Latisha K Ali

CT and MRI Early Vessel Signs Reflect Clot Composition in Acute Stroke

Background and Purpose— The purpose of this study was to provide the first correlative study of the hyperdense middle cerebral artery sign (HMCAS) and gradient-echo MRI blooming artifact (BA) with pathology of retrieved thrombi in acute ischemic stroke. Methods— Noncontrast CT and gradient-echo MRI studies before mechanical thrombectomy in 50 consecutive cases of acute middle cerebral artery ischemic stroke were reviewed blinded to clinical and pathology data. Occlusions retrieved by thrombectomy underwent histopathologic analysis, including automated quantitative and qualitative rating of proportion composed of red blood cells (RBCs), white blood cells, and fibrin on microscopy of sectioned thrombi. Results— Among 50 patients, mean age was 66 years and 48% were female. Mean (SD) proportion was 61% (±21) fibrin, 34% (±21) RBCs, and 4% (±2) white blood cells. Of retrieved clots, 22 (44%) were fibrin-dominant, 13 (26%) RBC-dominant, and 15 (30%) mixed. HMCAS was identified in 10 of 20 middle cerebral artery stroke cases with CT with mean Hounsfield Unit density of 61 (±8 SD). BA occurred in 17 of 32 with gradient-echo MRI. HMCAS was more commonly seen with RBC-dominant and mixed than fibrin-dominant clots (100% versus 67% versus 20%, P=0.016). Mean percent RBC composition was higher in clots associated with HMCAS (47% versus 22%, P=0.016). BA was more common in RBC-dominant and mixed clots compared with fibrin-dominant clots (100% versus 63% versus 25%, P=0.002). Mean percent RBC was greater with BA (42% versus 23%, P=0.011). Conclusions— CT HMCAS and gradient-echo MRI BA reflect pathology of occlusive thrombus. RBC content determines appearance of HMCAS and BA, whereas absence of HMCAS or BA may indicate fibrin-predominant occlusive thrombi.

A Brief Prehospital Stroke Severity Scale Identifies Ischemic Stroke Patients Harboring Persisting Large Arterial Occlusions

Background and Purpose— The Los Angeles Motor Scale (LAMS) is a brief 3-item stroke severity assessment measure designed for prehospital and Emergency Department use. Methods— The LAMS and NIHSS were scored in under-12-hour acute anterior circulation ischemic stroke patients. Stroke severity ratings were correlated with cervicocerebral vascular occlusion on CTA, MRA, and catheter angiography. Receiver operating curves, c statistics, and likelihood ratios were used to evaluate the predictive value for vascular occlusion of stroke severity ratings. Results— Among 119 patients, mean age was 67 (±18), 45% were male. Time from onset to ED arrival was mean 190 minutes (range 10 to 660). Persisting large vessel occlusions (PLVOs) were present in 62% of patients. LAMS stroke severity scores were higher in patients harboring a vascular occlusion, median 5 (IQR 4 to 5) versus 2 (IQR 1 to 3). Similarly, NIHSS stroke severity scores were higher in PLVO patients, 19 (14 to 24) versus 5 (3 to 7). ROC curves demonstrated that the LAMS was highly effective in identifying patients with PLVOs, c statistic 0.854. At the optimal threshold of 4 or higher, LAMS scores showed sensitivity 0.81, specificity 0.89, and overall accuracy 0.85. LAMS performance was comparable to NIHSS performance (c statistic 0.933). The positive likelihood ratio associated with a LAMS score ≥4 was 7.36 and the negative likelihood ratio 0.21. Conclusions— Stroke severity assessed by the LAMS predicts presence of large artery anterior circulation occlusion with high sensitivity and specificity. The LAMS is a promising instrument for use by prehospital personnel to identify select stroke patients for direct transport to Comprehensive Stroke Centers capable of endovascular interventions.

Early Neutrophilia Is Associated With Volume of Ischemic Tissue in Acute Stroke

Background and Purpose— Few data exist on the relationship between differential subpopulations of peripheral leukocytes and early cerebral infarct size in ischemic stroke. Using diffusion-weighted MR imaging (DWI), we assessed the relationship of early total and differential peripheral leukocyte counts and volume of ischemic tissue in acute stroke. Methods— All included patents had laboratory investigations and neuroimaging collected within 24 hours of stroke onset. Total peripheral leukocyte counts and differential counts were analyzed individually and by quartiles. DWI lesions were outlined using a semiautomated threshold technique. The relationship between leukocyte quartiles and DWI infarct volumes was examined using multivariate quartile regression. Results— 173 patients met study inclusion criteria. Median age was 73 years. Total leukocyte counts and DWI volumes showed a strong correlation (Spearman rho=0.371, P<000.1). Median DWI volumes (mL) for successive neutrophil quartiles were: 1.3, 1.3, 3.2, and 20.4 (P for trend <0.001). Median DWI volumes (mL) for successive lymphocyte quartiles were: 3.2, 8.1, 1.3, and 1.5 (P=0.004). After multivariate analysis, larger DWI volume remained strongly associated with higher total leukocyte and neutrophil counts (both probability values <0.001), but not with lymphocyte count (P=0.4971). Compared with the lowest quartiles, DWI volumes were 8.7 mL and 12.9 mL larger in the highest quartiles of leukocyte and neutrophil counts, respectively. Conclusions— Higher peripheral leukocyte and neutrophil counts, but not lymphocyte counts, are associated with larger infarct volumes in acute ischemic stroke. Attenuating neutrophilic response early after ischemic stroke may be a viable therapeutic strategy and warrants further study.

