Ischemic stroke in children and young adults with sickle cell disease in the post-STOP era

Neurocognitive Impairment in Ugandan Children with Sickle Cell Anemia Compared to Sibling Controls: A cross-sectional study

Introduction

Neurocognitive function in Ugandan children aged 1-12 years with sickle cell anemia (SCA) were compared to their non-SCA siblings to identify risk factors for disease-associated impairment.

Methods

This cross-sectional neurocognitive function study of children with SCA (N=242) and non-SCA siblings (N=127) used age- and linguistically-appropriate standardized tests of cognition, executive function and attention for children ages 1-4 and 5-12 years. Test scores were converted to locally derived age-normalized z-scores. The SCA group underwent standardized stroke examination for prior stroke and transcranial doppler ultrasound (TCD) to determine stroke risk by arterial flow velocity.

Results

The SCA group was younger than siblings (mean ages 5.46±3.0 versus 7.11±3.51 years, respectively; p <.001), with lower hemoglobin concentration (7.32±1.02 vs. 12.06±1.42, p <.001). Overall cognitive SCA z-scores were lower: -0.73 ±0.98 vs. siblings -0.25 ±1.12 (p<.001), with comparable findings for executive function of -1.09±0.94 versus -0.84±1.26 (p=0.045), respectively. Attention z-scores for ages 5-12 for the SCA group and controls were similar: -0.37±1.4 vs. -0.11±0.17 (p=.09). Overall differences by SCA status were largely driven by the older age group, as z-scores in the younger sub-sample did not differ from controls. Analyses revealed the strongest predictors of poor neurocognitive outcomes among the SCA sample to be the disease, age and prior stroke (each p<.001). Impact from anemia and SCA were indistinguishable.

Discussion

Neurocognitive testing in children with SCA compared to non-SCA siblings revealed poorer SCA-associated functioning in children older than age 4. Results indicate need for trials assessing impact from disease modification for children with SCA.

Barriers and facilitators to a task-shifted stroke prevention program for children with sickle cell anemia in a community hospital: a qualitative study

BACKGROUND

Children with sickle cell anemia (SCA) are at high risk for stroke. Protocols for stroke prevention including blood transfusions, screening for abnormal non-imaging transcranial Doppler (TCD) measurements, and hydroxyurea therapy are difficult to implement in low-resource environments like Nigeria. This study aimed to examine the contextual factors around TCD screening in a community hospital in Nigeria using qualitative interviews and focus groups.

METHODS

We conducted a descriptive qualitative study in a community hospital in Kaduna, Nigeria, using focus groups and interviews. Interview guides and analysis were informed by the Consolidated Framework for Implementation Research (CFIR) framework and the Theory of Planned Behavior. Transcripts were coded and analyzed using an iterative deductive (CFIR)/Inductive (transcribed quotes) qualitative methodology.

RESULTS

We conducted two focus groups and five interviews with health care workers (nurses and doctors) and hospital administrators, respectively. Themes identified key elements of the inner setting (clinic characteristics, resource availability, implementation climate, and tension for change), characteristics of individuals (normative, control, and behavioral beliefs), and the implementation process (engage, implement, and adopt), as well as factors that were influenced by external context, caregiver needs, team function, and intervention characteristics. Task shifting, which is already being used, was viewed by providers and administrators as a necessary strategy to implement TCD screening in a clinic environment that is overstressed and under-resourced, a community stressed by poverty, and a nation with an underperforming health system.

CONCLUSION

Task shifting provides a viable option to improve health care by making more efficient use of already available human resources while rapidly expanding the human resource pool and building capacity for TCD screening of children with SCD that is more sustainable.

TRIAL REGISTRATION

NCT05434000.

A-296G variant of THBS1 gene (rs1478605) is associated with a lower frequency of stroke in a Brazilian population with sickle cell anemia

OBJECTIVES

Stroke is a devastating clinical outcome that significantly contributes to the morbidity and mortality of sickle cell anemia (SCA) patients. Despite its advantages in predicting stroke risk, transcranial Doppler screening has limitations that restrict its applicability, highlighting the need for emerging prognostic tools. Thrombospondin-1 plays a crucial role in endothelial injury, platelet adhesion, and nitric oxide metabolism and may be implicated in stroke pathophysiology. Here, we aimed to evaluate the association of THBS1 genetic variations with the occurrence of stroke in SCA patients MATERIALS AND METHODS: By real-time PCR, 512 SCA patients were fully genotyped for THBS1 A-296G (rs1478605) polymorphism RESULTS: THBS1 GG genotype was associated with a lower risk for stroke occurrence [odds ratio (OR): 0.30; 95% confidence interval (CI): 0.11-0.78; P = 0.011], although these findings were not consistent with multivariate logistic regression analysis (OR: 0.73, 95% CI: 0.12 - 4.37; P = 0.736). In agreement, the cumulative incidence of stroke for patients with AG/AA genotypes was higher when compared to the GG genotype (P = 0.018). However, the association was not maintained in the multivariate proportional hazards model (hazard ratio: 0.67, 95% CI: 0.12-3.61; P = 0.643) CONCLUSIONS: In summary, the present study shows that the THBS1 A-296G (rs1478605) polymorphism may be a potential modifier for stroke in SCA.

