Intracranial and systemic atherosclerosis in the NAVIGATE ESUS trial: Recurrent stroke risk and response to antithrombotic therapy

Background: Non-stenotic intracranial and systemic atherosclerosis are associated with ischemic stroke. We report frequency and response to anticoagulant vs. antiplatelet prophylaxis of patients with embolic stroke of undetermined source (ESUS) who have non-stenotic intracranial atherosclerosis and/or systemic atherosclerosis. Methods: Exploratory analysis of the international NAVIGATE ESUS randomized trial comparing rivaroxaban 15mg daily with aspirin 100mg daily in 7213 patients with recent ESUS. Among participants with results of intracranial arterial imaging with either computed tomographic angiography (CTA) or magnetic resonance angiography (MRA), the frequency and predictors of non-stenotic intracranial and systemic atherosclerosis and responses to antithrombotic therapy were assessed. Results: Among 4723 participants with available intracranial CTA or MRA results (65% of the trial cohort), the prevalence of intracranial atherosclerosis was 16% (n=739). Patient features independently associated with intracranial atherosclerosis included East Asian region (odds ratio 2.7, 95%CI 2.2,3.3) and cervical carotid plaque (odds ratio 2.3, 95%CI 1.9,2.7), among others. The rate of recurrent ischemic stroke averaged 4.8%/year among those with intracranial atherosclerosis vs. 5.0.%/year for those without (HR 0.95, 95%CI 0.65, 1.4). Among those with intracranial atherosclerosis, the recurrent ischemic stroke rate was higher if assigned to rivaroxaban (5.8%/year) vs. aspirin (3.7%/year), but the difference was not statistically significant (HR 1.6, 95%CI 0.78, 3.3). There was trend for the effect of antithrombotic treatments to be different according to the presence or absence of intracranial atherosclerosis (pinteraction=0.09). Among participants with evidence of systemic atherosclerosis by either history or imaging (n=3820), recurrent ischemic stroke rates were similar among those assigned to rivaroxaban (5.5%/year) vs. aspirin (4.9%/year)(HR 1.1, 95%CI 0.84, 1.5). Conclusions: East Asia region was the strongest factor associated with intracranial atherosclerosis. There were no statistically significant differences between rivaroxaban and aspirin prophylaxis for recurrent ischemic stroke in patients with non-stenotic intracranial atherosclerosis and/or systemic atherosclerosis. © 202

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 previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE ESUS trial. Methods: NAVIGATE ESUS was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy. Findings: Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22–1·36), and the risk was similar for those without known PFO (1·06; 0·84–1·33; pinteraction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51–8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69–4·70; pinteraction=0·68). The random-effects meta-analysis combined data from NAVIGATE ESUS with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24–0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity. Interpretation: Among patients with ESUS who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted. Funding: Bayer and Janssen