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.

Therapeutic plasma exchange for neuromyelitis optica spectrum disorder: A multicenter retrospective study by the ASFA neurologic diseases subcommittee.

IMPORTANCE: Neuromyelitis optica/neuromyelitis optica spectrum disorder patients' response to therapeutic plasma exchange (TPE) is currently incompletely characterized. OBJECTIVE: Our study aims to understand the clinical status improvement of neuromyelitis optica/neuromyelitis optica spectrum disorder patients treated with TPE. DESIGN, SETTING, AND PARTICIPANTS: This is a multicenter retrospective study conducted between 1 January 2003 and 31 July 2017 at 13 US hospitals performing apheresis procedures. Subjects studied were diagnosed with neuromyelitis optica/neuromyelitis optica spectrum disorder who received TPE during presentation with acute disease. MAIN OUTCOMES AND MEASURES: The primary outcome was clinical status improvement in patients treated with TPE. Secondary measures were procedural and patient characteristics associated with response to treatment. RESULTS: We evaluated 114 patients from 13 institutions. There was a female predilection. The largest ethnic group affected was non-Hispanic Caucasian. The average age of diagnosis was 43.1 years. The average time to diagnosis was 3.1 years. On average, five procedures were performed during each treatment series. The most commonly performed plasma volume exchange was 1.0 to 1.25 using 5% albumin as replacement fluid. Most patients (52%) did not require an additional course of TPE and noted "mild" to "moderate" clinical status improvement. Maximal symptom improvement appeared by the fourth or fifth TPE treatment. CONCLUSION AND RELEVANCE: TPE improved the clinical status of patients. Adults responded more favorably than children. Procedural characteristics, including number of TPEs, plasma volume exchanged, and replacement fluid used, were similar between institutions. TPE was well-tolerated and had a low severe adverse event profile.

The sex parameter in estimation of total blood volume for pediatric erythrocytapheresis.

BACKGROUND AND OBJECTIVES: Estimation of the total blood volume (TBV) is fundamental to the control of automated red cell exchange (RCE). Error in the TBV estimate can produce outcomes that deviate from the prescribed targets, and may endanger the patient. Both the Spectra Optia and the COBE Spectra use the Nadler formulae to estimate TBV. There is a potential for large overestimates of TBV when the Nadler formula for males is applied to prepubertal boys. MATERIALS AND METHODS: This study uses our large clinical experience with RCE to examine procedure outcomes when RCE in prepubertal boys is programed with the female parameter instead of male. We determined the differences between programmed and measured values for three outcomes: (a) Programmed End Hematocrit - Post spun HCT by Hemata Stat II, (b) Programmed End Hematocrit - Post CBC HCT, and (c) Predicted Post Hgb S+C - Measured Post Hgb S+C. We defined the experimental group as Male-Female, where the biological sex was male but programmed sex was female, and two control groups where programmed and biological sex were the same. RESULTS: Small but statistically significant differences were demonstrated between the mean programmed-to-observed deviations of these outcome measures in all but two group and subgroup comparisons; however, the absolute magnitudes of the observed differences were not clinically significant. The suggested weight cutoff to begin programming males as male is 35 kg. CONCLUSION: The study provides experiential validation that performing RCE in prepubertal boys using the female parameter is safe.

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

The American Society for Apheresis (ASFA) conducted a one-day consensus conference on red blood cell exchange (RBCx) in sickle cell disease (SCD) during its annual meeting in San Antonio, TX, on May 5, 2015. The authors of this article, a subcommittee of ASFA's Clinical Applications Committee, developed several questions with regard to pathophysiology of SCD and use of RBCx in the management of various complications. These questions were provided to the seven invited speakers who are the experts in the field of SCD. Two experts in the field moderated the proceedings of the conference, which was attended by more than 150 participants. After each presentation, there was a summary of the main points by the moderators and an open discussion with questions from the audience. A video recording of the proceedings, as well as each presentation, was made available to the authors. Each author's summary was reviewed and approved by the respective speaker before submission of this manuscript. The subcommittee also developed several key questions to generate a consensus amongst the speakers on key issues for using RBCx for patients with SCD.

Report of the ASFA apheresis registry on muscle specific kinase antibody positive myasthenia gravis.