Prediction of hemorrhagic transformation after recanalization therapy using T2*-permeability magnetic resonance imaging

Predicting hemorrhagic transformation (HT) is critical in the setting of recanalization therapy for acute stroke. Dedicated magnetic resonance imaging (MRI) sequences for detection of increased blood–brain barrier (BBB) permeability recently have been developed. We evaluated the ability of a novel MRI permeability technique to detect baseline derangements predictive of various forms of HT after recanalization therapy.

Cholesterol level and symptomatic hemorrhagic transformation after ischemic stroke thrombolysis

Background: Prestroke statin use may improve ischemic stroke outcomes, yet there is also evidence that statins and extremely low cholesterol levels may increase the risk of intracranial hemorrhage. We evaluated the independent effect of statin use and admission cholesterol level on risk of symptomatic hemorrhagic transformation (sHT) after recanalization therapy for acute ischemic stroke. Methods: We analyzed ischemic stroke patients recorded in a prospectively maintained registry that received recanalization therapies (IV or intra-arterial fibrinolysis or endovascular embolectomy) at a university medical center from September 2002 to May 2006. The independent effect of premorbid statin use on sHT post intervention was evaluated by logistic regression, adjusting for prognostic and treatment variables known to predict increased HT risk after ischemic stroke. Results: Among 104 patients, mean age was 70 years, and 49% were men. Male sex, hypertension, statin use, low total cholesterol and low-density lipoprotein (LDL) cholesterol, current smoking, elevated glucose levels, and higher admission NIH Stroke Scale (NIHSS) score were all associated with a greater risk of sHT in univariate analysis. After adjusting for covariates, low LDL cholesterol (odds ratio [OR], 0.968 per 1-mg/dL increase; 95% CI, 0.941 to 0.995), current smoking (OR, 14.568; 95% CI, 1.590 to 133.493), and higher NIHSS score (OR, 1.265 per 1-point increase; 95% CI, 1.047 to 1.529) were independently associated with sHT risk. Conclusions: Lower admission low-density lipoprotein cholesterol level with or without statin use, current smoking, and greater stroke severity are associated with greater risk for symptomatic hemorrhagic transformation after recanalization therapy for ischemic stroke.

Statin enhancement of collateralization in acute stroke

Collateral circulation influences cerebral infarction occurrence and size. Statins may improve ischemic stroke outcomes. We evaluated the relationship between prestroke statin use and pretreatment angiographic collateral grade among acute ischemic stroke patients presenting with occlusion of a major cerebral artery. After adjusting for covariates, the statin-treated group had significantly higher collateral scores than non–statin users, suggesting an association between statin use and better collateralization during acute stroke.

Leukoaraiosis Predicts Parenchymal Hematoma After Mechanical Thrombectomy in Acute Ischemic Stroke

Background and Purpose— The purpose of this study was to determine whether leukoaraiosis (LA) predicts hemorrhagic transformation and poor outcome in patients with acute ischemic stroke treated by mechanical thrombectomy. Methods— We retrospectively analyzed patients with anterior circulation stroke treated with Merci devices and identified LA in the deep white matter (DWM) and periventricular white matter on the preintervention MR images. We dichotomized patients into those with moderate or severe LA in the DWM versus those without. Hemorrhage rates and outcomes were evaluated between 2 groups. We analyzed the association of moderate or severe LA with hemorrhagic transformation and poor outcome. Results— Twenty-six of 105 patients had moderate or severe LA in the DWM. Patients with moderate or severe LA in the DWM were older, had more severe neurological deficits and worse outcome, had higher rates of hemorrhagic transformation and parenchymal hematoma, but had equivalent rates of hemorrhagic infarct and subarachnoid hemorrhage when compared with those without. Patients with only periventricular LA did not have a higher rate of parenchymal hematoma. Moderate or severe LA in the DWM was an independent predictor of hemorrhagic transformation (OR, 3.4; P=0.019) and parenchymal hematoma (OR, 6.3; P=0.005). Patients with parenchymal hematoma were less often independent (modified Rankin Scale ⩽2, 3.8% versus 32.5%; P=0.003) and had greater in-hospital mortality (50% versus 10.4%; P<0.001). Conclusions— Moderate or severe LA in the DWM increases the risk of parenchymal hematoma after Merci thrombectomy for patients with acute stroke. These findings require validation in a larger prospective study.

