Chronic red blood cell exchange to prevent clinical complications in sickle cell disease

Automated red blood cell exchange with a post-procedure haematocrit targeted at 34% in the chronic management of sickle cell disease

Optimal targets for red blood cell exchange (RCE) are not well defined in the chronic management of sickle cell disease. We analysed transfusion requirements and iron-related outcomes in 101 patients on chronic RCE with a post-procedure haematocrit (Ht) targeted at 34%, which is higher than typically used. A majority were of HbSS/HbSβ0 genotype (n = 72) and enrolled for neurological complications (n = 53). Fifty patients had a positive Ht balance with RCE (>2% mean increase from pre-procedure level), while 43 patients maintained a neutral balance. The first group required fewer red blood cell units/year (65 vs. 80, p < 0.001), but a significant proportion were iron overloaded based on R2* with liver MRI (32% vs. none performed) and prescription of iron chelation (52% vs. 0%, p < 0.001, after a median of 19 months). The second group was more likely to receive iron supplementation (6% vs. 56%, p < 0.001). Chronic automated RCE with a post-procedure Ht targeted at 34% is not iron-neutral, and personalized Ht goals may be more appropriate in certain settings. This higher target should be compared with a lower Ht strategy in individuals with similar baseline red cell volumes to assess iron homeostasis and blood product requirements.

Logistics, risks, and benefits of automated red blood cell exchange for patients with sickle cell disease

Red blood cell (RBC) transfusions treat and prevent severe complications of sickle cell disease (SCD) and can be delivered as a simple or exchange transfusion. During an exchange, some of the patient's abnormal hemoglobin (Hb) S (HbS) RBCs are removed. An apheresis device can accomplish an automated RBC exchange, simultaneously removing patient's RBCs while returning other blood components along with normal RBCs. Automated RBC exchange is therefore an isovolemic transfusion that can efficiently decrease HbS RBCs while limiting iron loading and hyperviscosity. However, specialized equipment, trained personnel, appropriate vascular access, and increased RBC exposure are required compared to simple or manual RBC exchange. Therefore, risks and benefits must be balanced to make individualized decisions for patients with SCD who require transfusion.

Comprehensive guide to managing a chronic automated red cell exchange program in sickle cell disease

Sickle cell disease (SCD) is associated with significant morbidity and mortality, and limits both the quality and quantity of life. Transfusion therapy, specifically automated red cell exchange (aRCE), plays a key role in management of SCD and is beneficial for certain indications in the chronic, outpatient setting. The approach to maintain a successful chronic aRCE program for SCD is multifaceted. This review will highlight important considerations including indications for aRCE, patient selection, transfusion medicine pearls, vascular access needs, complications of therapy, aRCE prescription, and therapy optimization. Moreover, the importance of a multidisciplinary approach with frequent communication between the services involved cannot be overstated. Ultimately, the underlying goal of a chronic RCE program is to improve the quality of life and longevity of patients with SCD.

Automated exchange compared to manual and simple blood transfusion attenuates rise in ferritin level after 1 year of regular blood transfusion therapy in chronically transfused children with sickle cell disease

BACKGROUND

Optimal strategies for regular blood transfusion therapy are not well defined in sickle cell disease (SCD). This analysis tested the hypothesis that in the first of year of regular transfusions, when chelation therapy use is minimal, automated exchange transfusion would be the superior method for attenuating the rise in ferritin levels compared to simple and manual exchange transfusions.

STUDY DESIGN AND METHODS

The Silent Cerebral Infarct Multi-Center Clinical Trial randomly allocated children with SCD and silent cerebral infarcts to receive standard care or regular transfusions with a target pre-transfusion HbS concentration ≤ 30% and minimum hemoglobin level > 9.0 g/dL. Participants with at least nine transfusions and sufficient ferritin testing in the first year of the trial were included in a planned secondary analysis. Ferritin levels by the end of the first study year were compared between participants receiving automatic exchange transfusion, manual exchange transfusion, and simple transfusion.

