title: Transcranial Doppler in hemoglobin SC disease.
abstract: Stroke is a severe clinical disorder in sickle cell disease (SCD), and few studies have evaluated transcranial Doppler (TCD) flow velocities in hemoglobin SC disease (HbSC). The guidelines for stroke risk are based on evaluations in sickle cell anemia (SCA) or HbS/β thalassemia.
  
  
  
  In this study, we compare cerebral blood flow in patients with SCD stratified by genotypes. A total of 1,664 pediatric patients with SCD underwent TCD velocity screening, and the time-averaged maximum mean velocity (TAMM) was determined in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and distal intracranial internal carotid artery (ICA).
  
  
  
  Abnormal velocities were not identified in the ACA; therefore, we only use ICA and MCA velocities. TAMM from the left and right in the ICA and MCA was 134.3 ± 32.0 and 134.4 ± 32.6 cm/s in patients with SCA, and 105.2 ± 20.6 and 104.7 ± 20.0 cm/s in the patients with HbSC, respectively. Mean TAMM between right and left ICA/MCA was 134.5 ± 30.5 cm/s in the SCA group, and 104.9 ± 19.3 cm/s in the HbSC group. Notably, our data show that TCD velocities were significantly lower among the patients with HbSC compared to SCA. TAMM was negatively correlated with hemoglobin and hematocrit in both genotypes.
  
  
  
  These results suggest that a different cut-off value for abnormal TCD velocities could be considered for patients with HbSC. Additional studies are warranted to determine the actual risk of stroke in HbSC genotype associated with this possible TCD risk value.
authors.affiliation: Ambulatório Pediátrico de Doença Cerebrovascular, Hospital Universitário Professor Edgard Santos, Universidade Federal da Bahia, Bahia, Brazil.|Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Bahia, Brazil.
authors.forename: Camilo
authors.initials: C
authors.lastname: Vieira
authors.affiliation: Universidade Salvador, Bahia, Brazil.
authors.forename: Carolina Nogueira Costa
authors.initials: CN
authors.lastname: de Oliveira
authors.affiliation: Universidade Salvador, Bahia, Brazil.
authors.forename: Ludmila Araújo Borges
authors.initials: LA
authors.lastname: de Figueiredo
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Bahia, Brazil.|Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Rayra Pereira
authors.initials: RP
authors.lastname: Santiago
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Bahia, Brazil.|Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Corynne Stephanie Ahouefa
authors.initials: CS
authors.lastname: Adanho
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Bahia, Brazil.|Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Sanzio Silva
authors.initials: SS
authors.lastname: Santana
authors.affiliation: Departamento de Hematologia, Hospital Universitário Professor Edgard Santos, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Caroline Lang
authors.initials: CL
authors.lastname: Burak
authors.affiliation: Departamento de Hematologia, Hospital Universitário Professor Edgard Santos, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Isa Menezes
authors.initials: IM
authors.lastname: Lyra
authors.affiliation: Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz, Bahia, Brazil.|Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal da Bahia, Bahia, Brazil.
authors.forename: Marilda Souza
authors.initials: MS
authors.lastname: Goncalves
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity / Q000502:physiology*; D002536:Cerebral Arteries / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006450:Hemoglobin SC Disease / Q000000981:diagnostic imaging*; D006454:Hemoglobins / Q000032:analysis / Q000235:genetics; D006801:Humans; D008297:Male; D020521:Stroke / Q000000981:diagnostic imaging / Q000517:prevention & control*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*
chemical_list: D006454:Hemoglobins
keywords: hemoglobinopathies; neurology and sickle cell; sickle cell disease; transcranial Doppler ultrasound