scholarly journals Reduction in transcranial doppler ultrasound (TCD) velocity after regular blood transfusion therapy is associated with a change in hemoglobin S fraction in sickle cell anemia

2020 ◽  
Vol 95 (11) ◽  
Author(s):  
Lori C. Jordan ◽  
Mark Rodeghier ◽  
Manus J. Donahue ◽  
Michael R. DeBaun
Keyword(s):  
Blood Transfusion ◽  
Doppler Ultrasound ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Transfusion Therapy ◽  
Hemoglobin S

scholarly journals Use of a Electronic Sickle Cell Dashboard to Improve Annual Transcranial Doppler Ultrasound (TCD) Completion Rates

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3384-3384
Author(s):  
Joanna L. Gendreau ◽  
Kelli Fischbeck ◽  
Brooke Cook ◽  
Steve McCalley ◽  
Lori Wagner ◽  
...  
Keyword(s):  
Real Time ◽  
Doppler Ultrasound ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Cell Phenotype ◽  
Completion Rates ◽  
Transfusion Therapy ◽  
Annual Screening

Background: Stroke, a feared and common complication of sickle cell anemia can be prevented by early recognition of at-risk individuals using annual screening transcranial Doppler ultrasound (TCD) and subsequent treatment with chronic transfusion therapy. The landmark STOP trial established annual screening TCD from 2 to 16 years of age as a standard of care for children with sickle cell anemia. Compliance with this recommendation remains challenging in a majority of sickle cell centers due to various reasons. Methods: An analysis of the institutional process of obtaining TCD revealed several opportunities for improvement. Provider attention was diverted from TCD screening towards management of acute complications such as fever and pain, hydroxyurea management, vaccine administration and psychosocial issues. Other factors contributing to poor TCD completion rates included high no-show rates for annual comprehensive visits, routine preventive visits, and hospital follow-ups. In addition, there were barriers to scheduling and completion of TCD studies after order placement. We hypothesized that by utilizing information technology (IT) tools we could improve TCD ordering and completion rates. Our IT team, in collaboration with our hematology team, designed and optimized the electronic clinic note specific to sickle cell disease in order to capture data such as age, sickle cell phenotype, eligibility for TCD, and last completed TCD date. Utilizing these data an innovative, real-time, sickle-cell dashboard was created and made available to all clinicians. In a single screen view, the dashboard displayed data regarding TCD eligible patients that needed an order for TCD, had a TCD scheduled, or were over-due or near-due for TCD. Amongst these, those who had upcoming appointments were especially highlighted in order to coordinate their clinic and TCD visits on the same day. The dashboard also highlighted patients who were overdue for TCD with no scheduled clinic appointments This data was reviewed by sickle cell nurse coordinator, a physician champion and an IT representative at least weekly. Inaccuracies in data were identified and corrected. The action items were then presented at the weekly sickle cell team meeting and acted upon. We then measured TCD order and completion rates before and after the January 2019 implementation of the dashboard. Results: In 2018 thirty-six orders for TCD were placed with eighteen completed studies (50%) versus 47 orders placed with 42 completed TCD in the first 7 months of 2019 (89%). These results were clinically significant (p=0.0001, Two-sided Fisher's exact test). As of July 31, 2019 out of 68 eligible patients, all but 2 had TCD orders placed (97%). Fifty-one patients were current on their TCD (75%) and the majority of those patients with missing TCD were noncompliant with clinic and radiology appointments. For the first 6 months of the year, an average of 93% of patients were compliant with annual TCD at the time of their clinic visit Conclusion: An IT dashboard created using real-time data; collaboration and communication between clinical, IT and radiology teams; and action during regularly scheduled sickle cell team meetings resulted in marked improvement in TCD ordering and completion rates within a few months. The process was sustainable by training nursing and ancillary staff to utilize data. In the future, this sickle cell dashboard could be utilized to also improve other areas of sickle cell care such as immunizations and medication compliance. Disclosures Gomez: Alnylam: Consultancy; Novo Nordisk, Novartis, Pfizer, Sanofi, Takeda, UniQure: Research Funding.

scholarly journals Progression of central nervous system disease from pediatric to young adulthood in sickle cell anemia

