Hebun Erdur

Number of Cerebral Microbleeds and Risk of Intracerebral Hemorrhage After Intravenous Thrombolysis

Background and Purpose— Cerebral microbleeds (CMBs) are found in a substantial proportion of patients with ischemic stroke eligible for treatment with intravenous thrombolysis. Until now, there is limited data on the impact of multiple CMBs on occurrence of intracerebral hemorrhage (ICH) after intravenous thrombolysis. Methods— Between 2008 and 2013, all patients receiving MRI-based intravenous thrombolysis were identified within our prospective thrombolysis register. Number of CMBs was rated on pretreatment T2*-weighted MRI by a rater blinded to clinical data and follow-up. Outcomes of interest were occurrence of symptomatic ICH (sICH) and parenchymal hemorrhage (PH). Results— Among 326 included patients, 52 patients had a single CMB (16.0%), 19 had 2 to 4 CMBs (5.8%), and 10 had ≥5 CMBs (3.1%). Frequency of sICH/PH was 1.2%/5.7% in patients without CMBs, 3.8%/3.8% in patients with a single CMB, 10.5%/21.1% in patients with 2 to 4 CMBs, and 30.0%/30.0% in patients with ≥5 CMBs, respectively (each P for trend <0.01). The unadjusted odds ratio per additional CMB for sICH was 1.19 (95% confidence interval, 1.07–1.33; P<0.01) and for PH was 1.13 (95% confidence interval, 1.03–1.24; P=0.01). Compared with patients without CMBs, both patients with 2 to 4 CMBs (P=0.02/P=0.02) and patients with ≥5 CMBs (P<0.01/P<0.01) had significantly increased odds ratios for sICH and PH, whereas in patients with a single CMB, odds ratios were not significantly increased (P=0.21/P=0.59). The association of CMB burden with sICH/PH remained significant after adjustment for possible confounders (age, age-related white matter changes score, atrial fibrillation, onset-to-treatment time, prior statin use, and systolic blood pressure on admission). Conclusions— Our findings indicate a higher risk of sICH and PH after intravenous thrombolysis when multiple CMBs are present, with a graded relationship to increasing baseline CMB number.

Functional outcomes of pre-hospital thrombolysis in a mobile stroke treatment unit compared with conventional care: an observational registry study

BACKGROUND Specialised CT-equipped mobile stroke treatment units shorten time to intravenous thrombolysis in acute ischaemic stroke by starting treatment before hospital admission; however, direct effects of pre-hospital thrombolysis on clinical outcomes have not been shown. We aimed to compare 3-month functional outcomes after intravenous thrombolysis in patients with acute ischaemic who had received emergency mobile care or and conventional care. METHODS In this observational registry study, patients with ischaemic stroke received intravenous thrombolysis (alteplase) either within a stroke emergency mobile (STEMO) vehicle (pre-hospital care covering 1·3 million inhabitants of Berlin) or within conventional care (normal ambulances and in-hospital care at the Charité Campus Benjamin Franklin in Berlin). Patient data on treatment, outcome, and demographics were documented in STEMO (pre-hospital) or conventional care (in-hospital) registries. The primary outcome was the proportion of patients who had lived at home without assistance before stroke and had a 3-month modified Rankin Scale (mRS) score of 1 or lower. Our multivariable logistic regression was adjusted for demographics, comorbidities, and stroke severity. This study is registered with ClinicalTrials.gov, number NCT02358772. FINDINGS Between Feb 5, 2011, and March 5, 2015, 427 patients were treated within the STEMO vehicle and their data were entered into a pre-hospital registry. 505 patients received conventional care and their data were entered into an in-hospital thrombolysis registry. Of these, 305 patients in the STEMO group and 353 in the conventional care group met inclusion criteria and were included in the analysis. 161 (53%) patients in the STEMO group versus 166 (47%) in the conventional care group had an mRS score of 1 or lower (p=0·14). Compared with conventional care, adjusted odds ratios (ORs) for STEMO care for the primary outcome (OR 1·40, 95% CI 1·00-1·97; p=0·052) were not significant. Intracranial haemorrhage (p=0·27) and 7-day mortality (p=0·23) did not differ significantly between treatment groups. INTERPRETATION We found no significant difference between the proportion of patients with a mRS score of 1 or lower receiving STEMO care compared with conventional care. However, our results suggest that pre-hospital start of intravenous thrombolysis might lead to improved functional outcome in patients. This evidence requires substantiation in future large-scale trials. FUNDING Zukunftsfonds Berlin, the Technology Foundation Berlin with EU co-financing by the European Regional Development Fund via Investitionsbank Berlin, and the German Federal Ministry for Education and Research via the Center for Stroke Research Berlin.