BACKGROUND: Anti-muscle specific kinase antibody positive (MuSK Ab) myasthenia gravis (MG) patients are known to have different clinical course compared to anti-acetylcholine receptor Ab positive MG patients. Therapeutic plasma exchange (TPE) has been reported to be effective; however, little is known of the response and of TPE procedural information. An ASFA Apheresis Registry was developed to analyze those data. METHODS: The study collected detailed de-identified patient data, TPE procedures, and treatment outcome/complications. Collected data was described in aggregate. RESULTS: A total of 15 MuSK Ab MG patients with exacerbation of MG symptoms, 13 females/2 males, median age 44, were investigated. Thirty TPE courses (median 5 procedures/course, total 145 procedures) were evaluated. All TPE procedures were performed with citrate anticoagulation, 1 - 1.25 plasma volume exchange in 100% fluid balance, and 90% of courses used only albumin as replacement. Calcium was added to albumin or given orally as needed. TPE was performed every other day in 55% of courses. Adverse events occurred in 3.4% of procedures. Ten patients (67%) experienced relapses within a median of 7 weeks. Objective symptoms were resolved in more than 75% of courses. Overall subjective improvement rates were 94.1%/93.3% after 3/4 TPE procedures, respectively. Thirty-one percent of patients responded poorly with minimal recovery. CONCLUSION: Overall subjective improvement was seen up to 94% of patients after one course of TPE. Some patients were poor-responders. Five TPE may be adequate for initial course with additional TPE as needed. Based upon this preliminary data, we will modify our future data collection. J. Clin. Apheresis 32:5-11, 2017. © 2016 Wiley Periodicals, Inc.

Extracorporeal photopheresis practice patterns: An international survey by the ASFA ECP subcommittee.

BACKGROUND: Although many apheresis centers offer extracorporeal photopheresis (ECP), little is known about current treatment practices. METHODS: An electronic survey was distributed to assess ECP practice internationally. RESULTS: Of 251 responses, 137 met criteria for analysis. Most respondents were from North America (80%). Nurses perform ECP at most centers (84%) and the majority of centers treat adults only (52%). Most centers treat fewer than 50 patients/year (83%) and perform fewer than 300 procedures/year (70%). Closed system devices (XTS and/or Cellex) are used to perform ECP at most centers (96%). The most common indications for ECP are acute/chronic skin graft versus host disease (89%) and cutaneous T-cell lymphoma (63%). The typical wait time for ECP treatment is less than 2 weeks (91%). Most centers do not routinely perform quality control assessment of the collected product (66%). There are device-specific differences in treatment parameters. For example, XTS users more frequently have a minimum weight limit (P = 0.003) and use laboratory parameters to determine eligibility for treatment (P = 0.03). Regardless of device used, the majority of centers assess the clinical status of the patient before each procedure. Greater than 50% of respondents would defer treatment for hemodynamic instability due to active sepsis or heart failure, positive blood culture in the past 24 h or current fever. CONCLUSION: This survey based study describes current ECP practices. Further research to provide evidence for optimal standardization of patient qualifications, procedure parameters and product quality assessment is recommended.

Report of the ASFA apheresis registry study on Wilson's disease.

PURPOSE: Wilson's disease is a rare autosomal recessive genetic disorder that results in accumulation of copper in the liver, brain, cornea and kidney. Therapeutic plasma exchange (TPE) has been used to remove copper and provide a bridge to liver transplantation. We report here the collective experiences through the ASFA apheresis registry on Wilson's disease. METHODS: The ASFA apheresis registry is a multi-center registry study. Both prospective and retrospective data, with the latter involving data collection back to January 2000 are entered in the registry. The registry includes patient demographics, apheresis procedural information, treatment schedules, and treatment outcomes and complications. RESULTS: A total of 10 patients (3 males and 7 females) with Wilson's disease treated between 2005 and 2013 were included. Median age of first diagnosis and first TPE were 16 and 17 years, respectively. Via central venous access, these patients underwent a total of 43 TPEs; the median number of TPE procedures per patient was 3.5. All of the TPEs used ACD-A as anticoagulation, 42/43 TPEs targeted 1-1.25 plasma volumes, and 41/43 TPEs were performed with 100% fluid balance. Post TPE procedures, 9 patients underwent liver transplantation; all 10 patients had at least a 6-month survival. CONCLUSIONS: All 10 patients with Wilson's disease who underwent TPE had a positive outcome in terms of 6-month survival. In this first report of the ASFA apheresis registry study, we have demonstrated the value of using this registry to collect apheresis-related patient outcomes from multiple centers.

Venous access for hematopoietic progenitor cell collection: An international survey by the ASFA HPC donor subcommittee.