2021 ◽  
pp. 153537022110357
Author(s):  
Grace Champlin ◽  
Scott N Hwang ◽  
Andrew Heitzer ◽  
Juan Ding ◽  
Lisa Jacola ◽  
...  
Keyword(s):  
Young Adults ◽  
Doppler Ultrasound ◽  
Young Adulthood ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Brain Mri ◽  
Transcranial Doppler Ultrasound ◽  
Childhood And Adolescence ◽  
Cerebral Vessel

Silent cerebral infarcts and arteriopathy are common and progressive in individuals with sickle cell anemia. However, most data describing brain lesions in sickle cell anemia are cross-sectional or derive from pediatric cohorts with short follow-up. We investigated the progression of silent cerebral infarct and cerebral vessel stenosis on brain MRI and MRA, respectively, by describing the incidence of new or worsening lesions over a period of up to 25 years among young adults with sickle cell anemia and explored risk factors for progression. Forty-four adults with sickle cell anemia (HbSS or HbSβ0thalassemia), exposed to chronic transfusions ( n = 12) or hydroxyurea ( n = 32), median age 19.2 years (range 18.0–31.5), received a screening brain MRI/MRA and their results were compared with a clinical exam performed during childhood and adolescence. We used exact log-rank test to compare MRI and MRA progression among any two groups. The hazard ratio (HR) and 95% confidence interval (CI) were calculated from Cox regression analyses. Progression of MRI and MRA occurred in 12 (27%) and 4 (9%) young adults, respectively, relative to their pediatric exams. MRI progression risk was high among participants with abnormal pediatric exams (HR: 11.6, 95% CI: 2.5–54.7) and conditional or abnormal transcranial Doppler ultrasound velocities (HR: 3.9, 95% CI: 1.0–15.1). Among individuals treated with hydroxyurea, high fetal hemoglobin measured in childhood was associated with lower hazard of MRI progression (HR: 0.86, 95% CI: 0.76–0.98). MRA progression occurred more frequently among those with prior stroke (HR: 8.6, 95% CI: 1.2–64), abnormal pediatric exam ( P = 0.00084), and elevated transcranial Doppler ultrasound velocities ( P = 0.004). Brain MRI/MRA imaging in pediatrics can identify high-risk patients for CNS disease progression in young adulthood, prompting consideration for early aggressive treatments.

scholarly journals Transcranial Doppler Ultrasound (TCD) Outcomes for Children with Prior Normal TCD: Post-STOP Study Results

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 562-562
Author(s):  
Janet L. Kwiatkowski ◽  
Heather Fullerton ◽  
Jennifer Voeks ◽  
Lynette Brown ◽  
Ellen Debenham ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Doppler Ultrasound ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Stroke Prevention ◽  
Transcranial Doppler Ultrasound ◽  
The Mean ◽  
Outcomes For Children

