Each year, the CSTM conference scientific committee receives over a hundred abstracts to review for presentation the annual conference. The team preparing for the Montreal conference in 2023 brought forward the best in new transfusion medicine knowledge for conference participants and, from those, the top submissions were selected. Each year, the
top submissions are shared in Transfusion Medicine Reviews.
Here is a recap from the 2023 CSTM Conference Abstract Book of those top abstracts.
Abstracts for the 2024 Saskatoon conference are being reviewed now, and we can’t wait to see what we learn this year.
Addressing disparities in blood, stem cell, and organ & tissue donor pools: A mixed- methods evaluation of a workshop to guide medical students’ development as health advocates through advancing equity across donation products for racialized peoples
Abstract Author Names : Sylvia Okonofua
1 * ^, Murdoch Leeies
2 , Matthew Yan
3 , Biba Tinga
4 , Jennie Haw
5 , Warren Fingrut
6
Abstract Summary :
Introduction: Health advocacy is an important skill for medical students to develop, but is challenging to teach. Here, we describe the development and evaluation of a workshop to support Canadian medical students to develop as health advocates through advancing health equity across donation products for racialized peoples.
Methods: We developed a workshop for a Canadian medical school audience, "Addressing racial disparities in blood, stem cell, and organ and tissue donor pools" consisting of an online module followed by a virtual facilitated discussion group. The online module (available at stemcellclub.ca/training) outlined disparities in donor pools across donation products, barriers to donation impacting racialized/ ethnic populations, and structural racism in donation policies (i.e. policies which disproportionately impact racialized/ ethnic peoples). The module also presented content from a national campaign in Canada to engage Black peoples to donation (stemcellclub.ca/BlackDonorsSaveLives). The discussion group supported participants to reflect on how they can help overcome these challenges. Quantitative and qualitative analyses (using a constructivist grounded theory approach) were employed to evaluate participants' perspectives on the impact of the workshop on their development as health advocates.
Results: From 01/2023-03/2023, workshops were hosted at 9 Canadian medical schools, with 30 medical students participating (80% female; 70% from racialized populations; 66% pre-clerkship). Overall, 97% strongly agreed/agreed the workshop supported their development as health advocates, including the abilities to: advocate for patients beyond the clinical environment (83%); work with patients (87%) and communities (73%) to address and identify determinants of health that affect them; apply a process of continuous quality improvement to health promotion (83%); and contribute to a process to improve the health of a community (100%). All felt the workshop should be incorporated into the medical school curricula. Qualitative analysis identified rich examples of participants' development as health advocates through their participation in the workshop, including through identifying the need to prioritize inclusion; recognizing discrimination; understanding barriers to change; addressing disparities in collaboration with advocates; and building a culture to support inclusion.
Conclusion: We present the perspective of a national cohort of Canadian medical students that their participation in a workshop on advancing health equity across donation products for racialized peoples contributed to their development as health advocates. This workshop is a model for teaching health advocacy to medical students and is relevant to medical educators and curriculum developers.
Acknowledgements: We acknowledge funding from Canadian Blood Services BloodTechNet Award, Canadian Federation of Medical Students, and Doctors of BC.
RBC alloimmunization risk following transfusion in immune checkpoint inhibitor therapy patients.
Abstract Author Names : Lianne Rotin
1 * ^, Wenzie Ng
2 , Bailie Jones
3 , Brian Marsell
4 , Marcus Butler
5 , Christine Cserti-Gazdewich
6
Abstract Summary :
Introduction: Immune checkpoint inhibitors (ICIs) are cancer therapies that enable tumour cell targeting by a patient's own immune system. They also trigger non-specific immune system activation with adverse autoimmune events. After identifying 3 RBC alloimmunization events in a 6-month span in ICI recipients at our institution, we noted the absence of evidence on estimates of this particular risk, or guidance on best blood matching practices for this growing population.
Objective: To systematically evaluate contextual RBC alloimmunization rates in ICI treatment in order to potentially inform prophylactic matching practices.
Methods: All patients at our academic adult cancer centre, receiving at least one dose of ICI (programmed death 1 [PD1] inhibitors: pembrolizumab, nivolumab, durvalumab, atezolizumab, avelumab, cemiplimab; or cytotoxic T-lymphocyte antigen 4 [CTLA4] inhibitors: ipilimumab and tremelimumab), July 2018-June 2022, were included. Data on date, type, and number of ICI doses for each patient were extracted. Number of RBC transfusions, transfusion dates, antibody screen dates, and antibody screen results (positive vs. negative) were extracted from the laboratory information system (WellSky). Patients with positive screens were grouped based on timing of positive screen in relation to ICI and transfusion exposures. The Z-test was used to compare positive antibody screen rates between transfused and non-transfused ICI patients.
Results: Over a 4-year period, 2075 unique patients were treated with ICIs. Among these, 1315 underwent antibody screening, 616 (46.8%) of whom received at least 1 RBC transfusion on site. A total of 30 patients had positive antibody screens, with 21 (70%) screening-positive after ICI exposure, and 8 occurring after both ICI and recent RBC transfusion. Another 8 screened positive prior to any ICI exposure, with transfusion history absent in 5 and present in 3. One patient was excluded due to unclear timing of ICI exposure in relation to positive antibody screen. Using a 2-tailed Z-test, there was no significant difference between the proportion of positive screens in transfused vs. non-transfused ICI patients (8/616 [1.3%] vs. 5/699 [0.7%], z=-1.067, p=0.28).