A retrospective study for association between post-transfusion hemoglobin S level and pre-transfusion hemoglobin S level at the next scheduled transfusion

BACKGROUND

Patients with sickle cell disease (SCD) frequently undergo prophylactic red blood cell (RBC) exchange transfusion and simple transfusion (RCE/T) to prevent complications of disease, such as stroke. These treatment procedures are performed with a target hemoglobin S (HbS) of ≤30%, or a goal of maintaining an HbS level of <30% immediately prior to the next transfusion. However, there is a lack of evidence-based instructions for how to perform RCE/T in a way that will result in an HbS value <30% between treatments.

PRINCIPAL OBJECTIVE

To determine whether targets for post-treatment HbS (post-HbS) or post-treatment HCT (post-HCT) can help to maintain an HbS <30% or <40% between treatments.

MATERIALS AND METHODS

We performed a retrospective study of patients with SCD treated with RCE/T at Montefiore Medical Center from June 2014 to June 2016. The analysis included patients of all ages, and data including 3 documented parameters for each RCE/T event: post-HbS, post-HCT, and follow-up HbS (F/u-HbS), which is the pre-treatment HbS prior to the next RCE/T. Generalized linear mixed model was used for estimating the association between post-HbS or post-HCT levels and F/u-HbS <30%.

RESULTS

Based on our results, targeting post-HbS ≤10% was associated with higher odds of having events of F/u-HbS <30% between monthly treatments. Targeting post-HbS ≤15% was associated with higher odds of events of F/u-HbS < 40%. As compared to post-HCT ≤30%, a post-HCT >30%-36% did not contribute to more F/u-HbS <30% or HbS <40% events.

CONCLUSIONS

For patients with SCD undergoing regular RCE/T for stroke prevention, a post-HbS ≤10% can be used as a goal to help maintain an HbS <30% for 1 month, and a post-HbS ≤15% allowed patients to maintain HbS <40%.

Barriers and Facilitators to a Task-Shifted Stroke Prevention Program for Children with Sickle Cell Anemia in a Community Hospital: A Qualitative Study

Background

Children with sickle cell anemia (SCA) are at high risk for stroke. Protocols for stroke prevention including blood transfusions, screening for abnormal non-imaging transcranial Doppler (TCD) measurements, and hydroxyurea therapy are difficult to implement in low-resource environments like Nigeria. This study aimed to examine the contextual factors around TCD screening in a community hospital in Nigeria using qualitative interviews and focus groups.

Methods

We conducted focus groups with health care providers and interviews with administrative leadership of the community hospital. Interview guides and analysis were informed by the Consolidated Framework for Implementation Research (CFIR) framework. Transcripts were coded and analyzed using an iterative deductive (CFIR)/Inductive (transcribed quotes) qualitative methodology.

Results

We conducted two focus groups and five interviews with health care workers (nurses and doctors) and hospital administrators, respectively. Themes identified key elements of the inner setting (clinic characteristics, resource availability, implementation climate, and tension for change), characteristics of individuals (normative, control, and behavioral beliefs), and the implementation process (engage, implement, and adopt), as well as factors that were influenced by external context, caregiver needs, team function, and intervention characteristics. Task shifting, which is already being used, was viewed by providers and administrators as a necessary strategy to implement TCD screening in a clinic environment that is overstressed and under-resourced, a community stressed by poverty, and a nation with an underperforming health system.

Conclusion

Task shifting provides a viable option to improve health care by making more efficient use of already available human resources while rapidly expanding the human resource pool and building capacity that is more sustainable.

Trial registration

NCT05434000.

Hematologic Disorders and the Nervous System

OBJECTIVE

This article discusses the epidemiology, diagnosis, treatment, and prevention of neurologic complications of red blood cell, platelet, and plasma cell disorders.

LATEST DEVELOPMENTS

Cerebrovascular complications can occur in patients with blood cell and platelet disorders. Treatment strategies to prevent stroke are available for patients with sickle cell disease, polycythemia vera, and essential thrombocythemia. A diagnosis of thrombotic thrombocytopenic purpura should be considered in patients with neurologic symptoms, hemolytic anemia, thrombocytopenia, mild renal insufficiency, and fever. Plasma cell disorders can be associated with peripheral neuropathy, and classification of the monoclonal protein type and neuropathy aid in diagnosis. Patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) syndrome can present with arterial and venous neurologic events.

ESSENTIAL POINTS

This article discusses the neurologic complications of blood cell disorders and the most recent advances in prevention and treatment.