PURPOSE: Hematopoietic Progenitor Cell (HPC) collection by apheresis is performed in patients and donors to obtain HPCs for transplantation. Although studies have shown these procedures to be safe, successful collection cannot be performed without establishment of venous access. This project's objective was to ascertain the current practices of donor vein assessment and central venous catheter (CVC) usage. METHODS: The American Society for Apheresis (ASFA) HPC subcommittee created an electronic survey about precollection vein assessment and line placement, care, and removal in autologous and allogeneic donors. It was distributed to >5,000 possible participants, with one response analyzed per institution. RESULTS: One hundred centers performing autologous and/or allogeneic procedures provided adequate responses for analysis. Donor vein assessment is most often performed by apheresis staff more than 1 week prior to collection. For patients with questionable access, the next step performed most often is secondary assessment for autologous procedures and CVC placement for allogeneic procedures. Most centers use interventional radiology to place CVCs in jugular veins on collection day with placement verification through electronic medical records. Verbal and written postinsertion CVC care instructions are routinely provided. The apheresis team frequently provides postinsertion CVC care for autologous patients. Heparin is used most often for CVC lock. When used, tissue plasminogen activator is usually instilled for up to 60 min. CONCLUSION: These data summarize the largest single survey of donor vein assessment at institutions performing HPC collections by apheresis. The variations identified in donor venous access practice warrant further investigation and consensus to establish best practices. J. Clin. Apheresis 31:529-534, 2016. © 2015 Wiley Periodicals, Inc.

An international survey of pediatric apheresis practice.

INTRODUCTION: Pediatric apheresis (PA) has distinct characteristics compared to adult apheresis, and requires specialized knowledge and experience to perform safely, particularly in low-weight patients. As evidence-based medicine advances the field of therapeutic apheresis, increased attention must be paid to pediatric patients with conditions for which apheresis is indicated. METHODS: An electronic survey of >5,000 potential participants throughout the world was conducted to ascertain the scope and the current state of practice. RESULTS: The survey elicited 159 responses from 12 countries; 107 of the responses provided sufficient information for analysis. Participants performed an average of 176 PA procedures/year (range: 1-2,000). The types of PA procedures were therapeutic plasma exchange (92% of centers), red cell exchange (86%), leukocyte depletion (87%) and peripheral blood hematopoietic progenitor cell collection (72%). More than 65% of the centers had treated children older than 5 years with PA. Many centers had also performed PA on younger children; 40% have treated patients <12 months of age; 61% had treated patients 1-5 years old. 36% of centers reported that they would perform apheresis regardless of patient weight; 18% used a 5 kg threshold, 11% used 5-10 kg, and 17% used 10 kg as their weight threshold. CONCLUSION: This report is the largest single survey of centers performing PA. The results provide information about the scope and diversity of PA and identify areas where considerable variability in practice exists. Further exploration of these differences could establish best practices in PA through international research and collaboration.

Measures to reduce red cell use in patients with sickle cell disease requiring red cell exchange during a blood shortage.

The COVID-19 pandemic has created major disruptions in health care delivery, including a severe blood shortage. The inventory of Rh and K antigen-negative red cell units recommended for patients with hemoglobinopathies became alarmingly low and continues to be strained. Because patients with sickle cell disease requiring chronic red cell exchange (RCE) incur a large demand for red cell units, we hypothesized that implementation of 2 measures could reduce blood use. First, obtaining the pretransfusion hemoglobin S (HbS) results by procedure start time would facilitate calculation of exact red cell volume needed to achieve the desired post-RCE HbS. Second, as a short-term conservation method, we identified patients for whom increasing the targeted end procedure hematocrit up to 5 percentage points higher than the pretransfusion level (no higher than 36%) was not medically contraindicated. The goal was to enhance suppression of endogenous erythropoiesis and thereby reduce the red cell unit number needed to maintain the same target HbS%. These 2 measures resulted in an 18% reduction of red cell units transfused to 50 patients undergoing chronic RCE during the first 6 months of the COVID-19 pandemic. Despite reduction of blood use, pretransfusion HbS% target goals were maintained and net iron accumulation was low. Both strategies can help alleviate a shortage of Rh and K antigen-negative red cells, and, more generally, transfusing red cell units based on precise red cell volume required can optimize patient care and judicious use of blood resources.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis.

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Alternative method to determine the hematocrit of red blood cell units: a potential use in the apheresis unit.

BACKGROUND: In automated erythrocytapheresis procedures, achieving the desired-end hematocrit (Hct) requires that the COBE Spectra (CaridianBCT) machine be programmed with the mean Hct of the replacement red blood cell (RBC) units. To determine unit Hct, data derived from quality control (QC) Hct data were utilized. However, if a unit volume is outside the quality control (QC) volume parameters, the unit is accessed to measure its Hct. In this study, 21 percent of all RBC units need to be accessed to determine the Hct, which affects 47.5 percent of patient's erythrocytapheresis procedures. Spiking the unit compromises its integrity and hastens the expiration time of the unit. Nurses must wait until the patient arrives to check units outside QC parameters, thereby delaying the start time of procedures. Even if sampled units are kept refrigerated, they cannot be returned to the blood bank inventory once spiked. The goal of this study was to determine if accurate Hct levels from RBC units could be obtained from a unique segment. STUDY DESIGN AND METHODS: To determine the centrifuged Hct, samples were prepared from the RBC units and compared to that of the unique segment. RESULTS: The Hct of the unique segment exceeded that of the RBC unit by a small (1.2% in AS-1 units, 0.92% in AS-3 units), but statistically significant amount. CONCLUSION: The Hct from unique RBC segments closely approximates that of the original RBC unit. Unique segments can be made that will maintain the integrity and shelf life of RBC units.