Insular Cortex Lesions, Cardiac Troponin, and Detection of Previously Unknown Atrial Fibrillation in Acute Ischemic Stroke Insights From the Troponin Elevation in Acute Ischemic Stroke Study

Background and Purpose— Detection rates of paroxysmal atrial fibrillation (AF) after acute ischemic stroke increase with duration of ECG monitoring. To date, it is unknown which patient group may benefit most from intensive monitoring strategies. Therefore, we aimed to identify predictors of previously unknown AF during in-hospital ECG monitoring. Methods— All consecutive patients with imaging-confirmed ischemic stroke admitted to our tertiary care hospital from February 2011 to December 2013 were registered prospectively. Patients received continuous bedside ECG monitoring for at least 24 hours. Detection of previously unknown AF during in-hospital ECG monitoring was obtained from medical records. Patients with AF on admission ECG or known history of AF were excluded from analysis. Results— Among 1228 patients (median age, 73 years; median National Institutes of Health Stroke Scale, 4; 43.4% women), previously unknown AF was detected in 114 (9.3%) during a median time of continuous ECG monitoring of 3 days (interquartile range, 2–4 days). Duration of monitoring (P<0.01), older age (P<0.01), history of hypertension (P=0.03), insular cortex involvement (P<0.01), and higher high-sensitivity cardiac troponin T (P=0.04) on admission were independently associated with subsequent detection of AF in a multiple regression analysis. Addition of high-sensitivity cardiac troponin T, insular cortex stroke, or both to the CHADS2 score (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke [2P]) significantly improved c-statistics from 0.63 to 0.68 (P=0.01), 0.70 (P<0.01), and 0.72 (P<0.001), respectively. Conclusions— Insular cortex involvement, higher admission high-sensitivity cardiac troponin T, older age, hypertension, and longer monitoring are associated with new detection of AF during in-hospital ECG monitoring. Patients with higher high-sensitivity cardiac troponin T or insular cortex involvement may be candidates for prolonged ECG monitoring.

Recanalization therapies in acute ischemic stroke patients: impact of prior treatment with novel oral anticoagulants on bleeding complications and outcome

Background— We explored the safety of intravenous thrombolysis (IVT) or intra-arterial treatment (IAT) in patients with ischemic stroke on non-vitamin K antagonist oral anticoagulants (NOACs, last intake <48 hours) in comparison with patients (1) taking vitamin K antagonists (VKAs) or (2) without previous anticoagulation (no-OAC). Methods and Results— This is a multicenter cohort pilot study. Primary outcome measures were (1) occurrence of intracranial hemorrhage (ICH) in 3 categories: any ICH (ICHany), symptomatic ICH according to the criteria of the European Cooperative Acute Stroke Study II (ECASS-II) (sICHECASS-II) and the National Institute of Neurological Disorders and Stroke (NINDS) thrombolysis trial (sICHNINDS); and (2) death (at 3 months). Cohorts were compared by using propensity score matching. Our NOAC cohort comprised 78 patients treated with IVT/IAT and the comparison groups of 441 VKA patients and 8938 no-OAC patients. The median time from last NOAC intake to IVT/IAT was 13 hours (interquartile range, 8–22 hours). In VKA patients, median pre-IVT/IAT international normalized ratio was 1.3 (interquartile range, 1.1–1.6). ICHany was observed in 18.4% NOAC patients versus 26.8% in VKA patients and 17.4% in no-OAC patients. sICHECASS-II and sICHNINDS occurred in 2.6%/3.9% NOAC patients, in comparison with 6.5%/9.3% of VKA patients and 5.0%/7.2% of no-OAC patients, respectively. At 3 months, 23.0% of NOAC patients in comparison with 26.9% of VKA patients and 13.9% of no-OAC patients had died. Propensity score matching revealed no statistically significant differences. Conclusions— IVT/IAT in selected patients with ischemic stroke under NOAC treatment has a safety profile similar to both IVT/IAT in patients on subtherapeutic VKA treatment or in those without previous anticoagulation. However, further prospective studies are needed, including the impact of specific coagulation tests.