Hydroxyurea with dose escalation for primary stroke risk reduction in children with sickle cell anaemia in Tanzania (SPHERE): an open-label, phase 2 trial

BACKGROUND

Transcranial Doppler screening with chronic transfusions reduces stroke risk in children with sickle cell anaemia but is not feasible in low-resource settings. Hydroxyurea is an alternative treatment to decrease stroke risk. We aimed to estimate stroke risk in children with sickle cell anaemia in Tanzania and to determine the efficacy of hydroxyurea to decrease and prevent stroke.

METHODS

We did an open-label, phase 2 trial (SPHERE) at Bugando Medical Centre, Mwanza, Tanzania. Children aged 2-16 years with a diagnosis of sickle cell anaemia confirmed by haemoglobin electrophoresis were eligible for enrolment. Participants had transcranial Doppler ultrasound screening by a local examiner. Participants with elevated Doppler velocities, either conditional (170-199 cm/s) or abnormal (≥200 cm/s), received oral hydroxyurea starting at 20 mg/kg once daily and escalated every 8 weeks by 5 mg/kg per day to the maximum tolerated dose. Participants with normal Doppler velocities (<170 cm/s) received usual care from the sickle cell anaemia clinic and were rescreened after 12 months to determine whether they qualified for treatment on trial. The primary endpoint was change in transcranial Doppler velocity from the baseline visit to after 12 months of hydroxyurea treatment, analysed in all patients who had paired baseline and follow-up measurements collected after 12 months of treatment. Safety was analysed in the per-protocol population (all participants who received study treatment). This study is registered with ClinicalTrials.gov, NCT03948867.

FINDINGS

Between April 24, 2019, and April 9, 2020, 202 children were enrolled and had transcranial Doppler screening. Sickle cell anaemia was confirmed by DNA-based testing in 196 participants (mean age 6·8 years [SD 3·5], 103 [53%] were female, and 93 [47%] were male). At the baseline screening, 47 (24%) of 196 participants had elevated transcranial Doppler velocities (43 [22%] conditional, four [2%] abnormal); 45 initiated hydroxyurea at a mean dose of 20·2 mg/kg per day (SD 1·4) with escalation to a mean dose of 27·4 mg/kg per day (5·1) after 12 months. Treatment response was analysed after 12 months (± 1 month; median 11 months, IQR 11-12) and 24 months (±3 months; median 22 months, 22-22). Transcranial Doppler velocities decreased to a mean of 149 cm/s (SD 27) compared with 182 cm/s (12) at baseline, which was significantly lower than baseline (p<0·0001), with an average decline of 35 cm/s (SD 23) after 12 months of treatment in 42 participants with paired results available at baseline and 12 months. No clinical strokes occurred, and 35 (83%) of 42 participants reverted to normal transcranial Doppler velocities. Clinical adverse events were mild, and dose-limiting toxicities were uncommon. The most common grade 3 adverse events were malaria (12 [29%] episodes in 45 patients) and sepsis (13 [32%] episodes). There were three serious adverse events, none of which were treatment-related, and no treatment-related deaths occurred.

INTERPRETATION

Children with sickle cell anaemia in Tanzania have a high baseline stroke risk. Hydroxyurea at the maximum tolerated dose significantly lowers transcranial Doppler velocities and reduces primary stroke risk. Transcranial Doppler screening plus hydroxyurea at the maximum tolerated dose is an effective stroke prevention strategy, supporting wider hydroxyurea access for patients with sickle cell anaemia across sub-Saharan Africa.

FUNDING

American Society of Hematology, National Institutes of Health, Cincinnati Children's Research Foundation.

Managing the Cerebrovascular Complications of Sickle Cell Disease: Current Perspectives

The importance of protecting brain function for people with sickle cell disease (SCD) cannot be overstated. SCD is associated with multiple cerebrovascular complications that threaten neurocognitive function and life. Without screening and preventive management, 11% of children at 24% of adults with SCD have ischemic or hemorrhagic strokes. Stroke screening in children with SCD is well-established using transcranial Doppler ultrasound (TCD). TCD velocities above 200 cm/s significantly increase the risk of stroke, which can be prevented using chronic red blood cell (RBC) transfusion. RBC transfusion is also the cornerstone of acute stroke management and secondary stroke prevention. Chronic transfusion requires long-term management of complications like iron overload. Hydroxyurea can replace chronic transfusions for primary stroke prevention in a select group of patients or in populations where chronic transfusions are not feasible. Silent cerebral infarction (SCI) is even more common than stroke, affecting 39% of children and more than 50% of adults with SCD; management of SCI is individualized and includes careful neurocognitive evaluation. Hematopoietic stem cell transplant prevents cerebrovascular complications, despite the short- and long-term risks. Newer disease-modifying agents like voxelotor and crizanlizumab, as well as gene therapy, may treat cerebrovascular complications, but these approaches are investigational.

