Impact Of Red Blood Cells Research Articles

Contribution of Red Blood Cells and Platelets to Blood Clot Computed Tomography Imaging and Compressive Mechanical Characteristics

Thrombus computed tomography (CT) imaging characteristics may correspond with thrombus mechanical properties and thus predict thrombectomy success. The impact of red blood cell (RBC) content on these properties (imaging and mechanics) has been widely studied. However, the additional effect of platelets has not been considered. The objective of the current study was to examine the individual and combined effects of blood clot RBC and platelet content on resultant CT imaging and mechanical characteristics. Human blood clot analogues were prepared from a combination of preselected RBC volumes and platelet concentrations to decouple their contributions. The resulting clot RBC content (%) and platelet content (%) were determined using Martius Scarlet Blue and CD42b staining, respectively. Non-contrast and contrast-enhanced CT (NCCT and CECT) scans were performed to measure the clot densities. CECT density increase was taken as a proxy for clinical perviousness. Unconfined compressive mechanics were analysed by performing 10 cycles of 80% strain. RBC content is the major determinant of clot NCCT density. However, additional consideration of the platelet content improves the association. CECT density increase is influenced by clot platelet and not RBC content. Platelet content is the dominant component driving clot stiffness, especially at high strains. Both RBC and platelet content contribute to the clot’s viscoelastic and plastic compressive properties. The current in vitro results suggest that CT density is reflective of RBC content and subsequent clot viscoelasticity and plasticity, and that perviousness reflects the clot’s platelet content and subsequent stiffness. However, these indications should be confirmed in a clinical stroke cohort.

Cultured CD71+ erythroid cells modulate the host immune response.

The study aimed to determine the impact of Red Blood Cells (RBCs) generated from peripheral blood mononuclear cells (PBMCs) on T cell proliferation and host response following whole blood stimulation. Culturing RBCs is a potential solution for donor shortage. The impact of immature cultured RBCs which express CD71+ on host immune response is not known. PBMCs were seeded in an erythroid expansion medium. CD71+ cells were isolated at days 14 and 21 of culture and incubated with either purified T cells or with LPS-stimulated whole blood. Controls were incubated with medium. At day 9, the percentage of cells that expressed CD45 and CD71 reached to the highest level (32.9%, IQR; 26.2-39.05) while the percentage of cells that expressed CD71 and CD235a reached to the highest level on day 17 (70.2%, IQR; 66.1-72.8). Incubation of T cells with days 14 CD71+ cells and day 21 CD71+ cells increased T cell proliferation. In a whole blood stimulation assay, day 21 CD71+ cells, but not day 14 CD71+ cells, inhibited the production of IL-6 and TNFα. Cultured erythroid cells can modulate the immune response by promoting T cell proliferation and inhibiting cytokine secretions following whole blood stimulation.

Prognostic of red blood cell transfusion during extracorporeal membrane oxygenation therapy on mortality: A meta-analysis.

This meta-analysis aimed to explore the impact of red blood cell (RBC) transfusion on mortality during extracorporeal membrane oxygenation (ECMO). Previous studies investigated the prognostic impact of RBC transfusion during ECMO on the risk of mortality, but no meta-analysis has been published before. The PubMed, Embase, and the Cochrane library were systematically searched for papers published up to 13 December 2021, using the MeSH terms "ECMO", "'Erythrocytes", and "Mortality" to identify meta-analyses. Total or daily RBC transfusion during ECMO and mortality were examined. The random-effect model was used. Eight studies (794 patients, including 354 dead) were included. The total volume of RBC was associated with higher mortality standardized weighted difference (SWD = -0.62, 95% CI: -1.06,-0.18, p = .006; I2 = 79.7%, Pheterogeneity = 0.001). The daily volume of RBC was associated with higher mortality (SWD = -0.77, 95% CI: -1.11,-0.42, p < .001; I2 = 65.7%, Pheterogeneity = 0.020). The total volume of RBC was associated with mortality for venovenous (VV) (SWD = -0.72, 95% CI: -1.23, -0.20, p = .006) but not venoarterial ECMO (p = .126) or when reported together (p = .089). The daily volume of RBC was associated with mortality for VV (SWD = -0.72, 95% CI: -1.18, -0.26, p = 0.002; I2 = 0.0%, Pheterogeneity = 0.642) and venoarterial (SWD = -0.95, 95% CI: -1.32, -0.57, p < .001) ECMO, but not when reported together (p = .067). The sensitivity analysis suggested the robustness of the results. When considering the total and daily volumes of RBC transfusion during ECMO, the patients who survived received smaller total and daily volumes of RBC transfusion. This meta-analysis suggests that RBC transfusion might be associated with a higher risk of mortality during ECMO.