Recanalization Therapies in Acute Ischemic Stroke Patients: Impact of Prior Treatment with Novel Oral Anticoagulants on Bleeding Complications and Outcome - A Pilot Study

Background— We explored the safety of intravenous thrombolysis (IVT) or intra-arterial treatment (IAT) in patients with ischemic stroke on non-vitamin K antagonist oral anticoagulants (NOACs, last intake <48 hours) in comparison with patients (1) taking vitamin K antagonists (VKAs) or (2) without previous anticoagulation (no-OAC). Methods and Results— This is a multicenter cohort pilot study. Primary outcome measures were (1) occurrence of intracranial hemorrhage (ICH) in 3 categories: any ICH (ICHany), symptomatic ICH according to the criteria of the European Cooperative Acute Stroke Study II (ECASS-II) (sICHECASS-II) and the National Institute of Neurological Disorders and Stroke (NINDS) thrombolysis trial (sICHNINDS); and (2) death (at 3 months). Cohorts were compared by using propensity score matching. Our NOAC cohort comprised 78 patients treated with IVT/IAT and the comparison groups of 441 VKA patients and 8938 no-OAC patients. The median time from last NOAC intake to IVT/IAT was 13 hours (interquartile range, 8–22 hours). In VKA patients, median pre-IVT/IAT international normalized ratio was 1.3 (interquartile range, 1.1–1.6). ICHany was observed in 18.4% NOAC patients versus 26.8% in VKA patients and 17.4% in no-OAC patients. sICHECASS-II and sICHNINDS occurred in 2.6%/3.9% NOAC patients, in comparison with 6.5%/9.3% of VKA patients and 5.0%/7.2% of no-OAC patients, respectively. At 3 months, 23.0% of NOAC patients in comparison with 26.9% of VKA patients and 13.9% of no-OAC patients had died. Propensity score matching revealed no statistically significant differences. Conclusions— IVT/IAT in selected patients with ischemic stroke under NOAC treatment has a safety profile similar to both IVT/IAT in patients on subtherapeutic VKA treatment or in those without previous anticoagulation. However, further prospective studies are needed, including the impact of specific coagulation tests.

Prognostic relevance of cardiac troponin T levels and their dynamic changes measured with a high-sensitivity assay in acute ischaemic stroke: analyses from the TRELAS cohort.

