Association Between Spontaneous Internal Carotid Artery Dissection and Perivascular Adipose Tissue Attenuation on Computed Tomography Angiography

BACKGROUND

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 (PVAT_carotid) 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, PVAT_carotid was measured as the mean Hounsfield Unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA.

RESULTS

PVAT_carotid 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 PVAT_carotid 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 PVAT_carotid following multivariable adjustment for age and the presence of ICA occlusion.

CONCLUSION

PVAT_carotid is elevated in the presence of sCAD and may decrease following the acute event.

Cervical Artery Dissection in Postpartum Women after Cesarean and Vaginal Delivery

BACKGROUND 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.

Stroke care and collaborative academic research in Latin America

Objective. A narrative overview of regional academic research collaborations to address the increasing burden and gaps in care for patients at risk of, and who suffer from, stroke in Latin America (LA). Materials and methods. A summary of experiences and knowledge of the local situation is presented. No systematic literature review was performed. Results. The rapidly increasing burden of stroke poses immense challenges in LA, where prevention and manage­ment strategies are highly uneven and inadequate. Clinical research is increasing through various academic consortia and networks formed to overcome structural, funding and skill barriers. However, strengthening the ability to generate, analyze and interpret randomized evidence is central to further develop effective therapies and healthcare systems in LA. Conclusions. Regional networks foster the conduct of multicenter studies –particularly randomized controlled trials–, even in resource-poor regions. They also contribute to the external validity of international studies and strengthen systems of care, clinical skills, critical thinking, and international knowledge exchange.

Low blood pressure and adverse outcomes in acute stroke: HeadPoST study explanations

OBJECTIVE

As uncertainties exist over underlying causes, we aimed to define the characteristics and prognostic significance of low blood pressure (BP) early after the onset of acute stroke.

METHODS

Post hoc analyzes of the international Head Positioning in acute Stroke Trial (HeadPoST), a pragmatic cluster-crossover randomized trial of lying flat versus sitting up in stroke patients from nine countries during 2015-2016. Associations of baseline BP and death or dependency [modified Rankin scale (mRS) scores 3-6] and serious adverse events (SAEs) at 90 days were assessed in generalized linear mixed models with adjustment for multiple confounders. SBP and DBP was analysed as continuous measures fitted with a cubic spline, and as categorical measures with low (<10th percentile) and high (≥140 and ≥90 mmHg, respectively) levels compared with a normal range (≥10th percentile; 120-139 and 70-89 mmHg, respectively).

RESULTS

Among 11 083 patients (mean age 68 years, 39.9% women) with baseline BP values, 7.2 and 11.7% had low SBP (<120 mmHg) and DBP (<70 mmHg), respectively. Patients with low SBP were more likely to have preexisting cardiac and ischemic stroke and functional impairment, and to present earlier with more severe neurological impairment than other patients. Nonlinear 'J-shaped' relationships of BP and poor outcome were apparent: compared with normal SBP, those with low SBP had worse functional outcome (adjusted odds ratio 1.27, 95% confidence interval 1.02-1.58) and more SAEs, particularly cardiac events, with adjustment for potential confounders to minimize reverse causation. The findings were consistent for DBP and were stronger for ischemic rather than hemorrhagic stroke.

CONCLUSION

The prognostic significance of low BP on poor outcomes in acute stroke was not explained by reverse causality from preexisting cardiovascular disease, and propensity towards greater neurological deficits and cardiac events. These findings provide support for the hypothesis that low BP exacerbates cardiac and cerebral ischemia in acute ischemic stroke.

Influence of Including Patients with Premorbid Disability in Acute Stroke Trials: The HeadPoST Experience

BACKGROUND

Patients with premorbid functional impairment are generally excluded from acute stroke trials. We aimed to determine the impact of including such patients in the Head Positioning in acute Stroke Trial (HeadPoST) and early additional impairment on outcomes.

METHODS

Post hoc analyses of HeadPoST, an international, cluster-randomized crossover trial of lying-flat versus sitting-up head positioning in acute stroke. Associations of early additional impairment, defined as change in modified Rankin scale (mRS) scores from premorbid levels (estimated at baseline) to Day 7 ("early ΔmRS"), and poor outcome (mRS score 3-6) at Day 90 were determined with generalized linear mixed model. Heterogeneity of the trial treatment effect was tested according to premorbid mRS scores 0-1 versus 2-5.

