Longitudinal changes in ferritin during chronic transfusion: a report from the Stroke Prevention Trial in Sickle Cell Anemia (STOP)

American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults

BACKGROUND

Central nervous system (CNS) complications are among the most common, devastating sequelae of sickle cell disease (SCD) occurring throughout the lifespan.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology are intended to support the SCD community in decisions about prevention, diagnosis, and treatment of the most common neurological morbidities in SCD.

METHODS

The Mayo Evidence-Based Practice Research Program supported the guideline development process, including updating or performing systematic evidence reviews. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations.

RESULTS

The panel placed a higher value on maintaining cognitive function than on being alive with significantly less than baseline cognitive function. The panel developed 19 recommendations with evidence-based strategies to prevent, diagnose, and treat CNS complications of SCD in low-middle- and high-income settings.

CONCLUSIONS

Three of 19 recommendations immediately impact clinical care. These recommendations include: use of transcranial Doppler ultrasound screening and hydroxyurea for primary stroke prevention in children with hemoglobin SS (HbSS) and hemoglobin Sβ0 (HbSβ0) thalassemia living in low-middle-income settings; surveillance for developmental delay, cognitive impairments, and neurodevelopmental disorders in children; and use of magnetic resonance imaging of the brain without sedation to detect silent cerebral infarcts at least once in early-school-age children and once in adults with HbSS or HbSβ0 thalassemia. Individuals with SCD, their family members, and clinicians should become aware of and implement these recommendations to reduce the burden of CNS complications in children and adults with SCD.

Adherence to Iron Chelation Therapy with Deferasirox Formulations among Patients with Sickle Cell Disease and β-thalassemia

BACKGROUND

Individuals with hemoglobinopathies experience complications that often require management with multiple transfusions. These chronic transfusions can lead to iron overload, which places them at increased risk of organ damage, malignancy, and even death. Deferasirox is the most common iron chelator used to treat iron overload due to its safety, efficacy, and oral administration. The first formulation of deferasirox, a dispersible tablet for oral suspension (DT) called Exjade®, was associated with adherence challenges due to complaints from poor taste and side effects such as abdominal discomfort. A new film-coated tablet formulation (FCT) called Jadenu® was subsequently developed to overcome these challenges.

OBJECTIVE

The objective of this study was to compare adherence rates between formulations of deferasirox (DT versus FCT) and describe associations between adherence to chelation therapy and changes in hematological parameters among patients with SCD and β-thalassemia.

METHODS

In this retrospective study of 20 children and adults with sickle cell disease (SCD) and β-thalassemia with iron overload, we compared adherence rates for deferasirox DT versus deferasirox FCT. We reviewed data from the electronic medical record and pharmacy expense reports between 2014 and 2018. We calculated the mean medication possession ratio (MPR) and analyzed the mean paired difference in MPR and ferritin levels using paired sample t-test.

RESULTS

The overall mean MPR was 0.15 (0.25) for deferasirox DT and 0.44 (0.32) for deferasirox FCT. The mean paired difference in MPR when transitioning from deferasirox DT to deferasirox FCT was +0.29, p-value < 0.01 (95% CI: 0.19, 0.39). The mean paired difference in ferritin while on deferasirox DT compared to ferritin 6 months after transitioning to deferasirox FCT was -306 ng/mL p-value = 0.14 (95% CI: 719, 113).

CONCLUSION

There was significant improvement in adherence to iron chelation therapy when patients transitioned from deferasirox DT to deferasirox FCT.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease

BACKGROUND

Sickle cell disease is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. Sickle cell disease can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Stroke affects around 10% of children with sickle cell anaemia (HbSS). Chronic blood transfusions may reduce the risk of vaso-occlusion and stroke by diluting the proportion of sickled cells in the circulation. This is an update of a Cochrane Review first published in 2002, and last updated in 2017.

OBJECTIVES

To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease for primary and secondary stroke prevention (excluding silent cerebral infarcts).

SEARCH METHODS

We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 8 October 2019. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 19 September 2019.

SELECTION CRITERIA

Randomised controlled trials comparing red blood cell transfusions as prophylaxis for stroke in people with sickle cell disease to alternative or standard treatment. There were no restrictions by outcomes examined, language or publication status.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and the risk of bias and extracted data.

MAIN RESULTS

We included five trials (660 participants) published between 1998 and 2016. Four of these trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of sickle cell disease. Three trials compared regular red cell transfusions to standard care in primary prevention of stroke: two in children with no previous long-term transfusions; and one in children and adolescents on long-term transfusion. Two trials compared the drug hydroxyurea (hydroxycarbamide) and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children); and one in secondary prevention (children and adolescents). The quality of the evidence was very low to moderate across different outcomes according to GRADE methodology. This was due to the trials being at a high risk of bias due to lack of blinding, indirectness and imprecise outcome estimates. Red cell transfusions versus standard care Children with no previous long-term transfusions Long-term transfusions probably reduce the incidence of clinical stroke in children with a higher risk of stroke (abnormal transcranial doppler velocities or previous history of silent cerebral infarct), risk ratio 0.12 (95% confidence interval 0.03 to 0.49) (two trials, 326 participants), moderate quality evidence. Long-term transfusions may: reduce the incidence of other sickle cell disease-related complications (acute chest syndrome, risk ratio 0.24 (95% confidence interval 0.12 to 0.48)) (two trials, 326 participants); increase quality of life (difference estimate -0.54, 95% confidence interval -0.92 to -0.17) (one trial, 166 participants); but make little or no difference to IQ scores (least square mean: 1.7, standard error 95% confidence interval -1.1 to 4.4) (one trial, 166 participants), low quality evidence. We are very uncertain whether long-term transfusions: reduce the risk of transient ischaemic attacks, Peto odds ratio 0.13 (95% confidence interval 0.01 to 2.11) (two trials, 323 participants); have any effect on all-cause mortality, no deaths reported (two trials, 326 participants); or increase the risk of alloimmunisation, risk ratio 3.16 (95% confidence interval 0.18 to 57.17) (one trial, 121 participants), very low quality evidence. Children and adolescents with previous long-term transfusions (one trial, 79 participants) We are very uncertain whether continuing long-term transfusions reduces the incidence of: stroke, risk ratio 0.22 (95% confidence interval 0.01 to 4.35); or all-cause mortality, Peto odds ratio 8.00 (95% confidence interval 0.16 to 404.12), very low quality evidence. Several review outcomes were only reported in one trial arm (sickle cell disease-related complications, alloimmunisation, transient ischaemic attacks). The trial did not report neurological impairment, or quality of life. Hydroxyurea and phlebotomy versus red cell transfusions and chelation Neither trial reported on neurological impairment, alloimmunisation, or quality of life. Primary prevention, children (one trial, 121 participants) Switching to hydroxyurea and phlebotomy may have little or no effect on liver iron concentrations, mean difference -1.80 mg Fe/g dry-weight liver (95% confidence interval -5.16 to 1.56), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: risk of stroke (no strokes); all-cause mortality (no deaths); transient ischaemic attacks, risk ratio 1.02 (95% confidence interval 0.21 to 4.84); or other sickle cell disease-related complications (acute chest syndrome, risk ratio 2.03 (95% confidence interval 0.39 to 10.69)), very low quality evidence. Secondary prevention, children and adolescents (one trial, 133 participants) Switching to hydroxyurea and phlebotomy may: increase the risk of sickle cell disease-related serious adverse events, risk ratio 3.10 (95% confidence interval 1.42 to 6.75); but have little or no effect on median liver iron concentrations (hydroxyurea, 17.3 mg Fe/g dry-weight liver (interquartile range 10.0 to 30.6)); transfusion 17.3 mg Fe/g dry-weight liver (interquartile range 8.8 to 30.7), low quality evidence. We are very uncertain whether switching to hydroxyurea and phlebotomy: increases the risk of stroke, risk ratio 14.78 (95% confidence interval 0.86 to 253.66); or has any effect on all-cause mortality, Peto odds ratio 0.98 (95% confidence interval 0.06 to 15.92); or transient ischaemic attacks, risk ratio 0.66 (95% confidence interval 0.25 to 1.74), very low quality evidence.

