COVID-19 and Sickle Cell Disease in the Province of Quebec, Canada: Outcomes after Two Years of the Pandemic.

BACKGROUND: Patients with sickle cell disease (SCD) are considered at higher risk of severe COVID-19 infection. However, morbidity and mortality rates are variable among countries. To date, there are no published reports that document outcomes of SCD patients with COVID-19 in Canada. METHODS: A web-based registry was implemented in June 2020 capturing outcomes of SCD patients with COVID-19 from March 2020 to April 2022 and comparing them to the general population of Quebec, Canada. RESULTS: After 24 months of the pandemic, 185 SCD patients with confirmed SARS-CoV-2 infection were included in the registry. Overall, the population was young (median age 12 years old) and had few comorbidities. No deaths were reported. Risk of hospitalization and admission to intensive care unit (ICU) because of COVID-19 was higher in patients with SCD than in the general population (relative risks (RR) 5.15 (95% confidence interval (95% CI) 3.84-6.91), p ˂ 0.001 and 4.56 (95% CI 2.09-9.93) p ˂ 0.001). A history of arterial hypertension or acute chest syndrome in the past 12 months was associated with a higher risk of severe disease (RR = 3.06 (95% CI 1.85-5.06) p = 0.008 and 2.27 (95% CI 1.35-3.83) p = 0.01). Hospitalized patients had lower hemoglobin F than non-hospitalized patients (12% vs. 17%, p = 0.02). For those who had access to vaccination at the time of infection, 25 out of 26 patients were adequately vaccinated and had mild disease. CONCLUSIONS: The SCD population is at higher risk of severe disease than the general population. However, we report favorable outcomes as no deaths occurred. Registries will continue to be critical to document the impact of novel COVID-19 specific therapy and vaccines for the SCD population.

Haemoglobin transfusion threshold in traumatic brain injury optimisation (HEMOTION): a multicentre, randomised, clinical trial protocol.

INTRODUCTION: Traumatic brain injury (TBI) is the leading cause of mortality and long-term disability in young adults. Despite the high prevalence of anaemia and red blood cell transfusion in patients with TBI, the optimal haemoglobin (Hb) transfusion threshold is unknown. We undertook a randomised trial to evaluate whether a liberal transfusion strategy improves clinical outcomes compared with a restrictive strategy. METHODS AND ANALYSIS: HEMOglobin Transfusion Threshold in Traumatic Brain Injury OptimizatiON is an international pragmatic randomised open label blinded-endpoint clinical trial. We will include 742 adult patients admitted to an intensive care unit (ICU) with an acute moderate or severe blunt TBI (Glasgow Coma Scale ≤12) and a Hb level ≤100 g/L. Patients are randomly allocated using a 1:1 ratio, stratified by site, to a liberal (triggered by Hb ≤100 g/L) or a restrictive (triggered by Hb ≤70 g/L) transfusion strategy applied from the time of randomisation to the decision to withdraw life-sustaining therapies, ICU discharge or death. Primary and secondary outcomes are assessed centrally by trained research personnel blinded to the intervention. The primary outcome is the Glasgow Outcome Scale extended at 6 months. Secondary outcomes include overall functional independence measure, overall quality of life (EuroQoL 5-Dimension 5-Level; EQ-5D-5L), TBI-specific quality of life (Quality of Life after Brain Injury; QOLIBRI), depression (Patient Health Questionnaire; PHQ-9) and mortality. ETHICS AND DISSEMINATION: This trial is approved by the CHU de Québec-Université Laval research ethics board (MP-20-2018-3706) and ethic boards at all participating sites. Our results will be published and shared with relevant organisations and healthcare professionals. TRIAL REGISTRATION NUMBER: NCT03260478.

Loss of PTEN-induced kinase 1 (Pink1) reduces hippocampal tyrosine hydroxylase and impairs learning and memory.

Phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1) is involved in mitochondrial quality control, which is essential for maintaining energy production and minimizing oxidative damage from dysfunctional/depolarized mitochondria. Pink1 mutations are the second most common cause of autosomal recessive Parkinson's disease (PD). In addition to characteristic motor impairments, PD patients also commonly exhibit cognitive impairments. As the hippocampus plays a prominent role in cognition, we tested if loss of Pink1 in mice influences learning and memory. While wild-type mice were able to perform a contextual discrimination task, age-matched Pink1 knockout (Pink1-/-) mice showed an impaired ability to differentiate between two similar contexts. Similarly, Pink1-/- mice performed poorly in a delayed alternation task as compared to age-matched controls. Poor performance in these cognitive tasks was not the result of overt hippocampal pathology. However, a significant reduction in hippocampal tyrosine hydroxylase (TH) protein levels was detected in the Pink1-/- mice. This decrease in hippocampal TH levels was also associated with reduced DOPA decarboxylase and dopamine D2 receptor levels, but not post-synaptic dopamine D1 receptor levels. These presynaptic changes appeared to be selective for dopaminergic fibers as hippocampal dopamine beta hydroxylase, choline acetyltransferase, and tryptophan hydroxylase levels were unchanged in Pink1-/- mice. Administration of the dopamine D1 receptor agonist SKF38393 to Pink1-/- mice was found to improve performance in the context discrimination task. Taken together, our results show that Pink1 loss may alter dopamine signaling in the hippocampus, which could be a contributing mechanism for the observed learning and memory impairments.

