Browsing by Author "Illanes, Sergio"
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Item Accuracy of diffusion-weighted imaging in the diagnosis of stroke in patients with suspected cerebral infarct(American Heart Association, 2013) Brunser, Alejandro; Hoppe, Arnold; Illanes, Sergio; Díaz, Violeta; Muñoz, Paula; Cárcamo, Daniel; Olavarría, Verónica; Valenzuela, Marcela; Lavados, PabloBACKGROUND AND PURPOSE: The accuracy of diffusion-weighted imaging (DWI) for the diagnosis of acute cerebral ischemia among patients with suspected ischemic stroke arriving to an emergency room has not been studied in depth. METHODS: DWI was performed in 712 patients with acute or subacute focal symptoms that suggested an acute ischemic stroke (AIS), 609 of them with AIS. RESULTS: DWI demonstrated a sensitivity of 90% and specificity of 97%, a positive likelihood ratio of 31 and a negative likelihood ratio of 0.1 for detecting AIS. The overall accuracy was 95%. Of those patients who demonstrated abnormal DWI studies, 99.5% were AIS patients, and of those patients with normal DWI studies 63% were stroke mimics. CONCLUSIONS: DWI is accurate in detecting AIS in unselected patients with suspected AIS; a negative study should alert for nonischemic conditions.Item Exclusion Criteria for Intravenous Thrombolysis in Stroke Mimics: An Observational Study(2013) Brunser, Alejandro M.; Illanes, Sergio; Lavados, Pablo; Muñoz, Paula; Carcamo, Daniel; Hoppe, Arnold; Olavarria, Verónica; Delgado, Iris; Dıaz, VioletaBackground: Stroke mimics (SMs) are frequent in emergency departments (EDs), but are treated infrequently with intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis. We aimed at identifying the factors that lead to the exclusion of SMs from thrombolytic therapy.Methods: Consecutive patients presenting to the ED between December 2004 and March 2011 with symptoms that suggested acute ischemic stroke were included.Results: Eight hundred forty-two patients were included in this study; 113 (13.4%) were considered SMs; these patients were younger (P = .01), more frequently diabetic (P = .001), arrived later to the ED (P = .03), had lower National Institutes of Health Stroke Scale scores (P < .001), and higher frequencies of negative diffusion-weighted imaging studies (P = .002). The most common causes of cases of SM were toxic metabolic disorders (n = 34 [30.1%]) and seizures (n = 22 [19.5%]). The most frequent cause of consultation was aphasia (n = 43 [37.6%]). SM patients had a total of 152 contraindications for rt-PA, with 34 (30%) patients having >1 contraindication. The most frequent of these were being beyond the therapeutic window for thrombolysis (n = 96) and having deficits not measurable by the National Institutes of Health Stroke Scale or very mild symptoms before the start of rt-PA (n = 37). Twenty-four (21.2%) patients had both contraindications simultaneously. Two patients (1.76%) in the SM group were candidates for rt-PA but did not receive this treatment because they or their family rejected it. Of 729 stroke patients, 87 (11.9%) did receive rt-PA.Conclusions: SM patients frequently had exclusion criteria for systemic thrombolysis, the most frequent being presenting beyond the established thrombolytic windowItem Exclusion criteria for intravenous thrombolysis in stroke mimics: an observational study(Elsevier, 2013) Brunser, Alejandro; Illanes, Sergio; Lavados, Pablo; Muñoz, Paula; Carcamo, Daniel; Hoppe, Arnold; Olavarría, Verónica; Delgado, Iris; Diaz, VioletaBACKGROUND: Stroke mimics (SMs) are frequent in emergency departments (EDs), but are treated infrequently with intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis. We aimed at identifying the factors that lead to the exclusion of SMs from thrombolytic therapy. METHODS: Consecutive patients presenting to the ED between December 2004 and March 2011 with symptoms that suggested acute ischemic stroke were included. RESULTS: Eight hundred forty-two patients were included in this study; 113 (13.4%) were