Premature Macrophage Activation by Stored Red Blood Cell Transfusion Halts Liver Regeneration Post-Partial Hepatectomy in Rats.

Liver resection is a common treatment for various conditions and often requires blood transfusions to compensate for operative blood loss. As partial hepatectomy (PHx) is frequently performed in patients with a pre-damaged liver, avoiding further injury is of paramount clinical importance. Our aim was to study the impact of red blood cell (RBC) resuscitation on liver regeneration. We assessed the impact of RBC storage time on liver regeneration following 50% PHx in rats and explored possible contributing molecular mechanisms using immunohistochemistry, RNA-Seq, and macrophage depletion. The liver was successfully regenerated after PHx when rats were transfused with fresh RBCs (F-RBCs). However, in rats resuscitated with stored RBCs (S-RBCs), the regeneration process was disrupted, as detected by delayed hepatocyte proliferation and lack of hypertrophy. The delayed regeneration was associated with elevated numbers of hemorrhage-activated liver macrophages (Mhem) secreting HO-1. Depletion of macrophages prior to PHx and transfusion improved the regeneration process. Gene expression profiling revealed alterations in numerous genes belonging to critical pathways, including cell cycle and DNA replication, and genes associated with immune cell activation, such as chemokine signaling and platelet activation and adhesion. Our results implicate activated macrophages in delayed liver regeneration following S-RBC transfusion via HO-1 and PAI-1 overexpression.

Perioperative Red Blood Cell Transfusion Is Associated With Adverse Cardiovascular Outcomes in Heart Valve Surgery.

We examined the relationship between blood transfusion and long-term adverse events to evaluate the clinical impact of red blood cell (RBC) transfusion on patients undergoing cardiac valve surgery. From the National Health Insurance Service database, individuals undergoing heart valve surgery were verified, including aortic valve (AV), mitral valve (MV), tricuspid valve (TV), and complex valves (more than 2 valve surgeries). The interested outcomes were incidence of death, ischemic stroke, hemorrhagic stroke, and admission for myocardial infarction during follow-up. Associations between perioperative RBC transfusion and long-term cardiovascular events were analyzed with Cox-proportional hazard model. Perioperative RBC transfusion (±2 days from the day of surgery) was categorized into 0, 1, 2, and >3 units based on the number of packs transfused. From 2003 to 2019, the data of 58,299 individuals were retrieved (51.6% were male and 58% were aged above 60 years). The median follow-up duration was 5.53 years. Of the total cohort, 86.5% received at least 1 transfusion. In multivariable analysis, adverse cardiovascular event risk proportionally increased with transfusion in a dose-dependent manner. The adjusted hazard ratios and 95% confidence intervals of outcomes after the transfusion of 1, 2, and ≥3 units compared to those with no transfusion were as follows: death, 1.53 (1.41-1.66), 1.97 (1.81-2.14), and 3.03 (2.79-3.29); ischemic stroke, 1.27 (1.16-1.39), 1.31 (1.19-1.44), and 1.51 (1.38-1.66); hemorrhagic stroke, 1.38 (1.16-1.66), 1.71 (1.43-2.05), and 2.31 (1.94-2.76); and myocardial infarction 1.35 (1.13-1.62), 1.60 (1.33-1.91), and 1.99 (1.66-2.38), respectively (all P < .01). In the analysis of the national cohort, perioperative RBC transfusion during heart valve surgery was associated with adverse cardiovascular outcomes correlated with the volume of RBC transfusion.

Impact of red blood cell lysing on rare event analysis.