Combined erythropoietin and iron therapy for anaemic patients undergoing transcatheter aortic valve implantation: the EPICURE randomised clinical trial.

AIMS: The aim of this study was to evaluate, in anaemic patients, the efficacy of erythropoietin (EPO) in reducing red cell (RC) transfusion rates post TAVI. METHODS AND RESULTS: This was a randomised double-blind trial. Patients with severe symptomatic aortic stenosis and concomitant anaemia with an indication for TAVI were randomised (1:1) to receive two weight-based doses of EPO (darbepoetin alfa)+iron or placebo at days 10 (±4 days) and 1 (±1 day) pre TAVI. The primary outcome was the rate of RC transfusions at 30 days. A total of 100 patients (mean age 81±7 years, male 49%) were included: 48 patients received EPO (+iron) and 52 patients received placebo. Baseline characteristics and procedural findings were well balanced between groups except for baseline haemoglobin levels, which were lower in those patients receiving EPO (10.7±1.2 vs. 11.3±1.1 g/dl, p=0.01). The rate of 30-day RC transfusion was similar in both groups (27.1 vs. 25.0% in the EPO and placebo groups, respectively; adjusted odds ratio 1.05, 95% CI: 0.42-2.64, p=0.92), and no differences were observed in the number of RC units per transfused patient (1 [1-3] vs. 2 [1-2] in the EPO and placebo groups, respectively, adjusted p=0.99). Rates of 30-day mortality, stroke, new-onset atrial fibrillation, acute kidney injury, and troponin peak were also similar between groups (p>0.20 for all). CONCLUSIONS: EPO (+iron) administration failed to reduce RC transfusion rates or the per-patient number of transfusion units in anaemic patients undergoing TAVI.

Optimal conditions for the performance of a monocyte monolayer assay.

BACKGROUND: Various versions of the monocyte monolayer assay (MMA) have been used to assess clinical significance of red blood cell (RBC) alloantibodies in transfusion for more than 35 years. However, the optimal conditions, including anticoagulant used for whole blood samples, temperature and duration of storage, and optimal pH for assessing the response of monocytes to antibody-bound RBCs, have never been clearly delineated. STUDY DESIGN AND METHODS: Whole blood from healthy donors was collected in ACD, EDTA, or heparin and stored at room temperature (RT) versus 4°C for up to 2 days. pH was examined with and without buffers. Phagocytosis of anti-D-opsonized R2 R2 RBCs was used as the positive control for comparison studies. Whole blood was taken into ACD and kept at RT until testing, from patients with or without immune hemolytic anemia. RESULTS: No significant differences in the phagocytosis of the R2 R2 control RBCs were observed using ACD anticoagulant between freshly drawn or up to 36-hour-stored whole blood kept at RT, regardless of the donor. Physiologic pH during MMA was important for optimal monocyte interactions with antibody-opsonized RBCs. MMA results with patient samples, under optimal conditions, kept up to 30 hours in one instance of long-distance shipment, correlated with clinical hemolysis. CONCLUSION: MMA can be reliably performed on whole blood samples drawn into ACD and kept at RT for up to 36 hours and when physiologic pH is maintained during the assay. Future studies are required to confirm whether use of these conditions with patient monocytes can provide accurate determination of alloantibody significance in patients requiring blood transfusion.

The role of inflammation in intravenous immune globulin-mediated hemolysis.

Intravenous immune globulin (IVIG) therapy has shown great success in a number of autoimmune and inflammatory conditions and its use continues to increase worldwide. There is growing awareness of significant side effects of high-dose IVIG: however, particularly severe hemolysis in patients that are non-group O. It has been proposed that IVIG-associated hemolysis may be heralded by an existing inflammatory condition. In the work presented herein, we have provided a review of the pathophysiology of inflammation, particularly as it applies in immune-mediated red blood cell hemolysis, and a summary of previous publications that suggest an association between IVIG-mediated hemolysis and a state of existing inflammation. In addition, preliminary results from a prospective study to address the mechanism of IVIG-associated hemolysis are provided. These preliminary data support the idea of an existing inflammatory condition preceding overt hemolysis after high-dose IVIG therapy that: 1) is restricted to non-group O patients, 2) is seen when using IVIG doses of more than 2 g/kg, 3) involves an activated mononuclear phagocyte system, 4) may be presaged by a significant increase in the anti-inflammatory cytokine interleukin-1 receptor agonist, and 5) is independent of secretor status.

