Stroke Chameleons

Background: Many conditions called stroke mimics may resemble acute stroke. The converse of the stroke mimic is a presentation suggestive of another condition, which actually represents stroke. These would be stroke chameleons. The recognition of a chameleon as stroke has implications for therapy and quality of care. Methods: We performed a retrospective chart review, including all cases for 1 year in which patients had a stroke missed on hospital presentation. Initial erroneous diagnoses were compared for all patients correctly admitted with those diagnoses to determine positive predictive value (PPV) for each chameleon. Results: Ninetyfour cases were identified as chameleons where brain imaging revealed acute stroke. The common chameleons were initially diagnosed as altered mental status (AMS) (29, 31%), syncope (15, 16%), hypertensive emergency (12, 13%), systemic infection (10, 11%), and suspected acute coronary syndrome (ACS) (9, 10%). The total number of patients who were diagnosed with these conditions over the same year were AMS (393), syncope (326), hypertensive emergency (144), systemic infection (753), and suspected ACS (817) (total N = 2528). For each chameleon diagnosis, the PPV of each presentation for acute stroke was AMS (7%), syncope (4%), hypertensive emergency (8%), systemic infection (1%), and suspected ACS (1%). Conclusions: Stroke chameleons may result in patients not receiving appropriate care. The largest proportions of chameleons were AMS, syncope, hypertensive emergency, systemic infection, and suspected ACS. Patients diagnosed with hypertensive emergency or AMS had an 8% and 7% chance of having an acute stroke. Physicians should consider stroke in patients with these diagnoses with a lower threshold to obtain neuroimaging with subsequent appropriate management

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