The challenges associated with analyzing rare cells are dependent on a series of factors, which usually require large numbers of cells per sample for successful resolution. Among these is determining the minimum number of total events needed to be acquired as defined by the expected frequency of the target cell population. The choice of markers that identify the target population, as well as the event rate and the number of aborted events/second, will also determine the statistically significant detection of rare cell events. Sample preparation is another important but often overlooked factor in rare cell analysis, and in this study we examine Poisson theory and methods to determine the effect of sample manipulation on rare cell detection. After verifying the applicability of this theory, we have evaluated the potential impact of red cell lysis on rare cell analysis, and how cell rarity can be underestimated or overestimated based on erythrolytic sensitivity or resistance of healthy leukocytes and pathological rare cells.

Red blood cell transfusion and hemoglobin level on neurological outcome in the first 24 hours of traumatic brain injury

ObjectivesTarget hemoglobin (Hb) level is not clearly determined in patients followed up in the intensive care unit (ICU) for traumatic brain injury (TBI). This study aims to investigate the impact of red blood cell (RBC) transfusion and Hb level on the neurological outcome in the first 24 h in patients with TBI. MethodsIn this retrospective study, we reviewed the 2-year organizational database. We evaluated data from patients who underwent RBC transfusion and whose Hb values were 7–9 g/dL and >9 g/dL in the first 24 h. We considered that a Glasgow Outcome Score (GOS) of 1–3 at the time of discharge from the ICU was a poor neurological outcome (PO) and that a GOS > 3 was a good neurological outcome (GO). ResultsA total of 147 patients were included in the study 28.6% of whom were discharged from the intensive care unit with PO. The Hb (g/dL) values of PO patients in the first 24 h were lower compared to those of GO patients (median [interquartile range]; 9.2 [2.5] vs 11 [3.4], p < 0.01). RBC transfusion of PO patients in the first 24 h was also less compared to that of GO patients (median [interquartile range]; 15 [35.7] vs. 19 [18.1], p = 0.038). In logistic regression analyses, neither RBC transfusion (OR [95%CI]; 0.786 (0.108–5.740), p = 0.81) nor Hb level (OR [95% CI]; 0.50 (0.057–4.362), p = 0.53) was an independent risk factor for PO. ConclusionIn patients followed up in the ICU due to TBI, RBC transfusion and Hb values in the first 24 h are not associated with PO at the time of discharge from the ICU.

Impact of Red Blood Cells on Function and Metabolism of Porcine Deceased Donor Kidneys During Normothermic Machine Perfusion.

Background.Normothermic machine perfusion (NMP) protocols using blood-based solutions are commonly used in the assessment of kidneys before transplantation. This procedure is, nevertheless, limited by blood availability and warrants the search for alternatives. We compared a blood-based solution with a serum-like preservation solution (Aqix) enriched with colloids with and without red blood cells (RBCs).Methods.Porcine kidneys retrieved from an abattoir were subjected to 30 min of warm ischemia, followed by 3 h of hypothermic oxygenated machine perfusion at 4 °C. Subsequently, kidneys (n = 6 per group) were evaluated with NMP for 4 h with 5 different solutions: diluted blood, Aqix with BSA ± RBCs, or Aqix with dextran 40 ± RBCs.Results.Throughout NMP, markers of renal function and tubular metabolism were favorable in groups with RBCs. The addition of RBCs resulted in 4- to 6-fold higher oxygen consumption rates. Controls had significantly higher ATP levels post-NMP, exhibited decreased production of oxidative stress markers, and had the highest creatinine clearance. In conclusion, this study shows that the addition of RBCs during NMP reduced renal injury, improved function, and was associated with increased renal metabolism.Conclusions.Although the RBC-BSA–supplemented Aqix solution was also able to support metabolism and renal function, a blood-based perfusion solution remains superior.

Do not forget the platelets: The independent impact of red blood cell to platelet ratio on mortality in massively transfused trauma patients.

