[Telestroke in Chile: 1 year experience at 7 hospitals]. / Telestroke en Chile: resultados de 1 año de experiencia de la Unidad de TeleACV del Servicio de Salud Metropolitano Sur en 7 hospitales ejecutores.

BACKGROUND: Acute ischemic stroke (AIS) is one of the leading causes of death in Chile. Intravenous thrombolysis (IVT) is an effective treatment. Geographical barriers and lack of specialists limit its application. Telemedicine can overcome some of these pitfalls. AIM: To describe the implementation and results of AIS treatment by telemedicine at the TeleStroke Unit (TeleACV) of the Southern Metropolitan Health Service, connected with seven hospitals in Chile. MATERIAL AND METHODS: Descriptive analysis of a prospective tele-thrombolysis data-base that covers from 2016 to 2018, with an emphasis in the last year. RESULTS: During the analyzed period, seven remote telemedicine centers were activated as far as 830 kilometers on a continental level from the reference center and up to 3,700 kilometers on an island level. There were 1,024 telemedicine consultations, 144 (14%) of them resulted in an IVT treatment. During 2018, 597 tele-consultations were made, thrombolysis was done in 115 (19%) patients aged 66+-13 years; 54 (46.6%) being female. The median admission National Institute of Health Stroke Scale was 8 (interquartile range (IQR) 5-14). The median door-to-needle time was 56.5 (IQR 44.8-73.3) minutes; 60% of patients were treated within 60 minutes. Eight patients (7%) were referred for a subsequent mechanical thrombectomy to a center of greater complexity. Symptomatic intra-cranial hemorrhages occurred in four treated patients (4%). One patient had a systemic bleeding. CONCLUSIONS: The Telestroke Unit achieved a high rate of IVT and good door-to-needle times. This may help to overcome some of the geographic barriers and the specialist availability gap in our country.

Poor Collateral Circulation Assessed by Multiphase Computed Tomographic Angiography Predicts Malignant Middle Cerebral Artery Evolution After Reperfusion Therapies.

BACKGROUND AND PURPOSE: Collateral circulation (CC) has been associated with recanalization, infarct volume, and clinical outcome in patients undergoing acute reperfusion therapies. However, its relationship with the development to malignant middle cerebral artery infarction (mMCAi) has not been evaluated. Our aim was to determine the impact of CC using multiphase computed tomographic angiography (during the acute stroke phase in the prediction of mMCAi. METHODS: Patients with consecutive acute stroke with <4.5 hours who were evaluated for reperfusion therapies and presented with an M1-MCA or terminal internal carotid artery occlusion by CTA were included. CC was evaluated on 6 grades by multiphase CTA according to the University of Calgary CC Scale; CC status was defined as poor (grades, 0-3) or good (grades, 4-5). The mMCAi was defined according to clinical and radiological criteria. Recanalization was assessed with transcranial Doppler at 24 hours and final Thrombolysis in Brain Ischemia score≥2b in patients undergoing endovascular reperfusion treatment. RESULTS: Eighty-two patients were included. Mean age was 65.1±13.83 years, median baseline National Institutes of Health Stroke Scale score was 18 (interquartile range, 13-20), and 67.9% M1 and 32.1% terminal internal carotid artery occlusions. Fifty-three patients received endovascular reperfusion treatment. Fifteen patients developed mMCAi. In the univariate analysis, patients with mMCAi had lower CC scores (2.29 versus 3.71; P=0.001). Endovascular reperfusion treatment was associated with lower rate of mMCAi development than only intravenous reperfusion treatment (9.4% versus 29.6%; P=0.028). Patients with poor CC had higher risk of developing mMCAi (13% versus 2%; P=0.001). On the multivariate analysis adjusted by age, vessel occlusion, baseline National Institutes of Health Stroke Scale, and recanalization, the presence of poor CC by multiphase CTA was the only independent predictor of mMCAi (P=0.048; odds ratio, 9.72; 95% confidence interval, 1.387-92.53). CONCLUSIONS: CC assessment by multiphase CTA independently predicts malignant MCA infarction progression. In patients with persistent occlusion after reperfusion therapies, the presence of poor CC may improve the early mMCAi detection and management.

Potential blood pressure thresholds and outcome in acute intracerebral hemorrhage.

BACKGROUND: Little is known about the relationships between different systolic blood pressure (SBP) thresholds and their outcomes in acute intracerebral hemorrhage (ICH). We aimed to determine the associations of potential systolic blood pressure (SBP) thresholds with hematoma growth (HG) and clinical outcome in patients with acute ICH. METHODS: 117 patients with acute (<6 h) spontaneous supratentorial ICH underwent blood pressure monitoring at 15 min interval over the first 24 h. SBP thresholds of 140, 150, 160, 170, 180, 190, and 200 mm Hg were assessed by means of the percentage of 24-hour values exceeding each threshold (SBP load). HG at 24 h, early neurological deterioration (END), 24-hour and 90-day mortality, and poor outcome were recorded. RESULTS: SBP 170, 180, 190, and 200 loads were significantly correlated with the amount of both absolute and relative hematoma enlargement at 24 h. In multivariate analyses, SBP 170 load was related to HG and END, while SBP 160 load was associated with mortality at 24 h. No thresholds were independently related to outcomes at 90 days. CONCLUSION: In patients with acute ICH, SBP lowering to at least less than 160 mm Hg threshold may be needed to minimize the deleterious effect of high SBP on 24-hour outcomes.