Incidence and risk factors of hemolysis after transcatheter aortic valve implantation with a balloon-expandable valve.

There are currently no data evaluating the hematologic and biocompatibility profile of transcatheter aortic valves in vivo. We evaluated the incidence, predictive factors, and clinical consequences associated with hemolysis post-transcatheter aortic valve implantation (TAVI). A total of 122 patients who underwent TAVI with a balloon-expandable valve were included. Baseline blood sampling and echocardiography, followed by early post-TAVI echocardiography and repeat blood sampling, at 6 to 12 months post-TAVI were performed. Hemolysis post-TAVI was defined according to the established criteria. The incidence of hemolysis post-TAVI was 14.8% yet no patient experienced severe hemolytic anemia requiring transfusion. Compared with the nonhemolysis group, those with hemolysis demonstrated significant reductions in hemoglobin (p = 0.012), were more frequently women (67% vs 34%, p = 0.016), and had a higher incidence of post-TAVI severe prosthesis-patient mismatch (PPM) (44% vs 17%, p = 0.026). The rate of mild or more prosthetic valve regurgitation did not significantly differ between those patients with and without hemolysis (56% vs 37%, p = 0.44). Wall shear rate (WSR) and energy loss index (ELI), both indirect measures of shear stress, were higher (p = 0.039) and lower (p = 0.004), respectively, in those patients with hemolysis. Increasing PPM severity was also associated with significant stepwise WSR increments and ELI decrements (p <0.01 for both). In conclusion, subclinical hemolysis occurred in 15% of patients following TAVI. Although prosthetic valve regurgitation had no impact on hemolysis, a novel association between PPM and hemolysis was found, likely driven by higher shear stress as determined by WSR and ELI. These hematologic and biomechanical findings may have long-term clinical implications and could affect future transcatheter aortic valve design.

Effect on outcomes and exercise performance of anemia in patients with aortic stenosis who underwent transcatheter aortic valve replacement.

The objectives of this study were to determine the causes and impact of anemia and hemoglobin level on functional status, physical performance, and quality of life in the preprocedural evaluation and follow-up of transcatheter aortic valve replacement (TAVR) candidates. A total of 438 patients who underwent TAVR were included. Anemia was defined as a hemoglobin level <12 g/dl in women and <13 g/dl in men. Before TAVR, anemia was encountered in 282 patients (64.4%). A potential treatable cause of anemia was detected in 90.4% of patients and was attributed to iron deficiency in 53% of them. The occurrence of anemia was an independent predictor of poorer performance in the 6-minute walk test (6MWT), a lower Duke Activity Status Index score, and Kansas City Cardiomyopathy Questionnaires overall, clinical, and social limitation scores (p <0.05 for all). A lower hemoglobin level was associated with a higher prevalence of New York Heart Association class III to IV (p <0.001) and correlated negatively with the results of all functional tests (p <0.02 for all). At follow-up, anemia was found in 62% of patients and was associated with poorer performance in the 6MWT (p = 0.023). A lower hemoglobin level after TAVR was a predictor of poorer New York Heart Association class (p = 0.020) and correlated negatively with the distance walked in the 6MWT (r = -0.191, p = 0.004) and Duke Activity Status Index score (r = -0.158, p = 0.011) at 6-month follow-up. In conclusion, anemia was very common in TAVR candidates and was attributed to iron deficiency in more than half of them. The presence of anemia and lower hemoglobin levels determined poorer functional status before and after the TAVR procedure. These results highlight the importance of implementing appropriate measures for the diagnosis and treatment of this frequent co-morbidity to improve both the accuracy of preprocedural evaluation and outcomes of TAVR candidates.

The influence of bleeding on trigger changes for platelet transfusion in patients with chemotherapy-induced thrombocytopenia.

