Abstract
ObjectiveTo investigate orbital vascular resistance by Doppler velocimetry in patients with steady-state sickle cell anemia, as well as to characterize its relationship with biomarkers of hemolysis.Materials and MethodsThis was a cross-sectional study of two groups: 71 outpatients with sickle cell anemia; and 32 age- and gendermatched, healthy subjects (control group). All participants underwent Doppler velocimetry of the orbital arteries and laboratory tests.ResultsAll biochemical laboratory markers were abnormal in the sickle cell anemia patients (p < 0.0001 vs. controls). In the patient group, Doppler velocimetry revealed increased flow velocities in the ophthalmic artery and reduced flow velocities in the central retinal artery, as well as high values for the resistance index (RI) and pulsatility index (PI) in both arteries (p < 0.0001 vs. controls). Biomarkers of hemolysis were found to correlate significantly with the RI and PI indices. In the ophthalmic artery, the reticulocyte count showed a moderate direct correlation with RI and with PI. In the central retinal artery, hemoglobin showed a strong inverse correlation with RI and with PI.ConclusionOrbital vascular resistance, as evaluated by Doppler velocimetry, is elevated in patients with steady-state sickle cell anemia and shows a significant correlation with biomarkers of hemolysis.
Highlights
Sickle cell anemia, known as homozygous sickle cell disease (HbSS), is the most common hereditary hemo-Study conducted at the University Hospital of the Universidade Federal de Sergipe (UFS), Aracaju, SE, Brazil.1
All biomarkers were abnormal in the patients with HbSS in comparison with the controls (p < 0.0001 for all comparisons)
In the HbSS group, velocities were increased in the ophthalmic artery and reduced in the central retina artery, as well as that the resistance index (RI) and pulsatility index (PI) were elevated in both arteries
Summary
1. PhD, Radiologist, Assistant Professor in the Department of Medicine at the Universidade Federal de Sergipe (UFS), Aracaju, SE, Brazil. 2. PhD, Adjunct Professor in the Graduate Program in Health Sciences and Head of the Laboratory of Investigative Pathology at the Universidade Federal de Sergipe (UFS), Aracaju, SE, Brazil. 4. PhD, Pediatric Oncologist/Hematologist, Associate Professor in the Department of Medicine at the Universidade Federal de Sergipe (UFS), Aracaju, SE, Brazil. Estimates suggest that 250,000 children across the globe are born annually with HbSS. Brought to the Americas through the slave trade, HbSS is most common in communities where individuals of African descent predominate. It is estimated that approximately 2,500 children are born annually with HbSS in Brazil. Non-whites were estimated at 50.74% of the population in the 2010 Census, and 1–6% of such individuals reportedly have HbSS[3]
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