[Sonothrombolysis for acute ischemic stroke]. / Sonotrombolisis en el ataque cerebrovascular isquémico: once años de experiencia en Clínica Alemana de Santiago.

BACKGROUND: Sonothrombolysis (ST) is an emerging modality for the treatment of stroke. AIM: To assess the feasibility to perform ST in a Chilean hospital. MATERIAL AND METHODS: Patients attended at a private clinic with an acute ischemic stroke, between September 2002 and May 2013 and eligible for endovenous thrombolysis, were studied with a transcranial Doppler (Spencer PMD 100 or 150®). Those with an adequate sonographic window and a demonstrated arterial occlusion were monitored continuously with transcranial Doppler at the site of worst residual flow following the CLOTBUST study protocol. RESULTS: One thousand twenty six patients were studied, of whom 136 received intravenous thrombolysis (rt-PA) and 61, aged 66 ± 18 years (59% males), were subjected to ST (7% of total). Their median National Institutes of Health Stroke Scale score was 14, the lapse from symptom onset to rt-PA was 127 minutes (43-223). Middle cerebral artery (MCA) occlusion was found in 88.5% of patients. Complete recanalization was achieved in 44.3% of patients. Sixty percent had Modified Rankin Scale of 0 to 2 at 3 months (95% confidence intervals (CI) 48.1 to 72). Case fatality was 9.8% and asymptomatic intracranial hemorrhage occurred in 9.8% (95% CI: 4.3 to 20.2). CONCLUSIONS: ST can be carried out in a complex medical center and is safe.

Accuracy of diffusion-weighted imaging in the diagnosis of stroke in patients with suspected cerebral infarct.

BACKGROUND 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.

Exclusion criteria for intravenous thrombolysis in stroke mimics: an observational study.

BACKGROUND: 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.

Socioeconomic and cardiovascular variables explaining regional variations in stroke mortality in Chile: an ecological study.

BACKGROUND: 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.

Long-term monitoring for conservation: closing the distribution gap of Arctocephalus australis in central Chile.

OBJECTIVES: Here, we present the first record of stable colonies of the South American fur seal (Arctocephalus australis), in an area where their presence has never been documented (hereafter distribution gap), as well as an update of the current distribution range of the species in central Chile. RESULTS: A national synoptic aerial census of pinnipeds was performed during the austral summer of 2019 on the Chilean coast. An additional aerial census was conducted in the same area during the austral spring of 2019 as well as a maritime census during the austral summer of 2020. The data showed the presence of South American fur seals in central Chile within their well-known distribution gap. The total abundance was registered in three colonies where fur seals were sighted: one non-breeding colony, Punta Topocalma (summer 2019: mean = 46 ± 3; spring 2019: mean = 9 ± 1); and two breeding colonies, Punta Curaumilla (summer 2019: mean = 595 ± 7; spring 2019: mean = 45 ± 4; summer 2020: mean = 744 ± 5) and Isla Santa María (summer 2019: mean = 246 ± 6). Specifically, we suggest that it is crucial to elucidate the origin of the described settled colonies, and to determine whether there has been an augment in the distribution range from either the northern population, the southern population, or both simultaneously.

Additional information given to a multimodal imaging stroke protocol by transcranial Doppler ultrasound in the emergency room: a prospective observational study.

BACKGROUND: 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.

Transcranial Doppler as a Predictor of Ischemic Events in Carotid Artery Dissection.

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.

Telestroke en Chile: resultados de 1 año de experiencia de la Unidad de TeleACV del Servicio de Salud Metropolitano Sur en 7 hospitales ejecutores / Telestroke in Chile: 1 year experience at 7 hospitals

Background: Acute ischemic stroke (AIS) is one of the leading causes of death in Chile. Intravenous thrombolysis (IVT) is an effective treatment. Geographical barriers and lack of specialists limit its application. Telemedicine can overcome some of these pitfalls. Aim: To describe the implementation and results of AIS treatment by telemedicine at the TeleStroke Unit (TeleACV) of the Southern Metropolitan Health Service, connected with seven hospitals in Chile. Material and Methods: Descriptive analysis of a prospective tele-thrombolysis data-base that covers from 2016 to 2018, with an emphasis in the last year. Results: During the analyzed period, seven remote telemedicine centers were activated as far as 830 kilometers on a continental level from the reference center and up to 3,700 kilometers on an island level. There were 1,024 telemedicine consultations, 144 (14%) of them resulted in an IVT treatment. During 2018, 597 tele-consultations were made, thrombolysis was done in 115 (19%) patients aged 66+-13 years; 54 (46.6%) being female. The median admission National Institute of Health Stroke Scale was 8 (interquartile range (IQR) 5-14). The median door-to-needle time was 56.5 (IQR 44.8-73.3) minutes; 60% of patients were treated within 60 minutes. Eight patients (7%) were referred for a subsequent mechanical thrombectomy to a center of greater complexity. Symptomatic intra-cranial hemorrhages occurred in four treated patients (4%). One patient had a systemic bleeding. Conclusions: The Telestroke Unit achieved a high rate of IVT and good door-to-needle times. This may help to overcome some of the geographic barriers and the specialist availability gap in our country.

