Browsing by Author "Díaz, Violeta"
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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.Publication Cervical artery dissection in postpartum women after cesarean and vaginal delivery(2022) Urrutia, Francisca; Mazzon, Enrico; Brunser, Alejandro; Díaz, Violeta; Calderon, Juan; Stecher, Ximena; Bernstein, Tomas; Zuñiga, Paulo; Schilling, Andrea; Muñoz, PaulaBackground and aims: Cervical artery dissection (CAD) is an infrequent but potentially disabling and fatal disease, accounting for up to 25 % of strokes in young adults. Pregnancy-related hormonal changes and increased hemodynamic stress on artery walls during vaginal delivery have been associated to CAD. We aim to describe a series of women presenting CAD during postpartum (PP) after cesarean and vaginal delivery. Methods: CAD women admitted to one hospital in Santiago, Chile, between July 2018 and October 2020 were included in a prospective cohort. Demographic, clinical and imaging data were registered for the PP group. Results: Sixty-seven women were diagnosed with CAD, from which 10 were PP. Seven women had cesarean section and 3 had vaginal delivery. They presented CAD related symptoms after a median of 10.5 (IQR 5-15) days from delivery. All of them had headache as initial symptom, 9 presented cervical pain and 8 had a family history of stroke. Four patients presented preeclampsia during pregnancy. Acute treatment consisted mostly in antiplatelet agents and analgesics. None of these patients had a CAD related stroke. Demographic, clinical and imaging characteristics of these women with CAD during PP are described. Conclusions: This case series underpins the importance of clinical suspicion of CAD after delivery, highlighting the fact that CAD is not limited to women with vaginal delivery, thus alternative causes beyond acute hemodynamic stress could be involved. Further research is required to determine genetic components, along with deeper knowledge of modulating factors related to CAD in this setting.Item Cryptococcus bacillisporus (VGIII) Meningoencephalitis Acquired in Santa Cruz, Bolivia(2021) Thompson, Luis; Porte, Lorena; Díaz, Violeta; Díaz, María; Solar, Sebastián; Valenzuela, Pablo; Norley, Nicole; Pires, Yumai; Carreño, Fernando; Valenzuela, Sergio; Shabani, Rukmane; Rickerts, Volker; Weitzel, ThomasWe describe a case of chronic meningoencephalitis with hydrocephalus caused by Cryptococcus bacillisporus (VGIII) in an immunocompetent patient from Santa Cruz, Bolivia. This first report of a member of the Cryptococcus gattii species complex from Bolivia suggests that C. bacillisporus (VGIII) is present in this tropical region of the country and complements our epidemiological and clinical knowledge of this group of emerging fungal pathogens in South America.Item Diffusion-weighted imaging determinants for acute ischemic stroke diagnosis in the emergency room(2018) Brunser, Alejandro M.; Cavada, Gabriel; Muñoz Venturelli, Paula; Olavarría, Verónica; Rojo, Alexis; Almeida, Juan; Díaz, Violeta; Hoppe, Arnold; Lavados, PabloPurpose The aim of this study was to investigate the clinical-radiological determinants of diffusion-weighted image (DWI) abnormalities in patients with suspected acute ischemic stroke (AIS) seen at the emergency room (ER). Methods During the study period, 882 consecutive patients were screened at Clínica Alemana de Santiago, Chile; 786 had AIS and 711 (90.4%) were included. Results DWI demonstrated 87.3% sensitivity and 99.0% specificity, with a positive likelihood ratio of 79 and a negative likelihood ratio of 0.13 for the detection of AIS. In the univariate analysis, a positive DWI in AIS was associated with admission National Institute of Health Stroke Scale (NIHSS) score (OR 1.09, 95% CI 1.04–1.1%), time from symptom onset to DWI (OR 1.03, 95% CI 1.01–1.05), presence of a relevant intracranial artery occlusion (OR 3.18, 95% CI 1.75–5.76), posterior circulation ischemia (OR 0.44, 95% CI 0.28–0.7), brainstem location of the AIS (OR 0.16, 95% CI 0.093–0.27), infratentorial location of AIS (OR 0.44, 95% CI 0.28–0.70), and lacunar (OR 0.27, 95% CI 0.11–0.68) or undetermined stroke etiology (OR 0.12, 95% CI 0.3–0.31). In multivariate analysis, only admission NIHSS score (OR 1.07, 95% CI 1.01–1.13), time from symptom onset to DWI (OR 1.04, 95% CI 1.01–1.13), brainstem location (OR 0.13, 95% CI 0.051–0.37), and lacunar (OR: 0.4, 95% CI 0.21–0.78) or undetermined etiology (OR: 0.4, 95% CI 0.22–0.78) remained independently associated. Conclusion DWI detects AIS accurately; the positivity of these evaluations in the ER is associated only with NIHSS on admission, time to DWI, brainstem location, and AIS etiology.Item Incidence, risk factors, prognosis, and health-related quality of life after stroke in a low-resource community in Chile (ÑANDU): a prospective population-based study(2021) Lavados, Pablo; Hoffmeister, Lorena; Moraga, Ana M.; Vejar, Angélica; Vidal, Carolina; Gajardo, Constanza; Portales, María Bernardita; San Martín, Daniela; López, Eduardo; Rojo, Alexis; Olavarría, Verónica V.; Almeida, Juan; Brunser, Alejandro M.; Muñoz Venturelli, Paula; Hoppe, Arnold; Díaz, Violeta; Sacks, ClaudioBackground Stroke is a leading cause of disability and death worldwide. The best estimates of local, national, and global burden of stroke are derived from prospective population-based studies. We aimed to investigate the incidence, risk factors, long-term prognosis, care, and quality of life after stroke in the Ñuble region of Chile. Methods We did a prospective community-based study with use of multiple overlapping sources of hospitalised, ambulatory, and deceased cases. Standardised diagnostic criteria were used to identify and follow up all cases occurring in the resident population of the Ñuble region, Chile (in a low-income rural-urban population including predominantly people of