Point-of-Care Ultrasound in Neurology - Report of the EAN SPN/ESNCH/ERcNsono Neuro-POCUS Working Group

In the last decade, ultrasound examination in neurology has been undergoing a significant expansion of its modalities. In parallel, there is an increasing demand for rapid and high-quality diagnostics in various acute diseases in the prehospital setting, the emergency room, intensive care unit, and during surgical or interventional procedures. Due to the growing need for rapid answers to clinical questions, there is particular demand for diagnostic ultrasound imaging. The Neuro-POCUS working group, a joint project by the European Academy of Neurology Scientific Panel Neurosonology, the European Society of Neurosonology and Cerebral Hemodynamics, and the European Reference Centers in Neurosonology (EAN SPN/ESNCH/ERcNsono Neuro-POCUS working group), was given the task of creating a concept for point-of-care ultrasound in neurology called "Neuro-POCUS". We introduce here a new ultrasound examination concept called point-of-care ultrasound in neurology (Neuro-POCUS) designed to streamline conclusive imaging outside of the ultrasound center, directly at the bedside. The aim of this study is to encourage neurologists to add quick and disease-oriented Neuro-POCUS to accompany the patient in the critical phase as an adjunct not a substitution for computed tomography, magnetic resonance imaging, or standard comprehensive neurosonology examination. Another goal is to avoid unwanted complications during imaging-free periods, ultimately resulting in advantages for the patient.

Low Stroke Risk in Children With Sickle Cell Disease in French Guiana: A Retrospective Cohort Study

One in every 227 babies born in French Guiana has sickle cell disease, which represents the greatest incidence in France. This study aimed to determine the incidence of stroke in children with sickle cell disease and its associated risk factors. This retrospective cohort study included all children with sickle cell disease diagnosed in the neonatal period who were born in French Guiana between 01/01/1992 and 12/31/2002. Of a total of 218 records, 122 patients were included. There were 70 HbSS/Sβ0 (58%), 40 HbSC (33%), and 11 Sβ + thalassemia (9%). The number of emergency admissions was significantly different between genotypes, with a higher number in SS/Sβ0 children (p = 0.004). There were significantly more acute chest syndromes (p = 0.006) and more elevated Lactate Dehydrogenase in SS/Sβ0 patients (p = 0.003). Three of these patients had ischemic strokes at a mean age of 6.9 years, and one had a hemorrhagic stroke at the age of 9,2 years. The incidence rate of ischemic stroke for SS/Sβ0 children was 3.1 (95% CI: 1.0–9.7) per 1,000 patient-years, and the clinically apparent stroke risk by the age of 15 years and 3 months was 6,4%. The incidence of hemorrhagic stroke was 1.1 (95% CI: 0.1–7.4) per 1,000 patients-years. No patient with SC or Sβ + thalassemia genotypes experienced any stroke.

Clinical Significance and Value of Serum Homocysteine and Urine 11 Dehydrothromboxane B2 Combined with Transferrin-Specific Peptide in the Diagnosis of Cerebral Apoplexy

Objective

To explore the clinical significance and value of serum homocysteine (Hcy) and urine 11 dehydrothromboxane B2 (urine 11-DH-TXB2) combined with transferrin-specific peptide (TF-UP) in the diagnosis of stroke.

Methods

One hundred stroke patients treated from January 2019 to June 2021 were enrolled in our hospital as the study group. All the patients in the study group met the diagnostic criteria of stroke. The focus of stroke was confirmed by CT or MRI, and the first onset was less than 48 hours. One hundred healthy persons who went through physical examination in our hospital were enrolled as the control group. The comparison was taken to explore the clinical significance and value of Hcy and urine 11-DH-TXB2 combined with TF-UP in the diagnosis of stroke.

Results

There exhibited no significant difference in the history of smoking, drinking, and atrial fibrillation (P > 0.05). There were significant differences in systolic blood pressure, diastolic blood pressure, eGFR, history of hypertension, diabetes, and coronary heart disease (P < 0.05). In terms of the levels of Hcy, urine 11-DH-TXB2, and TF-UP, the levels of Hcy and urine 11-DH-TXB2 in the study group were higher compared to the control group, while the level of TF-UP in the study group was lower compared to the control group (P < 0.05). The results of logistic regression analysis indicated that there was a significant correlation between Hcy, urine 11-DH-TXB2, TF-UP, and stroke, and Hcy and urine 11-DH-TXB2 indicated positive correlation with stroke disease, while TF-UP level was negatively correlated with stroke disease (P < 0.05). The levels of Hcy, urine 11-DH-TXB2, and TF-UP were adopted as evaluation indexes to draw ROC curve. The results show that the area under the curve (AUC) of Hcy is 0.760 (95% CI 0.670~0.850). The best critical point was 3342.5 pg/mg Ucr, the sensitivity was 65.6%, and the specificity was 77.1%. The AUC of urine 11-DH-TXB2 was 0.773 (95% CI 0.685~0.861). The best critical point was 3354.44 pg/mg Ucr, the sensitivity was 71.2%, and the specificity was 78.3%. The AUC of TF-UP was 0.735 (95% CI 0.641~0.829). The best critical point was 3365.43 pg/mg Ucr, the sensitivity was 68.4%, and the specificity was 80.5%. If Hcy was detected in combination with other indexes, AUC increased to 0.749 when combined with urine 11-DH-TXB2, and AUC increased to 0.797 when combined with TF-UP. When the three are combined, the AUC can reach 0.836, the sensitivity is 79.1%, and the specificity is 80%. It shows that the combined detection of Hcy, urine 11-DH-TXB2, and TF-UP is of higher diagnostic value. The difference of data exhibited statistically significant (P < 0.05).