RESULTS

Of 8,285 patients (38.9% female, mean age 68 ± 13 years) with complete data, there were 1,984 (23.9%) with premorbid functional impairment (mRS 2-5). A significant linear association was evident for early ∆mRS and poor outcome (per 1-point increase in ΔmRS, adjusted odds ratio 1.20, 95% confidence interval 1.14-1.27; p < 0.0001). Patients with greater premorbid functional impairment were less likely to develop additional impairment, but their risk of poor 90-day outcome significantly increased with increasing (worse) premorbid mRS scores (linear trend p < 0.0001). There was no heterogeneity of the trial treatment effect by level of premorbid function.

CONCLUSIONS

Early poststroke functional impairment that exceeded premorbid levels was associated with worse 90-day outcome, and this association increased with greater premorbid functional impairment. Yet, including premorbid impaired patients in the HeadPoST did not materially affect the subsequent treatment effect.

CLINICAL TRIAL REGISTRATION

HeadPoST is registered at http://www.ClinicalTrials.gov (NCT02162017).

Timing of Recanalization and Functional Recovery in Acute Ischemic Stroke

Background and Purpose

Although onset-to-treatment time is associated with early clinical recovery in acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (tPA), the effect of the timing of tPA-induced recanalization on functional outcomes remains debatable.

Methods

We conducted a multicenter, prospective observational cohort study to determine whether early (within 1-hour from tPA-bolus) complete or partial recanalization assessed during 2-hour real-time transcranial Doppler monitoring is associated with improved outcomes in patients with proximal occlusions. Outcome events included dramatic clinical recovery (DCR) within 2 and 24-hours from tPA-bolus, 3-month mortality, favorable functional outcome (FFO) and functional independence (FI) defined as modified Rankin Scale (mRS) scores of 0–1 and 0–2 respectively.

Results

We enrolled 480 AIS patients (mean age 66±15 years, 60% men, baseline National Institutes of Health Stroke Scale score 15). Patients with early recanalization (53%) had significantly (jos-2019-01648P<0.001) higher rates of DCR at 2-hour (54% vs. 10%) and 24-hour (63% vs. 22%), 3-month FFO (67% vs. 28%) and FI (81% vs. 39%). Three-month mortality rates (6% vs. 17%) and distribution of 3-month mRS scores were significantly lower in the early recanalization group. After adjusting for potential confounders, early recanalization was independently associated with higher odds of 3-month FFO (odds ratio [OR], 6.19; 95% confidence interval [CI], 3.88 to 9.88) and lower likelihood of 3-month mortality (OR, 0.34; 95% CI, 0.17 to 0.67). Onset to treatment time correlated to the elapsed time between tPA-bolus and recanalization (unstandardized linear regression coefficient, 0.13; 95% CI, 0.06 to 0.19).

Conclusions

Earlier tPA treatment after stroke onset is associated with faster tPA-induced recanalization. Earlier onset-to-recanalization time results in improved functional recovery and survival in AIS patients with proximal intracranial occlusions.

[Intravenous thrombolysis after reversion of acenocoumarol anticoagulation. Report of one case]

We report an 89-year-old male under oral anticoagulant therapy with a therapeutic international normalized ratio, presenting at the emergency room with right side hemiparesis and aphasia. Neuroimaging was compatible with an acute middle cerebral artery ischemic stroke. Anticoagulation was reverted with the use of four factor prothrombin complex, followed by thrombolysis with alteplase, with a favorable evolution, returning to his basal functional status.

Sex differences in treatment and outcome after stroke: Pooled analysis including 19,000 participants

OBJECTIVE

To explore the sex differences in outcomes and management after stroke using a large sample with high-quality international trial data.

METHODS

Individual participant data were obtained from 5 acute stroke randomized controlled trials. Data were obtained on demographics, medication use, in-hospital treatment, and functional outcome. Study-specific crude and adjusted models were used to estimate sex differences in outcomes and management, and then pooled using random-effects meta-analysis.