Balanced blood component administration during massive transfusion is standard of care. Most literature focuses on the impact of red blood cell (RBC)/fresh frozen plasma (FFP) ratio, while the value of balanced RBC:platelet (PLT) administration is less established. The aim of this study was to evaluate and quantify the independent impact of RBC:PLT on 24-hour mortality in trauma patients receiving massive transfusion. Using the 2013 to 2018 American College of Surgeons Trauma Quality Improvement Program database, adult patients who received massive transfusion (≥10 U of RBC/24 hours) and ≥1 U of RBC, FFP, and PLT within 4 hours of arrival were retrospectively included. To mitigate survival bias, only patients with consistent RBC:PLT and RBC:FFP ratios between 4 and 24 hours were analyzed. Balanced FFP or PLT transfusions were defined as having RBC:PLT and RBC:FFP of ≤2, respectively. Multivariable logistic regression was used to compare the independent relationship between RBC:FFP, RBC:PLT, balanced transfusion, and 24-hour mortality. A total of 9,215 massive transfusion patients were included. The number of patients who received transfusion with RBC:PLT >2 (1,942 [21.1%]) was significantly higher than those with RBC:FFP >2 (1,160 [12.6%]) (p < 0.001). Compared with an RBC:PLT ratio of 1:1, a gradual and consistent risk increase was observed for 24-hour mortality as the RBC:PLT ratio increased (p < 0.001). Patients with both FFP and PLT balanced transfusion had the lowest adjusted risk for 24-hour mortality. Mortality increased as resuscitation became more unbalanced, with higher odds of death for unbalanced PLT (odds ratio, 2.48 [2.18-2.83]) than unbalanced FFP (odds ratio, 1.66 [1.37-1.98]), while patients who received both FFP and PLT unbalanced transfusion had the highest risk of 24-hour mortality (odds ratio, 3.41 [2.74-4.24]). Trauma patients receiving massive transfusion significantly more often have unbalanced PLT rather than unbalanced FFP transfusion. The impact of unbalanced PLT transfusion on 24-hour mortality is independent and potentially more pronounced than unbalanced FFP transfusion, warranting serious system-level efforts for improvement. Therapeutic/Care Management; Level IV.

Modelling haemoglobin incremental loss on chronic red blood cell transfusions.

Understanding the impact of red blood cell (RBC) lifespan, initial RBC removal, and transfusion intervals on patient haemoglobin (Hb) levels and total iron exposure is not accessible for chronic transfusion scenarios. This article introduces the first model to help clinicians optimize chronic transfusion intervals to minimize transfusion frequency. Hb levels and iron exposure from multiple transfusions were calculated from Weibull residual lifespan distributions, the fraction effete RBC removed within 24-h (Xe ) and the nominal Hb increment. Two-unit transfusions of RBCs initiated at patient [Hb]=7g/dl were modelled for different RBC lifespans and transfusion intervals from 18 to 90 days, and Xe from 0.1 to 0.5. Increased Xe requires shorter transfusion intervals to achieve steady-state [Hb] of 9g/dl as follows: 30 days between transfusions at Xe = 0.5, 36 days at Xe = 0.4, 42 days at Xe = 0.3, 48 days at Xe = 0.2 and 54 days at Xe = 0.1. The same transfusion interval/Xe pairs result in a steady-state [Hb]=8g/dl when the RBC lifespan was halved. By reducing transfused RBC increment loss from 30% to 10%, annual transfusions were decreased by 22% with iron addition decreased by 24%. Acute dosing of iron occurs at the higher values of Xe on the day after a transfusion event. Systematic trends in fractional Hb incremental loss Xe have been modelled and have a significant and calculatable impact on transfusion intervals and associated introduction of iron.