Abstract Background: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) and Optimizing Primary Stroke Prevention in Sickle Cell Anemia (STOP 2) study established routine transcranial Doppler ultrasound (TCD) screening with indefinite transfusions for children with abnormal TCD as standard of care. Children with normal TCD studies have the lowest risk of stroke of ~0.5-1% per year (y). Annual TCD screening is usually recommended for these children to detect possible subsequent conversion to high risk. We sought to determine the frequency of TCD screening utilized in “real world” clinical practice and the TCD outcomes for children with prior normal TCD. Subjects and Methods: During STOP and STOP2 (STOP/2), 3,837 children, ages 2 to 16 y with sickle cell disease type SS or S-Beta-0-thalassemia underwent screening TCD. The Post-STOP study was designed to follow-up the outcomes of children who were screened for or participated in one or both of these randomized trials. 19 of the 26 original study sites participated in Post-STOP, contributing a total of 3,541 (92%) of the STOP/2 subjects. After exit from STOP/2, these children received TCD screening and treatment according to local practices. Data abstractors visited each clinical site and obtained retrospective data from STOP/2 study exit to 2012-2014 (depending on site) on follow-up TCD results and clinical information using standard data collection forms. The rates of TCD re-screening and the proportion of children who converted to abnormal TCD were calculated. Factors associated with conversion to abnormal TCD were assessed. Results: Of the 3,541 subjects, follow-up data were available for 2,838 (80%). The mean age at the last TCD study obtained in STOP/2 was 9.5 y and the mean age at last follow-up in Post-STOP was 19.6 y. The mean duration of follow-up after exiting STOP/2 was 9.2 y. Subjects were classified by their worst TCD in STOP/2: the TCD was normal in 1,814 (64%), conditional in 479 (17%), abnormal in 357 (13%) and inadequate 188 (7%). Among the 1,814 children with only normal studies in STOP/2, follow-up TCD screening was obtained in the Post-STOP era on 842 (46%) at a median rate of 0.28 TCD studies/y (range, 0.05-3.04/y). Among these children, 26 (3.1%) developed an abnormal TCD at a median of 11.5 y (2.2-18.2 y) from the last STOP/2 study, while 77.5% still had normal TCD at a median of 10.7 y (0.7-18.3 y) from last STOP/2 study. The worst follow-up TCD classification for this group with prior normal TCD was conditional in 9.7% and inadequate in 9.6%. Among those that converted from prior normal to abnormal TCD, 12 had an interval conditional study (at median 2.8 y, 0.98-9.2 y) while 14 children converted from normal to abnormal at a median of 4.2 y (1.4-12.7 y) without documented interval conditional study. Children who developed abnormal TCD were younger at STOP/2 study exit (4.9 vs. 7.8 y, p<0.001) and had higher TCD velocity at their last STOP/2 TCD study (154 vs. 136 cm/s, p<0.001) than children whose TCD remained normal. There was no significant difference between the time interval from the last STOP/2 TCD and the first Post-STOP TCD in these 2 groups. Conclusions: In clinical practice, follow-up TCD for children with prior normal TCD was performed less frequently than the generally recommended annual basis. Among children re-screened, the risk of conversion to abnormal TCD was relatively low, but re-screening with TCD identified a subset of at-risk children who could benefit from transfusions to prevent a potentially devastating outcome. Predictors of conversion to abnormal TCD included younger age and prior TCD velocity in the high normal range. Disclosures Adams: Novartis: Consultancy.

scholarly journals Myth: Blood transfusion is effective for sickle cell anemia—associated priapism

CJEM ◽  
2006 ◽  
Vol 8 (02) ◽  
pp. 119-122 ◽  
Author(s):  
Andrew L. Merritt ◽  
Christopher Haiman ◽  
Sean O. Henderson
Keyword(s):  
Blood Transfusion ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Conventional Therapy ◽  
Case Reports ◽  
Complete Information ◽  
Effective Therapy ◽  
Transfusion Therapy ◽  
Medline Search ◽  
Neurologic Sequelae

ABSTRACTObjective:Priapism is a recognized complication of sickle cell anemia (SCA). When initial conventional treatments fail, simple or exchange blood transfusion has been advocated as a secondary intervention. However, recent literature suggests this may not be an effective therapy and may have significant neurologic sequelae. This paper reviews and summarizes the effectiveness and risks of blood transfusion compared with conventional priapism therapy.Methods:All relevant papers identified from a MEDLINE search were systematically examined for data related to the use of blood transfusion in the setting of priapism due to SCA. The effectiveness of conventional therapy was compared with transfusion therapy using the outcome of “time to detumescence” (TTD). In addition, papers documenting adverse neurologic sequela were reviewed and summarized.Results:Forty-two case reports were identified containing complete information with regard to patient age and TTD. The mean TTD was 8.0 days with conventional therapy (n= 16) and 10.8 days with blood transfusion therapy (n= 26). Adverse neurologic sequelae from blood transfusion therapy was described in 9 cases, with long term outcomes ranging from complete resolution to severe residual deficits.Conclusion:The current literature does not support the contention that blood transfusion is an effective therapy in the treatment of priapism due to SCA, as defined by an acceleration of TTD. In fact, numerous reports suggest that serious neurologic sequelae may result from this treatment. We feel the routine use of this therapy cannot be recommended.

