Red blood cell exchange: 2015 American Society for Apheresis consensus conference on the management of patients with sickle cell disease

Position paper on advancing sickle cell disease management in France by bridging the clinical practices and guidelines through expert insights

In France, sickle cell disease (SCD) is the most common rare disease and represents the most prevalent genetic disorder, with 19,800 to 32,400 patients diagnosed in 2016 and 1:714 newborns affected in 2019. SCD is caused by a single mutation in the β-globin gene, resulting in the production of abnormal hemoglobin (called HbS), chronic hemolytic anemia, and impaired red blood cell rheology. SCD patients face several severe acute and chronic complications, including stroke, acute chest syndrome (ACS), painful vaso-occlusive crisis (VOC), organ failure, and a high risk of infections. As patients' care pathway remains unclear in France, a roundtable advisory board meeting was organized in the country to provide insights into the management of SCD in alignment with clinical guidelines. The meeting brought together a panel of esteemed key opinion leaders (KOLs) in SCD management, encompassing both clinical practice and research. During the meeting, the KOLs discussed clinical practices and their alignment with French guidelines, identifying areas of concordance and discrepancy. They also addressed disparities in SCD clinical practices across regions and medical centers. The KOLs discussed the prophylactic and therapeutic options currently available for SCD patients in France, with a focus on transfusion therapies, especially automated red blood cell exchange (aRBCX). The results of this advisory board meeting provide a valuable platform for gathering expert perspectives on SCD management, clinical practices, guideline alignment, and the potential for contributions to guideline updates.

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.

Non-crisis related pain occurs in adult patients with sickle cell disease despite chronic red blood cell exchange transfusion therapy

BACKGROUND

Chronic red blood cell transfusions reduce acute care utilization for sickle cell disease (SCD) pain. However, little is known about whether chronic transfusions treat or prevent the development of non-crisis pain. We investigated patient-report of pain in adults with SCD receiving chronic exchange transfusions (CET) compared to adults not on CET with similar disease characteristics.

STUDY METHOD AND DESIGN

Eleven participants receiving chronic exchange transfusion (CET) for at least one year were compared to 33 participants not receiving CET. Participants completed validated patient-reported outcomes regarding pain impact and quality of life at regularly scheduled visits or before CET. One year of health care utilization and opioid prescriptions were examined.

RESULTS

After 1:1 propensity matching was performed for age, genotype, WBC and neutrophil counts, patients on CET had lower Pain Impact scores (-5.1, p = 0.03) and higher Neuropathic (7.4, p < 0.001) and Nociceptive Pain Quality (3.7, p < 0.001) scores, all indicating worse pain. However, CET was associated with a reduction in annual all cause admissions (-3.1, p < 0.001), length of stay (-2.1 days, p < 0.001) and ED visits (-2.7, p < 0.001). CET was not associated with differences in opioids dispensed.

CONCLUSIONS

After adjusting for disease characteristics, CET was associated with worse pain impact and neuropathic and nociceptive pain quality, lower health care utilization and with similar levels of opioids dispensed. This data suggest that CET may reduce hospitalizations for acute pain but may not adequately treat nociceptive or neuropathic pain in SCD.

Priming With Red Blood Cells Allows Red Blood Cell Exchange for Sickle Cell Disease in Low-Weight Children

Red blood cell exchanges are frequently used to treat and prevent cerebrovascular complications in patients with sickle cell anemia (SCA). However, the low weight of young children represents serious concerns for this procedure. The Spectra Optia device can perform automatic priming using red blood cells (RBCs) (RCE/RBC-primed) which could allow RBC exchanges (RCE) to be performed in young children without hypovolemic complications, but this method requires evaluation. We prospectively analyzed the clinical safety of the RCE/RBC-primed procedure in 12 SCA low-weight children under either a chronic RCE program or emergency treatment over 65 sessions. We monitored grade 2 adverse events (AEs) such as a decrease in blood pressure, increase in heart rate, fainting sensation, or transfusion reactions and identified the critical times during the sessions in which AEs could occur. Post-apheresis hematocrit (Hct) and a fraction of cell remaining (FCR) values were compared to the expected values. We also compared the impact of automatic RCE (n = 7) vs. RCE/RBC-primed (n = 8) on blood viscosity and RBC rheology. A low incidence of complications was observed in the 65 RCE sessions with only seven episodes of transient grade 2 AEs. Post-apheresis Hct and FCR reached expected values with the RCE/RBC-primed method. Both the automatic and priming procedures improved RBC deformability and decreased the sickling tendency during deoxygenation. Blood rheological features improved in both RCE/RBC-primed and automatic RCE without priming conditions. The RCE/RBC-primed procedure provides blood rheological benefits, and is safe and efficient to treat, notably in young children with SCA in prophylactic programs or curatively when a SCA complication occurs.