RESULTS

There were 19,652 participants, of whom 7,721 (40%) were women. After multivariable adjustments, women with ischemic stroke had higher survival at 3-6 months (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.70-0.97), higher likelihood of disability (OR 1.20, 95% CI 1.06-1.36), and worse quality of life (weighted mean difference -0.07, 95% CI -0.09 to 0.04). For management, women were more likely to be admitted to an acute stroke unit (OR 1.17, 95% CI 1.01-1.34), but less likely to be intubated (OR 0.58, 95% CI 0.36-0.93), treated for fever (OR 0.82, 95% CI 0.70-0.95), or admitted to an intensive care unit (OR 0.83, 95% CI 0.74-0.93). For preadmission medications, women had higher odds of being prescribed antihypertensive agents (OR 1.22, 95% CI 1.13-1.31) and lower odds of being prescribed antiplatelets (OR 0.86, 95% CI 0.79-0.93), glucose-lowering agents (OR 0.86, 95% CI 0.78-0.94), or lipid-lowering agents (OR 0.85, 95% CI 0.77-0.94).

CONCLUSIONS

This analysis suggests that women who had ischemic stroke had better survival but were also more disabled and had poorer quality of life. Variations in hospital and out-of-hospital management may partly explain the disparities.

Latin American Consensus Statement for the Use of Contrast-Enhanced Transcranial Ultrasound as a Diagnostic Test for Detection of Right-to-Left Shunt

BACKGROUND

The role of patent foramen ovale is a field of debate and current publications have increasing controversies about the patients' management in young undetermined stroke. Work up with echocardiography and transcranial Doppler (TCD) can aid the decision with better anatomical and functional characterization of right-to-left shunt (RLS). Medical and interventional strategy may benefit from this information.

SUMMARY

a group of experts from the Latin American participants of the Neurosonology Research Group (NSRG) of World Federation of Neurology created a task force to review literature and describe the better methodology of contrast TCD (c-TCD). All signatories of the present consensus statement have published at least one study on TCD as an author or co-author in an indexed journal. Two meetings were held while the consensus statement was being drafted, during which controversial issues were discussed and voted on by the statement signatories. The statement paper was reviewed and approved by the Executive Committee of the NSRG of the World Federation of Neurology. The main objective of this consensus statement is to establish a standardization of the c-TCD technique and its interpretation, in order to improve the informative quality of the method, resulting in expanding the application of TCD in the clinical setting. These recommendations optimize the comparison of different diagnostic methods and encourage the use of c-TCD for RLS screening and complementary diagnosis in multicenter studies.

[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.

Impact of Evidence-Based Stroke Care on Patient Outcomes: A Multilevel Analysis of an International Study

Background

The uptake of proven stroke treatments varies widely. We aimed to determine the association of evidence‐based processes of care for acute ischemic stroke (AIS) and clinical outcome of patients who participated in the HEADPOST (Head Positioning in Acute Stroke Trial), a multicenter cluster crossover trial of lying flat versus sitting up, head positioning in acute stroke.

Methods and Results

Use of 8 AIS processes of care were considered: reperfusion therapy in eligible patients; acute stroke unit care; antihypertensive, antiplatelet, statin, and anticoagulation for atrial fibrillation; dysphagia assessment; and physiotherapist review. Hierarchical, mixed, logistic regression models were performed to determine associations with good outcome (modified Rankin Scale scores 0–2) at 90 days, adjusted for patient and hospital variables. Among 9485 patients with AIS, implementation of all processes of care in eligible patients, or “defect‐free” care, was associated with improved outcome (odds ratio, 1.40; 95% CI, 1.18–1.65) and better survival (odds ratio, 2.23; 95% CI, 1.62–3.09). Defect‐free stroke care was also significantly associated with excellent outcome (modified Rankin Scale score 0–1) (odds ratio, 1.22; 95% CI, 1.04–1.43). No hospital characteristic was independently predictive of outcome. Only 1445 (15%) of eligible patients with AIS received all processes of care, with significant regional variations in overall and individual rates.

Conclusions

Use of evidence‐based care is associated with improved clinical outcome in AIS. Strategies are required to address regional variation in the use of proven AIS treatments.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique Identifier: NCT02162017.

