Automated Red Cell Exchange in the Management of Sickle Cell Disease

Red blood cell utilization in patients with sickle cell disease: A Canadian single-center experience

BACKGROUND

Red blood cell (RBC) utilization in patients with sickle cell disease (SCD) in Canada is poorly defined. This study describes RBC utilization in an SCD cohort at a single Canadian center.

STUDY DESIGN AND METHODS

All adults with SCD who received care at the Ottawa Hospital between January 2006 and May 2019 were included, and followed until December 2021. Data on hospital encounters and RBC transfusions were obtained from hospital databases.

RESULTS

Overall, 273 patients were included (median age: 25 years; 53.8% female; median follow-up: 8.1 years). During the study period, there were 23,127 hospital encounters (median: 45 [interquartile range (IQR) 18, 100] per patient), with 165 patients (60.4% of cohort) receiving 22,538 RBC units. Most RBC units (86.5%) were transfused in the outpatient setting. Although only 2.9% of patients had O-negative blood type, O-negative RBC units accounted for 29.1% of units transfused. One hundred forty-seven patients received 2205 RBC units (9.8% of total) as simple transfusions (median: 5 [IQR 3, 13] per patient), and 88 patients received 20,333 RBC units (90.2% of total) during 2702 red cell exchange (RCE) sessions (median: 14.5 (IQR 1, 47.5) RCE per transfused patient). A median of 7 RBC units (IQR 6, 9) were transfused per RCE session, with a median of 30 days (IQR 28, 40) between sessions.

DISCUSSION

Patients with SCD at our center frequently received O-negative units, and large RBC volumes were used for RCE. These results provide a utilization baseline for future education and quality improvement initiatives to optimize RBC stewardship.

Quality of life in people with sickle cell disease treated with automated red blood cell exchange

BACKGROUND AND OBJECTIVES

This review aims to explore the impact of sickle cell disease (SCD) on patients' quality of life (QoL) and the effectiveness of different transfusion modalities, particularly automated red blood cell exchange (aRBCX), in managing the factors that impact QoL.

MATERIALS AND METHODS

A systematic search was performed in PubMed to retrieve articles with data on QoL in SCD patients treated with aRBCX during the last 20 years. A targeted search for medical guidelines and a free search were added.

RESULTS

When assessing the impact of the transfusion modality on the QoL of patients with SCD, some studies indicated an improvement in health-related QoL when using aRBCX while others reported no differences. The benefits of aRBCX include a decrease in length of hospital stay, pain-related hospitalizations and procedure time. The drawbacks of aRBCX were also identified, including an increased number of procedure-related complications (despite the overall number of complications showing no significant differences) and a more complex vascular access. Chronic red blood cell exchange favours psychosocial factors such as anxiety and social functioning, but the impact of using aRBCX in these parameters is not determined yet.

CONCLUSION

aRBCX, known to be an efficient procedure to manage SCD, appears to be promising in improving patients' QoL. However, more comprehensive studies incorporating patient-reported outcomes are needed to fully understand the impact of different transfusion modalities on QoL in SCD patients. An integrated care approach, including psychological support and pain management, may further enhance QoL.

Physician perspectives about the diagnosis and management of acute chest syndrome

BACKGROUND

Acute chest syndrome (ACS) is the leading cause of mortality, accounting for 25% of all deaths among individuals with sickle cell disease (SCD). There is a lack of evidence-based laboratory and clinical risk stratification guidelines for the diagnosis and management of ACS.

STUDY DESIGN AND METHODS

To better understand physician practices for the management of ACS in the United States, we created an ACS Working Group including hematology and transfusion medicine physicians from four different SCD treatment centers in the United States. The working group created a physician survey that included physician demographics and ACS diagnostic criteria that they had to rate. The survey also included three case scenarios to assess physician attitudes about the management of ACS. Management options included supportive and preventive strategies in addition to transfusion therapy options.

RESULTS

Out of 455 physicians who received the survey, 195 responded (response rate = 43%). The respondents were primarily hematology/oncology physicians. The responses showed wide variability among physicians in how diagnostic criteria for ACS are used and how physicians risk-stratify ACS patients in their practice. The responses also reflected variability in the use of transfusions for ACS.

DISCUSSION

Based on our results, we conclude that ACS is diagnosed and managed inconsistently among expert physicians, especially in their transfusion practices due to a lack of consensus on risk stratification criteria. Our data suggest an urgent need for well-designed prospective studies to provide evidence-based guidelines and minimize management variability among physicians who care for individuals with SCD and ACS.

Iron metabolism in sickle cell disease patients undergoing chronic red blood cell exchange: A delicate homeostasis in balance

Sickle cell disease (SCD) is an inherited haemoglobinopathy associated with significant morbidity and mortality. Automated red blood cell exchange (aRCE) plays a key role in managing SCD, eliciting both therapeutic and prophylactic effects. The ideal post-apheresis Ht target for chronic aRCE treatment is not yet unanimously recognized, as well as iron homeostasis can be different among patients. Ross et al. reported their experience on the chronic management of SCD patients undergoing aRCE with a final post-exchange Ht higher than the value commonly adopted, analysing red blood cell transfusion requirements and iron-related outcomes in the study population. Commentary on: Ross et al. Automated red blood cell exchange with a post-procedure haematocrit targeted at 34% in the chronic management of sickle cell disease. Br J Haematol 2024; 205:1556-1564.

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.