Red blood cell exchange in children with sickle cell disease

The aim of our study was to assess the efficacy of red blood cell exchange (RBCx) using a Spectra Optia® automated apheresis system in children with sickle cell disease (SCD). We used automated RBCx to treat acute and chronic complications in 75 children with SCD who had a median age of 10 years [7-13]. We analyzed 649 RBCx sessions. Peripheral venous access was limited in a number of the children, and thus a femoral double-lumen central venous catheter was required. We recommend heparin locking with 500 units in each lumen of the catheter. To prevent complications, we ensured that all patients had achieved a post-RCE HbS level of < 30%. For chronic transfusion, with a post-RCE Hb level of approximately 10-11 g/dL, a blood exchange volume of ≥ 32 mL/kg, and an interval between each RBCx procedure of ≤ 30 days, the residual HbS level was maintained below 30%. For acute transfusion, a post-exchange Hb level ≥ 10 g/dL (p < 0.001) and a total exchange volume ≥ 35 mL/kg (p = 0.001) were the best way to reduce HbS to < 30%. AUC was 0.84. Our results show that erythrocytapheresis was useful and safe for children with SCD.

Advances in Sickle Cell Disease Treatments

Sickle Cell Disease (SCD) is an inherited disorder of red blood cells that is caused by a single mutation in the β -globin gene. The disease, which afflicts millions of patients worldwide mainly in low income countries, is characterized by high morbidity, mortality and low life expectancy. The new pharmacological and non-pharmacological strategies for SCD is urgent in order to promote treatments able to reduce patient's suffering and improve their quality of life. Since the FDA approval of HU in 1998, there have been few advances in discovering new drugs; however, in the last three years voxelotor, crizanlizumab, and glutamine have been approved as new therapeutic alternatives. In addition, new promising compounds have been described to treat the main SCD symptoms. Herein, focusing on drug discovery, we discuss new strategies to treat SCD that have been carried out in the last ten years to discover new, safe, and effective treatments. Moreover, non-pharmacological approaches, including red blood cell exchange, gene therapy and hematopoietic stem cell transplantation will be presented.

Red blood cell exchange in an emergency in sickle cell disease

Red blood cell exchange (RBCEx) has become a standard therapy to remove abnormal red blood cells (RBCs) in patients with sickle cell disease (SCD). In the last few decades, numerous RBCEx procedures have been performed chronically during regular programs, while numerous procedures have also been performed in an emergency for several indications, this therapeutic option being very efficient in vital and emergency situations. In both groups of indications, large amounts of sickle RBCs have to be removed, which requires great precision and the setting of specific hematological targets. The aim of this review is to discuss the aims, clinical and biological targets, and the requirements and precautions when performing RBCEx in an emergency. Moreover, we analyze how improvement of the techniques as well as the clinical and biological targets has led to optimization of the procedures in emergency settings. We also consider the outstanding issues that require additional investigation.

Role of prophylactic and therapeutic red blood cell exchange in pregnancy with sickle cell disease: Maternal and perinatal outcomes

BACKGROUND AND AIM

The incidence of fetomaternal complications during pregnancy is high for women with sickle cell disease (SCD), which is the most common hematologic genetic disorder worldwide. Prophylactic red blood cell exchange (pRBCX) has been shown to be efficient, safe, and feasible for preventing complications. The aim of this study was to observe maternal, perinatal, and neonatal outcomes of pregnancies in which pRBCX was.

METHOD

This was a single-center, retrospective, cross-sectional study, which recruited 46 consecutive adult pregnant women with SCD between January 2012 and June 2019. Obstetric features, SCD-related complications, and fetomaternal outcomes were compared between the 27 patients who received prophylactic exchange and the 19 who did not (therapeutic exchange was performed in 7 and was not performed in 12 cases).

RESULTS

Painful crises, preeclampsia, and preterm birth rates were significantly higher in the group that did not receive prophylactic exchange (control group; P = .001, P = .024, and P = .027, respectively). There was one maternal mortality in the control group (P = .41). Incidence of adverse fetal or maternal complications was significantly higher in the control group (P = .044 and P = .007, respectively).