Abstract WP106: Timing of Tissue-plasminogen-activator Induced Recanalization and Functional Recovery in Acute Ischemic Stroke

Introduction: Although onset-to-treatment time is associated with early clinical recovery in acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (tPA), the effect of the timing of tPA-induced recanalization on functional outcomes in AIS remains debatable.

Methods: We sought to determine whether early (within 1-hour from tPA-bolus) complete or partial recanalization assessed during 2-hour real-time transcranial Doppler (TCD) monitoring is independently associated with improved 3-month outcomes in tPA-eligible patients with proximal intracranial arterial occlusions. Outcome events included dramatic clinical recovery (DCR) within 2 and 24-hours from tPA-bolus, 3-month mortality, favorable functional outcome (FFO) and functional independence (FI) defined as modified Rankin Scale scores of 0-1 and 0-2 respectively.

Results: We prospectively enrolled 480 AIS patients (mean age 66±15 years, 60% men, baseline NIHSS score 15) during a 7-year period from 12 participating centers. Complete or partial early recanalization was detected in 53% of patients. Patients with early recanalization had (p<0.001) higher rates of 2-hour DCR (54% vs. 10%), 3-month FFO (67% vs. 28%), FI (81% vs. 39%) and lower mortality rates (6% vs. 17%) compared to patients with persisting occlusions. In multivariable analyses, recanalization during tPA infusion was independently (p<0.05) associated with higher probability of three-month FFO and lower likelihood of three-month mortality. Onset to treatment time correlated to the elapsed time between tPA-bolus and recanalization (Spearman’s rho= +0.151, p=0.009).

Conclusions: Earlier tPA treatment after stroke onset is associated with faster tPA-induced recanalization. Earlier onset-to-recanalization time results in improved functional recovery and survival in AIS patients with proximal intracranial occlusions.

Cluster-Randomized, Crossover Trial of Head Positioning in Acute Stroke

BACKGROUND

The role of supine positioning after acute stroke in improving cerebral blood flow and the countervailing risk of aspiration pneumonia have led to variation in head positioning in clinical practice. We wanted to determine whether outcomes in patients with acute ischemic stroke could be improved by positioning the patient to be lying flat (i.e., fully supine with the back horizontal and the face upwards) during treatment to increase cerebral perfusion.

METHODS

In a pragmatic, cluster-randomized, crossover trial conducted in nine countries, we assigned 11,093 patients with acute stroke (85% of the strokes were ischemic) to receive care in either a lying-flat position or a sitting-up position with the head elevated to at least 30 degrees, according to the randomization assignment of the hospital to which they were admitted; the designated position was initiated soon after hospital admission and was maintained for 24 hours. The primary outcome was degree of disability at 90 days, as assessed with the use of the modified Rankin scale (scores range from 0 to 6, with higher scores indicating greater disability and a score of 6 indicating death).

RESULTS

The median interval between the onset of stroke symptoms and the initiation of the assigned position was 14 hours (interquartile range, 5 to 35). Patients in the lying-flat group were less likely than patients in the sitting-up group to maintain the position for 24 hours (87% vs. 95%, P<0.001). In a proportional-odds model, there was no significant shift in the distribution of 90-day disability outcomes on the global modified Rankin scale between patients in the lying-flat group and patients in the sitting-up group (unadjusted odds ratio for a difference in the distribution of scores on the modified Rankin scale in the lying-flat group, 1.01; 95% confidence interval, 0.92 to 1.10; P=0.84). Mortality within 90 days was 7.3% among the patients in the lying-flat group and 7.4% among the patients in the sitting-up group (P=0.83). There were no significant between-group differences in the rates of serious adverse events, including pneumonia.

CONCLUSIONS

Disability outcomes after acute stroke did not differ significantly between patients assigned to a lying-flat position for 24 hours and patients assigned to a sitting-up position with the head elevated to at least 30 degrees for 24 hours. (Funded by the National Health and Medical Research Council of Australia; HeadPoST ClinicalTrials.gov number, NCT02162017 .).