Transcranial Doppler Ultrasound in Peninsular Arab Patients With Sickle Cell Disease

2018 ◽  
Vol 38 (1) ◽  
pp. 165-172 ◽  
Author(s):  
Adekunle Adekile ◽  
Meaad Hassan ◽  
Akram Asbeutah ◽  
Mohamed Al‐Hinai ◽  
Omar Trad ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Doppler Ultrasound ◽  
Sickle Cell ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Cell Disease

Academic Community Standards for Chronic Transfusion Therapy In Children with Sickle Cell Anemia and Abnormal Transcranial Doppler Velocities

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2643-2643
Author(s):  
Banu Aygun ◽  
Lisa Wruck ◽  
William Herbert Schultz ◽  
Isaac Odame ◽  
R. Clark Brown ◽  
...  
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Hemoglobin Concentration ◽  
Transfusion Practice ◽  
Academic Community ◽  
Eligibility Criteria ◽  
Transfusion Therapy ◽  
Number Of Patients ◽  
Community Standards

Abstract Abstract 2643 Children with sickle cell anemia (SCA) and abnormal transcranial Doppler (TCD) velocities receive chronic transfusion therapy in an effort to prevent a primary stroke. Typically the goal is maintaining sickle hemoglobin (HbS) <30%, however this goal may be difficult to achieve in actual clinical practice. The NHLBI-sponsored TCD With Transfusions Changing to Hydroxyurea (TWiTCH) trial will compare standard therapy (transfusions) with alternative therapy (hydroxyurea) for the prevention of primary stroke. The transfusions will be given according to current transfusion practices at the participating academic sites. To determine the current academic community standards for primary stroke prophylaxis in children with SCA, 32 potential clinical sites collected data for children with abnormal TCD velocities who are receiving chronic transfusion therapy to prevent a primary stroke. The eligibility criteria included all children with SCA, age 4.0–15.9 years who were on chronic transfusion therapy to prevent a primary stroke due to previous abnormal TCD examination. After IRB-approval, subject and transfusion-related data were collected for all TWiTCH-eligible patients over the 12-month period from 9/1/2008 to 8/31/2009. Variables included year of birth, gender, year chronic transfusions began, TCD velocities that led to transfusion therapy, weight, %HbS transfusion goal, type and volume, pre-transfusion hemoglobin concentration and %HbS, and interval between transfusions. Data were analyzed both “per transfusion” and “per patient.” A total of 3970 transfusions were administered to 340 pediatric patients (mean approximate age at time of survey 10.2 ± 4.1 years, M: F = 0.9:1) over the 12-month period, with a mean of 11.6 ± 2.8 transfusions per patient. The average of the highest TCD velocity that led to transfusion therapy was 221 ± 27 cm/sec. Maximum velocities for right and left hemispheres were 201.2 ± 35.3 and 207.7 ± 31.8 cm/sec, respectively, supporting equal susceptibility. The mean approximate age at the start of transfusion therapy was 6.2 ± 2.6 years with average transfusion duration of 4.0 years. Most children (79%) received primarily simple transfusions, while 19% had primarily exchange transfusions (11% manual and 8% automated), and 2% multiple transfusion types. The transfusion goal was HbS <30% at almost all sites (84%). An equal number of patients developed erythrocyte alloantibodies (13.6%) and autoantibodies (13.7%). Transfusions were considered late if administered later than 7 days beyond the scheduled date. On average, late transfusions were given 1.3 ± 5.5 days after the 7 day allowable window. The average pre-transfusion hemoglobin concentration was 9.0 ± 0.9 gm/dL. The average pre-transfusion %HbS was 34.1 ± 11.2%, with a median value of 32.9%. The 75th percentile for HbS values was 40.9%, while the 90th percentile was 49.5%. There were profound differences among institutional pre-transfusion %HbS values, ranging from 23 ± 14% HbS at one institution where 103 transfusions were given to 9 patients during the 12-month period to 48 ± 15% at another institution where 95 transfusions were administered to 9 patients during the same time frame. These data indicate that current transfusion practice to prevent primary stroke varies among academic pediatric institutions, and 30%HbS is not an easily attainable goal for the TWiTCH study that includes chronic transfusion therapy within the Standard Arm. As a result of this analysis, the TWiTCH study will recommend chronic transfusions with the goal of maintaining HbS <30%, but only record a protocol violation when the HbS value exceeds 45%. Disclosures: Off Label Use: It will include the use of hydroxyurea in children with sickle cell anemia.