Storage Differentially Impacts Immunization to Red Cell Antigens

Introduction: The impact of red blood cell (RBC) storage on alloimmunization rates after transfusion remains controversial, with clinical experience demonstrating conflicting results. Indeed, some reports suggest increased rates of alloimmunization associated with longer storage of RBC units, while others suggest no association between alloimmunization rates and length of storage. We hypothesized that this discrepancy may reflect the differential impact of storage on alloimmunization related to each unique antigen and the immune response elicited. Here we define the effect of red cell storage on two distinct antigens, including the Hel-Ova-Duffy (HOD) and KEL antigens, using a preclinical murine model of RBC storage and transfusion.Methods: RBCs singly expressing HOD (HOD RBC) or KEL (KEL RBC) antigens, in addition to those dually expressing both HOD and KEL (HOD x KEL RBC) antigens, were collected from respective transgenic donor mice into CPDA. Units of HOD, KEL or HOD x KEL RBC were generated and used immediately (fresh RBC), or stored for 8 (D8) or 14 (D14) days at 4C before transfusion into wildtype recipients. Recipient cytokine profiles were assessed 2 hours post-transfusion using a multiplex inflammation panel. Donor RBC survival at 24 hours post-transfusion was assessed by flow cytometry. Serum was collected from recipients on days 5 and 14 post-transfusion and analyzed for IgM or IgG development by flow-cytometric crossmatch using HOD or KEL RBC targets.Results: Post-transfusion RBC survival was decreased with increased storage, but was not significantly different between donor cell types (HOD, KEL or HOD x KEL). Recipient cytokine profiles demonstrated a distinct inflammatory profile associated with storage. Development of IgM antibodies against HOD in mice transfused fresh versus D8 or D14 HOD or HOD x KEL RBCs were not significantly different; however, significantly increased (p<0.05) IgG antibodies were detected in recipients transfused with D8 and D14 HOD or HOD x KEL RBCs as compared to those transfused fresh HOD or HOD x KEL RBCs. In contrast, and while the development of anti-KEL IgM antibodies was not significantly different in mice transfused fresh versus D8 or D14 KEL or HOD x KEL RBCs, the IgG response to KEL was abrogated with longer storage, with recipients generating significantly less (p<0.05) anti-KEL IgG following transfusion with stored KEL or HOD x KEL RBCs as compared to fresh HOD or HOD x KEL RBCs.Conclusions: Although the impact of RBC storage on various measures of transfusion efficacy have been determined, the impact of storage on alloimmunization remains incompletely understood. Using a murine model of transfusion, we demonstrate that storage differentially impacts immunization to red cell antigens, increasing the response to certain antigens, like HOD, while decreasing the response to others, like KEL. Although it is unclear whether these findings apply to other RBC antigens and what relevance this holds for human patients, our study provides insight into the impact of storage on red cell alloimmunization and may enlighten future storage protocols. DisclosuresStowell: Argenx: Speakers Bureau; Grifols: Speakers Bureau; Alexion: Consultancy.

Sex based analysis of the impact of red blood cell transfusion and vascular or bleeding complications related to TAVI – The TRITAVI-Women Study

BackgroundWomen present specific risks for transcatheter aortic valve replacement (TAVI) but there are scarce sex-based analysis. The aim of this study was to explore the risk of vascular/bleeding complications in females vs. males that underwent TAVI and the impact of red blood cell (RBC) transfusion. MethodsTRITAVI-Women is a retrospective analysis in 13 European institutions. Propensity score based on pairs of different sex was performed and global outcomes, vascular/bleeding risk factors were determined. Afterwards, the female population of the study was divided into two groups according to the need of RBC transfusion and the risk for mortality, AKI, MI, stroke at 30-days and at 1-year were compared as a combined endpoint (primary endpoint) and separately (secondary endpoints). ResultsThe global study population included 5837 patients. Females presented more advanced NYHA class, chronic kidney disease, and baseline anemia. Vascular/bleeding complications and RBC transfusion were more common in women. However, 1-year mortality was lower for women in the matched cohort (8.1% vs.10.3%, p = 0.028). The need for RBC transfusion was an independent predictor of higher incidence of the primary endpoint at 30-day and 1-year. The main predictor of RBC transfusion in women was the presence of baseline anemia. ConclusionsWomen present lower risk of mortality than men at 1-year follow up, but not at 30-day due to higher rates of vascular/bleeding complications. RBC transfusion was also more often required in women and was an independent predictor or poorer outcomes. The treatment of pre-existing anemia before TAVI might improve the short-term results in women.

Do Red Blood Cell Transfusions Influence Long-Term Outcomes in Patients Undergoing Primary Surgery for Oral Squamous Cell Carcinoma?

