source: American Society of Hematology

year: 2017

authors: Indrani Karpha, Louise Smith, Lawrence Abernathy, Kate LE Phillips, Russell D Keenan

Annual evaluation by Trans-Cranial Doppler (TCD) of cerebral artery blood flow is useful for determining stroke risk in children with sickle cell disease. Since the publication of the Stroke Prevention Trial in Sickle Cell Anaemia (STOP) results in 2006 it has been standard practice at our centre to perform annual TCD imaging scans on all children with sickle cell disease to identify individuals with high risk features. Data from the STOP trial demonstrated that the incidence of stroke was reduced by 90% in children with high risk TCDs when they were managed on a regular transfusion programme. In more recent years, the use of hydroxyurea as a disease modifying therapy has increasingly become our practice, particularly so since the publication of the BABY-HUG trial data in 2014. Hydroxyurea has significantly altered the clinical course of sickle cell disease in children and prior to this era, 11% of patients would experience a stroke before the age of 20 years. In light of the changing management strategies for children with sickle cell disease, we reviewed the past 10 years TCD results from our patients. Annual TCD evaluation of cerebral artery blood flow was performed by radiologists and radiographers accredited to the Kings College national training programme. Scans were performed using Philips iU22 scanners with dedicated F5-1 transducers as per the UK National Screening protocol. Velocities were measured in the middle (MCA), anterior (ACA) and posterior cerebral arteries (PCA), internal carotid artery (ICA) and bifurcation on right and left sides (10 measurements per scan). The TCD service at our centre has had a positive external peer review. Over the past 10 years, 303 TCD imaging scans have been performed on 53 children aged 2-18 years. The number of abnormal, high-risk results (cerebral blood flow velocity (CBF-V) >200 cm/s) has been zero. 137 scans were performed in children prior to those individuals commencing hydroxyurea therapy, and the results of 3 scans were conditional, based on an increased CBF-V (171–200 cm/s) detected in 1 or more arteries. The other 168 scans were performed on children who were receiving hydroxyurea, of which 4 results were conditional. 49 of the 53 children have continuously had a normal TCD with no conditional or abnormal results. 4 children developed transient conditional TCD.