Correlation Between Cerebral Blood Flow Velocities Measured By Magnetic Resonance and Transcranial Doppler Ultrasound in Children with Sickle Cell Anemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2496-2496
Author(s):  
Monica L. Hulbert ◽  
Dustin K. Ragan ◽  
Hongyu An ◽  
Cihat Eldeniz ◽  
Geetika Khanna ◽  
...  
Keyword(s):  
Blood Flow ◽  
Magnetic Resonance ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Transcranial Doppler ◽  
Arterial Stenosis ◽  
Acquisition Time ◽  
Transfusion Therapy ◽  
Blood Flow Velocities ◽  
Flow Velocities

Abstract Background Transcranial Doppler (TCD) ultrasonography is the standard stroke screening test for children with sickle cell anemia (SCA). However, approximately 10% of children have inadequate ultrasonographic windows for a successful TCD study, and some clinical sites may lack the equipment or personnel to perform TCDs in children. Magnetic resonance imaging (MRI) techniques can also measure blood flow velocities and could substitute for TCD in these clinical scenarios. We tested the hypothesis that MRI-derived middle cerebral artery (MCA) blood flow velocities would correlate with TCD-derived MCA blood flow velocities in children with SCA. Methods Children age 6 years and up with SCA at their baseline state of health underwent TCD and MRI as part of a prospective clinical study. Imaging TCD of the bilateral MCAs to determine time-average mean of maximum blood flow velocities (TCD-CBFV) were performed using clinical ultrasound equipment. MRIs were performed at 3T without sedation. MRI cerebral time-averaged mean blood flow velocities (MR-CBFV) were measured in the MCAs using phase contrast sequences without cardiac cycle gating to shorten acquisition time and reduce ghosting artifacts. TCD- and MR-CBFV of each hemisphere were compared. Silent cerebral infarctions (SCIs) were categorized as present or absent in each hemisphere. Non-parametric tests were used with a level of significance of <0.05. Statistics were performed in SPSS version 21. Results Twenty hemispheres from 15 children had both TCD-CBFV and MR-CBFV measurements. Median age was 9 years (IQR 6.25-10). In these children, two hemispheres had unobtainable TCDs due to skull thickness, and eight hemispheres had MR-CBFV excluded due to patient motion or poor positioning. The median TCD-CBFV was 116 cm/sec (IQR 90.25-124) and none of the included hemispheres had arterial stenosis or TCD-CBFV in the conditional or abnormal range. Eight included hemispheres were from children receiving chronic blood transfusion therapy for primary or secondary stroke prevention. There was a linear relationship between TCD-CBFV and MR-CBFV (Spearman correlation, ρ=0.781, p<0.001, Figure) although MR-CBFV values were lower than TCD-CBFV values (median difference 32.6%, IQR 26.7-42.8). When evaluating only the children not receiving chronic transfusion therapy, MR-CBFV was significantly higher in 8 hemispheres without SCIs (median 80 cm/sec, IQR 77.8-87.8) than in 4 hemispheres with SCIs (median 60 cm/sec, IQR 44.6-72.3, p=0.004). In a multivariate model adjusting for age, MR-CBFV continued to be associated with presence of SCIs (p=0.036). There was no significant difference in TCD-CBFV when analyzed by SCI status (p=0.2), consistent with published studies of TCD-CBFV and SCIs. Conclusions In this small cohort of children with SCA, MR-CBFV correlated significantly with TCD-CBFV, but MR-CBFV values were approximately 30% lower than TCD-CBFV. This may be due to the method of acquiring MR-CBFV via non-gated methodology, which is known to produce lower blood flow velocity estimates. Further work is needed to determine a threshold for high-risk MR-CBFV values before this modality could be used as a substitute for TCD screening. Lower MR-CBFV was associated with SCIs, suggesting a potential role for MR-CBFV in predicting SCI risk. The relationship between MR-CBFV and SCIs should be explored further. Disclosures Hulbert: Pfizer, Inc.: Other: spouse employment. Fields:NeuroPhage Pharmaceuticals: Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Transcranial Doppler Ultrasound Velocity, Cerebral Vasculopathy, and Silent Infarcts In Sickle Cell Disease

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 269-269
Author(s):  
Peter M.K. de Blank ◽  
Daniel M Hayward ◽  
Robert Zimmerman, MD ◽  
Avrum Pollock ◽  
Janet L Kwiatkowski
Keyword(s):  
Magnetic Resonance ◽  
Sickle Cell Disease ◽  
Doppler Ultrasound ◽  
Sickle Cell ◽  
Cerebral Artery ◽  
Transcranial Doppler ◽  
Transcranial Doppler Ultrasound ◽  
Cell Disease ◽  
Increased Risk ◽  
The Mean