Conclusion

There is imbalance between Hcy, urine 11-DH-TXB2, and TF-UP in patients with acute stroke. High Hcy, urine 11-DH-TXB2, and low TF-UP are closely related to the occurrence of cerebral infarction. Hcy, urine 11-DH-TXB2, and TF-UP may be the risk factors of stroke and positively correlated with the degree of neurological impairment. Effective monitoring of Hcy and urine 11-DH-TXB2 combined with TF-UP levels and positive intervention measures may effectively prevent the occurrence and development of cerebral infarction, reduce Hcy and urine 11-DH-TXB2, or increase the level of TF-UP, which may provide new ideas for the treatment of cerebrovascular diseases.

Brain Magnetic Resonance Imaging and Angiography in Children with Sickle Cell Anaemia in Uganda in a Cross-Sectional Sample

OBJECTIVE

Children with sickle cell anaemia (SCA) are highly susceptible to cerebrovascular injury. We performed brain magnetic resonance imaging and angiography (MRI-MRA) in Ugandan children with SCA to identify structural cerebrovascular abnormalities and examine their relationship to standardized clinical assessments.

METHODS

A sub-sample (n=81) was selected from a cross-sectional study of children attending SCA clinic, including 52 (64.2%) with and 29 (35.8%) without clinically detected abnormalities. Clinical evaluation included assessment for prior stroke, cognitive testing and cerebral arterial transcranial doppler (TCD) flow velocity. MRI-MRA scans were interpreted by at least two neuroradiologists.

RESULTS

Mean age was 6.5±2.7 years, with 39 (48.1%) female. Mean haemoglobin was 7.3±0.9 g/dl. Overall, 13 (16.0%) were malnourished. Infarcts and/or stenoses were detected in 55 (67.9%) participants, with stenoses primarily in the anterior circulation. Infarcts were seen in those with normal 17/29 (58.6%) or abnormal 34/52 (65.4%) clinical testing (p=0.181). Neither abnormal MRI nor MRA was associated with age, sex, haemoglobin, or malnutrition. Abnormal MRA was highly associated with infarcts (p<0.0001). Participants with abnormal imaging had two-fold higher proportion of stroke on exam and/or impaired cognition. Stroke on exam was strongly associated with an imaging abnormality after adjusting for age, sex, malnutrition, and haemoglobin (OR 11.8, 95%CI 1.87-74.2).

CONCLUSION

Over half of these SCA children had cerebrovascular infarcts and/or arterial stenoses. Cerebrovascular disease was frequently undetectable by clinical assessments. While rarely available in under-resourced settings, MRI-MRA brain imaging is an important tool for defining SCA cerebrovascular disease and for assessing impact of clinical intervention trials.

Trends in quality of care among children with sickle cell anemia

INTRODUCTION

For decades, it has been recommended that children with sickle cell anemia (SCA) receive antibiotic prophylaxis to prevent serious infections and undergo transcranial Doppler (TCD) screening to identify those at highest risk of overt stroke. We assessed recent temporal trends in antibiotic prophylaxis prescription fills and TCD screening among children with SCA using validated quality measures.

PROCEDURE

Using validated claims-based definitions, we identified children with SCA who were enrolled in Michigan or New York State (NYS) Medicaid programs (2011-2018). Among recommended age groups, two outcomes were assessed yearly: (a) filling of ≥300 days of antibiotics, and (b) receipt of greater than or equal to one TCD. The proportion of children with each outcome was calculated by state. Temporal trends in each preventive service were assessed using generalized linear models.

RESULTS

A total of 1784 children were eligible for antibiotic prophylaxis (Michigan: 384; NYS: 1400), contributing 3322 person-years. Annual rates of filling ≥300 days of antibiotics ranged from 16% to 22% and were similar by state. There was no change in rates of antibiotic filling over time in Michigan (p-value: .10), but there was a decrease in NYS (p-value: .02). A total of 3439 children with SCA were eligible for TCD screening (Michigan: 710; NYS: 2729), contributing 10,012 person-years. Annual rates of TCD screening ranged from 39% to 45%, were similar by state, and did not change over time (p-values >.05).

CONCLUSIONS

Most children with SCA do not receive recommended antibiotic prophylaxis and/or TCD screening. New, sustainable, and coordinated interventions across preventive services are urgently needed.

