Transfusion in orthopaedic surgery : a retrospective multicentre cohort study.

AIMS: Orthopaedic surgeries are complex, frequently performed procedures associated with significant haemorrhage and perioperative blood transfusion. Given refinements in surgical techniques and changes to transfusion practices, we aim to describe contemporary transfusion practices in orthopaedic surgery in order to inform perioperative planning and blood banking requirements. METHODS: We performed a retrospective cohort study of adult patients who underwent orthopaedic surgery at four Canadian hospitals between 2014 and 2016. We studied all patients admitted to hospital for nonarthroscopic joint surgeries, amputations, and fracture surgeries. For each surgery and surgical subgroup, we characterized the proportion of patients who received red blood cell (RBC) transfusion, the mean/median number of RBC units transfused, and exposure to platelets and plasma. RESULTS: Of the 14,584 included patients, the most commonly performed surgeries were knee arthroplasty (24.8%), hip arthroplasty (24.6%), and hip fracture surgery (17.4%). A total of 10.3% of patients received RBC transfusion; the proportion of patients receiving RBC transfusions varied widely based on the surgical subgroup (0.0% to 33.1%). Primary knee arthroplasty and hip arthroplasty, the two most common surgeries, were associated with in-hospital transfusion frequencies of 2.8% and 4.5%, respectively. RBC transfusion occurred in 25.0% of hip fracture surgeries, accounting for the greatest total number of RBC units transfused in our cohort (38.0% of all transfused RBC units). Platelet and plasma transfusions were uncommon. CONCLUSION: Orthopaedic surgeries were associated with variable rates of transfusion. The rate of RBC transfusion is highly dependent on the surgery type. Identifying surgeries with the highest transfusion rates, and further evaluation of factors that contribute to transfusion in identified at-risk populations, can serve to inform perioperative planning and blood bank requirements, and facilitate pre-emptive transfusion mitigation strategies. Cite this article: Bone Jt Open 2021;2(10):850-857.

Variation in prophylactic tranexamic acid administration among anesthesiologists and surgeons in orthopedic surgery: a retrospective cohort study.

PURPOSE: Tranexamic acid (TXA) reduces red blood cell transfusion in various orthopedic surgeries, yet the degree of practice variation in its use among anesthesiologists and surgeons has not been described. To target future knowledge transfer and implementation strategies, and to better understand determinants of variability in prophylactic TXA use, our primary objective was to evaluate the influence of surgical team members on the variability of prophylactic TXA administration. METHODS: This was a retrospective cohort study of all adult patients undergoing primary total hip arthroplasty (THA), hip fracture surgery, and spine fusion ± vertebrectomy at two Canadian hospitals between January 2014 and December 2016. We used Canadian Classification of Health Interventions procedure codes within the Discharge Abstract Database which we linked to the Ottawa Data Warehouse. We described the percentage of patients that received TXA by individual surgery, the specifics of TXA dosing, and estimated the effect of anesthesiologists and surgeons on prophylactic TXA using multivariable mixed-effects logistic regression analyses. RESULTS: In the 3,900 patients studied, TXA was most commonly used in primary THA (85%; n = 1,344/1,582), with lower use in hip fracture (23%; n = 342/1,506) and spine fusion surgery (23%; n = 186/812). The median [interquartile range] total TXA dose was 1,000 [1,000-1,000] mg, given as a bolus in 92% of cases. Anesthesiologists and surgeons added significant variability to the odds of receiving TXA in hip fracture surgery and spine fusion, but not primary THA. Most of the variability in TXA use was attributed to patient and other factors. CONCLUSION: We confirmed the routine use of TXA in primary THA, while observing lower utilization with more variability in hip fracture and spine fusion surgery. Further study is warranted to understand variations in use and the barriers to TXA implementation in a broader population of orthopedic surgical patients at high risk for transfusion.

