Transcranial doppler in sickle cell anaemia: evaluation of brain blood flow parameters in children of Aracaju, Northeast - Brazil

Transcranial doppler as screening method for sickling crises in children with sickle cell anemia: a latin America cohort study

Background

Sickle cell anemia (SCA) is the leading cause of childhood stroke. We aimed to evaluate whether altered cerebral flow velocities, as measured by transcranial Doppler (TCD), are associated with vaso-occlusive complications in addition to stroke in pediatric SCA patients.

Methods

We evaluated 37 children aged between 2 and 16 years with SCA who underwent screening for TCD between January 2012 and October 2018. Genotypic profiles and demographic data were collected, TCD examinations were performed during follow-up, and the presence of sickling crises was compared. Survival analyses were performed using simple frailty models, in which each predictor variable was analyzed separately in relation to the occurrence of a sickling crisis.

Results

The variables related to sickle cell crises in the univariate analysis were peak systolic velocity (PSV) in the middle cerebral artery (MCA), hazard ratio (HR) 1.01 (1.00—1.02) p = 0.04; end-diastolic velocity (EDV) in the MCA, HR 1.02 (1.01—1.04) p = 0.01; time average mean maximum velocity (TAMMV) in the basilar artery (BA), HR 1.02 (1.00—1.04) p = 0.04; hemoglobin, HR 0.49 (0.38—0.65) p < 0.001; hematocrit, HR 0.78 (0.71—0.85) p < 0.001; leukocyte counts, HR 1.1 (1.05—1.15) p < 0.001; platelets counts, HR 0.997 (0.994—0.999) p = 0.02; and reticulocyte numbers, HR 1.14 (1.06—1.23) p < 0.001.

Conclusions

Our results indicate PSV and EDV in the MCA and TAMMV in the BA as markers of risk for the occurrence of sickling crises in SCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03429-5.

Factors associated with abnormal cerebral blood flow in Egyptian children with sickle cell disease

Background:

Transcranial Doppler (TCD) is a well-established tool for cerebrovascular assessment. Estimating the flow velocity across the intracranial arteries helps to identify children with sickle cell anaemia who are at risk for stroke.

Objective:

Our aim is to correlate TCD findings with clinical condition in children with sickle cell disease (SCD) to determine the value of TCD assessment as a predictive tool for stroke in SCD and to identify any association of TCD findings with disease severity, transfusion therapy and treatment administered.

Methods:

Eighty-five paediatric SCD patients aged from 3 years to 18 years of both genders who were followed up at the Hematology Clinic of New Children’s Hospital at Cairo University were included in this cross-sectional observational study. All our participants underwent routine laboratory investigations and TCD assessments.

Results:

Oof the 85 patients, two patients (2.3%) died before completing the TCD study and eventually 83 patients were included in the analysis. Seventeen (20.5%) patients had abnormal TCD findings, seven (8.4%) patients showed high-risk findings and 10 (12.1%) patients had conditional flow pattern. Logistic linear regression analysis confirmed that annual frequency of blood transfusion and hydroxyurea (HU) dose were associated with a decreased risk of abnormal TCD findings.

Conclusion:

The current study demonstrates that our TCD data reproduce the findings of other studies and that it is very likely the results from large trials are applicable for Egyptian children. The annual frequency of blood transfusion and HU dose were associated with a decreased frequency of abnormal TCD findings.

Stroke Avoidance for Children in REpública Dominicana (SACRED): Protocol for a Prospective Study of Stroke Risk and Hydroxyurea Treatment in Sickle Cell Anemia

Background

In the Dominican Republic, where the burden of sickle cell anemia (SCA) is high, many children lack access to routine screening and preventative care. Children with SCA are at risk for stroke, an event that leads to significant morbidity and mortality. In the United States, screening via transcranial Doppler (TCD) identifies children with SCA at highest stroke risk, allowing early intervention with blood transfusions. The need for indefinite transfusions for primary stroke prevention limits their practicality in limited-resource countries. Hydroxyurea has been shown to lower TCD velocities and to prevent conversion from conditional (170 to 199 cm/sec) to abnormal (greater than or equal to 200 cm/sec) velocities. In resource-limited settings, implementation of a TCD screening program, coupled with hydroxyurea therapy, could reduce the burden of SCA and stroke.