Establishing Sickle Cell Disease Stroke Prevention Teams in Africa is Feasible: Program Evaluation Using the RE-AIM Framework

We used the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework to evaluate a Stroke Prevention Team's readiness to prevent strokes in children with sickle cell anemia living in northern Nigeria. The NIH sponsored Stroke Prevention Trial in Nigeria included a goal of a sustainable stroke prevention program. The program's 1-year reach for transcranial Doppler screening was 14.7% (4710/32,000) of which 6.0% (281/4710) had abnormal velocities (≥200 cm/s). All participants with abnormal transcranial Doppler velocities were started on hydroxyurea (effectiveness). The leaders of all 5 hospitals agreed to adopt the program. After 1 year, program-implementation and maintenance rates were 100%, demonstrating the program's feasibility and short-term sustainability.

Acute StrokeTreatment in Children: Are Adult Guidelines Applicable?

Purpose of this Review

This article provides an overview into acute treatments in stroke which are widely studied and available for adults and their applicability in the pediatric population.

Recent Findings

Arterial ischemic stroke is an important cause of morbidity and mortality in the pediatric population. Neurological deficits and etiologies are age-dependent and more challenging to diagnose than in the adult population. Advancements in imaging and treatment modalities including increased treatment windows in acute stroke have led to improvement in the diagnosis and management of pediatric arterial ischemic disease. Accordingly, hyperacute treatments, such as endovascular therapy, are becoming increasingly available in an attempt to improve outcomes in children.

Summary

Significant scientific and technological advances have transformed the hyperacute treatment of stroke in the recent years, allowing for improvement in the diagnosis and treatment of cerebrovascular pathologies in children. Optimization in the approach, and validation of existing stroke pathways/protocols is expected to further advance acute stroke therapy in pediatric patient care. Given that the lifelong individual, family, and societal burden of acute stroke is likely to be greater than in adults because infants and children surviving stroke live more years with disability, we must be knowledgeable about this pathology and the medical and therapeutic options available for this unique population as detailed in this review.

Association Between Patent Foramen Ovale and Overt Ischemic Stroke in Children With Sickle Cell Disease

Ischemic stroke is one of the most devastating complications of sickle cell anemia (SCA). Previous studies have shown that intracardiac shunting including patent foramen ovale (PFO) can be a potential risk factor for stroke in children with SCA. This study investigates the association between PFO and overt ischemic stroke in the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study cohort of 5,247 children with SCA of whom 1,414 had at least one clinical non-contrast transthoracic echocardiogram. Presence of PFO was taken from the clinical report. Further, we assessed the association between PFO and other clinical and hemolytic factors in children with SCA such as history of abnormal sickle stroke screen [elevated Transcranial Doppler ultrasound (TCD) velocity] and patient's baseline hemoglobin. In 642 children for whom all data were available, the adjusted odds ratio (OR) for overt stroke was higher in those with PFO but this was not statistically significant (OR: 1.49, 95% CI: 0.20-11.03, p = 0.6994). With an OR of 0.85, the study suggested less PFOs in those with abnormal TCD, but this was not statistically significant (95% CI: 0.17-4.25, p = 0.8463). Overall, the prevalence of PFO in this large sub study of non-contrast echocardiography amongst children with SCA is much lower than previous smaller studies using bubble contrast echocardiography. Overt stroke was non-statistically more common in children with SCA and PFO, but there was no evidence that PFO was more common in those with abnormal TCD, the most important pediatric sickle stroke screen.

Transcranial Doppler Screening in a Current Cohort of Children With Sickle Cell Anemia: Results From the DISPLACE Study

Stroke prevention guidelines for sickle cell anemia (SCA) recommend transcranial Doppler (TCD) screening to identify children at stroke risk; however, TCD screening implementation remains poor. This report describes results from Part 1 of the 28-site DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study, a baseline assessment of TCD implementation rates. This report describes TCD implementation by consortium site characteristics; characteristics of TCDs completed; and TCD results based on age. The cohort included 5247 children with SCA, of whom 5116 were eligible for TCD implementation assessment for at least 1 study year. The majority of children were African American or Black, non-Hispanic and received Medicaid. Mean age at first recorded TCD was 5.9 and 10.5 years at study end. Observed TCD screening rates were unsatisfactory across geographic regions (mean 49.9%; range: 30.9% to 74.7%) independent of size, institution type, or previous stroke prevention trial participation. The abnormal TCD rate was 2.9%, with a median age of 6.3 years for first abnormal TCD result. Findings highlight real-world TCD screening practices and results from the largest SCA cohort to date. Data informed the part 3 implementation study for improving stroke screening and findings may inform clinical practice improvements.

A case of Sβ+ sickle cell disease diagnosed in adulthood following acute stroke: it's 2021, are we there yet?

In this report, we present a 29-year-old African American female who was brought to a local emergency department after being found unresponsive by her mother. The etiology of her stroke and severe hemolysis remained unknown, despite her mother reporting the patient's history of co-inheritance of sickle cell trait and beta-thalassemia trait, and extensive workup during her prolonged hospitalization. She was diagnosed with sickle cell disease (Sβ+ type) two years after discharge when she was referred to a sickle cell specialist for persistent anemia. Here, we also briefly review the challenges to diagnose rarer subtypes of sickle cell disease (SCD), in this case Sβ+ type, as well as the pathophysiology and current management of stroke in SCD.