There is no consensus on the impact of red blood cell (RBC) transfusion on patients with oral squamous cell carcinoma (OSCC). The purpose of this study was to investigate the association between RBC transfusions and overall survival (OS) and tumor-free survival (TFS) after operative treatment of OSCC. In this retrospective cohort study, all patients treated with primary surgery between 2003 and 2017 because of OSCC were chart reviewed. The occurrence and amount of RBC transfusions (0; 1-3; >3 units) was correlated with OS and TFS by Kaplan-Meier survival and Cox regression analyses. Demographic, clinical, and pathological parameters were also evaluated in order to identify confounding factors. Of 420 patients (243 [57.9%] male) with a mean age of 62.6years, 67 (16.0%) received RBC transfusion. There were statistically significant (P<.01) differences in 5-year OS respectively TFS in transfused patients for the Kaplan-Meier survival analysis (0 units=70.6%; [95% confidence interval {CI}: 65.0-75.4%] respectively 63.2% [95% CI: 57.4-68.4%], 1-3 units=47.2% [95% CI: 29.4-63.1%] respectively 40.6% [95% CI: 24.6-55.95%] and >3 units=48.9% [95% CI: 20.9-72.1%] respectively 30.5% [95% CI: 8.9-55.8%]). After multivariate adjustments for demographic, clinical, and pathological parameters, RBC transfusion could not be sustained as a significant prognostic factor in OS respectively TFS (1-3 units: hazard ratio=1.5 [95% CI: 0.7-3.2] respectively 1.3 [95% CI: 0.7-2.6]; >3 units: hazard ratio=1.2 [95% CI: 0.5 - 3.0] respectively 1.1 [95% CI: 0.5-2.4]). Although RBC transfusion was not identified as a significant prognostic parameter in multivariate analysis, a clear trend for shorter OS and TFS for transfused patients in univariate and Kaplan-Meier survival analysis could be shown.

Randomized controlled trial of 7, 28, vs 42 day stored red blood cell transfusion on oxygen delivery (VO2 max) and exercise duration.

Few studies have rigorously assessed the impact of red blood cell (RBC) transfusion on oxygen delivery. Several large trials demonstrated no clinical outcome differences between transfusion of shorter-storage vs prolonged-storage RBCs. These trials did not directly assess functional measures of oxygen delivery. Therefore, it is not clear if 42-day stored RBCs deliver oxygen as effectively as 7-day stored RBCs. Leukocyte-reduced RBCs were collected by apheresis in AS-3. Thirty subjects were randomized (1:1:1) to receive 2 units of autologous RBCs at either 7, 28, or 42 days following donation. VO2 max testing, using a standardized protocol to exhaustion, was performed 2 days before (Monday) and 2 days after (Friday) the transfusion visit (Wednesday). The primary endpoint was the percent increase in VO2 max between Monday and Friday. The secondary endpoint was the percent change in duration of exercise for the same time points. Hemoglobin levels decreased by 2.8 ± 1.4 g/dL after donation and increased by 2.1 ± 0.6 g/dL after transfusion. This change in hemoglobin was associated with expected decreases (then increases after transfusion) in VO2 max and exercise duration. No differences were observed between 7-day and 42-day RBC transfusion for percent increase in median [IQR] VO2 max (10.5 [0.2-17.3] vs 10.9 [5.7-16.8], P = .41) or for percent increase in exercise duration (5.4 [4.1-6.9] vs 4.9 [2.0-7.2], P = .91), respectively. Results were similar for 28-day RBCs and were consistent across the ITT and per-protocol analysis populations. These data indicate that 42-day, 28-day, and 7-day RBCs have similar ability to deliver oxygen.