AUTHORS' CONCLUSIONS

There is no evidence for managing adults, or children who do not have HbSS sickle cell disease. In children who are at higher risk of stroke and have not had previous long-term transfusions, there is moderate quality evidence that long-term red cell transfusions reduce the risk of stroke, and low quality evidence they also reduce the risk of other sickle cell disease-related complications. In primary and secondary prevention of stroke there is low quality evidence that switching to hydroxyurea with phlebotomy has little or no effect on the liver iron concentration. In secondary prevention of stroke there is low-quality evidence that switching to hydroxyurea with phlebotomy increases the risk of sickle cell disease-related events. All other evidence in this review is of very low quality.

Blood transfusions for treating acute chest syndrome in people with sickle cell disease

BACKGROUND

Sickle cell disease is an inherited autosomal recessive blood condition and is one of the most prevalent genetic blood diseases worldwide. Acute chest syndrome is a frequent complication of sickle cell disease, as well as a major cause of morbidity and the greatest single cause of mortality in children with sickle cell disease. Standard treatment may include intravenous hydration, oxygen as treatment for hypoxia, antibiotics to treat the infectious cause and blood transfusions may be given. This is an update of a Cochrane Review first published in 2010 and updated in 2016.

OBJECTIVES

To assess the effectiveness of blood transfusions, simple and exchange, for treating acute chest syndrome by comparing improvement in symptoms and clinical outcomes against standard care.

SEARCH METHODS

We searched The Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register, which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. Date of the most recent search: 30 May 2019.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing either simple or exchange transfusion versus standard care (no transfusion) in people with sickle cell disease suffering from acute chest syndrome.

DATA COLLECTION AND ANALYSIS

Both authors independently selected trials and assessed the risk of bias, no data could be extracted.

MAIN RESULTS

One trial was eligible for inclusion in the review. While in the multicentre trial 237 people were enrolled (169 SCC, 42 SC, 15 Sβ⁰-thalassaemia, 11Sβ⁺-thalassaemia); the majority were recruited to an observational arm and only ten participants met the inclusion criteria for randomisation. Of these, four were randomised to the transfusion arm and received a single transfusion of 7 to 13 mL/kg packed red blood cells, and six were randomised to standard care. None of the four participants who received packed red blood cells developed acute chest syndrome, while 33% (two participants) developed acute chest syndrome in standard care arm. No data for any pre-defined outcomes were available.

AUTHORS' CONCLUSIONS

We found only one very small randomised controlled trial; this is not enough to make any reliable conclusion to support the use of blood transfusion. Whilst there appears to be some indication that chronic blood transfusion may play a roll in reducing the incidence of acute chest syndrome in people with sickle cell disease and albeit offering transfusions may be a widely accepted clinical practice, there is currently no reliable evidence to support or refute the perceived benefits of these as treatment options; very limited information about any of the potential harms associated with these interventions or indeed guidance that can be used to aid clinical decision making. Clinicians should therefore base any treatment decisions on a combination of; their clinical experience, individual circumstances and the unique characteristics and preferences of adequately informed people with sickle cell disease who are suffering with acute chest syndrome. This review highlights the need of further high quality research to provide reliable evidence for the effectiveness of these interventions for the relief of the symptoms of acute chest syndrome in people with sickle cell disease.

GSTM1 and Liver Iron Content in Children with Sickle Cell Anemia and Iron Overload

Chronic blood transfusions in patients with sickle cell anemia (SCA) cause iron overload, which occurs with a degree of interpatient variability in serum ferritin and liver iron content (LIC). Reasons for this variability are unclear and may be influenced by genes that regulate iron metabolism. We evaluated the association of the copy number of the glutathione S-transferase M1 (GSTM1) gene and degree of iron overload among patients with SCA. We compared LIC in 38 children with SCA and ≥12 lifetime erythrocyte transfusions stratified by GSTM1 genotype. Baseline LIC was measured using magnetic resonance imaging (MRI), R2*MRI within 3 months prior to, and again after, starting iron unloading therapy. After controlling for weight-corrected transfusion burden (mL/kg) and splenectomy, mean pre-chelation LIC (mg/g dry liver dry weight) was similar in all groups: GSTM1 wild-type (WT) (11.45, SD±6.8), heterozygous (8.2, SD±4.52), and homozygous GSTM1 deletion (GSTM1-null; 7.8, SD±6.9, p = 0.09). However, after >12 months of chelation, GSTM1-null genotype subjects had the least decrease in LIC compared to non-null genotype subjects (mean LIC change for GSTM1-null = 0.1 (SD±3.3); versus -0.3 (SD±3.0) and -1.9 (SD±4.9) mg/g liver dry weight for heterozygous and WT, respectively, p = 0.047). GSTM1 homozygous deletion may prevent effective chelation in children with SCA and iron overload.

Sickle cell disease: Clinical presentation and management of a global health challenge

Sickle cell disease is an autosomal recessive, multisystem disorder, characterised by chronic haemolytic anaemia, painful episodes of vaso-occlusion, progressive organ failure and a reduced life expectancy. Sickle cell disease is the most common monogenetic disease, with millions affected worldwide. In well-resourced countries, comprehensive care programs have increased life expectancy of sickle cell disease patients, with almost all infants surviving into adulthood. Therapeutic options for sickle cell disease patients are however, still scarce. Predictors of sickle cell disease severity and a better understanding of pathophysiology and (epi)genetic modifiers are warranted and could lead to more precise management and treatment. This review provides an extensive summary of the pathophysiology and management of sickle cell disease and encompasses the characteristics, complications and current and future treatment options of the disease.

