Rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source: a prespecified subgroup analysis from the NAVIGATE ESUS trial

Background: Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (ESUS). Subgroup analyses from prior studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesized that anticoagulant treatment with rivaroxaban, an oral factor-Xa inhibitor, would reduce the risk of recurrent stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE-ESUS trial. Methods: The NAVIGATE-ESUS double-blind, randomised trial assessed the efficacy and safety of rivaroxaban 15mg versus aspirin 100mg once daily for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined based on transthoracic(TTE) and transesophageal echocardiography(TEE). The primary efficacy outcome was time-to-recurrent ischemic stroke between treatment groups. In addition, a systematic review of the literature incorporated prior studies in which patients with cryptogenic stroke and PFO were randomly assigned to anticoagulant or antiplatelet therapy. Findings: 7213 participants were enrolled and followed for a mean of 11 months due to early trial termination. PFO was reported as present in 534 (7.4%) patients based on either TTE or TEE. Aspirinassigned patients with PFO had a recurrent stroke rate of 4.8% per year. Among patients with known PFO, there was insufficient evidence to support a difference in hazards between rivaroxaban and aspirin (HR 0.54; 95%CI:0.22-1.36), while hazards were high similar for those without known PFO (HR 1.06; 95%CI:0.84-1.33); the interaction was not statistically significant (p=0.18). Major bleeding was likely increased with rivaroxaban compared with aspirin (HR 2.05; 95%CI:0.51-8.2) in patients with PFO. Systematic review that included 2 prior trials yielded a summary odds ratio of 0.48 (95%CI:0.24-0.96; p=0.04) in favour of anticoagulation, without evidence of heterogeneity. Interpretation: Among patients with ESUS who have PFO, anticoagulation may reduce the risk of recurrent stroke by about half, though substantial imprecision remains. Dedicated trials of anticoagulation vs. antiplatelet therapy and/or PFO closure are warranted

From micro‐ to macro‐structures in multiple sclerosis: what is the added value of diffusion imaging

Diffusion imaging has been instrumental in understanding damage to the central nervous system as a result of its sensitivity to microstructural changes. Clinical applications of diffusion imaging have grown exponentially over the past couple of decades in many neurological and neurodegenerative diseases, such as multiple sclerosis (MS). For several reasons, MS has been extensively researched using advanced neuroimaging techniques, which makes it an ‘example disease’ to illustrate the potential of diffusion imaging for clinical applications. In addition, MS pathology is characterized by several key processes competing with each other, such as inflammation, demyelination, remyelination, gliosis and axonal loss, enabling the specificity of diffusion to be challenged. In this review, we describe how diffusion imaging can be exploited to investigate micro‐, meso‐ and macro‐scale properties of the brain structure and discuss how they are affected by different pathological substrates. Conclusions from the literature are that larger studies are needed to confirm the exciting results from initial investigations before current trends in diffusion imaging can be translated to the neurology clinic. Also, for a comprehensive understanding of pathological processes, it is essential to take a multiple‐level approach, in which information at the micro‐, meso‐ and macroscopic scales is fully integrated

Endovascular mechanical thrombectomy for the treatment of acute ischemic stroke due to arterial dissection.

Arterial dissections account for 2% of strokes in all age groups, and up to 25% in patients aged 45 years or younger. The safety of endovascular intervention in this patient population is not well characterized. We identified all patients in the Merci registry - a prospective, multi-center post-market database enrolling patients treated with the Merci Retriever thrombectomy device - with arterial dissection as the most likely stroke etiology. Stroke presentation and procedural details were obtained prospectively; data regarding procedural complications, intracerebral hemorrhage (ICH), and the use of stenting of the dissected artery were obtained retrospectively. Of 980 patients in the registry, ten were identified with arterial dissection (8/10 ICA; 2/10 vertebrobasilar). The median age was 48 years with a baseline NIH stroke scale score of 16 and median time to treatment of 4.9 h. The procedure resulted in thrombolysis in cerebral ischemia (TICI) scores of 2a or better in eight out of ten and TICI 2b or better in six out of ten patients. Stenting of the dissection was performed in four of nine (44%). The single complication (1/9; 11%) - extension of a dissected carotid artery - was treated effectively with stenting. No symptomatic ICH or stroke in a previously unaffected territory occurred. A favorable functional outcome was observed in eight out of ten patients. Despite severe strokes on presentation, high rates of recanalization (8/10) and favorable functional outcomes (8/10) were observed. These results suggest that mechanical thrombectomy in patients with acute stroke resulting from arterial dissection is feasible, safe, and may be associated with favorable functional outcomes