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BackgroundMagnetic resonance imaging of carotid plaque can aid in stroke risk stratification in patients with carotid stenosis. However, the prevalence of complicated carotid plaque in patients with cryptogenic stroke is uncertain, especially as assessed by plaque imaging techniques routinely included in acute stroke magnetic resonance imaging protocols. We assessed whether the magnetic resonance angiography–defined presence of intraplaque high-intensity signal (IHIS), a marker of intraplaque hemorrhage, is associated with ipsilateral cryptogenic stroke.Methods and ResultsCryptogenic stroke patients with magnetic resonance imaging evidence of unilateral anterior circulation infarction and without hemodynamically significant (≥50%) stenosis of the cervical carotid artery were identified from a prospective stroke registry at a tertiary-care hospital. High-risk plaque was assessed by evaluating for IHIS on routine magnetic resonance angiography source images using a validated technique. To compare the presence of IHIS on the ipsilateral versus contralateral side within individual patients, we used McNemar’s test for correlated proportions. A total of 54 carotid arteries in 27 unique patients were included. A total of 6 patients (22.2%) had IHIS-positive nonstenosing carotid plaque ipsilateral to the side of ischemic stroke compared to 0 patients who had IHIS-positive carotid plaques contralateral to the side of stroke (P=0.01). Stroke severity measures, diagnostic evaluations, and prevalence of vascular risk factors were not different between the IHIS-positive and IHIS-negative groups.ConclusionsOur findings suggest that a proportion of strokes classified as cryptogenic may be mechanistically related to complicated, nonhemodynamically significant cervical carotid artery plaque that can easily be detected by routine magnetic resonance imaging/magnetic resonance angiography acute stroke protocols.

Background Mobile stroke units ( MSU s) reduce time to intravenous thrombolysis in acute ischemic stroke. Whether this advantage exists in densely populated urban areas with many proximate hospitals is unclear. Methods and Results We evaluated patients from the METRONOME (Metropolitan New York Mobile Stroke) registry with suspected acute ischemic stroke who were transported by a bi‐institutional MSU operating in Manhattan, New York, from October 2016 to September 2017. The comparison group included patients transported to our hospitals via conventional ambulance for acute ischemic stroke during the same hours of MSU operation (Monday to Friday, 9  am to 5  pm) . Our exposure was MSU care, and our primary outcome was dispatch‐to‐thrombolysis time. We estimated mean differences in the primary outcome between both groups, adjusting for clinical, demographic, and geographic factors, including numbers of nearby designated stroke centers and population density. We identified 66 patients treated or transported by MSU and 19 patients transported by conventional ambulance. Patients receiving MSU care had significantly shorter dispatch‐to‐thrombolysis time than patients receiving conventional care (mean: 61.2 versus 91.6 minutes; P =0.001). Compared with patients receiving conventional care, patients receiving MSU care were significantly more likely to be picked up closer to a higher mean number of designated stroke centers in a 2.0‐mile radius (4.8 versus 2.7, P =0.002). In multivariable analysis, MSU care was associated with a mean decrease in dispatch‐to‐thrombolysis time of 29.7 minutes (95% CI , 6.9–52.5) compared with conventional care. Conclusions In a densely populated urban area with a high number of intermediary stroke centers, MSU care was associated with substantially quicker time to thrombolysis compared with conventional ambulance care.

Objective: Stroke frequently complicates infective endocarditis (IE). However, the temporal relationship between these diseases is uncertain.Methods: We performed a retrospective study of adult patients hospitalized for IE between July 1, 2007, and June 30, 2011, at nonfederal acute care hospitals in California. Previously validated diagnosis codes were used to identify the primary composite outcome of ischemic or hemorrhagic stroke during discrete 1-month periods from 6 months before to 6 months after the diagnosis of IE. The odds of stroke in these periods were compared with the odds of stroke in the corresponding 1-month period 2 years earlier, which was considered the baseline risk of stroke.Results: Among 17,926 patients with IE, 2,275 strokes occurred within the 12-month period surrounding the diagnosis of IE. The risk of stroke was highest in the month after diagnosis of IE (1,640 vs 17 strokes in the corresponding month 2 years prior). This equaled an absolute risk increase of 9.1% (95% confidence interval 8.6%-9.5%) and an odds ratio of 96.5 (95% confidence interval 60.1-166.0). Stroke risk was significantly increased beginning 4 months before the diagnosis of IE and lasting 5 months afterward. Similar temporal patterns were seen when ischemic and hemorrhagic strokes were considered separately. Conclusions:The association between IE and stroke persists for longer than previously reported.Most diagnoses of stroke and IE are made close together in time, but a period of heightened stroke risk becomes apparent several months before the diagnosis of IE and lasts for several months afterward. Infective endocarditis (IE) occurs in 1.7 to 6.2 per 100,000 people per year in the United States and Europe.1 Stroke often complicates IE, affecting approximately 16% to 25% of patients with IE.2,3 Cerebral embolism heralding or following a diagnosis of IE substantially increases morbidity and mortality.3-5 However, knowledge is limited regarding the time period during which patients with IE face a heightened stroke risk, with reports ranging from as early as 40 days before IE is recognized to as late as 5 weeks after the start of antibiotic treatment.3,4,6-8 Recent data suggest that IE may increase stroke risk for even longer periods of time, as one European cohort study reported that patients had a moderately increased risk of embolic events up to 180 days after community-acquired bacteremia. 9 We hypothesized that the risk of stroke in the setting of IE persists for longer than current data suggest. Therefore, we sought to better delineate the time period during which patients diagnosed with IE face an increased stroke risk.METHODS Study design. We performed a retrospective study of the temporal relationship between IE and stroke diagnoses using administrative claims data from California. The California Office of Statewide Health Planning and Development collects data about all emergency department (ED) visits and hospital stays at nonfederal acute care hospitals in California. After quality checking, these...