Partial manual exchange reduces iron accumulation during chronic red cell transfusions for sickle cell disease

Pubertal patterns in children with sickle cell anemia: A case-control study in Cameroon

BACKGROUND

Puberty may be impaired in children with sickle cell anemia (SCA). Therefore, we aimed to explore the clinical and hormonal features of puberty in Cameroonian children.

METHODS

In a case-control study, we included 64 children aged 8-18 years with SCA matched to healthy controls. We assessed height, weight, body mass index, body composition, and Tanner stages. Hormonal measurements included anti-mullerian hormone, follicle-stimulating hormone, luteinizing hormone, and sex hormones (estrogens/testosterone). We used the Mann-Whitney Wilcoxon test to compare the median values between cases and controls. We looked for associations between the severity criteria of SCA and delayed puberty through multivariate analysis.

RESULTS

Delayed puberty was reported in 27.3% of girls and 10% of boys with SCA. The median age of menarche was delayed by 2 years compared to controls. SCA patients had a low lean body mass compared to controls (p = 0.03). Anti-mullerian hormone levels were significantly higher in boys with SCA than those of controls (45.9 ng/mL vs. 17.65 ng/mL; p = 0.018). A history of severe infection, acute chest syndrome, and low hemoglobin level was associated with delayed sexual maturation in children with SCA.

CONCLUSION

Our study revealed delayed puberty in children with SCA. Moreover, puberty is affected by the severity of the disease. This highlights the importance of regular monitoring of puberty during the follow-up of these children.

Increased complications of chronic erythrocytapheresis compared with manual exchange transfusions in children and adolescents with sickle cell disease

BACKGROUND

Children and adolescents with sickle cell disease (SCD) are at high risk of strokes and are frequently treated with red blood cell (RBC) transfusions. The goal is to suppress hemoglobin (Hb) S while minimizing transfusion-induced iron overload. RBCs may be given via simple transfusion, manual exchange transfusion (MET), or erythrocytapheresis (aRBCX). Chronic transfusion practices vary among institutions.

METHODS

This single-institution, retrospective cohort study compares Hb S control and therapy complication rates between MET and aRBCX in a cohort of children and adolescents with SCD and stroke during a 5-year period from 2008 through 2012. Duration and mode of transfusion therapy, achievement of Hb S suppression goal, iron burden by ferritin levels, and catheter complications were evaluated.

RESULTS

Thirty-seven children were included in analysis. The prevalence of catheter complications was 75% in aRBCX recipients compared with 0% in MET recipients (P < 0.001). There was no significant difference between modalities in achieving Hb S suppression or ferritin goals, but those receiving aRBCX had a greater likelihood of discontinuing chelation therapy. Among aRBCX recipients, adherence to >90% of transfusion appointments was associated with achieving Hb S suppression goals.

CONCLUSION

aRBCX may have increased complication risks compared with MET for chronic transfusion therapy in SCD. Risks and benefits of aRBCX and MET should be considered when selecting a chronic transfusion modality. Transfusion therapy modalities should be compared in prospective studies for stroke prevention in children with SCD.

How we manage iron overload in sickle cell patients

Blood transfusion plays a prominent role in the management of patients with sickle cell disease (SCD), but causes significant iron overload. As transfusions are used to treat the severe complications of SCD, it remains difficult to distinguish whether organ damage is a consequence of iron overload or is due to the complications treated by transfusion. Better management has resulted in increased survival, but prolonged exposure to iron puts SCD patients at greater risk for iron-related complications that should be treated. The success of chelation therapy is dominated by patient adherence to prescribed treatment; thus, adjustment of drug regimens to increase adherence to treatment is critical. This review will discuss the current biology of iron homeostasis in patients with SCD and how this informs our clinical approach to treatment. We will present the clinical approach to treatment of iron overload at our centre using serial assessment of organ iron by magnetic resonance imaging.

Sickle Cell Disease and Stroke: Diagnosis and Management

Both adult and pediatric patients with sickle cell disease face a higher risk of stroke than the general population. Given the different underlying pathophysiology predisposing these patients to stroke, providers should be aware of differences in guidelines for stroke management. This paper reviews diagnostic considerations and recommendations during the evaluation and acute management of patients with sickle cell disease presenting with stroke, focusing on recent updates in the literature. Given the high recurrence rate of stroke in these patients, secondary prevention and curative measures will also be reviewed.

Effectiveness of red blood cell exchange, partial manual exchange, and simple transfusion concurrently with iron chelation therapy in reducing iron overload in chronically transfused sickle cell anemia patients

BACKGROUND

Chronic transfusion therapy (CTT) is indicated for stroke prevention in children with sickle cell anemia (SCA) and is complicated by iron overload and alloimmunization. CTT is performed by simple transfusion (ST), partial manual exchange (PME), or erythrocytapheresis (RCE). Although small case series have demonstrated RCE in combination with iron chelation therapy stabilizes and/or decreases ferritin, there are no reports comparing the effect of ST, PME, and RCE on liver iron concentration (LIC). CTT modality effect on serum ferritin and LIC were compared in SCA patients on iron chelation, with hemoglobin (Hb)S goal of 30%.

