Primary stroke prevention for sickle cell disease in north-east Italy: the role of ethnic issues in establishing a Transcranial Doppler screening program

Background: Stroke is a serious complication of sickle cell disease (SCD) in children. Transcranic Doppler (TCD) is a well-established predictor of future cerebrovascular symptoms: a blood flow velocity > 200 cm/sec in the Middle Cerebral Artery (MCA) correlates with a high risk of stroke in cohorts of African-american HbS/HbS patients. In North-East Italy the recent increase in SCD patients is mainly due to immigration from Africa. A comprehensive care program for children with SCD was established in our Center since 2004, but a wide and routine screening for Primary stroke prevention needs to be developed. Methods: In order to verify the feasibility of TCD and Transcranial color coded Sonography (TCCS) screening in our setting and the applicability of international reference values of blood velocities to our population of African immigrants with HbS/HbS SCD, we performed TCD and TCCD in 12 HbS/HbS African children and two groups of age-matched controls of Caucasian and African origin respectively. TCD and TCCS were performed on the same day of the scheduled routine hematologic visit after parental education. Results: All parents accepted to perform the sonography to their children. TCD and TCCD were performed in all patients and an adequate temporal window could be obtained in all of them. Pulsatility index and depth values in both the MCA and the Basilar Artery (BA) were similar at TCD and TCCS evaluation in the three groups while time-average maximum velocities (TAMM), peak systolic velocity and diastolic velocity in the MCA and BA were higher in the patients' group on both TCD and TCCS evaluation. African and Caucasian healthy controls had similar lower values. Conclusion: Our preliminary data set the base to further evaluate the implementation of a primary stroke prevention program in our setting of HbS/HbS African immigrants and HbS/beta thalassemia Italians. Parental education-preferably in the native language-on stroke risk and prevention in SCD increases compliance and should be a necessary part of the program. Ethnic background does not seem to influence TCD velocity and internationally accepted reference values already validated in African-American SCD pediatric patients can be used, but long prospective trials are needed to verify their efficacy in defining stroke risk in our setting.