ADAMTS-13 activity in stroke of known and unknown cause: Relation to vascular risk factor burden.

Background: The identification of the underlying mechanism in ischemic stroke has important implications for secondary prevention. A disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS-13) has antithrombotic properties and was repeatedly implicated in the pathophysiology of stroke. In this study, we, therefore, aimed to investigate whether ADAMTS-13 is associated with stroke etiology and the burden of vascular risk factors. Methods: We determined ADAMTS-13 activity in two prospectively recruited stroke cohorts in the long-term course after the event. Cohort 1 (n = 88) consisted of patients who suffered a stroke due to embolic stroke of undetermined source (ESUS), cardioembolic stroke due to atrial fibrillation (AF), large-artery atherosclerosis, or small vessel disease. In cohort 2, patients with cryptogenic stroke and patent foramen ovale (PFO) scheduled for PFO closure (n = 38) were enrolled. As measures of vascular risk factor burden, the CHA2DS2VASC score, the Essen Stroke Risk Score (ESRS), and the Risk of Paradoxical Embolism (RoPE) score were calculated, as appropriate. Results: ADAMTS-13 activity was lower in patients with AF-related stroke compared to patients with ESUS (p = 0.0227), which was, however, due to confounding by vascular risk factors. ADAMTS-13 activity inversely correlated with the ESRS (r = -0.452, p < 0.001) and CHA2DS2VASC (r = -0.375, p < 0.001) in cohort 1. In accordance with these findings, we found a positive correlation between ADAMTS-13 activity and the RoPE score in cohort 2 (r = 0.413, p = 0.010). Conclusion: ADAMTS-13 activity is inversely correlated with the number of vascular risk factors across different stroke etiologies. Further study is warranted to establish ADAMTS-13 as a mediator of cerebrovascular risk.

Nonstenotic Carotid Plaque in Embolic Stroke of Undetermined Source: Interplay of Arterial and Atrial Disease.

BACKGROUND AND PURPOSE: Approximately one-sixth of all ischemic strokes are attributable to embolic stroke of undetermined source (ESUS). Recent analyses suggest that atrial cardiopathy and nonstenotic carotid plaque (nsCP) may represent 2 distinct underlying causes in patients with ESUS, although both diseases share common risk factors and are pathophysiologically intertwined. In this study, we, therefore, aimed to search for associations between nsCP and markers of atrial remodeling and function in patients with embolic stroke. METHODS: Sixty-eight patients with ESUS or atrial fibrillation (AF)-related stroke proven by imaging who underwent comprehensive echocardiographic studies, including measurements of left atrial function and remodeling, were considered. Patients with ESUS underwent a follow-up of at least 1 year after index stroke. For 20 patients with ESUS, NT-proBNP (N-terminal pro-B-type natriuretic peptide) values were available. Presence of nsCP was evaluated considering Duplex sonography and computed tomography angiography and was further categorized in possibly or probably symptomatic nsCP. RESULTS: ESUS patients with nsCP tended to have higher values of septal and lateral total atrial conduction times (P=0.071 and P=0.072, respectively), left atrial volume index (P=0.077), and revealed significantly higher strain rates during early diastole (P=0.013) as well as higher NT-proBNP values (P=0.010) than ESUS patients without nsCP. Moreover, septal total atrial conduction time was significantly longer in ESUS patients with possibly symptomatic nsCP compared with those without (P=0.015). Comparison of ESUS with AF patients revealed significantly higher proportions of nsCP (P=0.010), possibly symptomatic nsCP (P=0.037), and probably symptomatic nsCP (P=0.036) in patients with atrial fibrillation-related stroke. In the regression analysis adjusted for vascular risk factors probably symptomatic nsCP remained significantly associated with AF (P=0.048, odds ratio: 4.46 [95% CI, 1.02-19.56]). CONCLUSIONS: Presence of nsCP is associated with AF and markers of left atrial disease in patients with embolic stroke. Therefore, a thorough evaluation regarding atrial cardiopathy and AF in patients with ESUS should not be restricted if nsCP are found, even if high-risk plaque characteristics are evident.

Markers of endothelial pathology to support detection of atrial fibrillation in embolic stroke of undetermined source.

A relevant part of embolic strokes of undetermined source (ESUS) is assumed to be cardiogenic. As shown previously, certain biomarkers of endothelial pathology are related to atrial fibrillation (AF). In this long-term follow-up study, we aimed to investigate whether these biomarkers are associated with subsequently diagnosed AF and with atrial cardiopathy. In 98 patients who suffered ischemic stroke of known and unknown origin L-arginine, Asymmetric (ADMA) and Symmetric Dimethylarginine (SDMA) have been measured on follow-up at least one year after index stroke. Stroke-diagnostics were available for all patients, including carotid Intima-Media-Thickness (CIMT) and comprehensive echocardiography studies. CIMT was larger in AF- compared with ESUS-patients (P < 0.001), independently from CHA2DS2VASC in the regression analysis (P = 0.004). SDMA-values were stable over time (P < 0.001; r = 0.788), whereas for ADMA moderate correlation with the initial values could be found (P = 0.007; r = 0.356). According to Kaplan-Meier-analyses, AF-detection rates were associated with CIMT (P = 0.003) and SDMA (P < 0.001). SDMA correlated with left atrial volume-index within the whole collective (P = 0.003, r = 0.322) and within the ESUS-subgroup (P = 0.003; r = 0.446). These associations were independent from CHA2DS2VASC and renal function in the regression analysis (P = 0.02 and P = 0.005, respectively). In conclusion, these results highlight SDMA and CIMT as potential markers of atrial cardiopathy and AF in ESUS-patients.