Conclusions: In this preliminary analysis, there was no statistically significant difference in alloimmunization according to the known transfusion status of patients treated with ICI. A limitation of this low-frequency finding is the assessed sample size to date. While our laboratory policy has not precautionarily changed on its depth-of-matching for this subpopulation, we recommend ongoing surveillance of alloimmunization events to assess for shifts in their scale and significance.
Under-reporting of transfusion associated circulatory overload (TACO) in cardiology units at a large center
Abstract Author Names : Natasha Le Blanc
1 * ^, Anne-Sophie Lemay
2 , Benjamin Rioux-Masse
3 , Bertrand Routy
4 , Veronique Cyr
5 , Claudia Bouchard
6
Abstract Summary :
Introduction: The incidence of transfusion-associated circulatory overload (TACO) ranges from 1% to 12% and is the leading cause of transfusionassociated mortality. TACO remains under-reported by medical teams due to lack of recognition, attribution of overload to other patient risk factors or to an alternative diagnosis of volume overload. The aim of this study was to determine the actual incidence of TACO in patients hospitalized in cardiology units.
Methods and Design: A retrospective chart review study was conducted among 161 patients hospitalized in cardiology (cardiac ICU and ward) who received at least one blood component between May 1, 2021, and April 30, 2022. Cryoprecipitates were excluded. The primary objective was to establish the true incidence of TACO according to the ISBT 2018 definition. The secondary objective was to evaluate and compare the prevalence of the various known risk factors of patients that developed TACO.
Results: Among 320 transfusion episodes that occurred in 161 patients included in the study, only one TACO was officially reported while 25 episodes were identified by chart review (incidence by passive reporting 0.3%, actual incidence 7.8%; p = 0.001). Of these TACOs, 5 (20%) were classified as life threatening, 5 (20%) as severe, 15 (60%) as non-severe, and all occurred following transfusion of red blood cell components. In 44% of cases, the nursing staff didn't recognize the signs of TACO nor notify the medical team. Diuretics were prescribed prophylactically in 31% of cases without TACO versus 20% of patients with TACO (p=0.24). In TACO patients, double-unit transfusion occurred in 12% versus 7.5% without TACO (p=ns). Pre-transfusion hemoglobin level was superior to 80 g/L in 24% of TACO patients compared to 17% in patients without TACO (p=ns). We didn't find any statistically significant association between the prevalence of known risk factors including age, heart failure (with or without preserved left ventricle ejection fraction), creatinine, transfusion rate or volume (p =ns) and the occurrence of TACO.
Conclusion: TACO is under-reported in patients admitted in cardiology with an actual incidence reaching 8%. While numerical differences were observed for TACO transfusion-related risk factors (diuretics usage, number of units, lesser restrictive transfusion strategy), none of these were statistically significant, but the study was probably underpowered to evaluate this aspect. Nevertheless, this study will help guide interventions with medical teams to increase awareness, optimize reporting and explore prevention strategies.
A Negligible Impact of Real-World Transient Warming Exposures on the Quality of Cryopreserved Red Cell Concentrates
Abstract Author Names : Jayme Kurach 1 * ^, Carly Olafson 2 , Mackenzie Brandon-Coatham 3 , Tracey Turner 4 , Gwen Clarke 5 , Jason Acker 6
Abstract Summary :
Introduction: In North America, red cell concentrates (RCCs) are cryopreserved using a high glycerol (40%) method, which allows for long-term storage (~ 30 years) at temperatures below -65 °C. Freezer failures, human errors, or routine inventory management are all unintentional ways stored units may be warmed above -65 °C. These transient warming events (TWEs) may cause unwanted cell damage due to ice recrystallization. The aim of this study was to assess if cryopreservation protocols, that incorporate high glycerol concentrations, provide protection to cryopreserved red blood cells (RBCs) against instances of RCC unit temperature fluctuations.
Design and Methods: Thirty previously cryopreserved RCCs, documented as having experienced at least one TWE, were selected and classified according to exposure event: (1) > -65 °C for 34 minutes (n=5), (2) > -65 °C for approximately 2 days reaching a peak temperature of -30 °C (n=23), and (3) exposure to both Event 1 and Event 2 (n=2). Ten previously cryopreserved RCCs documented as having no TWE were selected as controls. All RCCs were thawed (37 °C), deglycerolized and resuspended in AS-3 using the ACP 215 Cell Processor. Units were stored hypothermically and tested at 0, 1, 7, and 14 days post-deglycerolization for RBC quality using an extensive panel of in vitro tests, including hemoglobin (Hb) content, RBC hemolysis, adenosine triphosphate (ATP), RBC indices, and RBC deformability. Multiple group comparisons were performed using Sidak's multiple comparisons test. Results: When compared to RCC units having experienced no TWEs, the quality of RCCs exposed to one or two authentic TWEs was not significantly different over 14 days of hypothermic storage. Furthermore, all RCCs met CSA specifications for transfusion at all time points.
Conclusion: Our results indicate that isolated exposures to genuine TWEs did not significantly impact the quality of RCCs postdeglycerolization. Further assessments and validation will need to be undertaken by blood centers to determine the impact of the frequency and duration of TWEs on product quality to help define more evidence-based criteria. With these criteria, blood centers could retain these valuable and potentially rare RCCs that current blood inventory management strategies require to be discarded after even one exposure to storage temperatures warmer than -65 °C.
Acknowledgments: This research received funding support from Canadian Blood Services Blood Efficiency Accelerator Program. We are grateful to Canadian Blood Services' blood donors who made this research possible.