BACKGROUND/OBJECTIVES To assess the prognostic relevance of cardiac troponin T (cTnT) values and their serial changes as measured with a high-sensitivity assay in acute ischaemic stroke. METHODS AND RESULTS In total, 1016 consecutive acute ischaemic stroke patients were registered prospectively within a two-year period. High-sensitivity cTnT was quantitated on admission and the following day. Patients were stratified into three groups: below the 99 th percentile of a healthy reference population (< 14 ng/l; n = 409), moderately elevated cTnT (below the median of remaining patients, 14-30 ng/l; n=299) and high cTnT (> 30 ng/l; n = 308). Outcome measures were unfavourable outcome (modified Rankin Scale ≥ 2 at hospital discharge, n=604) and in-hospital mortality (n = 36). Peak cTnT levels were significantly associated with unfavourable outcome (adjusted odds ratios versus reference for moderately elevated cTnT 1.7, 95% confidence interval [CI] 1.1-2.7 and for high cTnT 3.1, 95% CI 1.8-5.6). The optimal cut-off for determining unfavourable outcome proved to be 16 ng/l. Adding this cut-off to clinical variables led to a significant improvement of c-statistics (0.851 versus 0.838, p=0.02). Dynamic changes (δ ≥ 50%) of cTnT were detected in 137 patients (13%). Multiple Cox regression analysis showed an independent association of dynamic changes in cTnT with in-hospital mortality (hazard ratio 2.3, 95% CI 1.1-4.7). The model-fitting (p<0.001) and c-statistics (0.889 versus 0.863, p = 0.08) improved most after dynamic change in cTnT had been added to a regression model which included clinical variables alone. CONCLUSIONS Our study adds novel findings relevant for interpretation of highly sensitive cTnT assays in acute ischaemic stroke: a) Myocardial injury is detectable in more than half of patients; b) even moderately elevated cTnT is associated with unfavourable outcome (optimal cut-off 16 ng/l); and c) dynamic changes in cTnT indicate an increased risk of in-hospital death.

In-Hospital Stroke Recurrence and Stroke After Transient Ischemic Attack Frequency and Risk Factors

Background and Purpose— We aimed to assess the risk of recurrent ischemic events during hospitalization for stroke or transient ischemic attack (TIA) with optimal current management and to identify associated risk factors. Methods— We performed a retrospective analysis of all patients treated for acute ischemic stroke or TIA in 3 stroke units between 2010 and 2013. Recurrent stroke was defined as new persisting (≥24 hours) neurological deficit occurring >24 hours after the index event and not attributable to other causes of neurological deterioration. Cox proportional hazard regression identified risk factors associated with recurrent stroke. Results— The study included 5106 patients. During a median length of stay of 5 days (interquartile range, 4–8), stroke recurrence (or stroke after TIA) occurred in 40 patients (0.8%) and was independently associated with history of TIA, symptomatic carotid stenosis (≥70%), or other determined etiology. Patients with recurrent stroke and other determined etiology had cervical arterial dissection (n=2), primary angiitis of the central nervous system (n=1), giant cell arteritis (n=1), and lung cancer with nonbacterial thrombotic endocarditis (n=1). In patients with initial TIA or minor stroke (National Institutes of Health Stroke Scale ⩽5) recurrence was associated additionally with pneumonia after the inciting ischemic event but before stroke recurrence. Patients with initial stroke and aphasia had a lower stroke recurrence rate and there were no recurrences in patients with lacunar stroke. Recurrence was associated with significantly higher in-hospital mortality (17.5% versus 3.1%; P<0.001). Conclusions— In-hospital stroke recurrence was low with optimal current management. Patients with a history of TIA, severe symptomatic carotid stenosis, or uncommon causes of stroke were at higher risk. Pneumonia was associated with a higher risk of stroke recurrence in patients with initial TIA or minor stroke but not in the overall population studied. Aphasia may bias the detection rate by concealing new neurological symptoms.

Heart rate on admission independently predicts in-hospital mortality in acute ischemic stroke patients

BACKGROUND Higher heart rate (HR) is associated with worse outcomes - in particular death - in long term follow-up of patients with vascular diseases. We investigated the association between HR measured on admission and early in-hospital mortality in acute ischemic stroke patients. METHODS Over a period of 30 months all patients admitted to our hospital with acute ischemic stroke but without atrial fibrillation were prospectively enrolled. Univariate and multiple logistic regression analyses were conducted to estimate the impact of HR on in-hospital mortality. HR was analyzed as continuous and categorical variable (tertiles). RESULTS A total of 1335 patients (median age 73 (IQR 65-81), median National Institutes of Health Stroke Scale score 4 (IQR 2-8), median length of stay 5 days (IQR 4-7), female sex 46%) were studied. In-hospital mortality was 2.6%. When analyzed as categorical variable, HR ≥ 83 bpm was independently associated with in-hospital mortality after adjustment for predictors of poor outcome compared to the reference tertile (HR ≤ 69 bpm) (adjusted odds ratio 4.42, 95% CI 1.36-14.42, p=0.01). When HR was modeled as continuous variable, relative risk for in-hospital death was elevated by 40% for every additional 10-bpm (p=0.003). These results were not changed by including beta-blockers as covariate into the multiple regression model. CONCLUSIONS HR on admission is independently associated with in-hospital mortality in acute ischemic stroke patients suggesting early negative effects of autonomic imbalance. HR may represent a therapeutic target to improve outcome after ischemic stroke.