Objective

The aims of the Stroke Avoidance for Children in REpública Dominicana (SACRED) trial are (1) to screen children with SCA for stroke risk using TCD and to determine the prevalence of elevated velocities in a cross-sectional sample; (2) to identify clinical and laboratory correlates of elevated velocities; and (3) to obtain longitudinal data on the natural history of TCD velocities and to measure therapeutic effects of hydroxyurea.

Methods

This prospective trial, designed and conducted by Cincinnati Children’s Hospital Medical Center (CCHMC) and Hospital Infantil Robert Reid Cabral (HIRRC) with Centro de Obstetricia y Ginecología, includes a baseline cross-sectional epidemiological survey of the distribution of TCD velocities across a large cohort of children with SCA in the Dominican Republic. Children with conditional velocities are eligible to begin protocol-directed hydroxyurea if laboratory criteria are met. The treatment schedule begins with a fixed-dose of approximately 20 mg/kg/day for 6 months, after which it escalates to maximum tolerated dose (MTD). All participants undergo longitudinal annual TCD evaluation, while those on hydroxyurea have semi-annual evaluations during the 3-year study period. Data are collected using an Internet-based Research Electronic Data Capture (REDCap) system with forms translated into Spanish; both remote and on-site monitoring are used.

Results

To date, 122 children with SCA have enrolled in SACRED including 85 (69.7%, 85/122) with normal, 29 (23.8%, 29/122) with conditional, 5 (4.1%, 5/122) with abnormal, and 3 (2.5%, 3/122) with inadequate TCD velocities. Of the 29 children with conditional TCD velocities, 17 (59%, 17/29) have initiated hydroxyurea per protocol, with plans for escalation to MTD.

Conclusions

The SACRED trial will provide novel epidemiologic data about the prevalence of children with SCA and increased stroke risk in the Dominican Republic. The study also includes an investigation of the impact of hydroxyurea at MTD on elevated TCD velocities, as well as clinical and laboratory parameters. The design and implementation of SACRED reflect a successful international institutional partnership, one that features local capacity building and training in research methods and clinical care. The trial’s results have important implications for screening and prevention of primary stroke in children with SCA living in resource-limited settings.

Trial Registration

ClinicalTrials.gov NCT02769845; https://www.clinicaltrials.gov/ct2/show/NCT02769845 (Archived by WebCite at http://www.webcitation.org/6qf6n0Egh)

Patients with sickle cell disease are frequently excluded from the benefits of transcranial doppler screening for the risk of stroke despite extensive and compelling evidence

ABSTRACT Transcranial doppler (TCD) is a strategic component of primary stroke prevention in children with sickle cell disease (SCD). This study was conducted to examine the TCD characteristics of children with SCD in nine different medical centers in Brazil. Methods: Transcranial doppler was performed in accordance with the Stroke Prevention Trial in Sickle Cell Anemia Protocol. Results: Of the 396 patients, 69.5% had homozygous SS hemoglobin. The TCD result was abnormal in 4.8%, conditional in 12.6%, inadequate in 4.3% and abnormally low in 1% of patients. The highest mean flow velocities were 121±23.83cm/s and 124±27.21cm/s in the left and right middle cerebral artery respectively. A total of 28.8% patients (mean age 9.19±5.92 years) were evaluated with TCD for the first time. Conclusions: The SCD patients were evaluated with TCD at an older age, representing an important missed opportunity for stroke prevention. Since TCD screening in patients with SCD is important to detect those at high risk for stroke, it is recommended that this screening should be made more readily available.

[Transcranial doppler in sickle cell disease (SCD) in Malagasy children]

INTRODUCTION

Transcranial Doppler is an effective diagnostic tool to detect sickle cell children at risk for stroke.

METHODS

We conducted a cross-sectional descriptive study of Malagasy children aged between 24 months and 15 years (group 1: 57 sickle cell diseases, group 2: 43 controls) to assess the cerebral artery velocimetry in the patient population. Transcranial doppler ultrasound with analysis of cerebral blood flow was performed in children of both groups.

