Browsing by Author "Diaz, Violeta"
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Item Additional Information Given to a Multimodal Imaging Stroke Protocol by Transcranial Doppler Ultrasound in the Emergency Room: A Prospective Observational Study(2010) Brunser, Alejandro M.; Lavados, Pablo; Cárcamo, Daniel A.; Hoppe, Arnold; Olavarría, Verónica; Diaz, Violeta; Rivas, RodrigoBackground: Transcranial Doppler (TCD) ultrasound can demonstrate dynamic information. We aimed to evaluate whether TCD generates useful additional information in the emergency room after a multimodal stroke imaging protocol and also whether this modified the management of patients with cerebral infarction. Methods: Patients admitted between April 2006 and June 2007 with ischemic stroke of less than 24 h were subjected to a protocol consisting of non-contrast brain CT, computed tomography angiography, diffusion-weighted magnetic resonance imaging and then TCD within the following 6 h by an observer blinded to the results of imaging studies. Results: Seventy-nine patients were included. The imaging protocol was performed 457 (+/-346) min after stroke symptoms and TCD after 572 (+/-376) min. TCD provided additional information in 28 cases (35.4%, 95% CI 25.7-46.4). More that one piece of additional information was obtained in 6 patients. The most frequent additional information was collateral pathways. Multivariate analysis demonstrated that intracranial vessel occlusion was the variable most associated with additional information. In 7 patients (8.8%, 95% CI 4.3-17.1), additional information changed management: in 4 an additional angiography was performed, in 2 patients angiography was suspended and in 1 aggressive neurocritical care was indicated. Patients with NIHSS >10 were significantly more likely to have their initial treatment changed (p = 0.004). Conclusions: TCD can provide additional information to a multimodal acute ischemic stroke imaging protocol in a third of patients. This can result in changes in the management in some of these patients.Publication Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography(2023) Cheng, Kevin; Lin, Andrew; Stecher, Ximena; Bernstein, Tomas; Zuñiga, Paulo; Mazzon, Enrico; Brunse, Alejandro; Diaz, Violeta; Martinez, Gonzalo; Cameron, William; Nicholls, Stephen; Patel, Sanjay; Dey, Damini; Wong, Dennis; Muñoz Venturelli, PaulaBackground: Spontaneous cervical artery dissection (sCAD) is a leading cause of ischemic stroke in young patients. Studies using high-resolution magnetic resonance imaging and positron emission tomography have suggested vessel wall inflammation to be a pathogenic factor in sCAD. Computed tomography (CT) attenuation of perivascular adipose tissue (PVAT) is an established non-invasive imaging biomarker of inflammation in coronary arteries, with higher attenuation values reflecting a greater degree of vascular inflammation. Objectives: We evaluate the CT attenuation of PVAT surrounding the internal carotid artery (PVATcarotid) with and without spontaneous dissection. Methods: Single-centre prospective observational study of 56 consecutive patients with CT-verified spontaneous dissection of the internal carotid artery (ICA) admitted between 2011 and 2018. Of these patients, 6 underwent follow-up CTA. 22 patients who underwent CTA for acute neurological symptoms but did not have dissection formed the control group. Using semiautomated research software, PVATcarotid was measured as the mean Hounsfield Unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA. Results: PVATcarotid was significantly higher around dissected ICA compared with non-dissected contralateral ICA in the same patients (-58.7±10.2 vs. -68.9±8.1 HU, P<0.0001) and ICA of patients without dissection (-58.7±10.2 vs. -69.3±9.3 HU, P<0.0001). After a median follow-up of 89 days, there was a significant reduction in PVATcarotid around dissected ICA (from -57.5±13.4 to -74.3±10.5 HU, P<0.05); while no change was observed around non-dissected contralateral ICA (from -71.0±4.4 to -74.1±4.1 HU, P=0.19). ICA dissection was an independent predictor of PVATcarotid following multivariable adjustment for age and the presence of ICA occlusion.Item 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 Transcranial doppler as a predictor of ischemic events in carotid artery dissection(Wiley, 2017) Brunser, Alejandro; Lavados, Pablo; Hoppe, Arnold; Muñoz Venturelli, Paula; Sujima, Emi; Lopez, Javiera; Eloy, Mansilla; Carcamo, Daniel; Diaz, VioletaAbstract BACKGROUND: We aim to evaluate clinical features and transcranial Doppler (TCD) elements, as predictors of the development of ischemic events (IEs) in patients suffering from spontaneous carotid arterial dissection without stroke (CCADW). METHODS: Consecutive patients with CCADW, seen in Clínica Alemana de Santiago between April 2004 and January 2015, were evaluated clinically, and with TCD, microembolic signals (MES) monitoring and breath hold Index (BHI) test were performed. RESULTS: Forty-one patients with 45 CCADW were included. Mean age 41.9 years, 31 male, and 12 (29.1%) patients present with multiple CCADW. At the moment of TCD evaluation, 17 (41.4%) patients were being treated with antiplatelets and the rest under Heparin. TCD monitoring lasted in average 53.3 minutes and demonstrated at the moment of evaluation, MES in four carotid arteries (11.1%) of 3 patients and 13 (28.8%) abnormal BHI in 11 patients. Six IEs occurred in 3 patients, 3 strokes, and 3 transient ischemic attacks. In the univariate analysis correlating IE with clinical and ultrasonographic findings, the degree of carotid stenosis, the presence of multiple CAD, and the presence of MES plus abnormalities of BHI were significantly associated with the risk of an IE. Multivariable analysis showed that only the presence of MES plus abnormal BHI were significant (P < .001). MES and abnormal BHI were present in the 3 patients and in four arterial territories that had IE. CONCLUSIONS: TCD can identify a subgroup of patients with CCADW who are at high risk of IE.Item Transcranial Doppler in a Hispanic-Mestizo population with neurological diseases: a study of sonographic window and its determinants(John Wiley & Sons, 2012) Brunser, Alejandro; Silva, Claudio; Carcamo, Daniel; Muñoz, Paula; Hoppe, Arnold; Olavarría, Verónica; Diaz, Violeta; Abarca, JuanBetween 5% and 37% of patients are not suitable for transtemporal insonation with transcranial Doppler (TCD). This unsuitability is particularly frequent in elderly females and non-Caucasians. We aim to evaluate TCD efficiency in a mixed Hispanic population in Santiago, Chile and to determine whether factors associated with the presence of optimal windows depend exclusively on patient-related elements. Seven hundred forty-nine patients were evaluated with power mode TCD. Optimal temporal windows (TWs) included detection of the middle, anterior, posterior cerebral arteries and terminal carotid. The patient's age and sex, the location of the examination, the time of day, whether the test was conducted on weekends and whether mechanical ventilation was used were recorded. Percentages of optimal windows were calculated. Examinations were deemed ideal if both TWs were optimal. TWs were obtained in 82% of cases. In univariate analyses, male sex (P < 0.001), an age below 60 years (P < 0.0001) and mechanical ventilation (P= 0.04) correlated with ideal TWs. Using logistic regression where dependent variable was a non-ideal window only male sex odds ratio (OR) 2.3 (1.51–3.45) and age below 60 OR 13.8 (7.8–24.6) were statistically significant. Our findings indicate that Hispanic populations have detection rates for TWs similar to Europeans and are affected by patient-related elements.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.