RESULTS

A total of 83 participants were analyzed. During the first year of the study, 75.9% of the participants had >80% of transfusions via one transfusion method. At baseline no significant differences in ferritin levels were observed in the three transfusion groups (p = 0.1). After 1 year of transfusions the median (interquartile range) ferritin levels in the simple transfusion (n = 40), manual exchange transfusion (n = 34) and automatic exchange transfusion (n = 9) groups were 1800 ng/mL (1426-2204 ng/mL), 1530 ng/mL (1205-1805 ng/mL), and 355 ng/mL (179-579 ng/mL), respectively (p < 0.001).

CONCLUSION

Automated exchange transfusion, when compared to other transfusion methods, is the optimal transfusion strategy for attenuating increase in ferritin levels in children with SCD.

American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support

BACKGROUND

Red cell transfusions remain a mainstay of therapy for patients with sickle cell disease (SCD), but pose significant clinical challenges. Guidance for specific indications and administration of transfusion, as well as screening, prevention, and management of alloimmunization, delayed hemolytic transfusion reactions (DHTRs), and iron overload may improve outcomes.

OBJECTIVE

Our objective was to develop evidence-based guidelines to support patients, clinicians, and other healthcare professionals in their decisions about transfusion support for SCD and the management of transfusion-related complications.

METHODS

The American Society of Hematology formed a multidisciplinary panel that was balanced to minimize bias from conflicts of interest and that included a patient representative. The panel prioritized clinical questions and outcomes. The Mayo Clinic Evidence-Based Practice Research Program supported the guideline development process. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to form recommendations, which were subject to public comment.

RESULTS

The panel developed 10 recommendations focused on red cell antigen typing and matching, indications, and mode of administration (simple vs red cell exchange), as well as screening, prevention, and management of alloimmunization, DHTRs, and iron overload.

CONCLUSIONS

The majority of panel recommendations were conditional due to the paucity of direct, high-certainty evidence for outcomes of interest. Research priorities were identified, including prospective studies to understand the role of serologic vs genotypic red cell matching, the mechanism of HTRs resulting from specific alloantigens to inform therapy, the role and timing of regular transfusions during pregnancy for women, and the optimal treatment of transfusional iron overload in SCD.

Current challenges in the management of patients with sickle cell disease - A report of the Italian experience

Sickle cell disease (SCD) is an inherited red blood cell disorder caused by a structural abnormality of hemoglobin called sickle hemoglobin (HbS). Clinical manifestations of SCD are mainly characterized by chronic hemolysis and acute vaso-occlusive crisis, which are responsible for severe acute and chronic organ damage. SCD is widespread in sub-Saharan Africa, in the Middle East, Indian subcontinent, and some Mediterranean regions. With voluntary population migrations, people harboring the HbS gene have spread globally. In 2006, the World Health Organization recognized hemoglobinopathies, including SCD, as a global public health problem and urged national health systems worldwide to design and establish programs for the prevention and management of SCD. Herein we describe the historical experience of the network of hemoglobinopathy centers and their approach to SCD in Italy, a country where hemoglobinopathies have a high prevalence and where SCD, associated with different genotypes including ß-thalassemia, is present in the native population.

Automatic depletion with Spectra Optia allows a safe 16% reduction of red blood cell pack consumption in exchanged sickle cell anemia patients

BACKGROUND

Chronic red blood cell exchanges (RBCXs) are frequently used to prevent complications in patients with sickle cell anemia, but the scarcity of matched red blood cell packs (RBCPs) is a serious concern. The main goal of this study was to compare the number of RBCPs used during RBCXs between the Spectra Optia (SO) device (with the automatic depletion step) and the former Cobe Spectra (CSP) device.

STUDY DESIGN AND METHODS

The performances and safety of 300 SO sessions using the automatic depletion step (SO/DE) in 50 patients with sickle cell anemia under a chronic transfusion program over a 1-year period were prospectively analyzed. The numbers of RBCPs saved using this protocol compared to the SO device without depletion and to the CSP device were determined.