RESULTS

In subjects with sickle cell disease, the mean velocity (MV) in the middle cerebral artery was 100.9 ± 26.8 cm/s, pulsatility index (PI) was 0.73 ± 0.20, the difference between the right and left middle cerebral artery (MCA) was 19.8 ± 21.5 cm/s, anterior cerebral artery/middle cerebral artery flow velocity ratio (ACA / MCA) was 0.7 ± 0.2. In children without sickle cell disease, MV: 80.6 ± 19.3 cm/s, IP: 0.79 ± 0.14, ACMr: 17 ± 20.1 cm/s, ACA/ACM: 0,8 ± 0,2. The velocity in children with sickle cell disease was higher than in the control group. Velocities were correlated with hemoglobin and age but not with sex and mean corpuscular volume.

CONCLUSION

Cerebral Circulation Speeds are higher in children with sickle cell disease and are influenced by hemoglobin levels and age.

Stroke in sickle cell anemia patients: a need for multidisciplinary approaches

Sickle cell anemia (SCA) is an autosomal recessive disorder, with Mendelian inheritance pattern, caused by a missense mutation in the β-polypeptide chain of the hemoglobin B. SCA preferentially affects populations in countries where malaria was/is present (e.g. Africa, USA, Brazil). Thereby, in USA, the incidence of SCA is relatively high, around 1/500, and the prevalence is about 1/1000. In Brazil, SCA represents a major public health problem with an incidence ranging from 1/2000 to 1/600 depending on the regions. Homozygotic patients present more severe medical conditions and reduced life expectancy than heterozygous individuals who generally are asymptomatic. Eventually, this life-threatening disease displays a complex etiology owing to heterogeneous phenotypes and clinical outcomes, subsequently affecting the management of the patients. One of the most critical complications associated with SCA is stroke, a leading neurologic cause of death and disability. About 24% of SCA patients have a stroke by the age of 45 and 11% by the age of 20. From the general population, twin and familial aggregation studies as well as genome-wide association studies (GWAS), mostly in pediatric populations with ischemic stroke, showed that the risk of stroke has a substantial genetic component. Nevertheless, to fully characterize genomic contributors of stroke and permit reliable personalized medicine, multidisciplinary studies incorporating knowledge from clinical medicine, epidemiology, genetics, and molecular biology, are required. In this manuscript, stroke in SCA patients is extensively reviewed with emphasis to the US and Brazilian populations. Recent advances in genomics analysis of stroke in SCA patients are highlighted.

Retinal changes in children and adolescents with sickle cell disease attending a paediatric hospital in Cairo, Egypt: risk factors and relation to ophthalmic and cerebral blood flow

BACKGROUND

Sickle cell disease (SCD) is characterised by occlusion of small blood vessels. This study aimed to assess retinal changes in patients with SCD and its correlation with time-averaged mean flow velocity (TAMV) in middle cerebral arteries (MCA) and ophthalmic arteries (OA).

METHODS

Sixty SCD patients (aged 3-18 years) attending a paediatric hospital in Cairo, Egypt, during March 2010 to November 2011, were compared with 30 healthy controls. All underwent clinical and fundus examination by indirect ophthalmoscopy, and assessment of TAMV in MCAs and OAs by transcranial Doppler, repeated 1 year later for those with conditional velocities.

RESULTS

HbS/β was diagnosed in 32 patients and HbSS in 28; 50 patients had normal fundus and 10 had bilateral non-proliferative retinopathy. Risk factors for retinopathy included HbSS, age, previous stroke, non-compliant hydroxyurea (HU) therapy, frequency of sickling crises and HbS level. TAMVs were increased in MCAs, but not in OAs, in sicklers. TAMVs in MCAs and OAs increased with non-compliant HU therapy, previous stroke, age, frequency of sickling crises and level of HbS. No significant interhemispheric difference was found.

CONCLUSION

Sickle retinopathy was correlated with TAMV in MCAs but not in OAs. A significant difference was found between initial and follow-up TAMVs in the MCAs, after 1 year of regular HU and transfusion therapy, in those with conditional velocities.