To exchange or not exchange: That is the question

See article on page 1509–1519, in this issue

Chronic automated red cell exchange therapy for sickle cell disease

BACKGROUND

The data to support chronic automated red cell exchange (RCE) in sickle cell disease (SCD) outside of stroke prevention, is limited, especially in adults.

STUDY DESIGN AND METHODS

A retrospective analysis was conducted of patients with SCD who were referred for chronic RCE at our institution over a 10-year period. Data that were evaluated included patient demographics, referral indications, and procedural details (e.g., vascular access, adverse events, etc.). In a subanalysis, the number of annual acute care encounters during 3 years of chronic RCE was compared with that in the year preceding the first RCE.

RESULTS

A total of 164 patients were referred for chronic RCE: median age was 28 years (interquartile range [IQR] = 22-36) at referral and 60% were female. Seventy (42.6%) were naïve to chronic transfusion (simple or RCE) prior to referral. The leading indications for referral were refractory pain (73/164, 44.5%) and iron overload (57/164, 34.7%). A total of 5090 procedures occurred during the study period (median = 19, IQR = 5-45). Of the 138 patients who had central vascular access, 8 (6%) and 16 (12%) had ≥1 central-line-related thrombosis and/or infection, respectively. Of those who were not RBC alloimmunized at initiation of RCE, 12/105 (11.4%) developed new antibodies during chronic RCE. In those 30 patients who were adherent to therapy for 3 years, there was no significant difference in acute care encounters following initiation of RCE.

CONCLUSION

Prospective clinical trials are needed to determine which patients are most likely to benefit from chronic RCE and refine selection accordingly.

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.

Emergency red cell exchange for the management of acute complications in sickle cell disease: Automated versus manual

BACKGROUND

Red blood cell exchange is the cornerstone of the management for acute complications of sickle cell disease. It improves anaemia and improvesperipheral tissue oxygen delivery while at the same time reduces the proportion of circulating sickle erythrocytes. Even though automated red cell exchange is very effective in rapidly lowering the Hb S level, 24-h availability is currently not feasible for most specialist centres including our own.

OBJECTIVE

Here, we describe our experience using both automated and manual red cell exchange for the management of acute sickle cell complications.

METHODS

Eighty-six such episodes have been recorded between June 2011 and June 2022 comprising of 68 episodes of automated and 18 episodes of manual red cell exchange.

RESULTS

The post procedure Hb S/S + C level was 18% after automated and 36% after manual red cell exchange. The platelet count dropped by 41% and 21% after automated and manual red cell exchange respectively. The clinical outcomes including need for organ support, duration of stay in the intensive care unit and overall length of hospitalisation was comparable between the two groups.

CONCLUSION

In our experience, manual red cell exchange is a safe and effective alternative to an automated procedure that can be used while specialist centres are building up their capacity to offer automated red cell exchange for all patients requiring the intervention.

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.

Tocilizumab in the management of posttransfusion hyperhemolysis syndrome in sickle cell disease: The experience so far

BACKGROUND

Posttransfusion hyperhemolysis syndrome is a rare but life-threatening form of delayed hemolytic transfusion reaction with lysis of both transfused and autologous red cells, seen predominantly in patients with sickle cell disease. Macrophage activation is thought to play a major role in its pathophysiology. Standard treatment is with intravenous immunoglobulin and steroids but refractory cases pose a major clinical problem. Tocilizumab is a humanized monoclonal antibody against the IL-6 receptor that can inhibit IL-6 induced macrophage activation.

METHODS AND MATERIALS

We describe the case of a 33-year-old woman with sickle cell anemia and posttransfusion hyper hemolysis syndrome refractory to standard therapy, treated with Tocilizumab. We also review all cases reported in the literature where Tocilizumab was used for posttransfusion hyperhemolysis.

RESULTS

Treatment with Tocilizumab was well tolerated with no observed adverse events. There was no further drop in Hb after day 2 of treatment with subsequent continuous gradual improvement. Her bilirubin dropped significantly after the first dose and continued to improve, while ferritin and LDH reduced significantly after day 2 of treatment with Tocilizumab and continued to drop thereafter. Like in our case, all other cases in the literature where Tocilizumab was used for posttransfusion hyperhemolysis led to rapid clinical responses and no adverse events.

DISCUSSION

Even though the number of cases of posttransfusion hyper hemolysis syndrome treated with Tocilizumab are few, they have all been associated with rapid clinical responses with no observed adverse events suggesting that the role of Tocilizumab in this context needs to be further explored.

Sickle Cell Disease-Induced Pulmonary Hypertension: A Review of Pathophysiology, Management, and Current Literature

Sickle cell disease is an inherited hemoglobinopathy leading to the synthesis of hemoglobin S. Hemoglobin S results in the formation of abnormal sickle-shaped erythrocytes that lead to hematologic abnormalities such as hemolytic anemia and increased risks of thrombosis. Another particular problem encountered with the disease is pulmonary hypertension. The objective of this narrative review is to discuss the prevalence, pathophysiology mechanisms, diagnostic techniques, treatment options, and prognostic indicators in the setting of sickle cell disease with pulmonary hypertension. Additionally, the review also highlights other advancements that are being investigated. Considering the significant morbidity, mortality, and prevalence of pulmonary hypertension in patients with sickle cell disease, it is important to account for the aforementioned domains in the future guidelines to provide optimal and individualized care to the high-risk individuals as well as reduce the progression of disease, morbidity, and mortality rates.