BACKGROUND: For patients with thrombocytopenia without bleeding risk factors, a platelet transfusion trigger of 10 × 10(9) /L is recommended. No studies have evaluated the clinicians' decision-making process leading to trigger changes. STUDY DESIGN AND METHODS: We report on the evaluation of trigger changes and the relation with bleeding. Eighty patients previously enrolled in the SPRINT trial represent the patient population for the current analysis. RESULTS: Seventy-four patients had a starting trigger of 10 × 10(9) /L. Only a minority of patients treated with chemotherapy alone (3/12, 25%) and autologous transplant (6/15, 40%) had a change in their trigger in contrast to the majority of allogeneic transplant (37/47, 79%; p = 0.001 and p = 0.009, respectively, when compared to allogeneic transplant group). Bleeding was the main reason reported by clinicians for a trigger change, but the occurrence of significant bleeding (Grade 2-4) was similar in patients with or without a trigger change (51 and 54%, p = 1.00). Clinicians were influenced by the bleeding system: grade 1 mucocutaneous bleeding leading to a trigger change was overrepresented (71% of cases), as was grade 2 genitourinary bleeding not leading to a trigger change (57% of cases). CONCLUSION: A universal trigger of 10 × 10(9) /L may not be maintained in a diverse population of patients with their respective bleeding risk factors. Because the trigger is changed often, it may not be as effective as previously believed.

Comparative net cost impact of the utilization of romiplostim and intravenous immunoglobulin for the treatment of patients with immune thrombocytopenia in Québec, Canada.

OBJECTIVES: Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by platelet destruction, sub-optimal platelet production, and mild-to-severe bleeding. Nplate® (romiplostim), a thrombopoietin receptor agonist, and intravenous immunoglobulin (IVIg), an expensive and occasionally scarce blood product, are used in the treatment of ITP. The objective of this study was to compare the total cost of treating patients with romiplostim vs IVIg in Québec, Canada. METHODS: A net cost impact model was developed to calculate the annual cost of romiplostim compared with IVIg based on actual practice observations in all patients (n = 95) treated for chronic ITP with IVIg from April 2010 to March 2011 in two participating hospitals. The model included costs of: drug acquisition, drug preparation and administration, patient monitoring, and indirect costs. Healthcare practitioners were consulted regarding romiplostim and IVIg treatment algorithms and the resources involved in patient monitoring. RESULTS: The average annual drug acquisition costs of romiplostim and IVIg were $48,024 and $98,868, respectively. Lower costs for drug preparation and administration ($309 vs $1245) and less time lost from work ($256 vs $2086) were attributed to romiplostim. The cost of follow-up monitoring was the same for both romiplostim and IVIg ($121). The total average annual per patient costs for romiplostim vs IVIg were, respectively, $48,710 and $102,320. The use of romiplostim was projected to save, on average, almost $54,000 per patient per year. LIMITATIONS: The study was conducted in two hospitals in Québec. Romiplostim may show different cost savings in other hospitals and other provincial and national jurisdictions. CONCLUSIONS: Scarce blood products must be used wisely. Romiplostim can allow for improved healthcare resource allocation by reserving IVIg for use in other areas of greater need while also providing cost savings for the overall provincial healthcare budget.

Cell loss and recovery in umbilical cord blood processing: a comparison of postthaw and postwash samples.

BACKGROUND: Engraftment after umbilical cord blood (UCB) transplantation is highly dependent on nucleated cell (NC) and CD34+ cell content. Current standard postthaw (PT) processing includes a wash step to remove dimethyl sulfoxide (DMSO), lysed red cells, and stroma. The contribution of the wash step to cell loss and ultimately the dose of cells available for transplant have yet to be systematically reported. This study examines the effect of the wash step as well as that of PT storage on various quality control variables of UCB units. STUDY DESIGN AND METHODS: Ten units were thawed and washed based on the New York Blood Center method. Samples were removed from each unit at six time points: prefreeze (PF), immediately PT, immediately postwash (PW), and 1, 2, and 5 hours PW. On each sample, total nucleated cell (TNC) count, CD34+ cell enumeration, colony-forming unit (CFU)-granulocyte-macrophage, and viability assays (fluorescence microscopy [acridine orange/propidium iodide, or AO/PI] and flow cytometry [7-aminoactinomycin]) were obtained. RESULTS: TNC counts decreased PT and at subsequent time points; the PT TNC recovery was 89 percent compared to 82 percent PW (p < 0.01). TNC recovery decreased to 90 percent of PW (82% of PT) values (p < 0.01) and 83 percent of PW (76% of PT) values (p < 0.001), at 2 and 5 hours PW, respectively. CD34+ cell loss PT was not significant. Viability by AO/PI decreased PT and plateaued over time. In contrast, viability by flow cytometry remained higher and increased slightly over time. CFUs were significantly lower PT, recovering PW. CONCLUSIONS: Our data indicate that the thawing and washing results in a substantial loss of cells, with TNC loss approaching 20 percent when compared with PF counts; the wash step was responsible for nearly half of the cell loss. The reduced PT viability was expected. Elapse of time PW resulted in further loss of NCs but no detectable significant changes in CD34+ cell content and viability and/or CFU.