CONCLUSIONS

Our center's experience over a 7.5-year period, as described above, demonstrates that pRBCX in SCD affects the course of pregnancy positively by ameliorating negative fetomaternal outcomes.

Process mapping of the urgent red cell exchange procedure for patients with severe complications of sickle cell disease at a centralized hemapheresis service

Sickle cell disease (SCD) patients require urgent red cell exchange (RCE) procedures for acute chest syndrome (ACS), demanding a coordinated effort of multiple clinical services. Execution of RCE is a multistep process from the time the procedure is requested to the time the procedure is initiated. A retrospective review of patients with SCD requiring urgent RCE for ACS and stroke from 2012 to 2017 was performed at a centralized hemapheresis service covering a multihospital healthcare system. A total of 30 urgent RCE procedures performed on 28 patients were evaluated. The time required for red blood cell (RBC) preparation was the longest step in the process (median 3.8 hours). Furthermore, RBC preparation time was longer for sickle cell patients with RBC alloimmunization compared with nonalloimmunized patients (8.6 vs 3.8 hours, P = .03). One mortality event occurred in Ab- group. This study identified potentially modifiable factors, which impact the time to implementation of RCE in one service area. It highlights the importance of a structured and coordinated approach for the efficient and timely delivery of this vital treatment modality.

Transfusion support in patients with sickle cell disease

Blood transfusions are an integral component of the management of acute and chronic complications of sickle cell disease. Red cells can be administered as a simple transfusion, part of a modified exchange procedure involving manual removal of autologous red cells and infusion of donor red cells, and part of an automated red cell exchange procedure using apheresis techniques. Individuals with sickle cell disease are at risk of multiple complications of blood transfusions, including transfusional hemosiderosis, auto- and alloimmunization to minor red cell and human leukocyte antigens, delayed hemolytic transfusion reactions, and hyper-hemolysis. In low- and middle-income countries in sub-Saharan Africa, where a directed donor system is prevalent and limited laboratory methods are in place to perform extended red cell phenotyping, leukodepletion of cellular products, and infectious disease screening, there are additional challenges to providing safe and adequate transfusion support for this patient population. We review current indications for acute and chronic transfusions in sickle cell disease that are derived primarily from randomized controlled trials and observational studies in children living in high-income countries. We will highlight populations with unique transfusion needs, such as pregnant women and children, as well as the role of the transfusion medicine consultative service for individuals with sickle cell disease planning to have curative hematopoietic stem cell transplantation or gene therapy. Finally, we will discuss risk factors for alloimmunization in individuals with sickle cell disease, emerging new strategies to prevent alloimmunization in this population, and critical gaps in the implementation of transfusion guidelines for sickle cell disease in high- and low-income countries.

Indications for therapeutic apheresis in hematological disorders

The early apheresis devices were developed in 1930s, but therapeutic apheresis only became widely used decades later, when automated cell separators were introduced. Progress in technical development of these devices continues to this day. Initial use of therapeutic apheresis has not been evidence based. Documents such as the Guidelines by the American Society for Apheresis provided hematologist with better tools to assess the role of therapeutic apheresis in daily practice. This review focuses on the use of therapeutic apheresis in patients with hematological disorders. Four separate apheresis modalities most encountered by hematologists are discussed: therapeutic plasma exchange, therapeutic leukocytapheresis, red blood cell exchange, and extracorporeal photopheresis. Examples of indications are provided and discussed. The future of therapeutic apheresis and its role in different diseases is undergoing continuous re-evaluation as disease pathogenesis is better understood and new treatment options become available.

Red cell exchange for patients with sickle cell disease: an international survey of current practices

INTRODUCTION

Red cell exchange (RCE) therapy is increasingly used to treat patients with acute or chronic manifestations of sickle cell disease (SCD). However, little is known regarding the most safe and effective practice parameters associated with this particular therapy.

METHODS

A SCD subcommittee of members of the American Society for Apheresis (ASFA) developed a 122-question survey and administered it via email to other ASFA members. The survey inquired about clinical indications for treatment, practice patterns, and transfusion policies for RCE when used for patients with SCD.

