Transcranial Doppler Velocities among Sickle Cell Disease Patients in Steady State

Role of transcranial Doppler in assessment of cerebral blood flow in full term neonates with extreme unconjugated hyperbilirubinemia

PURPOSE

To evaluate the difference in cerebral blood flow in neonates with and without extreme unconjugated hyperbilirubinemia.

METHODS

Transcranial Doppler parameters of 26 full term newborns with extreme unconjugated hyperbilirubinemia (UCH) were compared to 13 postnatal age and sex matched normal healthy neonates serving as controls. Resistance index (RI), pulsatility index (PI) and peak systolic velocity (PSV) were measured in the middle cerebral, internal carotid and posterior cerebral arteries on both sides by transcranial color Doppler ultrasound.

RESULTS

An increase in cerebral blood flow (decreased RI, PI and increased PSV) was observed in the extreme unconjugated hyperbilirubinemia (UCH) group. There was positive correlation between total serum bilirubin level and peak systolic velocity and vice versa with resistivity and pulsatility indices. Eight neonates developed clinical features of acute bilirubin encephalopathy and showed significantly increased peak systolic velocity in the right middle cerebral artery compared to those with normal outcome. Resistivity index and pulsatility index were lower in patients managed by exchange transfusion compared to those managed with phototherapy.

CONCLUSION

An increase in cerebral blood flow was observed in neonates with UCH compared to those without hyperbilirubinemia. By assessing the cerebral blood flow velocity, resistivity index (RI), and pulsatility index (PI) of particular intracranial arteries, the transcranial Doppler can identify the at-risk neonates, for development of neurological affliction in extreme unconjugated hyperbilirubinemia.

Transcranial doppler as screening method for sickling crises in children with sickle cell anemia: a latin America cohort study

Background

Sickle cell anemia (SCA) is the leading cause of childhood stroke. We aimed to evaluate whether altered cerebral flow velocities, as measured by transcranial Doppler (TCD), are associated with vaso-occlusive complications in addition to stroke in pediatric SCA patients.

Methods

We evaluated 37 children aged between 2 and 16 years with SCA who underwent screening for TCD between January 2012 and October 2018. Genotypic profiles and demographic data were collected, TCD examinations were performed during follow-up, and the presence of sickling crises was compared. Survival analyses were performed using simple frailty models, in which each predictor variable was analyzed separately in relation to the occurrence of a sickling crisis.

Results

The variables related to sickle cell crises in the univariate analysis were peak systolic velocity (PSV) in the middle cerebral artery (MCA), hazard ratio (HR) 1.01 (1.00—1.02) p = 0.04; end-diastolic velocity (EDV) in the MCA, HR 1.02 (1.01—1.04) p = 0.01; time average mean maximum velocity (TAMMV) in the basilar artery (BA), HR 1.02 (1.00—1.04) p = 0.04; hemoglobin, HR 0.49 (0.38—0.65) p < 0.001; hematocrit, HR 0.78 (0.71—0.85) p < 0.001; leukocyte counts, HR 1.1 (1.05—1.15) p < 0.001; platelets counts, HR 0.997 (0.994—0.999) p = 0.02; and reticulocyte numbers, HR 1.14 (1.06—1.23) p < 0.001.

Conclusions

Our results indicate PSV and EDV in the MCA and TAMMV in the BA as markers of risk for the occurrence of sickling crises in SCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03429-5.

Epidemiology of Stroke in Sickle Cell Disease

Sickle cell disease is the most common cause of stroke in childhood, both ischaemic and haemorrhagic, and it also affects adults with the condition. Without any screening or preventative treatment, the incidence appears to fall within the range 0.5 to 0.9 per 100 patient years of observation. Newborn screening with Penicillin prophylaxis and vaccination leading to reduced bacterial infection may have reduced the incidence, alongside increasing hydroxyurea prescription. Transcranial Doppler screening and prophylactic chronic transfusion for at least an initial year has reduced the incidence of stroke by up to 10-fold in children with time averaged mean of the maximum velocity >200 cm/s. Hydroxyurea also appears to reduce the incidence of first stroke to a similar extent in the same group but the optimal dose remains controversial. The prevention of haemorrhagic stroke at all ages and ischaemic stroke in adults has not yet received the same degree of attention. Although there are fewer studies, silent cerebral infarction on magnetic resonance imaging (MRI), and other neurological conditions, including headache, epilepsy and cognitive dysfunction, are also more prevalent in sickle cell disease compared with age matched controls. Clinical, neuropsychological and quantitative MRI screening may prove useful for understanding epidemiology and aetiology.