STUDY DESIGN AND METHODS

Medical records of SCA patients on CTT and deferasirox (≥25 mg/kg/day) were retrospectively reviewed. Mean HbS%, change in ferritin and LIC, and alloimmunization rate were determined for each CTT group.

RESULTS

Twenty-eight patients were included; six crossed over (one from ST to PME, one from ST to PME then to RCE, three from ST to RCE, and one from PME to RCE) to include 36 transfusion modality intervals. Median pretransfusion HbS% levels were 32.7% (ST), 36.2% (PME), and 34.7% (RCE; p = 0.732). Median ferritin changes were +15 (-17 to +45), +38 (+24 to +105), and -91 (-141 to -48) ng/mL/month (p = 0.003), and median LIC changes (available in 22 patient transfusion modality intervals) were +1.3 (-1.6 to +4.3), +2.3 (-6.5 to +8.9), and -5.7 (-10.7 to -0.5) mg/g/year (p = 0.024) in ST, PME, and RCE, respectively. There was no significant difference in alloimmunization rate between ST/PME and RCE groups.

CONCLUSION

We recommend RCE plus chelation as an effective method for reducing iron overload, while maintaining HbS at 30% to 35%.

Long-term Erythrocytapheresis Is Associated With Reduced Liver Iron Concentration in Sickle Cell Disease

BACKGROUND

Erythrocytapheresis procedures are increasingly used in sickle cell disease. Serum ferritin and noninvasive magnetic resonance imaging measurements of liver iron concentration (LIC) are frequently used to monitor iron overload secondary to hypertransfusion. There is a paucity of data describing the impact of long-term erythrocytapheresis (LTE) on LIC.

MATERIALS AND METHODS

We measured magnetic resonance imaging liver and cardiac iron on LTE subjects and stratified them into 2 groups: higher LIC (>3 mg/g) and lower LIC (<3 mg/g). χ(2) and t test were used to test for differences between the 2 groups. Logistic regression and generalized linear mixed-effects models were used to test what impacted LIC.

RESULTS

None of 29 sickle cell disease subjects maintained on LTE had high cardiac iron concentration. LIC was associated with serum ferritin (r=0.697, P<0.001) but was not associated with the total number of LTE procedures (r=-0.088, P=0.656) or total number of simple transfusions (r=0.316, P=0.108). The total number of LTE procedures was not associated with serum ferritin (r=0.040, P=0.838), the total number of simple transfusions (r=-0.258, P=0.184), or LIC group (r=-0.111, P=0.566).

CONCLUSION

There was no significant correlation between duration of LTE maintenance and LIC.

How I treat and manage strokes in sickle cell disease

Neurologic complications are a major cause of morbidity and mortality in sickle cell disease (SCD). In children with sickle cell anemia, routine use of transcranial Doppler screening, coupled with regular blood transfusion therapy, has decreased the prevalence of overt stroke from ∼11% to 1%. Limited evidence is available to guide acute and chronic management of individuals with SCD and strokes. Current management strategies are based primarily on single arm clinical trials and observational studies, coupled with principles of neurology and hematology. Initial management of a focal neurologic deficit includes evaluation by a multidisciplinary team (a hematologist, neurologist, neuroradiologist, and transfusion medicine specialist); prompt neuro-imaging and an initial blood transfusion (simple followed immediately by an exchange transfusion or only exchange transfusion) is recommended if the hemoglobin is >4 gm/dL and <10 gm/dL. Standard therapy for secondary prevention of strokes and silent cerebral infarcts includes regular blood transfusion therapy and in selected cases, hematopoietic stem cell transplantation. A critical component of the medical care following an infarct is cognitive and physical rehabilitation. We will discuss our strategy of acute and long-term management of strokes in SCD.

A pilot study of manual chronic partial exchange transfusion in children with sickle disease

Objective Red cell exchange transfusion is frequently used in the management of patients with sickle cell disease (SCD) either electively or chronically to maintain hemoglobin S (HbS) <30%. The purpose of this retrospective study was to evaluate the results of manual chronic partial exchange transfusion (MCPET) on level of Hb and HbS, on iron load and on the need for chelation, on risk of immunization, monitoring transfusion-transmitted viral infection, and clinical outcome. Methods We reviewed the long-term effect of MCPET in 10 children (six men and four women) with SCD and evaluated the iron balance during a median follow-up of 20 months (range: 6-36) in which 248 exchanges were performed. Results The pre-exchange median Hb value was 9.5 g/dl (range: 7.7-10.9 g/dl) and the median post-exchange value was 9.4 g/dl (range: 8.4-11.1 g/dl).The majority of patients reached an HbS of <50% with a median HbS value of 40.04% (range: 30-54). At start of the MCPET program, the median ferritin was 439 ng/ml (range: 80-1704 ng/ml). In the final evaluation, the median value of ferritin was 531 ng/ml (range: 84-3840 ng/ml). The annual calculated iron balance was 0. 28 ± 0.08 mg/kg/day. MCPET was well tolerated, and adverse effects were limited. Discussion MCPET in children with SCD is safe to prevent iron overload, and is effective and easy to use in our cohort. Conclusion Indication for chronic exchange blood transfusion is essential for patients with SCD with recurrent and frequent crises who do not respond to hydroxyurea. However, there is no consensual study for the period at which chronic transfusion can safely be stopped and further research in large population of patients with SCD will need to clarify this question.