Predictors of Subarachnoid Hemorrhage in Acute Ischemic Stroke With Endovascular Therapy

Background and Purpose— Subarachnoid hemorrhage (SAH) is a potential hemorrhagic complication after endovascular intracranial recanalization. The purpose of this study was to describe the frequency and predictors of SAH in acute ischemic stroke patients treated endovascularly and its impact on clinical outcome. Methods— Acute ischemic stroke patients treated with primary mechanical thrombectomy, intra-arterial thrombolysis, or both were analyzed. Postprocedural computed tomography and magnetic resonance images were reviewed to identify the presence of SAH. We assessed any decline in the National Institutes of Health Stroke Scale score 3 hours after intervention and in the outcomes at discharge. Results— One hundred twenty-eight patients were treated by primary thrombectomy with MERCI Retriever devices, whereas 31 were treated by primary intra-arterial thrombolysis. Twenty patients experienced SAH, 8 with pure SAH and 12 with coexisting parenchymal hemorrhages. SAH was numerically more frequent with primary thrombectomy than in the intra-arterial thrombolysis groups (14.1% vs 6.5%, P=0.37). On multivariate analysis, independent predictors of SAH were hypertension (odds ratio=5.39, P=0.035), distal middle cerebral artery occlusion (odds ratio=3.53, P=0.027), use of rescue angioplasty after thrombectomy (odds ratio=12.49, P=0.004), and procedure-related vessel perforation (odds ratio=30.72, P<0.001). Patients with extensive SAH or coexisting parenchymal hematomas tended to have more neurologic deterioration at 3 hours (28.6% vs 0%, P=0.11), to be less independent at discharge (modified Rankin Scale ≤2; 0% vs 15.4%, P=0.5), and to experience higher mortality during hospitalization (42.9% vs 15.4%, P=0.29). Conclusions— Procedure-related vessel perforation, rescue angioplasty after thrombectomy with MERCI devices, distal middle cerebral artery occlusion, and hypertension were independent predictors of SAH after endovascular therapy for acute ischemic stroke. Only extensive SAH or SAH accompanied by severe parenchymal hematomas may worsen clinical outcome at discharge.

The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) Study Protocol

Background and Purpose— Epidemiological studies of intracerebral hemorrhage (ICH) have consistently demonstrated variation in incidence, location, age at presentation, and outcomes among non-Hispanic white, black, and Hispanic populations. We report here the design and methods for this large, prospective, multi-center case–control study of ICH. Methods— The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study is a multi-center, prospective case–control study of ICH. Cases are identified by hot-pursuit and enrolled using standard phenotype and risk factor information and include neuroimaging and blood sample collection. Controls are centrally identified by random digit dialing to match cases by age (±5 years), race, ethnicity, sex, and metropolitan region. Results— As of March 22, 2013, 1655 cases of ICH had been recruited into the study, which is 101.5% of the target for that date, and 851 controls had been recruited, which is 67.2% of the target for that date (1267 controls) for a total of 2506 subjects, which is 86.5% of the target for that date (2897 subjects). Of the 1655 cases enrolled, 1640 cases had the case interview entered into the database, of which 628 (38%) were non-Hispanic black, 458 (28%) were non-Hispanic white, and 554 (34%) were Hispanic. Of the 1197 cases with imaging submitted, 876 (73.2%) had a 24 hour follow-up CT available. In addition to CT imaging, 607 cases have had MRI evaluation. Conclusions— The ERICH study is a large, case–control study of ICH with particular emphasis on recruitment of minority populations for the identification of genetic and epidemiological risk factors for ICH and outcomes after ICH.

Indices of Kidney Dysfunction and Discharge Outcomes in Hospitalized Stroke Patients without Known Renal Disease

Background: The utility of clinical measurements of impairments in glomerular barrier or filtration rate among hospitalized stroke patients without known chronic kidney disease (CKD) has not been well studied. We determined whether various indices of CKD would predict discharge outcomes in persons hospitalized with a recent ischemic stroke. Methods: Presence of proteinuria and estimated low glomerular filtration rate (GFR) <60 ml/min per 1.73 m2 on admission were assessed in consecutive ischemic stroke and transient ischemic attack patients admitted to a university hospital over 18 months, who had no history of CKD. The primary discharge outcomes assessed (among stroke patients only) were death or disability (modified Rankin Scale score ≥2) and being discharged home directly from hospital. Independent effects of CKD indices on the outcomes were evaluated using multivariable regression modeling. Results: Of 251 patients with recent ischemic cerebrovascular events, 198 ischemic stroke patients (79%), met the study criteria. In crude analyses, persons with proteinuria or low GFR were significantly more likely to die in the hospital (p < 0.05). After adjusting for confounders, proteinuria was independently linked with lower odds of going home directly from the hospital (OR = 0.38, 95% CI = 0.16–0.92) and poorer discharge functional status (OR = 3.19, 95% CI = 1.37–7.46), but low GFR was not independently related to either of these outcomes. Conclusions: Among hospitalized ischemic stroke patients without known CKD, presence of proteinuria on admission is independently associated with poorer discharge functional activity and lower likelihood of being discharged home directly. Low GFR was not related to either outcome in these patients without known CKD.