Results from transcranial Doppler examination on children and adolescents with sickle cell disease and correlation between the time-averaged maximum mean velocity and hematological characteristics: a cross-sectional analytical study

Abstract

CONTEXT AND OBJECTIVE: Transcranial Doppler (TCD) detects stroke risk among children with sickle cell anemia (SCA). Our aim was to evaluate TCD findings in patients with different sickle cell disease (SCD) genotypes and correlate the time-averaged maximum mean (TAMM) velocity with hematological characteristics. DESIGN AND SETTING: Cross-sectional analytical study in the Pediatric Hematology sector, Universidade Federal de São Paulo. METHODS: 85 SCD patients of both sexes, aged 2-18 years, were evaluated, divided into: group I (62 patients with SCA/Sß0 thalassemia); and group II (23 patients with SC hemoglobinopathy/Sß+ thalassemia). TCD was performed and reviewed by a single investigator using Doppler ultrasonography with a 2 MHz transducer, in accordance with the Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol. The hematological parameters evaluated were: hematocrit, hemoglobin, reticulocytes, leukocytes, platelets and fetal hemoglobin. Univariate analysis was performed and Pearson's coefficient was calculated for hematological parameters and TAMM velocities (P < 0.05). RESULTS: TAMM velocities were 137 ± 28 and 103 ± 19 cm/s in groups I and II, respectively, and correlated negatively with hematocrit and hemoglobin in group I. There was one abnormal result (1.6%) and five conditional results (8.1%) in group I. All results were normal in group II. Middle cerebral arteries were the only vessels affected. CONCLUSION: There was a low prevalence of abnormal Doppler results in patients with sickle-cell disease. Time-average maximum mean velocity was significantly different between the genotypes and correlated with hematological characteristics.

Transcranial doppler ultrasonography in children with sickle cell anemia: Clinical and laboratory correlates for elevated blood flow velocities

“…Low hematocrit and low Hb have also been consistently reported in literature to be associated with elevated TAMMV and increased stroke risk in SCA. 19,21 Our findings would suggest that children with SCA living in a malaria-endemic area have cerebrovascular dynamics demonstrable by TCD that are similar to other children with SCA in malaria-free regions of the world. The observed similarities may be related to the presence of similar haplotypes of the Hb S in the two populations, as the Benin haplotype, which is the most prevalent in Nigeria, has also been found to be the most prevalent among African-American children with SCA.…”

Patients with sickle cell disease are frequently excluded from the benefits of transcranial doppler screening for the risk of stroke despite extensive and compelling evidence

“…These findings are consistent with previous reports 8, 9 . In a study evaluating Brazilian children with homozygous SS, 1.6% had abnormal TCD velocities and none of those with heterozygous SCD had any abnormality 10 . Another Brazilian series also demonstrated that TCD velocities of children with SCD from Sergipe, northeast Brazil, was similar to international standards 11 .…”

Transcranial Doppler Ultrasound in Peninsular Arab Patients With Sickle Cell Disease

“…Table shows reported transcranial Doppler values from the United States, France, Brazil, Tanzania, Nigeria, and Iran in which the proportions with abnormal values ranged from 1.6% to 20.7%. However, the 2 studies from the Arabian Peninsula (Oman and Kuwait) did not record any abnormal values, whereas the study from Iran reported 3% .…”