Interleukin 10-Mediated Response and Correlated Anemia in a Patient with Advanced Non-Small Cell Lung Carcinoma

Anemia in cancer patients is associated with poor quality of life, reduced response to therapy, and decreased overall survival. We describe a case of a 56-year old woman with advanced metastatic non-small cell lung carcinoma who demonstrated marked response to a novel combinational immunotherapy approach involving a long-acting PEGylated construct of recombinant human Interleukin-10 with Nivolumab, an anti-PD-L1 checkpoint inhibitor. While on treatment, the patient developed severe anemia and hyper-ferritinemia requiring RBC transfusion support. Here we discuss a possible novel immune mechanism of IL10-mediated anemia in correlation with tumor response.

Prospective evaluation of chronic organ damage in adult sickle cell patients: A seven-year follow-up study

Organ damage in sickle cell disease (SCD) is a crucial determinant for disease severity and prognosis. In a previous study, we analyzed the prevalence of SCD-related organ damage and complications in adult sickle cell patients. We now describe a seven-year follow-up of this cohort.All patients from the primary analysis in 2006 (n = 104), were included for follow-up. Patients were screened for SCD-related organ damage and complications (microalbuminuria, renal failure, elevated tricuspid regurgitation flow velocity (TRV) (≥2.5 m/seconds), retinopathy, iron overload, cholelithiasis, avascular osteonecrosis, leg ulcers, acute chest syndrome (ACS), stroke, priapism and admissions for vaso-occlusive crises (VOC) biannually. Upon 7 years of follow-up, progression in the prevalence of avascular osteonecrosis (from 12.5% to 20.4%), renal failure (from 6.7% to 23.4%), retinopathy (from 39.7% to 53.8%) was observed in the whole group. In HbSS/HbSβ⁰ -thal patients also progression in microalbuminuria (from 34% to 45%) and elevated TRV (from 40% to 48%) was observed while hardly any progression in the prevalence of cholelithiasis, priapism, stroke or chronic ulcers was seen. The proportion of patients with at least one episode of ACS increased in the group of HbSS/HbSβ⁰ -thal patients from 32% to 49.1%. In conclusion, 62% of the sickle cell patients in this prospective cohort study developed a new SCD-related complication in a comprehensive care setting within 7 years of follow-up. Although the hospital admission rate for VOC remained stable, multiple forms of organ damage increased substantially. These observations underline the need for continued screening for organ damage in all adult patients with SCD.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease

BACKROUND

Sickle cell disease is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta globin) genes. Sickle cell disease can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Stroke affects around 10% of children with sickle cell anaemia (HbSS). Chronic blood transfusions may reduce the risk of vaso-occlusion and stroke by diluting the proportion of sickled cells in the circulation.This is an update of a Cochrane Review first published in 2002, and last updated in 2013.

OBJECTIVES

To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease for primary and secondary stroke prevention (excluding silent cerebral infarcts).

SEARCH METHODS

We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 04 April 2016.We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register: 25 April 2016.

SELECTION CRITERIA

Randomised controlled trials comparing red blood cell transfusions as prophylaxis for stroke in people with sickle cell disease to alternative or standard treatment. There were no restrictions by outcomes examined, language or publication status.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and the risk of bias and extracted data.

MAIN RESULTS

We included five trials (660 participants) published between 1998 and 2016. Four of these trials were terminated early. The vast majority of participants had the haemoglobin (Hb)SS form of sickle cell disease.Three trials compared regular red cell transfusions to standard care in primary prevention of stroke: two in children with no previous long-term transfusions; and one in children and adolescents on long-term transfusion.Two trials compared the drug hydroxyurea (hydroxycarbamide) and phlebotomy to long-term transfusions and iron chelation therapy: one in primary prevention (children); and one in secondary prevention (children and adolescents).The quality of the evidence was very low to moderate across different outcomes according to GRADE methodology. This was due to the trials being at a high risk of bias due to lack of blinding, indirectness and imprecise outcome estimates. Red cell transfusions versus standard care Children with no previous long-term transfusionsLong-term transfusions probably reduce the incidence of clinical stroke in children with a higher risk of stroke (abnormal transcranial doppler velocities or previous history of silent cerebral infarct), risk ratio 0.12 (95% confidence interval 0.03 to 0.49) (two trials, 326 participants), moderate quality evidence.Long-term transfusions may: reduce the incidence of other sickle cell disease-related complications (acute chest syndrome, risk ratio 0.24 (95% confidence interval 0.12 to 0.48)) (two trials, 326 participants); increase quality of life (difference estimate -0.54, 95% confidence interval -0.92 to -0.17) (one trial, 166 participants); but make little or no difference to IQ scores (least square mean: 1.7, standard error 95% confidence interval -1.1 to 4.4) (one trial, 166 participants), low quality evidence.We are very uncertain whether long-term transfusions: reduce the risk of transient ischaemic attacks, Peto odds ratio 0.13 (95% confidence interval 0.01 to 2.11) (two trials, 323 participants); have any effect on all-cause mortality, no deaths reported (two trials, 326 participants); or increase the risk of alloimmunisation, risk ratio 3.16 (95% confidence interval 0.18 to 57.17) (one trial, 121 participants), very low quality evidence. Children and adolescents with previous long-term transfusions (one trial, 79 participants)We are very uncertain whether continuing long-term transfusions reduces the incidence of: stroke, risk ratio 0.22 (95% confidence interval 0.01 to 4.35); or all-cause mortality, Peto odds ratio 8.00 (95% confidence interval 0.16 to 404.12), very low quality evidence.Several review outcomes were only reported in one trial arm (sickle cell disease-related complications, alloimmunisation, transient ischaemic attacks).The trial did not report neurological impairment, or quality of life. Hydroxyurea and phlebotomy versus red cell transfusions and chelationNeither trial reported on neurological impairment, alloimmunisation, or quality of life. Primary prevention, children (one trial, 121 participants)Switching to hydroxyurea and phlebotomy may have little or no effect on liver iron concentrations, mean difference -1.80 mg Fe/g dry-weight liver (95% confidence interval -5.16 to 1.56), low quality evidence.We are very uncertain whether switching to hydroxyurea and phlebotomy has any effect on: risk of stroke (no strokes); all-cause mortality (no deaths); transient ischaemic attacks, risk ratio 1.02 (95% confidence interval 0.21 to 4.84); or other sickle cell disease-related complications (acute chest syndrome, risk ratio 2.03 (95% confidence interval 0.39 to 10.69)), very low quality evidence. Secondary prevention, children and adolescents (one trial, 133 participants)Switching to hydroxyurea and phlebotomy may: increase the risk of sickle cell disease-related serious adverse events, risk ratio 3.10 (95% confidence interval 1.42 to 6.75); but have little or no effect on median liver iron concentrations (hydroxyurea, 17.3 mg Fe/g dry-weight liver (interquartile range 10.0 to 30.6)); transfusion 17.3 mg Fe/g dry-weight liver (interquartile range 8.8 to 30.7), low quality evidence.We are very uncertain whether switching to hydroxyurea and phlebotomy: increases the risk of stroke, risk ratio 14.78 (95% confidence interval 0.86 to 253.66); or has any effect on all-cause mortality, Peto odds ratio 0.98 (95% confidence interval 0.06 to 15.92); or transient ischaemic attacks, risk ratio 0.66 (95% confidence interval 0.25 to 1.74), very low quality evidence.

