concept of embolic stroke of undetermined source (ESUS). The cause of ESUS could be an under-recognized cardiac source or a non-stenosing arterial lesion. Despite seminal studies in the 1990s that have identified a causal association between protruding plaques in the aortic arch and ischemic stroke, aortic arch atherosclerosis (AAA) is often overlooked during routine stroke work-up, thus falling into the category of stroke of undetermined etiology.
The current manuscript published by Ntaios and colleagues reports the exploratory analysis of the subgroup of individuals who participated in the New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source (NAVIGATE-ESUS) trial and underwent transesophageal echocardiogram (TEE) for evaluation of AAA. The authors found a prevalence of 19% of AAA among patients with ESUS, from which one-third (8% of the total cohort) were considered to have high-risk complex plaques as defined by the presence of ulceration, thickness greater than 4 mm, or presence of a mobile thrombus. As noticed by the authors, the prevalence of AAA might be underestimated due to lower atherosclerotic risk factors in those who underwent TEE. Increasing age, diabetes mellitus and aortic valve disease, as well as geographic region (east Asia and eastern Europe), were significant determinants of AAA in the multivariable analysis. In addition, chronic infarcts and multi-territorial infarcts were associated with AAA, arguing against the common belief that multifocal strokes are exclusively cardioembolic. There was a non-significant trend for higher rate of stroke recurrence in patients with complex AAA (7.2% annualized rate) when compared to those without AAA (5.6% annualized rate). Data from this analysis was merged with two other randomized controlled trials to construct a meta-analysis of anticoagulation versus antiplatelet therapy in patients with cryptogenic stroke and AAA. The meta-analysis found no significant difference in the rate of stroke recurrence between the two antithrombotic approaches.