Indigenous-European heritage), for 1 year. Participants were included if they had a clinical diagnosis of stroke confirmed according to the study criteria. All cases were adjudicated by vascular neurologists. Incidence rates of first-ever stroke were calculated from the population of Ñuble according to the 2017 national census. Findings From April 1, 2015, to March 31, 2016, we ascertained 1103 stroke cases, of which 890 (80·7%) were first-ever incident cases. The mean age of patients with first-ever stroke was 70·3 years (SD 14·1) and 443 (49·8%) were women. A CT scan was obtained in 801 (90%) of 890 patients (mean time from symptom onset to scan of 13·4 h (SD 29·8). The incidence of first-ever stroke age-adjusted to the world population was 121·7 (95% CI 113·7–130·1) per 100 000. The age-adjusted incidence rates, per 100000 inhabitants, by main pathological subtypes were as follows: ischaemic stroke (101·5 [95% CI 90·9–113·0]); intracerebral haemorrhage (17·9 [13·5–23·4]), and subarachnoid haemorrhage (4·2 [2·1–7·3]). The 30-day case-fatality rate was 24·6% (21·9–27·6). At 6 months after the stroke, 55·9% (432 of 773) of cases had died or were disabled, which increased to 61·0% (456 of 747) at 12 months. Health-related quality of life in survivors was low at 6 months, improving slightly at 12 months after the stroke. Interpretation The incidence of stroke in this low-resource population was higher than our previous finding in northern Chile and within the mid-range of most population-based stroke studies. This result was due mainly to a higher incidence of ischaemic stroke, probably associated with increasing age and a high prevalence of cardiometabolic risk factors in the population studied. Our findings suggest that more should be done for the prevention and care of stroke in communities like the Ñuble population. Funding The National Agency for Research and Development and the Technology-Health Research Fund, Clínica Alemana de Santiago, Boehringer Ingelheim, Bristol Meyers Squibb, The Herminda Martin Clinical Hospital of Chillán, Universidad Mayor, and Universidad de Concepción.Item Socioeconomic and Cardiovascular Variables Explaining Regional Variations in Stroke Mortality in Chile: An Ecological Study(2011) Lavados, Pablo; Díaz, Violeta; Jadue, Liliana; Olavarría, Verónica; Delgado, Iris; Cárcamo, DanielBackground: Regional differences in stroke mortality rates have been described in Chile. These could be related to the distribution of cardiovascular risk factors, the quality of medical care or socioeconomic status influencing incidence or case fatality rates. Our objective was to investigate variables explaining the variability in stroke mortality rates in the different regions of Chile. Methods: Adjusted stroke mortality rates in different regions were calculated for the year 2003. Variables were added from three sources: the National Death Certificate Database, the National Socioeconomic Characterization Survey and the National Health Survey. A logistic regression model was used to investigate regions, demographic variables and socioeconomic variables associated with the risk of death from stroke. A linear regression model was used to study the association of socioeconomic variables and cardiovascular risk factors with the standardized mortality rate by region and the contribution of these to the variability. Results: A twofold increase was found in adjusted stroke mortality rates among regions. Greater risk was associated with older age, female gender and residence in regions V, VII, VIII and IX. Sixty-two percent of the regional variability rate was explained by the combined prevalence of poverty (34%), diabetes (17%), sedentarism (8%) and overweight (3%). Conclusion: The risk of death from stroke in Chile is associated with age, sex and living in four specific regions of the country. The majority of the increased risk in these regions is explained by the prevalence of poverty, diabetes, a sedentary lifestyle and overweight. Copyright (C) 2011 S. Karger AG, BaselItem Transcranial Doppler as a Predictor of Ischemic Events in Vertebral Artery Dissection(2020) Brunser, Alejandro; Lavados, Pablo; Cavada, Gabriel; Muñoz Venturelli, Paula; Olavarría, Verónica; Navia, Víctor; Mansilla, Eloy; Díaz, VioletaBackground and purpose: Transcranial Doppler (TCD) helps identify patients with carotid dissections at risk of ischemic events (IEs). There is paucity of data identifying independent predictors of IE in vertebral arterial dissection (VAD). We sought to investigate the clinical and ultrasound predictors of IE. Methods: Patients with VAD admitted between June 2017 and February 2020 were evaluated clinically and with TCD; sonographic curves, microembolic signals (MES), and the breath-holding index (BHI) test were applied. Covariates found on univariate screen (P < .25) were included in a multivariable linear regression to identify independent predictors of IEs. Results: Of 88 patients with 100 VAD, 75 (85.2%) were females with a mean age 37.9 ± 7.5 years. All patients received antiplatelet treatment. TCD monitoring lasted an average of 21 ± 2.1 minutes. TCD was abnormal in 23 cases (26.1%); 21 patients had abnormal sonographic curves in the vertebral/basilar arteries, while in 4 cases, MES were present and in 5 (4.5%), BHI was abnormal. None of the patients with a normal TCD had an IE. Six strokes occurred during follow up. On univariate analysis, male sex, diabetes, dyslipidemia, a previous myocardial infarct, migraine, time of consultation to the ER, bilateral VAD, MES, BHI abnormalities, post stenotic flow in the basilar artery (PFB), and basilar/vertebral velocities were significantly associated with the risk of IEs. In the multivariate analysis, only the presence of PFB was a significant predictor of IE (OR: 68.6, 95% CI 5-937, <.001). Conclusions: TCD in VAD predicts patients at high risk of IE.