AUTHORS' CONCLUSIONS

There is no evidence for managing adults, or children who do not have HbSS sickle cell disease.In children who are at higher risk of stroke and have not had previous long-term transfusions, there is moderate quality evidence that long-term red cell transfusions reduce the risk of stroke, and low quality evidence they also reduce the risk of other sickle cell disease-related complications.In primary and secondary prevention of stroke there is low quality evidence that switching to hydroxyurea with phlebotomy has little or no effect on the liver iron concentration.In secondary prevention of stroke there is low-quality evidence that switching to hydroxyurea with phlebotomy increases the risk of sickle cell disease-related events.All other evidence in this review is of very low quality.

Iron metabolism following intravenous transfusion with stored versus fresh autologous erythrocyte concentrate in healthy dogs

OBJECTIVE To determine effects of IV transfusion with fresh (3-day-old) or stored (35-day-old) autologous erythrocyte concentrate on serum labile iron concentration, iron-binding capacity, and protein interaction with iron in dogs. ANIMALS 10 random-source healthy dogs. PROCEDURES Dogs were randomly assigned to receive autologous erythrocyte concentrate stored for 3 days (n = 5) or 35 days (5). One unit of whole blood was collected from each dog, and erythrocyte concentrates were prepared and stored as assigned. After erythrocyte storage, IV transfusion was performed, with dogs receiving their own erythrocyte concentrate. Blood samples were collected from each dog before and 5, 9, 24, 48, and 72 hours after transfusion. Serum was harvested for measurement of total iron, labile iron, transferrin, ferritin, hemoglobin, and haptoglobin concentrations. RESULTS For dogs that received fresh erythrocytes, serum concentrations of the various analytes largely remained unchanged after transfusion. For dogs that received stored erythrocytes, serum concentrations of total iron, labile iron, hemoglobin, and ferritin increased markedly and serum concentrations of transferrin and haptoglobin decreased after transfusion. CONCLUSIONS AND CLINICAL RELEVANCE Transfusion with autologous erythrocyte concentrate stored for 35 days resulted in evidence of intravascular hemolysis in healthy dogs. The associated marked increases in circulating concentrations of free iron and hemoglobin have the potential to adversely affect transfusion recipients.

Long-term treatment follow-up of children with sickle cell disease monitored with abnormal transcranial Doppler velocities

Children with normalized TCD on transfusions were safely switched to hydroxyurea treatment, but trimestrial Doppler follow-up is required. Allogeneic transplant allowed the safe stop of transfusions in all patients, even in those with abnormal velocities before transplant.

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.

Initial serum ferritin predicts number of therapeutic phlebotomies to iron depletion in secondary iron overload

BACKGROUND

Therapeutic phlebotomy is increasingly used in patients with transfusional siderosis to mitigate organ injury associated with iron overload (IO). Laboratory response variables and therapy duration are not well characterized in such patients.

STUDY DESIGN AND METHODS

We retrospectively evaluated 99 consecutive patients undergoing therapeutic phlebotomy for either transfusional IO (TIO, n = 88; 76% had undergone hematopoietic transplantation) or nontransfusional indications (hyperferritinemia or erythrocytosis; n = 11). Complete blood cell count, serum ferritin (SF), transferrin saturation, and transaminases were measured serially. Phlebotomy goal was an SF level of less than 300 μg/L.

RESULTS

Mean SF levels before phlebotomy among TIO and nontransfusional subjects were 3093 and 396 μg/L, respectively. Transfusion burden in the TIO group was 94 ± 108 (mean ± SD) RBC units; approximately half completed therapy with 24 ± 23 phlebotomies (range, 1-103). One-third were lost to follow-up. Overall, 15% had mild adverse effects, including headache, nausea, and dizziness, mainly during first phlebotomy. Prior transfusion burden correlated poorly with initial ferritin and total number of phlebotomies to target in the TIO group. However, number of phlebotomies to target was strongly correlated with initial SF (R(2) = 0.8; p < 0.0001) in both TIO and nontransfusional groups. ALT decreased significantly with serial phlebotomy in all groups (mean initial and final values, 61 and 39 U/L; p = 0.03).

CONCLUSIONS

Initial SF but not transfusion burden predicted number of phlebotomies to target in patients with TIO. Despite good treatment tolerance, significant losses to follow-up were noted. Providing patients with an estimated phlebotomy number and follow-up duration, and thus a finite endpoint, may improve compliance. Hepatic function improved with iron offloading.

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.

An official American Thoracic Society clinical practice guideline: diagnosis, risk stratification, and management of pulmonary hypertension of sickle cell disease

BACKGROUND

In adults with sickle cell disease (SCD), an increased tricuspid regurgitant velocity (TRV) measured by Doppler echocardiography, an increased serum N-terminal pro-brain natriuretic peptide (NT-pro-BNP) level, and pulmonary hypertension (PH) diagnosed by right heart catheterization (RHC) are independent risk factors for mortality.

METHODS

A multidisciplinary committee was formed by clinician-investigators experienced in the management of patients with PH and/or SCD. Clinically important questions were posed, related evidence was appraised, and questions were answered with evidence-based recommendations. Target audiences include all clinicians who take care of patients with SCD.

RESULTS

Mortality risk stratification guides decision making. An increased risk for mortality is defined as a TRV equal to or greater than 2.5 m/second, an NT-pro-BNP level equal to or greater than 160 pg/ml, or RHC-confirmed PH. For patients identified as having increased mortality risk, we make a strong recommendation for hydroxyurea as first-line therapy and a weak recommendation for chronic transfusions as an alternative therapy. For all patients with SCD with elevated TRV alone or elevated NT-pro-BNP alone, and for patients with SCD with RHC-confirmed PH with elevated pulmonary artery wedge pressure and low pulmonary vascular resistance, we make a strong recommendation against PAH-specific therapy. However, for select patients with SCD with RHC-confirmed PH who have elevated pulmonary vascular resistance and normal pulmonary capillary wedge pressure, we make a weak recommendation for either prostacyclin agonist or endothelin receptor antagonist therapy and a strong recommendation against phosphodiesterase-5 inhibitor therapy.

