Stroke prevention in sickle cell disease – The role of cervical echo-doppler

Abstract

Objective: Cerebrovascular disease is the main cause of mortality and chronic morbidity in pediatric sickle cell disease (SCD) patients. Systematic screening using transcranial doppler (TCD) stratifies the risk of stroke and allows effective primary prevention. The role of cervical vasculopathy remains unclear and some patients present stroke events with normal TCD. Methods: In this retrospective study we included all children/adolescents with HbSS, HbSC or HbSβ0 and at least one appointment in our Pediatric Hematology clinic from January 2013 to December 2015. After 2 years old, they performed TCD and cervical echo-doppler and attended a Pediatric Neurology appointment, according to our Cerebrovascular Prevention Program. We collected patient's information regarding: demographic data, therapy, stroke history, neurological exam, last cranial and cervical echo-doppler and cranial MRI results. Results: A total of 110 patients were included with median age of 10. From the group of 102 patients older than 2 years, 98 (96%) have at least one TCD. In the last TCD, only 1 (1%) had a time-averaged maximum mean (TAMM) velocity ≥ 200 cm/sec and 4 (4%) had velocities in the conditional range (170–199 cm/sec). Thirty-six patients (33%) performed cranial MRI, 16 (44%) had vascular pathological findings – 6 stroke, 10 silent cerebral infarcts (5 isolated), 6 intracranial stenosis or moya–moya pattern and 3 other changes. Six patients (5.5%) had a stroke (5 ischemic and 1 hemorrhagic), 5 with normal TCD but 5 with abnormal cervical doppler velocities. In the last years the clinical presentation of ischemic strokes (2) was mild limb paresis diagnosed in the pediatric neurology appointment, in patients with normal TCD, abnormal cervical echo-doppler and evidence of cranial vasculopathy in MRI. Conclusion: More studies are needed to clarify the role of cervical vasculopathy in cerebrovascular disease and the best prevention treatment in patients with abnormal cervical echo-doppler remains unclear.