considered SMs; these patients were younger (P = .01), more frequently diabetic (P = .001), arrived later to the ED (P = .03), had lower National Institutes of Health Stroke Scale scores (P < .001), and higher frequencies of negative diffusion-weighted imaging studies (P = .002). The most common causes of cases of SM were toxic metabolic disorders (n = 34 [30.1%]) and seizures (n = 22 [19.5%]). The most frequent cause of consultation was aphasia (n = 43 [37.6%]). SM patients had a total of 152 contraindications for rt-PA, with 34 (30%) patients having >1 contraindication. The most frequent of these were being beyond the therapeutic window for thrombolysis (n = 96) and having deficits not measurable by the National Institutes of Health Stroke Scale or very mild symptoms before the start of rt-PA (n = 37). Twenty-four (21.2%) patients had both contraindications simultaneously. Two patients (1.76%) in the SM group were candidates for rt-PA but did not receive this treatment because they or their family rejected it. Of 729 stroke patients, 87 (11.9%) did receive rt-PA. CONCLUSIONS: SM patients frequently had exclusion criteria for systemic thrombolysis, the most frequent being presenting beyond the established thrombolytic window.Item Hematoma size as major modulator of the cellular immune system after experimental intracerebral hemorrhage(2011) Illanes, Sergio; Liesz, Arthur; Sun, Li; Dalpke, Alexander; Zorn, Markus; Veltkamp, RolandInflammatory cascades are increasingly recognized as an important pathophysiological mechanism in intracerebral hemorrhage (ICH). In contrast, the effect of ICH on the systemic immune system has barely been investigated. We examined the effects of different hematoma volumes on immune cell subpopulations in experimental murine ICH. In C57BL/6 mice, ICH was induced by striatal injection of autologous blood (10,30 or 50 mu L). Control animals received the respective sham operation. Three days after ICH induction, differential blood leukocyte counting was performed. Lymphocyte subpopulations were further characterized by flow cytometry in blood, spleen, lymph node and thymus. Infectious complications were studied using microbiological cultures of blood and lungs. Only after large ICH a marked decrease of leukocyte counts and most lymphocyte subsets was observed in all organs. Despite this general leuko-cytopenia, a significant, up to 10-fold increase, was detected in the monocyte population after extensive hemorrhage. After moderate ICH induction, only specific lymphocyte subpopulations were differentially affected. Mature thymic cells were unaffected while immature CD4+CD8+ cells were depleted by over 90% after large ICH. A significant proportion of mice with extensive ICH (36.4%) developed spontaneous pneumonia and/or bacteremia while none of the sham operated mice had infectious complications. The ICH size determines the extent of systemic immunomodulation. Large ICH predisposes animals to infections. (C) 2011 Published by Elsevier Ireland Ltd.Item Intraventricular Bleeding and Hematoma Size as Predictors of Infection Development in Intracerebral Hemorrhage: A Prospective Cohort Study(Elsevier, 2016) Vial Undurraga, Felipe; Brunser, Alejandro; Lavados, Pablo; Illanes, SergioBACKGROUND: Acute intracerebral hemorrhage (ICH) is associated with increased susceptibility to bacterial infection. The physiopathology of this phenomenon is not very clear. We conducted a prospective observational study investigating the correlation and independent predictors of infections in patients with ICH. PATIENTS AND METHODS: Patients admitted between April 1997 and June 2013 with ICH diagnosis were evaluated for inclusion and exclusion criteria. RESULTS: Two hundred twenty-two patients were included in this study. Ninety four patients (42.6%) presented with an infection during hospitalization being more common than pneumonia (30%) and urinary tract infections (14%). Intraventricular hemorrhage (IVH) (95% confidence interval [CI], 62.7% versus 