CONCLUSIONS

Evidence-based recommendations for the management of patients with SCD with increased mortality risk are provided, but will require frequent reassessment and updating.

Blood transfusion for preventing primary and secondary stroke in people with sickle cell disease

BACKGROUND

In sickle cell disease, a common inherited haemoglobin disorder, abnormal haemoglobin distorts red blood cells, causing anaemia, vaso-occlusion and dysfunction in most body organs. Without intervention, stroke affects around 10% of children with sickle cell anaemia (HbSS) and recurrence is likely. Chronic blood transfusion dilutes the sickled red blood cells, reducing the risk of vaso-occlusion and stroke. However, side effects can be severe.

OBJECTIVES

To assess risks and benefits of chronic blood transfusion regimens in people with sickle cell disease to prevent first stroke or recurrences.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and conference proceedings.Date of the latest search of the Group's Haemoglobinopathies Trials Register: 28 January 2013.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing blood transfusion as prophylaxis for stroke in people with sickle cell disease to alternative or no treatment.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed the risk of bias of the included trials and extracted data.

MAIN RESULTS

Searches identified three eligible randomised trials (n = 342). The first two trials addressed the use of chronic transfusion to prevent primary stroke; the third utilized the drug hydroxycarbamide (hydroxyurea) and phlebotomy to prevent both recurrent (secondary) stroke and iron overload in patients who had already experienced an initial stroke. In the first trial (STOP) a chronic transfusion regimen for maintaining sickle haemoglobin lower than 30% was compared with standard care in 130 children with sickle cell disease judged (through transcranial Doppler ultrasonography) as high-risk for first stroke. During the trial, 11 children in the standard care group suffered a stroke compared to one in the transfusion group, odds ratio 0.08 (95% confidence interval 0.01 to 0.66). This meant the trial was terminated early. The transfusion group had a high complications rate, including iron overload, alloimmunisation, and transfusion reactions. The second trial (STOP II) investigated risk of stroke when transfusion was stopped after at least 30 months in this population. The trial closed early due to a significant difference in risk of stroke between participants who stopped transfusion and those who continued as measured by reoccurrence of abnormal velocities on Doppler examination or the occurrence of overt stroke in the group that stopped transfusion. The third trial (SWiTCH) was a non-inferiority trial comparing transfusion and iron chelation (standard management) with hydroxyurea and phlebotomy (alternative treatment) with the combination endpoint of prevention of stroke recurrence and reduction of iron overload. This trial was stopped early after enrolment and follow up of 133 children because of analysis showing futility in reaching the composite primary endpoint. The stroke rate (seven strokes on hydroxyurea and phlebotomy, none on transfusion and chelation, odds ratio 16.49 (95% confidence interval 0.92 to 294.84)) was within the non-inferiority margin, but the liver iron content was not better in the alternative arm.

AUTHORS' CONCLUSIONS

The STOP trial demonstrated a significantly reduced risk of stroke in participants with abnormal transcranial Doppler ultrasonography velocities receiving regular blood transfusions. The follow-up trial (STOP 2) indicated that individuals may revert to former risk status if transfusion is discontinued. The degree of risk must be balanced against the burden of chronic transfusions. The combination of hydroxyurea and phlebotomy is not as effective as "standard" transfusion and chelation in preventing secondary stroke and iron overload. Ongoing multicentre trials are investigating the use of chronic transfusion to prevent silent infarcts, the use of hydroxyurea as an alternative to transfusion in children with abnormal transcranial Doppler ultrasonography velocities, and the use of hydroxyurea to prevent conversion of transcranial Doppler ultrasonography velocities from conditional (borderline) to abnormal values.

Iron overload during follow-up after tandem high-dose chemotherapy and autologous stem cell transplantation in patients with high-risk neuroblastoma

Multiple RBC transfusions inevitably lead to a state of iron overload before and after high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT). Nonetheless, iron status during post-SCT follow-up remains unknown. Therefore, we investigated post-SCT ferritin levels, factors contributing to its sustained levels, and organ functions affected by iron overload in 49 children with high-risk neuroblastoma who underwent tandem HDCT/autoSCT. Although serum ferritin levels gradually decreased during post-SCT follow-up, 47.7% of the patients maintained ferritin levels above 1,000 ng/mL at 1 yr after the second HDCT/autoSCT. These patients had higher serum creatinine (0.62 vs 0.47 mg/mL, P = 0.007) than their counterparts (< 1,000 ng/mL). Post-SCT transfusion amount corresponded to increased ferritin levels at 1 yr after the second HDCT/autoSCT (P < 0.001). A lower CD34(+) cell count was associated with a greater need of RBC transfusion, which in turn led to a higher serum ferritin level at 1 yr after HDCT/autoSCT. The number of CD34(+) cells transplanted was an independent factor for ferritin levels at 1 yr after the second HDCT/autoSCT (P = 0.019). Consequently, CD34(+) cells should be transplanted as many as possible to prevent the sustained iron overload after tandem HDCT/autoSCT and consequent adverse effects.

Management of transfusional iron overload - differential properties and efficacy of iron chelating agents

Regular red cell transfusion therapy ameliorates disease-related morbidity and can be lifesaving in patients with various hematological disorders. Transfusion therapy, however, causes progressive iron loading, which, if untreated, results in endocrinopathies, cardiac arrhythmias and congestive heart failure, hepatic fibrosis, and premature death. Iron chelation therapy is used to prevent iron loading, remove excess accumulated iron, detoxify iron, and reverse some of the iron-related complications. Three chelators have undergone extensive testing to date: deferoxamine, deferasirox, and deferiprone (although the latter drug is not currently licensed for use in North America where it is available only through compassionate use programs and research protocols). These chelators differ in their modes of administration, pharmacokinetics, efficacy with regard to organ-specific iron removal, and adverse-effect profiles. These differential properties influence acceptability, tolerability and adherence to therapy, and, ultimately, the effectiveness of treatment. Chelation therapy, therefore, must be individualized, taking into account patient preferences, toxicities, ongoing transfusional iron intake, and the degree of cardiac and hepatic iron loading.

Quality-of-care indicators for children with sickle cell disease

OBJECTIVE

To develop a set of quality-of-care indicators for the management of children with sickle cell disease (SCD) who are cared for in a variety of settings by addressing the broad spectrum of complications relevant to their illness.