RESULTS

The SO/DE protocol appeared to be safe, as only 5% and 17% of the sessions were characterized by a significant decrease in blood pressure and increase in heart rate (grade 2 adverse events), respectively. Postapheresis hematocrit and fraction of cells remaining reached expected values. The SO/DE protocol required 16% fewer RBCPs compared to SO without depletion, allowing a mean saving of 12 RBCPs per patient and per year and 13% fewer compared to CSP device. Interestingly, the saving was more important for patients with high total blood volume and/or high preapheresis hematocrit.

CONCLUSION

The SO/DE protocol is an efficient, safe and cost-effective procedure for patients with sickle cell anemia under a chronic transfusion program.

Comparative efficacy in red blood cell exchange transfusions with different apheresis machines in patients with sickle cell disease

The purpose of this study is to compare the efficacy and side effects of two red blood cell exchange (RBCX) transfusion systems in sickle cell disease (SCD). The data is collected retrospectively from the January 2010 to March 2015. 447 RBCX transfusions were performed to 165 patients. Side effects, clinical and technical efficacy were compared in between procedures with Cobe Spectra (CS) and Spectra Optia (SO) systems. Furthermore a subgroup analyses was performed for 40 patients who had RBCX transfusions with both system at least two times. Vasoocclusive crises, preoperative period and foot ulcers (49.6, 13, and 15.2% respectively) were the common indications of RBCX transfusion. While the levels of post-RBCX HbS and the actual fraction of cells remaining (FCRa) were found significantly higher in the SO compared to CS system (p = 0.018 and p = 0.016 respectively), the rate of targeted hemoglobin S (HbS) levels (< 30%) were same in both. The length of procedure and replacement volume were significantly lower in SO compared to CS system (p = 0.025 and 0.044 respectively). Subgroup analyses of 40 patients did not reveal any statistically significant differences regarding post-procedure HbS levels, FCRa levels, replacement volume and procedure duration. The inter-rater correlation coefficient for FCRa was calculated to be 0.82. Serious adverse reactions were not observed from either system. Both systems are efficiently achieved the targeted post-procedure HbS level. The recently introduced SO apheresis system is as effective and safe as the CS system, which has been used for all indications of SCD for years.

Spectra Optia® for Automated Red Blood Cell Exchange in Patients with Sickle Cell Disease: A NICE Medical Technology Guidance

The Spectra Optia® automated apheresis system, indicated for red blood cell exchange in people with sickle cell disease, underwent evaluation by the National Institute for Health and Care Excellence, which uses its Medical Technologies Advisory Committee to make recommendations. The company (Terumo Medical Corporation) produced a submission making a case for adoption of its technology, which was critiqued by the Newcastle and York external assessment centre. Thirty retrospective observational studies were identified in their clinical submission. The external assessment centre considered these were of low methodological and reporting quality. Most were single-armed studies, with only six studies providing comparative data. The available data showed that, compared with manual red blood cell exchange, Spectra Optia reduces the frequency of exchange procedures as well as their duration, but increases the requirement for donor blood. However, other clinical and patient benefits were equivocal because of an absence of robust clinical evidence. The company provided a de novo model to support the economic proposition of the technology, and reported that in most scenarios Spectra Optia was cost saving, primarily through reduced requirement of chelation therapy to manage iron overload. The external assessment centre considered that although the cost-saving potential of Spectra Optia was plausible, the model and its clinical inputs were not sufficiently robust to demonstrate this. However, taking the evidence together with expert and patient advice, the Medical Technologies Advisory Committee considered Spectra Optia was likely to save costs, provide important patient benefits, and reduce inequality, and gave the technology a positive recommendation in Medical Technology Guidance 28.

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.

A safe therapeutic apheresis protocol in paediatric patients weighing 11 to 25 kg

BACKGROUND AND OBJECTIVES

Erythrocytapheresis and leukapheresis (LPE) of small children are logistically complex and many centres are reluctant to perform these procedures. In children, both sickle cell and leukaemic emergencies demand prompt action to prevent additional morbidity but detailed protocols for small children are lacking, and often are performed using guidelines shown to work in larger patients. We report a 3-year experience with children weighing 11-25 kg at a large academic medical centre.