Epidemiology of Stroke in Sickle Cell Disease

Sickle cell disease is the most common cause of stroke in childhood, both ischaemic and haemorrhagic, and it also affects adults with the condition. Without any screening or preventative treatment, the incidence appears to fall within the range 0.5 to 0.9 per 100 patient years of observation. Newborn screening with Penicillin prophylaxis and vaccination leading to reduced bacterial infection may have reduced the incidence, alongside increasing hydroxyurea prescription. Transcranial Doppler screening and prophylactic chronic transfusion for at least an initial year has reduced the incidence of stroke by up to 10-fold in children with time averaged mean of the maximum velocity >200 cm/s. Hydroxyurea also appears to reduce the incidence of first stroke to a similar extent in the same group but the optimal dose remains controversial. The prevention of haemorrhagic stroke at all ages and ischaemic stroke in adults has not yet received the same degree of attention. Although there are fewer studies, silent cerebral infarction on magnetic resonance imaging (MRI), and other neurological conditions, including headache, epilepsy and cognitive dysfunction, are also more prevalent in sickle cell disease compared with age matched controls. Clinical, neuropsychological and quantitative MRI screening may prove useful for understanding epidemiology and aetiology.

MRI detection of brain abnormality in sickle cell disease

Introduction: Over the past decades, neuroimaging studies have clarified that a significant proportion of patients with sickle cell disease (SCD) have functionally significant brain abnormalities. Clinically, structural magnetic resonance imaging (MRI) sequences (T2, FLAIR, diffusion-weighted imaging) have been used by radiologists to diagnose chronic and acute cerebral infarction (both overt and clinically silent), while magnetic resonance angiography and venography have been used to diagnose arteriopathy and venous thrombosis. In research settings, imaging scientists are increasingly applying quantitative techniques to shine further light on underlying mechanisms.Areas covered: From a June 2020 PubMed search of 'magnetic' or 'MRI' and 'sickle' over the previous 5 years, we selected manuscripts on T1-based morphometric analysis, diffusion tensor imaging, arterial spin labeling, T2-oximetry, quantitative susceptibility, and connectivity.Expert Opinion: Quantitative MRI techniques are identifying structural and hemodynamic biomarkers associated with risk of neurological and neurocognitive complications. A growing body of evidence suggests that these biomarkers are sensitive to change with treatments, such as blood transfusion and hydroxyurea, indicating that they may hold promise as endpoints in future randomized clinical trials of novel approaches including hemoglobin F upregulation, reduction of polymerization, and gene therapy. With further validation, such techniques may eventually also improve neurological and neurocognitive risk stratification in this vulnerable population.

Nocturnal hypertension associated with stroke and silent cerebral infarcts in children with sickle cell disease

BACKGROUND

Strokes and silent cerebral infarcts (SCIs) lead to significant morbidity and mortality in children with sickle cell disease (SCD). Higher systolic blood pressures increase risk for stroke and SCIs; however, patients with SCD often have lower clinic blood pressures than the general population. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) allows for more robust examination of blood pressures. This study evaluated associations between abnormal ABPM measurements with stroke and SCIs.

PROCEDURE

A cross-sectional study was performed. Children with SCD completed 24-hour ABPMs. Children with a documented magnetic resonance imaging (MRI) brain within a year of the ABPM were included in the analysis. Bivariate analyses were performed to identify associations between ABPM parameters with cerebrovascular outcomes.

RESULTS

Forty-two children with a median age of 13 years (10, 17) were included in the analysis. Seven (17%) had history of stroke and seven (17%) had SCIs. Nocturnal hypertension, elucidated via 24-hour ABPM, was noted in 25% of subjects. The presence of nocturnal hypertension was significantly higher in the SCI/stroke group (55% vs 12%, P = .01). Sensitivity analyses were performed during which stroke patients were removed from analysis. Nocturnal hypertension remained significantly associated with the presence of SCIs (P = .006).

CONCLUSIONS

This study reveals an association between nocturnal hypertension and a higher prevalence of SCI and stroke in children with SCD. Larger, prospective studies are needed to confirm these findings and evaluate the contributory nature of blood pressure abnormalities to cerebrovascular events in children with SCD.

Pediatric stroke in the emergency department

Strokes are more commonly seen in adults but also occur in the pediatric population. Similar to adult strokes, pediatric strokes are considered medical emergencies and require prompt diagnosis and treatment to maximize favorable outcomes. Unfortunately, the diagnosis of stroke in children is often delayed, commonly because of parental delay or failure to consider stroke in the differential diagnosis. Children, especially young children, often present differently than adults. Much of the treatment for pediatric strokes has been adapted from adult guidelines but the optimal treatment has not been clearly defined. In this article, we review pediatric strokes and the most recent recommendations for treatment.

Interventions for preventing silent cerebral infarcts in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Silent cerebral infarcts are the commonest neurological complication in children and probably adults with SCD. Silent cerebral infarcts also affect academic performance, increase cognitive deficits and may lower intelligence quotient.