Microbleeds, Cerebral Hemorrhage, and Functional Outcome After Stroke Thrombolysis: Individual Patient Data Meta-Analysis

Background and Purpose— We assessed whether the presence, number, and distribution of cerebral microbleeds (CMBs) on pre-intravenous thrombolysis MRI scans of acute ischemic stroke patients are associated with an increased risk of intracerebral hemorrhage (ICH) or poor functional outcome. Methods— We performed an individual patient data meta-analysis, including prospective and retrospective studies of acute ischemic stroke treated with intravenous tissue-type plasminogen activator. Using multilevel mixed-effects logistic regression, we investigated associations of pre-treatment CMB presence, burden (1, 2–4, ≥5, and >10), and presumed pathogenesis (cerebral amyloid angiopathy defined as strictly lobar CMBs and noncerebral amyloid angiopathy) with symptomatic ICH, parenchymal hematoma (within [parenchymal hemorrhage, PH] and remote from the ischemic area [remote parenchymal hemorrhage, PHr]), and poor 3- to 6-month functional outcome (modified Rankin score >2). Results— In 1973 patients from 8 centers, the crude prevalence of CMBs was 526 of 1973 (26.7%). A total of 77 of 1973 (3.9%) patients experienced symptomatic ICH, 210 of 1806 (11.6%) experienced PH, and 56 of 1720 (3.3%) experienced PHr. In adjusted analyses, patients with CMBs (compared with those without CMBs) had increased risk of PH (odds ratio: 1.50; 95% confidence interval: 1.09–2.07; P=0.013) and PHr (odds ratio: 3.04; 95% confidence interval: 1.73–5.35; P<0.001) but not symptomatic ICH. Both cerebral amyloid angiopathy and noncerebral amyloid angiopathy patterns of CMBs were associated with PH and PHr. Increasing CMB burden category was associated with the risk of symptomatic ICH (P=0.014), PH (P=0.013), and PHr (P<0.00001). Five or more and >10 CMBs independently predicted poor 3- to 6-month outcome (odds ratio: 1.85; 95% confidence interval: 1.10–3.12; P=0.020; and odds ratio: 3.99; 95% confidence interval: 1.55–10.22; P=0.004, respectively). Conclusions— Increasing CMB burden is associated with increased risk of ICH (including PHr) and poor 3- to 6-month functional outcome after intravenous thrombolysis for acute ischemic stroke.

Ontology-Based Information Extraction: Identifying Eligible Patients for Clinical Trials in Neurology

In this paper, we present a case study in using ontologies within a system for identifying patients who are eligible for clinical trials. The main purpose of this clinical research data warehouse (CRDW) is to support patient recruitment based on routine data from the clinical information system. In contrast to most other systems for similar purposes, the CRDW also makes use of information extracted from clinical documents like admission reports, radiological findings and discharge letters. The so-called linguistic pipeline of the CDRW recognizes negated and coordinated phrases. It is supported by clinical application ontologies, which enable the identification of main terms and their properties, as well as semantic search with synonyms, hypernyms, and syntactic variants. In the paper, we discuss questions related to designing the ontologies and filling them with content. The CRDW is currently being tested at several departments of the Charité—Universitätsmedizin Berlin and the Vivantes—Netzwerk für Gesundheit GmbH. In the article, we provide a thorough evaluation of the deployed systems based on real data related to clinical trials conducted by our neurology departments.