METHODS

We used the Rand/University of California Los Angeles appropriateness method, a modified Delphi method, to develop the indicators. The process included a comprehensive literature review with ratings of the evidence and 2 rounds of anonymous ratings by an expert panel (nominated by leaders of various US academic societies and the National Heart, Lung, and Blood Institute). The panelists met face-to-face to discuss each indicator in between the 2 rounds.

RESULTS

The panel recommended 41 indicators that cover 18 topics; 17 indicators described routine health care maintenance, 15 described acute or subacute care, and 9 described chronic care. The panel identified 8 indicators most likely to have a large positive effect on improving quality of life and/or health outcomes for children with SCD, which covered 6 topics: timely assessment and treatment of pain and fever; comprehensive planning; penicillin prophylaxis; transfusion; and the transition to adult care.

CONCLUSIONS

Children with SCD are at risk for serious morbidities and early mortality, yet efforts to assess and improve the quality of their care have been limited compared with other chronic childhood conditions. This set of 41 indicators can be used to assess quality of care and provide a starting point for quality-improvement efforts.

Advantages of isovolemic hemodilution-red cell exchange therapy to prevent recurrent stroke in sickle cell anemia patients

Chronic simple hypertransfusion (every 3 to 4 weeks) effectively prevents secondary stroke in children with sickle cell anemia but leads to iron overload despite chelation therapy. Conventional red blood cell exchange (C-RBCx) has advantages over simple transfusion: no net iron gain and less frequent hospital visits. However, C-RBCx requires more red blood cell units, an apheresis instrument and skilled personnel; it is also more expensive. We developed a modified procedure where isovolemic hemodilution precedes RBCx (IHD-RBCx) to decrease RBC units required and to increase the interval between procedures. Twenty patients underwent IHD-RBCx over a period of 7 years. IHD-RBCx required 11% fewer RBC units and increased inter-procedure interval from 37 to 53 days compared to C-RBCx. The median number of annual procedures decreased from 9.8 to 7.0 per patient, resulting in estimated savings of more than $4.5 million over 10 years for 20 patients while providing improved care. Five patients have discontinued chelation therapy; three while on C-RBCx and two while on IHD-RBCx. No adverse events occurred related to the isovolemic hemodilution phase and no patients had recurrent stroke. IHD-RBCx is a safe, efficient, and cost effective therapy for secondary prevention of stroke in patients with sickle cell anemia.

Serum ferritin level changes in children with sickle cell disease on chronic blood transfusion are nonlinear and are associated with iron load and liver injury

Chronic blood transfusion is increasingly indicated in patients with sickle cell disease. Measuring resulting iron overload remains a challenge. Children without viral hepatitis enrolled in 2 trials for stroke prevention were examined for iron overload (STOP and STOP2; n = 271). Most received desferrioxamine chelation. Serum ferritin (SF) changes appeared nonlinear compared with prechelation estimated transfusion iron load (TIL) or with liver iron concentrations (LICs). Averaged correlation coefficient between SF and TIL (patients/observations, 26 of 164) was r = 0.70; between SF and LIC (patients/observations, 33 of 47) was r = 0.55. In mixed models, SF was associated with LIC (P = .006), alanine transaminase (P = .025), and weight (P = .026). Most patients with SF between 750 and 1500 ng/mL had a TIL between 25 and 100 mg/kg (72.8% +/- 5.9%; patients/observations, 24 of 50) or an LIC between 2.5 and 10 mg/g dry liver weight (75% +/- 0%; patients/observations, 8 of 9). Most patients with SF of 3000 ng/mL or greater had a TIL of 100 mg/kg or greater (95.3% +/- 6.7%; patients/observations, 7 of 16) or an LIC of 10 mg/g dry liver weight or greater (87.7% +/- 4.3%; patients/observations, 11 of 18). Although SF changes are nonlinear, levels less than 1500 ng/mL indicated mostly acceptable iron overload; levels of 3000 ng/mL or greater were specific for significant iron overload and were associated with liver injury. However, to determine accurately iron overload in patients with intermediately elevated SF levels, other methods are required. These trials are registered at www.clinicaltrials.gov as #NCT00000592 and #NCT00006182.

Iron overload and toxicity: the hidden risk of multiple blood transfusions

BACKGROUND

The quantity of iron in body is carefully regulated, primarily by control of iron absorption, and excess total body iron can be extremely toxic. Since humans have no mechanism for elimination of excess iron, multiple transfusions of red blood cells, which are required for the management of a number of disorders, inevitably result in iron overload. Cumulative iron overload, in turn, leads to iron toxicity with organ dysfunction and damage.

MATERIALS

This review examines the relationship between iron metabolism and hematologic disorders treated with multiple transfusions, with emphasis on the diagnosis and current methods of management of iron overload and toxicity in transfusion-dependent patients. Primarily using key words, we identified and reviewed more than 100 pertinent articles in English and other languages in the Medline database plus an additional number of abstracts of presentations at recent meetings of relevant scientific associations.

RESULTS

Transfusion-dependent disorders include those characterized by decreased red blood cell production, increased red blood cell destruction, or chronic blood loss. Patients receiving chronic transfusion therapy should be screened and monitored for iron overload, yet in our opinion, this is not always done routinely. Once iron overload has been identified, it should be treated to reduce the risk of morbidity and mortality from iron toxicity, which particularly affects the liver and heart.

CONCLUSION

Increased awareness of the risks of iron overload from chronic transfusion therapy should result in greater use of interventions such as iron chelation to reduce total body iron and the risk of long-term sequelae.

Microarray analysis of liver gene expression in iron overloaded patients with sickle cell anemia and beta-thalassemia

Chronic transfusion therapy is used clinically to supply healthy erythrocytes for patients with sickle cell anemia (SCA) or beta-thalassemia major (TM). Despite the benefits of red blood cell transfusions, chronic transfusions lead to iron accumulation in key tissues such as the heart, liver, and endocrine glands. Transfusion-acquired iron overload is recognized as a cause of morbidity and mortality among patients receiving chronic transfusions. At present, there is little understanding of molecular events that occur during transfusional iron loading and the reasons for the large inter-individual variation observed clinically in transfusion-acquired iron accumulation. To address these issues, we examined whether any liver-expressed genes in SCA or TM patients with transfusional iron overload were associated with the degree of iron accumulation. Specifically, we performed microarray analysis on liver biopsy specimens comparing SCA patients with mild or severe iron overload and also compared SCA with TM patients. Fifteen candidate genes were identified with significantly differential expression between the high and low liver iron concentrations. SCA patients and 20 candidate genes were detected between the SCA and TM patient comparison. Subsequent quantitative PCR experiments validated 12 candidate genes; with GSTM1, eIF5a, SULF2, NTS, and HO-1 being particularly good prospects as genes that might affect the degree of iron accumulation. Future work will determine the baseline expression of these genes prior to transfusional iron overload and elucidate the full impact of these genes on the inter-individual variation observed clinically in transfusion-acquired iron accumulation.