RESULTS

Ninety-nine distinct institutions completed the survey. Twenty-one (21%) were from outside of the US. Twenty-two (22%) provided chronic transfusion therapy to >10 patients, and both adult (25%) and pediatric-focused services (20%) were represented. Common acute indications for RCE included acute chest syndrome, acute ischemic stroke, and pre-surgical prophylaxis. Common chronic indications included primary stroke prophylaxis, secondary stroke prophylaxis, and recurrent acute chest syndrome. Respondents most commonly set a post-RCE treatment target of 30% for the hematocrit and hemoglobin S levels, regardless of the therapeutic indication. Units for RCE were phenotypically matched in 95% of cases. About 40% of respondents reported using isovolemic hemodilution.

CONCLUSIONS

This survey solicited the current practice variations in RCE from a diverse range of practice sites. Many sites reported similar practice patterns and challenges but some variations emerged. To our knowledge, this survey represents the largest and most in-depth investigation of the use of RCE for patients with SCD, and could inform future studies in the field.

Red Blood Cells: Exchange, Transfuse, or Deplete

Erythrocytapheresis, red blood cell (RBC) depletion, and RBC exchange transfusions are apheresis techniques used to rapidly lower the circulating RBC mass or to exchange the patient erythrocyte mass with donor RBC. Automated RBC exchange is performed using an apheresis device, while manual RBC exchange is based on sequential phlebotomies and isovolemic replacement. Compared to simple RBC transfusions, RBC exchange offers several advantages, e.g., a lower risk for iron accumulation and efficient control of pathological erythrocyte populations. Disadvantages are the higher costs of the procedure, the increased use of donor RBC, and the requirement of apheresis devices and trained hospital staff. The most frequent indication for RBC exchange is sickle cell disease (SCD). RBC exchange transfusions are standard treatment in SCD patients with a history of or a risk for acute stroke and are clinical options for other acute complications of SCD. The most common indication for RBC depletion is the removal of donor RBC from the bone marrow grafts in major ABO-incompatible allogeneic hematopoietic stem cell transplantation to avoid immediate hemolysis. Rare indications for RBC exchange are severe infections with intraerythrocytic pathogens such as malaria or babesiosis and severe erythrocytosis or hereditary hemochromatosis where the aim is to rapidly decrease RBC populations or the iron content. However, only few high-quality studies are available looking at the efficacy of RBC exchange in the different disease entities, and treatment is often based on low levels of evidence and should therefore be decided in close collaboration with a transfusion medicine specialist.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Sickle Cell Disease: Monitoring, Current Treatment, and Therapeutics Under Development

Screening and early detection of organ injury, as well as expanded use of red cell transfusion and hydroxyurea in children have changed best practices for clinical care in sickle cell disease. The current standard of care for children with sickle cell disease is discussed through a review of screening recommendations, disease monitoring, and approach to treatment. Novel pharmacologic agents under investigation in clinical trials are also reviewed.

Recommendations for the use of red blood cell exchange in sickle cell disease

Sickle cell disease (SCD) is a genetic disorder characterised by a single mutation of the beta globin gene, causing the production of an abnormal haemoglobin called sickle haemoglobin (HbS). In its deoxygenated form, HbS polymerises, causing major rheological disorders, which presents clinically as periodic vaso-occlusive crises, chronic haemolysis and chronic vascular dysfunction. Patients often resort to a background treatment, and transfusion remains the cornerstone in the management of the disease, significantly reducing morbidity and mortality. The aim of red blood cell exchange (RBCX) is to improve tissue oxygenation by increasing haemoglobin levels while lowering HbS levels. RBCX can be performed by manual or automated exchange, and each technique has its own set of advantages and disadvantages. This article will outline the transfusion indications for the main complications of SCD, as well as the most appropriate strategy to use.

Limited Exchange Transfusion Can Be Very Beneficial in Sickle Cell Anemia with Acute Chest Syndrome: A Case Report from Tanzania

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD) with blood transfusion an integral part in its management. Red cell exchange (RCE) transfusion is usually regarded as preferable to top-up transfusion, because it reduces the proportion of Hemoglobin (Hb) S while at the same time avoiding circulatory overload. Despite its obvious benefits, RCE is underutilized, particularly in low-resource settings which may be due to scarcity of blood products and of expertise in carrying out exchange transfusion. We report on a young woman with SCD with severe ACS who responded promptly and dramatically to a RCE of only 0.95 L (instead of the recommended 1.4 L) and had in the end an HbS level of 48% (instead of the recommended level below 30%). Limited RCE resulted in significant clinical improvement. We suggest that limited RCE may be of benefit than no RCE in SCD patients with ACS, particularly in settings where RCE is not available.