39.3%; P < .001) and higher ICH score (95% CI, 2.31% versus 1.67%; P = .0014) were more common in patients who had infections. We found the following risk factors for having an infection in patients with ICH: IVH (odds ratio [OR] 2.3; 95% IC, 1.3-4.1), each point of ICH score (OR 1.3; 95% CI, 1.1-1.6), and having a hematoma volume larger than 30 cc (OR 2.0; 95% CI, 1.1-3.5). The localization of the hematoma was not found to be relevant. CONCLUSIONS: ICH score, size of the hematoma, and presence of IVH are independent risk factors for having an infection after ICH.Item Reliability of hand-held transcranial doppler with M-mode ultrasound in middle cerebral artery measurement(Elsevier, 2017) Muñoz, Paula; Gaete, Javier; Illanes, Sergio; López, Javiera; Olavarría, Verónica; Reccius, Andrés; Brinck, Pablo; González, Francisca; Cavada, Gabriel; Lavados, Pablo; Brunser, AlejandroPurpose: To determine the intra- and interrater agreement of mean flow velocity (MFV) and pulsatility index (PI) measurement in middle cerebral arteries, assessed by transcranial Doppler (TCD) with M-mode. Methods: Masked experienced neurosonologists performed TCD with M-mode using handheld probe in healthy adult volunteers. The Bland–Altman method for concordance and intraclass correlation coefficient were used. Results: Seventy-seven healthy volunteers and seven raters participated (3 on regular TCD shift and 4 off-shift). The intrarater absolute mean difference between measurements was 5.5 cm/s [95% confidence interval (CI), 4.7–6.3] for MVF and 0.073 (95% CI, 0.063–0.083) for PI. The difference between MFV measurements was significantly higher in off-shift raters (p = 0.015). The interrater absolute mean difference between measurements was 6.5 cm/s (95% CI, 5.5–7.5) for MVF and 0.065 (95% CI, 0.059–0.071) for PI. No influence was found for the middle cerebral artery side, volunteer's sex, or age, and there was no significant difference between raters. The intraclass correlation coefficient was 82.2% (95% CI 77.8–85.6) and 72.9% (95% CI 67.4–77.6) for MFV and PI, respectively. Conclusions: There exists good intra- and interrater agreement in MFV and PI measurements using M-mode TCD. These results support the use of this noninvasive tool and are important for clinical and investigational purposes.Item Trombolisis intravenosa en cuadros imitadores de isquemia cerebral: experiencia de un centro(Sociedad Medica de Santiago, 2016) Brunser, Alejandro; Hoppe, Arnold; Muñoz, Paula; Lavados, Pablo; Illanes, Sergio; Diaz, Violeta; Olavarria, VeronicaBackground: The effectiveness of intravenous thrombolysis (IVT) in cerebral ischemia is time dependent. Stroke mimics (SM) are frequent in emergency rooms. The effort to reduce door to needle time, can lead to administer thrombolytics to SM. Aim: To describe the frequency and prognosis of SM treated with IVT. Material and Methods: Prospective analysis of all patients evaluated in a Chilean private clinic between December 2004 and July 2015 with a suspected acute ischemic stroke (AIS). We calculated the number of SM that were treated with IVT. In these patients, we analyzed the presence of symptomatic cerebral hemorrhage defined as the presence of a neurological deterioration of four points or more on the National Institute of Health Stroke Scale, the presence of extracranial bleeding according to Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries criteria and the patient’s functional status at three months by modified Rankin scale (MRS). Results: We evaluated 1,417 patients with suspected AIS, of which 240 (16.9%) were finally diagnosed as SM. A total of 197 patients were treated with IVT, of these 10 (5%) corresponded to SM. All SM patients treated with thrombolytic drugs were functionally independent at 3 months and showed no bleeding complications. Conclusions: Occasionally SM patients were treated with IVT. This treatment was not associated with bleeding complications and the prognosis of these patients at three months was favorable.