Transcranial Doppler (TCD) and Neurological Manifestations in Brazilian Pediatric Patients with SCD.

Standardize TCD examination of children with SCD in three Sickle Cell Units in Brazil, to assess TAMMV in consecutive children with SCD, to allow treatment decisions for such children, based on TCD results and to estimate the prevalence of neurological complications in Brazilian children with SCD (before and after newborn screening).

All of the pediatric patients with SCD from newborn screening, who underwent a TCD examination between 2 and 11 y.o. were included. Consecutive patients seen at three tertiary-care hematology centers (HEMORIO, HEMOPE and HEMOMINAS) made TCD screening, with determination of blood flow-velocity.

This study begun in January, 2008. Legal representatives of patients assigned the informed consent TCD procedures followed the technique used in STOP study (Adams et al 1998). Identical equipment and software were used (2-MHz pulsed Doppler- Nicolet EME) in the three Sickle Cell Units and investigators studied transtemporal and transforaminal windows and recorded the highest time-averaged mean of the maximun velocity (TAMMV) in middle cerebral artery (MCA), distal internal carotid artery (ICA), anterior cerebral artery (ACA) and biffurcation (BIF). All TCD studies were performed by one physician of each Sickle Cell Unit (ACC Leite – HEMORIO, C Silva – HEMOMINAS and R Azevedo – HEMOPE). Data were collected and stored in EPIDATA and exported to SPSS for Statistical analysis.

From January 2008 to July 2009 (18 months) the three centers followed about one thousand children with HbSS or SB-thalassemia, who underwent at least one TCD examination. There is no difference about gender. The mean age of the first TCD was 3.2 yo (HEMOPE), 5.8 (HEMRIO and 6.8 (HEMOMINAS). The main genotype was SS (95%). In the study of acute preliminary event there was high prevalence of acute chest syndrome and dactilitis in the three hemocenters and statisitical significant correlation between ACS and dactilitis versus abnormal TCD. The principal compromised artery was media cerebral (MCA). When we performed MRA and MRI in patients with abnormal TCD we found significant number of silent infarcts.

TCD screening has had a substantial impact to prevent primary stroke in SCD patients. The transfusions were efficacious but discontinuation resulted in new events. Long term therapy is needed (HU?). In patients with conditional TCD and comorbidities (ACS and dactilitis) the risk to develop stroke is higher than in patients with normal TCD and then, the use of hydroxiurea should be considered. The patient number of inadequate TCD is still significant. Since the cost of MRI in Brazil is high we suggest TCD imaging as screening if suspect of severe arterial disease.

No relevant conflicts of interest to declare.