The effect of red blood cell transfusion on fatigability after hospital discharge

AbstractIn patients with anemia, there is interest in understanding the impact of red blood cell (RBC) transfusion on patient-reported outcomes such as fatigue. However, data from previous studies are mixed as to whether transfusion improves fatigue. One explanation for this is that prior studies have not examined whether changes in fatigue from transfusion may also affect patient activity levels. This is important because if transfusion reduces fatigue, patients may become more active, which could increase their fatigue. Thus, testing whether transfusion affects patients' fatigability, a measure of fatigue in the context of activity, may be more useful than testing the effect of transfusion on fatigue alone. The objective of this study was to test the effect of transfusion during hospitalization on patients' fatigability 7 days postdischarge. This prospective observational study included hospitalized general medicine patients with hemoglobin levels <10 g/dL. Patient-reported fatigability was collected during hospitalization and by telephone 7 days after discharge. Multivariable linear regression was used to test the association between receipt of a transfusion and fatigability 7 days postdischarge. Among the 350 patients participating, larger reductions in fatigability were observed with more transfused RBCs. Receipt of 1 U of RBCs was associated with a smaller reduction in fatigability, whereas receipt of 2 to 3 U of RBCs was associated with reductions in fatigability nearly 1 standard deviation from baseline and 3 times greater than patients receiving 1 U of RBCs. In hospitalized patients with anemia, receipt of a transfusion is associated with reductions in fatigability 7 days after hospital discharge.

Clinical impact of red blood cell transfusion on adverse clinical events in acute heart failure patients with anemia

BackgroundAnemia has been recognized as an important comorbidity in patients with acute heart failure (AHF) and is associated with adverse clinical events. However, the clinical impact of red blood cell (RBC) transfusion in such patients is unclear. MethodThis study was a retrospective single-center registry including AHF patients admitted to Kyorin University Hospital between 2007 and 2014. Anemia was defined as a hemoglobin level < 130 g/L in males or < 120 g/L in females. Those with major bleeding with a fall in hemoglobin concentration of >20 g/L were excluded. AHF readmission at 3 months and in-hospital and 2-year all-cause mortality were evaluated. ResultsOf 501 AHF patients, 38 were excluded owing to major bleeding; finally, 463 (age, 77 ± 11 years; males, 58%) were evaluated. RBC transfusion during hospitalization was performed in 112 patients (24%). Hemoglobin level on admission was 105 ± 16 g/L (transfusion, 89 ± 17 g/L; no transfusion, 110 ± 12 g/L; p < 0.001). AHF readmission at 3 months and in-hospital and 2-year all-cause mortality were observed in 46 (10%), 16 (3%), and 121 (26%) patients, respectively. Univariate Cox regression analysis demonstrated that RBC transfusion was not associated with AHF readmission at 3 months (hazard ratio: 0.80; 95% confidence interval: 0.39–1.66) The association did not differ at any hemoglobin concentration or left ventricular ejection fraction value. Multivariate Cox regression analysis revealed similar results. Furthermore, RBC transfusion was not correlated with in-hospital and 2-year all-cause mortality. ConclusionsRBC transfusion was not associated with AHF readmission or all-cause mortality.

Sepsis-related anemia in a pediatric intensive care unit: transfusion-associated outcomes.

Pediatric patients with sepsis in intensive care units are at high risk of developing anemia, which might have adverse effects on their prognosis. This study aimed to evaluate the impact of red blood cell (RBC) transfusion on the outcomes of patients admitted to a pediatric intensive care unit (PICU) with sepsis. We conducted a prospective randomized clinical trial, enrolling 67 children, aged 2 to 144 months who were admitted to a PICU with a new episode of sepsis from November 2017 to April 2018. Patients were allocated randomly to two groups: Group 1, liberal transfusion strategy group, including 33 patients who had initial hemoglobin (Hb) between 7 or greater and less than 10 g/dL and received an RBC top-up transfusion to 12 g/dL; and Group 2, restrictive strategy group, including 34 patients who had the same Hb range and did not receive RBCs. Patients with Hb less than 7 or greater than 10 g/dL were excluded. Of 33 patients who received liberal transfusions, 31 (93.94%) required ventilation, and 29 (87.88%) had multiorgan dysfunction. They had a significantly lengthier hospital stay and a higher incidence of acute respiratory distress syndrome and acute lung injury. Moreover, mortality was significantly higher in the liberal transfusion group (42.4% vs. 17.6%). Compared to the restrictive transfusion strategy, liberal transfusion might be associated with a worse outcome. However, the possible role of other known and unknown confounding factors and minor protocol violations should be taken into consideration. We recommend minimizing factors worsening anemia in PICU patients to reduce the need for transfusion.