RéSUMé: OBJECTIF: L'acide tranexamique (ATX) réduit la transfusion d'érythrocytes dans diverses chirurgies orthopédiques. Cependant, les variations de pratique quant à son utilisation parmi les anesthésiologistes et les chirurgiens n'ont pas été décrites. Afin de cibler les stratégies futures de transfert des connaissances et de mise en œuvre, et pour mieux comprendre les déterminants de la variabilité dans l'utilisation prophylactique d'ATX, notre objectif principal était d'évaluer l'influence des membres de l'équipe chirurgicale sur la variabilité de l'administration prophylactique d'ATX. MéTHODE: Il s'agissait d'une étude de cohorte rétrospective de tous les patients adultes subissant une arthroplastie totale primaire de la hanche (ATH), une chirurgie de fracture de la hanche et une fusion intervertébrale ± vertébrectomie dans deux hôpitaux canadiens entre janvier 2014 et décembre 2016. Nous avons utilisé les codes de procédure de la Classification canadienne des interventions en santé dans la Base de données sur les congés des patients, que nous avons liée à la banque de données d'Ottawa. Nous avons décrit le pourcentage de patients qui ont reçu de l'ATX par chirurgie individuelle, les détails du dosage de l'ATX, et avons estimé l'effet des anesthésiologistes et des chirurgiens sur l'ATX prophylactique en réalisant des analyses de régression logistique multivariées à effets mixtes. RéSULTATS: Parmi les 3900 patients étudiés, l'ATX était le plus fréquemment utilisé lors d'une ATH primaire (85 %; n = 1344/1582), avec une utilisation plus faible lors de chirurgie de fracture de la hanche (23 %; n = 342/1506) et de chirurgie de fusion intervertébrale (23 %; n = 186/812). La dose totale médiane [écart interquartile] d'ATX était de 1000 mg [1000 à 1000], administrés dans 92 % des cas sous forme de bolus. Les anesthésiologistes et les chirurgiens ont ajouté une variabilité significative aux probabilités de recevoir de l'ATX lors d'une chirurgie de fracture de la hanche et de fusion, mais pas lors d'ATH primaire. La majeure partie de la variabilité dans l'utilisation d'ATX était attribuable aux facteurs liés au patient et à d'autres facteurs. CONCLUSION: Nous avons confirmé l'utilisation de routine de l'ATX dans l'ATH primaire, tout en observant une utilisation moins répandue et plus variable lors de chirurgie de fracture de la hanche et de fusion intervertébrale. Une étude plus approfondie est nécessaire pour comprendre les variations d'utilisation et les obstacles à la mise en œuvre de l'ATX dans une population plus étendue de patients de chirurgie orthopédique à haut risque de transfusion.

Lysosomal Destabilizing Drug Siramesine and the Dual Tyrosine Kinase Inhibitor Lapatinib Induce a Synergistic Ferroptosis through Reduced Heme Oxygenase-1 (HO-1) Levels.

Ferroptosis is an iron-dependent type of cell death distinct from apoptosis or necrosis characterized by accumulation of reactive oxygen species. The combination of siramesine, a lysosomotropic agent, and lapatinib, a dual tyrosine kinase inhibitor (TKI), synergistically induced cell death in breast cancer cells mediated by ferroptosis. In this study, we showed that this combination of siramesine and lapatinib induces synergistic cell death in glioma cell line U87 and lung adenocarcinoma cell line A549. This cell death was characterized by the increase in iron content, reactive oxygen species (ROS) production, and lipid peroxidation accumulation after 24 hours of treatment. Moreover, iron chelator DFO and ferrostatin-1, a ferroptosis inhibitor, significantly reduced cell death. The mechanism underlying the activation of the ferroptotic pathway involves lysosomal permeabilization and increase in reactive iron levels in these cells. In addition, the downregulation of heme oxygenase-1 (HO-1) protein occurred. Overexpression of HO-1 resulted in reduction of ROS and lipid peroxidation production and cell death. Furthermore, knocking down of HO-1 combined with siramesine treatment resulted in increased cell death. Finally, we found that the inhibition of the proteasome system rescued HO-1 expression levels. Our results suggest that the induction of ferroptosis by combining a lysosomotropic agent and a tyrosine kinase inhibitor is mediated by iron release from lysosomes and HO-1 degradation by the proteasome system.

Identification and Characterization of Novel Receptor-Interacting Serine/Threonine-Protein Kinase 2 Inhibitors Using Structural Similarity Analysis.

