Timed Average Mean Maximum Velocity (TAMMV) of Cerebral Blood Flow of Children and Adolescents with Sickle cell Disease: correlation with clinical and hematological profiles in country

Bartholomew Chukwu¹, Lyra Menezes², Thiago Fukuda³, Jamary Filho³, Marilda Goncalves⁴

1. Department of Paediatrics, Faculty of Medical Sciences, University of Nigeria, Nsukka
2. Hospital Univesitario Professor Edgard Santos, Paediatric Haematology Service, Universidade Federal de Bahia, Brazil
3. Ambulatorio Pediatrico de doenca cerobrovascular, Universidade Federal da Bahia, Brazil
4. Departmento de Anelises Clinicas e Toxicalogicas, Facuidade da Farmacia, Universidade Federal da Bahia, Brazil

Correspondence: Bartholomew Chukwu (barth.chukwu@unn.edu.ng)

Abstract
Background
Detection of abnormal TAMMV with transcranial Doppler is fundamental in primary stroke prevention in children with sickle cell disease (SCD). The study aimed at evaluating TAMMV and correlating it with clinical and hematological profiles of children and adolescent with SCD.
Methods
Transcranial Doppler was performed on subjects aged 2-16 years, using a 2 MHz probe placed over the transtemporal windows. Pulse oximetry was used to determine the peripheral oxygen saturation while clinical and hematological profiles were retrieved from their medical records.
Results
One hundred and thirty five patients were recruited. The mean TAMMV was 125cm/s. Patients with HbSS had a significantly higher TAMMV (131cm/s) than those with HbSC (107cm/s). Only one (0.74%) patient had abnormal TAMMV. TAMMV correlated inversely with oxygen saturation, Hct and patient’s age, and positively with white cell and platelet counts. Previous history of acute chest syndrome (ACS) and recurrent painful crises increased the risk of development of abnormal and conditional velocity.
Conclusion
Frequency of abnormal TAMMV in this study was low. Younger children and those with HbSS had higher TAMMV. Age, oxygen saturation and haematocrit correlated negatively while white cell and platelet counts correlated positively with TAMMV. Previous history of ACS and recurrent bone pain were associated with increased risk of having abnormal and conditional TAMMV.
Key words: sickle cell disease, TAMMV, Transcranial Doppler, children, adolescents, Salvador.