Oral iron chelators

Effective chelation therapy can prevent or reverse organ toxicity related to iron overload, yet cardiac complications and premature death continue to occur, largely related to difficulties with compliance in patients who receive parenteral therapy. The use of oral chelators may be able to overcome these difficulties and improve patient outcomes. A chelator's efficacy at cardiac and liver iron removal and side-effect profile should be considered when tailoring individual chelation regimens. Broader options for chelation therapy, including possible combination therapy, should improve clinical efficacy and enhance patient care.

Erythrocytapheresis: Do Not Forget a Useful Therapy!

SUMMARY: In patients with pathologically altered erythrocytes, red blood cell exchange is a very efficient therapeutic measure without important side effects. With increasing migration more patients with e.g. severe malaria or sickle cell anemia have to be treated. In minor or bidirectional ABO-mismatched stem cell transplantations after reduced intensity conditioning, hemolysis can be prevented by prophylactic erythrocytapheresis. Other rare indications for red blood cell exchange are advanced erythropoietic protoporphyria and babesiosis. Sickle cell anemia can be treated with hydroxyurea. Transfusions are administered when necessary, but this results in iron overload in the long term. An expensive but safe and very efficient treatment alternative is red blood cell exchange. In cases with stroke, acute chest syndrome and other severe complications, erythrocytapheresis reproducibly breaks the vicious circle of sickling and increasing oxygen deficiency. At the same time one can aim at an exact end hematocrit. In severe malaria, erythrocytapheresis both reduces parasite load to the designated extent and reconstitutes reduced oxygen transport capacity without serious adverse effects. Here we describe our experience of erythrocytapheresis in long-term prophylaxis of complications in sickle cell anemia and sickle cell thalassemia patients. The documentation of improved iron balance was carried out by liver susceptometry.

Hydroxyurea therapy lowers transcranial Doppler flow velocities in children with sickle cell anemia

Hydroxyurea has hematologic and clinical efficacy in sickle cell anemia (SCA), but its effects on transcranial Doppler (TCD) flow velocities remain undefined. Fifty-nine children initiating hydroxyurea therapy for clinical severity had pretreatment baseline TCD measurements; 37 with increased flow velocities (≥ 140 cm/s) were then enrolled in an institutional review board (IRB)–approved prospective phase 2 trial with TCD velocities measured at maximum tolerated dose (MTD) and one year later. At hydroxyurea MTD (mean ± 1 SD = 27.9 ± 2.7 mg/kg per day), significant decreases were observed in the right middle cerebral artery (MCA) (166 ± 27 cm/s to 135 ± 27 cm/s, P < .001) and left (MCA) (168 ± 26 cm/s to 142 ± 27 cm/s, P < .001) velocities. The magnitude of TCD velocity decline was significantly correlated with the maximal baseline TCD value. At hydroxyurea MTD, 14 of 15 children with conditional baseline TCD values improved, while 5 of 6 with abnormal TCD velocities whose families refused transfusions became less than 200 cm/s. TCD changes were sustained at follow-up. These prospective data indicate that hydroxyurea can significantly decrease elevated TCD flow velocities, often into the normal range. A multicenter trial is warranted to determine the efficacy of hydroxyurea for the management of increased TCD values, and ultimately for primary stroke prevention in children with SCA.

Limitations of clinical trials in sickle cell disease: a case study of the Multi-center Study of Hydroxyurea (MSH) trial and the Stroke Prevention (STOP) trial

In the past two decades, two landmark randomized controlled trials (RCT) have been completed among individuals with sickle cell disease (SCD), the Multi-center Study of Hydroxyurea (MSH) trial and the Stroke Prevention (STOP) trial. The MSH trial tested the hypothesis that hydroxyurea will reduce the frequency of painful episodes for adults with hemoglobin SS who had a history of 3 or more painful episodes per year. The STOP trial tested the hypothesis that among children with hemoglobin SS and an elevated transcranial Doppler (TCD) velocity measurement, blood transfusion therapy would decrease the risk of an initial stroke. After completion, both trials have defined standard care for individuals with hemoglobin SS. The purpose of this review is to examine the limitations of the MSH and STOP trials. In the context of these trials, we will examine the effects of narrow inclusion criteria that primarily include participants with hemoglobin SS and secondary analyses that are prone to false-positive results. In addition, we describe how after publication of these two trials use of hydroxyurea and TCD assessment has drifted towards a standard practice without evidence of therapeutic efficacy among groups that were excluded from the trials. Finally, we suggest that rigorously conducted RCTs or at the minimum multicenter observation studies with strong methodology should be performed in these excluded subgroups to confirm a benefit of hydroxyurea or TCD measurement.

Discontinuing prophylactic transfusions used to prevent stroke in sickle cell disease

BACKGROUND

Prophylactic transfusion prevents strokes in children with sickle cell anemia who have abnormalities on transcranial Doppler ultrasonographic examination. However, it is not known how long transfusion should be continued in these children.

METHODS

We studied children with sickle cell disease who had a high risk of stroke on the basis of a transcranial Doppler screening examination and who had received transfusions for 30 months or longer, during which time the Doppler readings became normal. The children were randomly assigned to continued transfusion or no continued transfusion. Children with severe stenotic lesions on cerebral magnetic resonance angiography were excluded. The composite primary end point was stroke or reversion to a result on Doppler examination indicative of a high risk of stroke.

RESULTS

The study was stopped after 79 children of a planned enrollment of 100 underwent randomization. Among the 41 children in the transfusion-halted group, high-risk Doppler results developed in 14 and stroke in 2 others within a mean (+/-SD) of 4.5+/-2.6 months (range, 2.1 to 10.1) of the last transfusion. Neither of these events of the composite end point occurred in the 38 children who continued to receive transfusions. The average of the last two transcranial Doppler results before transfusion was started was the only predictor of the composite end point (P=0.05).

CONCLUSIONS

Discontinuation of transfusion for the prevention of stroke in children with sickle cell disease results in a high rate of reversion to abnormal blood-flow velocities on Doppler studies and stroke. (ClinicalTrials.gov number, NCT00006182.)

Risk factors and prediction of outcomes in children and adolescents who have sickle cell anemia

This article discusses risk factors and prediction in children and adolescents who have sickle cell anemia.