Statistical analysis plan for the Head Position in Stroke Trial (HeadPoST): An international cluster cross-over randomized trial

Background There is evidence to indicate that the lying flat head position increases cerebral blood flow and oxygenation in patients with acute ischemic stroke, but how these physiological effects translate into clinical outcomes is uncertain. The Head Position in Stroke Trial aims to determine the comparative effectiveness of lying flat (0°) compared to sitting up (≥30°) head positioning, initiated within 24 h of hospital admission for patients with acute stroke. Design An international, pragmatic, cluster-randomized, crossover, open, blinded outcome assessed clinical trial. Each hospital with an established acute stroke unit (cluster) site was required to recruit up to 140 consecutive cases of acute stroke (one phase of head positioning before immediately crossing over to the other phase of head positioning), including both acute ischemic stroke and intracerebral hemorrhage, in each randomized head position as a 'business as usual' policy. Objective To outline in detail the predetermined statistical analysis plan for the study. Methods All accumulated data will be reviewed and formally assessed. Information regarding baseline characteristics of patients, their process of care and management will be outlined, and for each item, statistically relevant descriptive elements will be described. For the trial outcomes, the most appropriate statistical comparisons are described. Results A statistical analysis plan was developed that is transparent, verifiable, and predetermined before completion of data collection. Conclusions We developed a predetermined statistical analysis plan for Head Position in Stroke Trial to avoid analysis bias arising from prior knowledge of the findings, in order to reliably quantify the benefits and harms of lying flat versus sitting up early after the onset of acute stroke. Trial registration ClinicalTrials.gov identifier NCT02162017; ANZCTR identifier ACTRN12614000483651.

The distribution of the modified Rankin scale scores change according to eligibility criteria in acute ischemic stroke trials: A consideration for sample size calculations when using ordinal regression analysis

Background

Distribution shifts of the modified Rankin scale (mRs) is used as outcome measure in acute ischemic stroke (AIS) randomized controlled trials (RCT). Distribution across strata of mRs is relevant for sample size calculations and may be affected by eligibility criteria.

Aim

We aimed to assess the distribution of mRs scores across its different strata in AIS according to usual eligibility criteria.

Methods

We computed follow-up mRs strata distribution between an unselected cohort and samples with (a) time from symptom onset < 6 h (b) National Institutes of Health Stroke Scale (NIHSS) scores > 3 and < 25, and (c) both criteria combined. We compared distributions with the Mann-Whitney U Test and calculated sample sizes for each distribution.

Results

We included 5849 AIS patients. The unselected sample had a non-normal distribution with a median of 2. All selection criteria yielded significantly different distributions of mRs (p = 004, 0.02 and 0.02 respectively). This resulted in a significant variation in the calculated sample size when applying different selection criteria, with smaller numbers when RCT selection criteria are used (3616 versus 1553).

Conclusions

The use of usual RCT eligibility criteria result in significant differences in mRs distribution and smaller sample sizes compared to unselected AIS samples.

Statistical analysis plan of the head position in acute ischemic stroke trial pilot (HEADPOST pilot)

Background The HEADPOST Pilot is a proof-of-concept, open, prospective, multicenter, international, cluster randomized, phase IIb controlled trial, with masked outcome assessment. The trial will test if lying flat head position initiated in patients within 12 h of onset of acute ischemic stroke involving the anterior circulation increases cerebral blood flow in the middle cerebral arteries, as measured by transcranial Doppler. The study will also assess the safety and feasibility of patients lying flat for ≥24 h. The trial was conducted in centers in three countries, with ability to perform early transcranial Doppler. A feature of this trial was that patients were randomized to a certain position according to the month of admission to hospital. Objective To outline in detail the predetermined statistical analysis plan for HEADPOST Pilot study. Methods All data collected by participating researchers will be reviewed and formally assessed. Information pertaining to the baseline characteristics of patients, their process of care, and the delivery of treatments will be classified, and for each item, appropriate descriptive statistical analyses are planned with comparisons made between randomized groups. For the outcomes, statistical comparisons to be made between groups are planned and described. Results This statistical analysis plan was developed for the analysis of the results of the HEADPOST Pilot study to be transparent, available, verifiable, and predetermined before data lock. Conclusions We have developed a statistical analysis plan for the HEADPOST Pilot study which is to be followed to avoid analysis bias arising from prior knowledge of the study findings. Trial registration The study is registered under HEADPOST-Pilot, ClinicalTrials.gov Identifier NCT01706094.

[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.

[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 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.