OBJECTIVES

To assess the effectiveness of interventions to reduce or prevent silent cerebral infarcts in people with SCD.

SEARCH METHODS

We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 14 November 2019. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 07 October 2019.

SELECTION CRITERIA

Randomised controlled trials comparing interventions to prevent silent cerebral infarcts in people with SCD. There were no restrictions by outcomes examined, language or publication status.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included five trials (660 children or adolescents) published between 1998 and 2016. Four of the five trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of SCD. One trial focused on preventing silent cerebral infarcts or stroke; three trials were for primary stroke prevention and one trial dealt with secondary stroke prevention. Three trials compared the use of regular long-term red blood cell transfusions to standard care. Two of these trials included children with no previous long-term transfusions: one in children with normal transcranial doppler (TCD) velocities; and one in children with abnormal TCD velocities. The third trial included children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children), and one in secondary prevention (children and adolescents). The quality of the evidence was moderate to very low across different outcomes according to GRADE methodology. This was due to trials being at high risk of bias because they were unblinded; indirectness (available evidence was only for children with HbSS); and imprecise outcome estimates. Long-term red blood cell transfusions versus standard care Children with no previous long-term transfusions and higher risk of stroke (abnormal TCD velocities or previous history of silent cerebral infarcts) Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, risk ratio (RR) 0.11 (95% confidence interval (CI) 0.02 to 0.86) (one trial, 124 participants, low-quality evidence); but make little or no difference to the incidence of silent cerebral infarcts in children with previous silent cerebral infarcts on magnetic resonance imaging and normal or conditional TCDs, RR 0.70 (95% CI 0.23 to 2.13) (one trial, 196 participants, low-quality evidence). No deaths were reported in either trial. Long-term red blood cell transfusions may reduce the incidence of: acute chest syndrome, RR 0.24 (95% CI 0.12 to 0.49) (two trials, 326 participants, low-quality evidence); and painful crisis, RR 0.63 (95% CI 0.42 to 0.95) (two trials, 326 participants, low-quality evidence); and probably reduces the incidence of clinical stroke, RR 0.12 (95% CI 0.03 to 0.49) (two trials, 326 participants, moderate-quality evidence). Long-term red blood cell transfusions may improve quality of life in children with previous silent cerebral infarcts (difference estimate -0.54; 95% confidence interval -0.92 to -0.17; one trial; 166 participants), but may have no effect on cognitive function (least squares means: 1.7, 95% CI -1.1 to 4.4) (one trial, 166 participants, low-quality evidence). Transfusions continued versus transfusions halted: children and adolescents with normalised TCD velocities (79 participants; one trial) Continuing red blood cell transfusions may reduce the incidence of silent cerebral infarcts, RR 0.29 (95% CI 0.09 to 0.97 (low-quality evidence). We are very uncertain whether continuing red blood cell transfusions has any effect on all-cause mortality, Peto odds ratio (OR) 8.00 (95% CI 0.16 to 404.12); or clinical stroke, RR 0.22 (95% CI 0.01 to 4.35) (very low-quality evidence). The trial did not report: comparative numbers for SCD-related adverse events; quality of life; or cognitive function. Hydroxyurea and phlebotomy versus transfusions and chelation Primary prevention, children (121 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts (no infarcts); all-cause mortality (no deaths); risk of stroke (no strokes); or SCD-related complications, RR 1.52 (95% CI 0.58 to 4.02) (very low-quality evidence). Secondary prevention, children and adolescents with a history of stroke (133 participants; one trial) We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: silent cerebral infarcts, Peto OR 7.28 (95% CI 0.14 to 366.91); all-cause mortality, Peto OR 1.02 (95%CI 0.06 to 16.41); or clinical stroke, RR 14.78 (95% CI 0.86 to 253.66) (very low-quality evidence). Switching to hydroxyurea and phlebotomy may increase the risk of SCD-related complications, RR 3.10 (95% CI 1.42 to 6.75) (low-quality evidence). Neither trial reported on quality of life or cognitive function.

AUTHORS' CONCLUSIONS

We identified no trials for preventing silent cerebral infarcts in adults, or in children who do not have HbSS SCD. Long-term red blood cell transfusions may reduce the incidence of silent cerebral infarcts in children with abnormal TCD velocities, but may have little or no effect on children with normal TCD velocities. In children who are at higher risk of stroke and have not had previous long-term transfusions, long-term red blood cell transfusions probably reduce the risk of stroke, and other SCD-related complications (acute chest syndrome and painful crises). In children and adolescents at high risk of stroke whose TCD velocities have normalised, continuing red blood cell transfusions may reduce the risk of silent cerebral infarcts. No treatment duration threshold has been established for stopping transfusions. Switching to hydroxyurea with phlebotomy may increase the risk of silent cerebral infarcts and SCD-related serious adverse events in secondary stroke prevention. All other evidence in this review is of very low-quality.