Abstract Abstract 269 Background: Approximately one-fourth of children with sickle cell disease (SCD), type SS, show evidence of cerebral ischemia on magnetic resonance imaging (MRI) without overt neurologic symptoms. Children with these silent infarcts have an increased risk of neuropsychological abnormalities and overt stroke. The pathophysiology of silent infarcts is unclear. Elevated transcranial Doppler ultrasound (TCD) velocities in the internal cerebral artery (ICA) and middle cerebral artery (MCA) are associated with an increased risk of overt stroke, but have not been associated previously with silent infarct. However, prior studies of silent infarcts failed to examine the association with anterior cerebral artery (ACA) vessel abnormalities, despite a predominantly frontal distribution of these infarcts. In addition, the relationship of magnetic resonance angiography (MRA) abnormalities to silent infarcts has not been extensively studied, although children with abnormal TCD velocity who also have stenosis or occlusion of vessels by MRA have the highest risk of overt stroke. We hypothesized that elevated ACA velocity and/or significant vasculopathy of the cerebral vessels demonstrated by MRA would be associated with a higher risk of silent stroke. Methods: A retrospective analysis of children followed at our Sickle Cell Center with SCD, type SS or Sb0-thalassemia was performed. Children with TCD (with ACA velocity) and brain MRI/A performed within a year of each other were included. TCD studies performed while on chronic transfusions were excluded. The last eligible MRI/TCD combination was used for patients who had multiple studies. Laboratory values obtained within a year of the MRI also were analyzed. Results: Of the 254 eligible subjects, 54% were male and the mean age was 10.6 ± 5.2 years. Silent infarcts were present in 78/254 (30.7%); the location was frontoparietal in 68%. The mean time-averaged mean of the maximal velocity (TAMMvel) of qualifying STOP vessels (MCA, bifurcation, and ICA) was 139±35cm/s, while the mean TAMMvel of the ACA was 117±34cm/s, which is 84% of the velocity of the other anterior vessels. As previously reported, TAMMvel inversely correlated with age (r=-0.40, p<0.0001) and hemoglobin concentration (r=-0.30, p<0.0001). There was no significant difference in TAMMvel in STOP qualifying vessels (MCA, bifurcation, DICA; 137cm/s vs. 145cm/s, p=0.08) among those with and without silent infarct. However, silent infarcts were associated with abnormal TAMMvel (≥200cm/s, 69/239 with normal/conditional vs. 9/15 with abnormal TAMMvel p=0.01) in these vessels. TAMMvel in the ACA was significantly higher (125 cm/s vs. 113 cm/s, p=0.004) in children with silent infarcts, and elevated ACA TAMMvel (≥170cm/s) was associated with silent infarcts (70/242 with normal vs. 8/12 with elevated velocity, p=0.006). No other single vessel velocity was significantly associated with silent infarct. Abnormal ICA/MCA TAMMvel was associated with stenosis of these vessels by MRA (p<0.001), and abnormal ACA velocities were associated with ACA stenosis by MRA (p<0.001). Further, stenosis by MRA in the ICA/MCA was associated with silent infarct (p<0.006) as were abnormalities of the ACA vessels (p=0.001). Conclusions: Unlike prior studies, we demonstrate a significant association between abnormal ICA/MCA velocity and silent infarcts. We also show an association between ACA velocity and silent infarct, which may in part be due to the predominantly frontoparietal distribution of these lesions. This, together with the association of MRA abnormalities of all three anterior vessels (ICA, MCA, ACA) with silent infarcts suggests a possible role of larger cerebral vessel vasculopathy in the pathophysiology of silent infarcts. This could be due to decreased distal blood flow related to the larger vessel narrowing, embolization of thrombus in larger vessels, or small vessel vasculopathy associated with larger vessel disease. However, mechanisms other than larger vessel vasculopathy are also likely to be involved given that silent infarcts occur in a substantial number of children without elevated TCD velocity or vasculopathy by MRA. Nonetheless, assessment of TCD velocity and MRA abnormalities may help provide information on risk assessment for CNS disease in children with SCD. Disclosures: No relevant conflicts of interest to declare.

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