Screening children for sickle cell vasculopathy: guidelines for transcranial Doppler evaluation

Cerebral infarction is a major cause of morbidity and mortality in children with sickle cell disease. Prevention of primary stroke might be feasible with a way to identify children at greatest risk. Transcranial Doppler (TCD) has been shown to be a noninvasive, reliable, inexpensive method of identifying children at highest risk for cerebral infarction. The pros and cons of imaging and non-imaging TCD techniques are discussed. The protocol for the stroke prevention trial in sickle cell anemia (STOP), including data acquisition and interpretation, is reviewed. Providing TCD to sickle cell patients can be a valuable service that results in a significant decrease in first stroke rates.

Iron chelation therapy in sickle-cell disease and other transfusion-dependent anemias

Regular red cell transfusion therapy may be life-saving or may reduce complications substantially in several hematological disorders. The inevitable consequence of repeated transfusions is iron loading, which, if untreated, leads to organ failure and death. Chelation therapy with deferoxamine is the standard of care for patients who have transfusional iron overload. The necessity to administer this drug parenterally limits compliance; this has prompted the search for a safe and effective orally-administered chelator. Deferiprone, the first extensively studied orally active chelator, is now licensed for use in Europe for patients who are unable to use deferoxamine effectively or safely. ICL670, a newer oral chelator, is being tested in large clinical trials. Combined therapies, potentially including transfusional methods to reduce iron loading with parenteral and oral chelators, may improve compliance and efficacy in some patients who are transfused chronically.

Prevention of secondary stroke and resolution of transfusional iron overload in children with sickle cell anemia using hydroxyurea and phlebotomy

OBJECTIVE

Transfusions prevent secondary stroke in children with sickle cell anemia (SCA) but also cause iron overload. Alternatives for stroke prophylaxis with effective therapy to reduce iron burden are needed.

STUDY DESIGN

For 35 children with SCA and stroke, transfusions were prospectively discontinued. Hydroxyurea was prescribed for stroke prophylaxis, and phlebotomy removed excess iron. Initial patients discontinued transfusions before hydroxyurea therapy, but later patients overlapped transfusions with hydroxyurea until tolerating full-dose therapy.

RESULTS

Children received hydroxyurea for 42 +/- 30 months (range, 3-104 months). Hydroxyurea (26.7 +/- 4.8 mg/kg per day) led to mild neutropenia (3.9 +/- 2.3 x 10(9)/L) with significant increases in hemoglobin concentration, mean corpuscular volume, and fetal hemoglobin. Stroke recurrence rate was 5.7 events per 100 patient-years, but children receiving overlapping hydroxyurea therapy had only 3.6 events per 100 patient-years. For 26 children with >6 months of phlebotomy, 14,311 +/- 12,459 mL blood (315 +/- 214 mL/kg) was removed, with serum ferritin decreasing from a median of 2722 to 298 ng/mL. Among patients completing phlebotomy, liver biopsy documented normal histology and no excess iron deposition.

CONCLUSIONS

For children with SCA and stroke, hydroxyurea effectively prevents secondary stroke and serial phlebotomy leads to complete resolution of transfusional iron overload.

Identification of hemochromatosis gene polymorphisms in chronically transfused patients with sickle cell disease

Three polymorphic gene mutations in the human hemochromatosis (HFE) gene (C282Y, H63D, S65C) are associated with non-transfusion-related iron overload in Caucasians. More recently, these mutations have also been identified in African-Americans. However, the prevalence of HFE gene mutations in African-Americans with sickle cell disease (SCD) has not been described. The presence of these mutations in this population is particularly important, because patients with SCD may be placed on chronic red cell transfusion therapy and are thus at further risk for iron overload. Thus, we attempted to establish the gene mutation prevalence in African-Americans with SCD, to compare this frequency with published gene frequencies in African-Americans, and to evaluate their significance with regard to transfusion-related iron overload. Eighty-nine African-American patients with SCD, all of whom were receiving chronic red cell transfusion therapy, were screened by DNA analysis for the three HFE gene mutations. Two patients were heterozygous for the C282Y HFE mutation (2.3%), six were heterozygous for the H63D mutation (6.8%), none carried the S65C mutation (0.0%), and no homozygous or compound heterozygous subjects were identified. The prevalence of C282Y and H63D in the SCD population was similar to that observed in the general African-American population. In addition, there was no increased mutation prevalence when comparing those SCD patients on chronic transfusion therapy who had ferritin levels greater than 2,500 ng/mL and those less than 2,500 ng/mL. This study represents the first identification of the known HFE gene mutations by DNA analysis in the SCD population. We conclude that the presence of recognized HFE coding region mutations do not seem to have an impact on the degree of iron overload in patients with SCD receiving chronic transfusion therapy.

Blood transfusion for preventing stroke in people with sickle cell disease

BACKGROUND

Sickle cell disease is a common inherited haemoglobin disorder. The abnormal haemoglobin causes distortion of red blood cells, anaemia, vaso-occlusion and dysfunction in virtually any organ system in the body. Stroke occurs in around 10% of children with sickle cell anaemia, and recurrences after a first stroke are likely. Chronic blood transfusion regimes are often used in an attempt to dilute the sickled red blood cells, thus reducing the risk of vaso-occlusion and stroke. However, the side-effects of such regimens can be severe.

OBJECTIVES

To assess the relative risks and benefits of chronic blood transfusion regimes in patients with sickle cell disease to prevent a first stroke or further strokes.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Date of the most recent search of the Group's specialised register: July 2001

SELECTION CRITERIA

All those randomised or quasi-randomised controlled trials in which blood transfusion as a preventative measure for stroke in patients with sickle cell disease are compared to an alternative treatment or to no treatment.

DATA COLLECTION AND ANALYSIS

Both reviewers independently assessed trial quality and extracted data from the study included.

MAIN RESULTS

One trial was identified by the initial search and this met the inclusion criteria for the review. The trial compared a chronic transfusion regime to maintain sickle haemoglobin at less than 30% with standard care in 130 children with sickle cell disease who were judged to be at high risk of a first stroke through transcranial doppler ultrasonography. Eleven children in the standard care group suffered a stroke during the trial, compared to only one in the transfusion group. Because of this 92% relative risk reduction, the trial was terminated 16 months early. It had been planned that all patients would be treated for 30 months, but median follow-up only 21.1 months. However, a high rate of complications such as iron overload, alloimmunisation and transfusion reactions were seen in the children who were receiving transfusions. No randomised controlled trials were identified which investigated use of transfusion for preventing recurrence of stroke.

REVIEWER'S CONCLUSIONS

While the included study demonstrated a significantly reduced risk of stroke in patients receiving regular blood transfusions, the degree of risk must be balanced against the burden of a chronic transfusion regime. Further research is required to establish the use of transfusion in preventing secondary stroke, the age, or length of time after an event, at which transfusion can safely be stopped, and to further define risk factors for stroke in order to reduce the chance of unnecessarily putting children onto a chronic transfusion regime.