MATERIALS AND METHODS

All patients were treated with the COBE® Spectra apheresis system; circuit was primed with blood not adjusted for haematocrit and anticoagulant citrate dextrose A was used as anticoagulation. Procedures were performed in the paediatric intensive care unit by apheresis nursing staff.

RESULTS

Twenty-five apheresis procedures in 19 patients were performed; 17 of 19 patients presented with sickle cell-related acute complications and two (2/19) with newly diagnosed acute leukaemia and hyperleucocytosis. None of the patients required medications during the procedures. Vital signs and clinical condition remained stable and did not worsen during or postapheresis. One patient had a delayed haemolytic transfusion reaction 1 week posterythrocytapheresis as he developed alloantibodies as a result of the procedure. All sickle cell patients achieved a target haematocrit of 21-30% and Haemoglobin A of ≥68%. Both leukaemia patients who underwent LPE had no further signs of leukostasis and achieved marked reductions in leucocyte counts.

CONCLUSIONS

Apheresis of children weighing 11-25 kg can be safely performed without increased morbidity. We outline a protocol that can be used to perform apheresis with minimal complications.

Current approach to iron chelation in children

Transfusion-dependent children, mostly with thalassaemia major, but also and occasionally to a more significant degree, with inherited bone marrow failures, can develop severe iron overload in early life. Moreover, chronic conditions associated with ineffective erythropoiesis, such as non-transfusion-dependent thalassaemia (NTDT), may lead to iron overload through increased gut absorption of iron starting in childhood. Currently, the goal of iron chelation has shifted from treating iron overload to preventing iron accumulation and iron-induced end-organ complications, in order to achieve a normal pattern of complication-free survival and of quality of life. New chelation options increase the likelihood of achieving these goals. Timely initiation, close monitoring and continuous adjustment are the cornerstones of optimal chelation therapy in children, who have a higher transfusional requirements compared to adults in order to reach haemoglobin levels adequate for normal growth and development. Despite increased knowledge, there are still uncertainties about the level of body iron at which iron chelation therapy should be started and about the appropriate degree of iron stores' depletion.

Sickle cell crisis and pregnancy

Pregnant women with sickle cell disease appear to be more likely to experience antepartum, intrapartum, and postpartum complications when compared with unaffected women. Access to high-risk obstetric care, patient education, and close follow-up is important to minimize maternal morbidity and mortality. A high index of suspicion and good diagnostic acumen is necessary to obtain optimal results in the pregnant patient affected by sickle cell crisis.

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.

[Therapeutic erythrocytapheresis: technical aspects and clinical applications]

PURPOSE

Therapeutic erythrocytapheresis is a selective red cell-depletion aphaeresis technique.

CURRENT KNOWLEDGE AND KEY POINT

Using a discontinuous or continuous flow blood cell separator, the technique safely allows quickly and automatically collecting a large volume of red cells. The main obstacle of implementation is a poor peripheral venous access. The procedure is well-tolerated. Polycythemia vera, hereditary hemochromatosis, complicated sickle-cell-disease and retinal venous occlusion are the main clinical applications.

PROSPECT AND PROJECT

Therapeutic erythrocytapheresis is a more modern and more effective method than the classic patient-bleeding. It has to be preferred in the early treatment of patients with polycythemia vera and hereditary hemochromatosis.

Automated red cell exchange procedures in patients with sickle cell disease

In automated red cell exchange, about 60% of the patient's red blood cells are exchanged via apheresis for those of the donor. We report the outcome of 83 patients with sickle cell anemia (48 women and 35 men; age range, 17-49 years) who underwent a total of 196 apheresis procedures between December 2003 and October 2006 at our institution. We found that automated red cell exchange involving a reduced citrate infusion rate may provide benefit in the prevention or treatment of vaso-occlusive complications in patients with sickle cell disease and may be associated with protean effects on biochemical dynamics.