Red cell exchange: special focus on sickle cell disease.

The primary function of red blood cells (RBCs) is to deliver oxygen from the lungs to tissues. Tissue hypoxia occurs when the oxygen-carrying capacity of RBCs is compromised due primarily to 3 causes: (1) a reduction in circulating RBC mass, (2) an increase in circulating RBC mass, or (3) abnormal hemoglobin (Hb) that either does not sufficiently release oxygen to tissues (high-oxygen-affinity hemoglobin) or occludes the microvasculature due to deformed RBCs (sickled RBCs). To improve oxygenation in patients with reduced or increased RBC mass, RBC administration (simple transfusion) or RBC removal (RBC depletion) is performed, respectively. However, for patients with abnormal Hb, RBCs containing abnormal Hb are removed and replaced by healthy volunteer donor RBCs by red cell exchange (RCE). RCE can be performed by manual exchange or by automated exchange using a blood cell separator (erythrocytapheresis). In this review, indications for RCE in sickle cell disease using the evidence-based American Society for Apheresis categories(1) are presented and the rationale for RCE in each disorder are discussed. Simple transfusion versus RCE and manual RCE versus automated RCE are compared. Finally, this review briefly presents some of the challenges of performing erythrocytapheresis in small children and discusses various choices for central venous access during RCE.(2.)

Use of laboratory tests to guide initiation of autologous hematopoietic progenitor cell collection by apheresis: results from the multicenter hematopoietic progenitor cell collection by Apheresis Laboratory Trigger Survey.

Limited literature describes the value of laboratory "triggers" to guide collection of peripheral blood (PB) hematopoietic progenitor cells (HPCs) by apheresis [HPC(A)]. We used a web-based survey to determine which parameters are used to initiate autologous HPC(A) collection in adult and pediatric patients and to identify common practice patterns. Members of the AABB Cellular Therapy Product Collection and Clinical Practices Subsection and the American Society for Apheresis HPC Donor Subcommittee drafted and developed relevant survey questions. A web link to the survey was distributed by electronic newsletter or email. Responses from 67 programs that perform autologous HPC(A) collections, including academic medical centers (n = 46), blood centers (n = 10), community hospitals (n = 5), and a variety of other medical institutions (n = 6), were analyzed. Ninety-three percent (62/67) of programs used a laboratory parameter to initiate HPC(A) collection. In both adult (40/54, 74%) and pediatric (29/38, 76%) patients, the PB CD34+ cell count was the most common parameter used to initiate HPC(A) collection. The median PB CD34+ trigger value was 10/µL for both patient populations. Among centers routinely using the PB CD34+ cell count to initiate apheresis, 51% (22/43) first sent the test before the patient presented for collection. Although more than 90% of centers used a laboratory test to trigger apheresis in cytokine-mobilized (44/48) or chemomobilized patients (50/53), only 57% (30/53) used a laboratory trigger if the patient was mobilized with granulocyte colony-stimulating factor plus plerixafor. Forty-two percent (21/50) of programs that routinely measured the PB CD34+ count before collection and discontinued further HPC(A) collection based on product CD34+ cell yield also stopped if the PB CD34+ value before apheresis was considered too low to proceed. Most programs use the PB CD34+ cell count to trigger autologous HPC(A) collection. Some centers also use this parameter to stop further collections. Laboratory tests are used less frequently to initiate apheresis when patients are mobilized with plerixafor. These data reveal ongoing diversity in clinical practices and suggest that consensus guidelines on use of laboratory parameters may further optimize HPC(A) collection.

Category IV indications for therapeutic apheresis: ASFA fourth special issue.

The American Society for Apheresis (ASFA) Committee on Clinical Applications systematically and critically reviews published information on the use of therapeutic apheresis in clinical practice. On the basis of this review, selected diseases are assigned one of five categories (category I, II, III, IV, and P). The diseases, which were classified as category IV indications, and the rationale for such assignment are reviewed in this article. The diseases assigned to category I, II, III, and newly created category P are discussed in a separate article in this issue.

Guidelines on the use of therapeutic apheresis in clinical practice: evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis.

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.