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

Abstract

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.

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

“…We found no increased risk of stroke or abnormal TCD among those with PFO compared to those without PFO in children with SCA. This could be due to the fact that overall DISPLACE recorded a much lower frequency of abnormal TCD than reported in older studies ( 25 ). We believe that even though PFO may be associated with increased risk of overt ischemic stroke in the general population, in children with SCA, other known risk factors including anemia, hypertension, silent infarction and history of acute chest syndrome, likely play a more important role.…”

“…DISPLACE study retrospectively collected data on 5,247 children with SCA aged between 2 and 16 years from 28 centers in the US including clinical and laboratory assessments from defined study years of 2012–2016 ( 25 ). These data included baseline values of heart rate and blood pressure measurements, anthropometric measurements including height and weight and presence or absence of sickle cell disease-related therapies including chronic red cell transfusion (CRCT) and hydroxyurea (HU) therapies.…”

“…Institutional Review Board (IRB) approval and data use agreement for the DISPLACE study were obtained at and between each clinical institution and the sponsoring institution using a common protocol ( 25 ). All data were de-identified at time of entry and all data were retrospective; thus, consent was not required from individual patients or their families.…”

“…Recently, the DISPLACE (Dissemination and Implementation of Stroke Prevention Looking at the Care Environment) study was funded by National Heart Lung and Blood Institute (NHLBI) to evaluate implementation of TCD screening and assess barriers and facilitators to evidence-based stroke prevention for children with SCA across 28 sites in the USA ( 25 ). As part of DISPLACE study, data were collected on children with SCA who were aged 2–16 at the time of the study and included TCD results, MRI results, Echocardiogram information (if done for clinical assessment) as well as laboratory and demographic information.…”

Epidemiology of Stroke in Sickle Cell Disease

“…Two of 48 (4%) of Spanish children with SCD had abnormal TCD [ 80 ]. Recent data from the 28-center DISPLACE consortium in the USA reported a lower rate of 2.9% with a median age for the first abnormal TCD of 6.3 years, but there were difficulties in implementation across sites and age at first TCD was typically only slightly lower than this [ 81 ]. The rate in Jamaica was reported as 6.7% but some of these children had prior stroke [ 82 ].…”