Receptor-interacting protein kinase 2 (RIP2 or RICK, herein referred to as RIPK2) is linked to the pathogen pathway that activates nuclear factor κ-light-chain-enhancer of activated B cells (NFκB) and autophagic activation. Using molecular modeling (docking) and chemoinformatics analyses, we used the RIPK2/ponatinib crystal structure and searched in chemical databases for small molecules exerting binding interactions similar to those exerted by ponatinib. The identified RIPK2 inhibitors potently inhibited the proliferation of cancer cells by > 70% and also inhibited NFκB activity. More importantly, in vivo inhibition of intestinal and lung inflammation rodent models suggests effectiveness to resolve inflammation with low toxicity to the animals. Thus, our identified RIPK2 inhibitor may offer possible therapeutic control of inflammation in diseases such as inflammatory bowel disease, asthma, cystic fibrosis, primary sclerosing cholangitis, and pancreatitis.

Ferroptosis and autophagy induced cell death occur independently after siramesine and lapatinib treatment in breast cancer cells.

Ferroptosis is a cell death pathway characterized by iron-dependent accumulation of reactive oxygen species (ROS) within the cell. The combination of siramesine, a lysosome disruptor, and lapatinib, a dual tyrosine kinase inhibitor, has been shown to synergistically induce cell death in breast cancer cells mediated by ferroptosis. These treatments also induce autophagy but its role in this synergistic cell death is unclear. In this study, we determined that siramesine and lapatinib initially induced ferroptosis but changes to an autophagy induced cell death after 24 hours. Furthermore, we found that intracellular iron level increased in a time dependent manner following treatment accompanied by an increase in ROS. Using the iron chelator deferoxamine (DFO) or the ROS scavenger alpha-tocopherol decreased both autophagy flux and cell death. We further discovered that decreased expression of the iron storage protein, ferritin was partially dependent upon autophagy degradation. In contrast, the expression of transferrin, which is responsible for the transport of iron into cells, is increased following treatment with lapatinib alone or in combination with siramesine. This indicates that ferroptosis and autophagy induced cell death occur independently but both are mediated by iron dependent ROS generation in breast cancer cells.

Functional Myeloid-Derived Suppressor Cell Subsets Recover Rapidly after Allogeneic Hematopoietic Stem/Progenitor Cell Transplantation.

Myeloid-derived suppressor cells (MDSCs) are regulatory cell populations that have the ability to suppress effector T cell responses and promote the development of regulatory T cells (Tregs). They are a heterogeneous population of immature myeloid progenitors that include monocytic and granulocytic subsets. We postulated that given the rapid expansion of myeloid cells post-transplant, these members of the innate immune system may be important contributors to the early immune environment post-transplant. To evaluate the kinetics of recovery and function of MDSCs after allogeneic hematopoietic stem cell transplant (HSCT), 26 patients undergoing allogeneic HSCT were studied at 6 time points in the first 3 months after HSCT. Both MDSC subsets recovered between 2 and 4 weeks, well before the recovery of T and B lymphocytes. MDSC subset recovery positively correlated with T, B, and/or double-negative T cell numbers after HSCT. MDSCs isolated from patients post-transplant were functional in that they suppressed third-party CD4(+) T cell proliferation and Th1 differentiation and promoted Treg development. In conclusion, functional MDSC are present early after HSCT and likely contribute to the regulatory cell population post-transplant.

Routine filtration of hematopoietic stem cell products: the time has arrived.

BACKGROUND: Most blood products are infused at the time of transfusion through a standard blood filter, designed to capture macroaggregates and cellular debris that might be harmful to the patient if infused. Hematopoietic stem cell products are not universally filtered, likely due to concern about loss of viable stem cells in the filtration process. STUDY DESIGN AND METHODS: We conducted a two-phase study to better understand the safety of routine filtration. First, surplus cryopreserved stem cell products were thawed and filtered, with markers of viability and potency measured. Second, routine filtration was implemented as part of routine practice at our center, and date of neutrophil and platelet (PLT) recovery was compared to historical controls. RESULTS: In the first phase, there was no difference seen in any markers of viability or potency for products after routine filtration. Based on those results, routine filtration was implemented. There was no difference in neutrophil or PLT engraftment. Thus, in this study, routine filtration did not impact the number of viable stem cells and did not delay engraftment. CONCLUSION: Given the very real harm posed by infusion of macroaggregates and cellular debris, and no clear disadvantage to filtration, routine filtration of stem cell products should be considered the standard of care.