Transcranial Doppler in a Hispanic-Mestizo population with neurological diseases: a study of sonographic window and its determinants.

Between 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.

[Validation of transcranial Doppler in the diagnosis of brain death]. / Validez del Doppler transcraneal en el diagnóstico de muerte encefálica.

BACKGROUND: The clinical diagnosis of brain death is complex. AIM: To evaluate the diagnostic accuracy of transcranial Doppler (TCD) for brain death. PATIENTS AND METHODS: Patients seen on the intensive care unit of a private hospital between January 2004 to December 2008, were included if they were in structural coma, had no craniectomy and had a blind evaluation by a neurologist and TCD done in less than three hours. The diagnosis of brain death was based on a clinical evaluation that considered the absence of sedative drugs, median blood pressure>60 mmHg, body temperature over 35 masculine Celsius and complete absence of brainstem reflexes. An expert neurosonologist, with a TCD-PMD-100, 2 Mhz transducer, used an institutional protocol that considers the examination as positive for brain circulatory arrest when there is presence of reverberating, small systolic peaks or the disappearance of a previous signal present on both middle cerebral arteries and intracranial vertebral arteries. RESULTS: Fifty three patients were evaluated, 25 with clinical brain death. On 45 cases (84.9%), the interval between both evaluations was less than one hour. The sensitivity, specificity, positive and negative predictive values for the diagnosis of brain death with TCD were 100, 96, 96.1 and 100% respectively. Positive and negative likelihood ratios for brain death were 28 and 0, respectively. CONCLUSIONS: TCD is a valid and useful technique for the diagnosis of brain death and can be used on complicated cases.

Sonotrombolisis en el ataque cerebrovascular isquémico: once años de experiencia en Clínica Alemana de Santiago / Sonothrombolysis for acute ischemic stroke

Background: Sonothrombolysis (ST) is an emerging modality for the treatment of stroke. Aim: To assess the feasibility to perform ST in a Chilean hospital. Material and Methods: Patients attended at a private clinic with an acute ischemic stroke, between September 2002 and May 2013 and eligible for endovenous thrombolysis, were studied with a transcranial Doppler (Spencer PMD 100 or 150®). Those with an adequate sonographic window and a demonstrated arterial occlusion were monitored continuously with transcranial Doppler at the site of worst residual flow following the CLOTBUST study protocol. Results: One thousand twenty six patients were studied, of whom 136 received intravenous thrombolysis (rt-PA) and 61, aged 66 ± 18 years (59% males), were subjected to ST (7% of total). Their median National Institutes of Health Stroke Scale score was 14, the lapse from symptom onset to rt-PA was 127 minutes (43-223). Middle cerebral artery (MCA) occlusion was found in 88.5% of patients. Complete recanalization was achieved in 44.3% of patients. Sixty percent had Modified Rankin Scale of 0 to 2 at 3 months (95% confidence intervals (CI) 48.1 to 72). Case fatality was 9.8% and asymptomatic intracranial hemorrhage occurred in 9.8% (95% CI: 4.3 to 20.2). Conclusions: ST can be carried out in a complex medical center and is safe.

Validez del Doppler transcraneal en el diagnóstico de muerte encefálica / Validation of transcranial Doppler in the diagnosis of brain death

Background: The clinical diagnosis of brain death is complex. Aim: To evaluate the diagnostic accuracy of transcranial Doppler (TCD) for brain death. Patients and Methods: Patients seen on the intensive care unit of a private hospital between January 2004 to December 2008, were included if they were in structural coma, had no craniectomy and had a blind evaluation by a neurologist and TCD done in less than three hours. The diagnosis of brain death was based on a clinical evaluation that considered the absence of sedative drugs, median blood pressure >60 mmHg, body temperature over 35º Celsius and complete absence of brainstem refexes. An expert neurosonologist, with a TCD-PMD-100, 2 Mhz transducer, used an institutional protocol that considers the examination as positive for brain circulatory arrest when there is presence of reverberating, small systolic peaks or the disappearance of a previous signal present on both middle cerebral arteries and intracranial vertebral arteries. Results: Fifty three patients were evaluated, 25 with clinical brain death. On 45 cases (84.9 percent), the interval between both evaluations was less than one hour. The sensitivity, specifcity, positive and negative predictive values for the diagnosis of brain death with TCD were 100, 96, 96.1 and 100 percent respectively. Positive and negative likelihood ratios for brain death were 28 and 0, respectively. Conclusions: TCD is a valid and useful technique for the diagnosis of brain death and can be used on complicated cases.