Red blood cells stabilize flow in brain microvascular networks.

Capillaries are the prime location for oxygen and nutrient exchange in all tissues. Despite their fundamental role, our knowledge of perfusion and flow regulation in cortical capillary beds is still limited. Here, we use in vivo measurements and blood flow simulations in anatomically accurate microvascular network to investigate the impact of red blood cells (RBCs) on microvascular flow. Based on these in vivo and in silico experiments, we show that the impact of RBCs leads to a bias toward equating the values of the outflow velocities at divergent capillary bifurcations, for which we coin the term “well-balanced bifurcations”. Our simulation results further reveal that hematocrit heterogeneity is directly caused by the RBC dynamics, i.e. by their unequal partitioning at bifurcations and their effect on vessel resistance. These results provide the first in vivo evidence of the impact of RBC dynamics on the flow field in the cortical microvasculature. By structural and functional analyses of our blood flow simulations we show that capillary diameter changes locally alter flow and RBC distribution. A dilation of 10% along a vessel length of 100 μm increases the flow on average by 21% in the dilated vessel downstream a well-balanced bifurcation. The number of RBCs rises on average by 27%. Importantly, RBC up-regulation proves to be more effective the more balanced the outflow velocities at the upstream bifurcation are. Taken together, we conclude that diameter changes at capillary level bear potential to locally change the flow field and the RBC distribution. Moreover, our results suggest that the balancing of outflow velocities contributes to the robustness of perfusion. Based on our in silico results, we anticipate that the bi-phasic nature of blood and small-scale regulations are essential for a well-adjusted oxygen and energy substrate supply.

Blood Transfusion and Outcome After Transfemoral Transcatheter Aortic Valve Replacement

To investigate the prognostic impact of red blood cell (RBC) transfusion on the outcome after transfemoral transcatheter aortic valve replacement (TAVR). Nationwide, retrospective multicenter study. Five University Hospitals. The nationwide FinnValve registry included data from 2,130 patients who underwent TAVR for aortic stenosis from 2008 to 2017. After excluding patients who underwent TAVR through nontransfemoral accesses, 1,818 patients were selected for this analysis. TAVR with or without coronary revascularization. RBCs were transfused in 293 patients (16.1%). Time-trend analysis showed that the rates of RBC transfusion decreased significantly from 27.5% in 2012 to 10.0% in 2017 (p < 0.0001). Among 281 propensity score matched pairs, RBC transfusion was associated with higher 30-day mortality (7.1% v 0%, p < 0.0001), late mortality (at 5-year, 59.1% v 43.3%, p = 0.008), as well as increased risk of acute kidney injury (17.0% v 4.4%, p < 0.0001), renal replacement therapy (3.6% v 0.4, p < 0.0001) and prolonged hospital stay (mean, 8.5 v 4.7 days, p < 0.0001) compared with patients who did not receive blood transfusion. In the overall series, the risk of adverse events increased significantly with the increasing amount of transfused RBC units and when operation for excessive bleeding was necessary. Consistently with these findings, postoperative hemoglobin drop and nadir level were associated with higher early and late mortality. Patients who received blood transfusion after TAVR had an increased risk of early and late adverse events. These adverse effects were particularly evident with increasing amount of RBC transfusion and operations for excessive bleeding.

No Significant Association Between the Transfusion of Small Volumes of Leukocyte-Depleted Red Blood Cells and Mortality Over 7 Years of Follow-up in Patients Undergoing Cardiac Surgery: A Propensity Score Matched Analysis.

The impact of red blood cell (RBC) transfusion on long-term clinical outcome is controversial. We prospectively recorded follow-up data of 6124 cardiac surgical patients who received no transfusion (RBC- group) or 1-2 units of leukocyte-depleted RBC (RBC+ group) at our institution. The primary end point was overall mortality up to 7 years after cardiac surgery; secondary end point was coronary artery revascularization during follow-up. To correct for nonrandomized group assignment, propensity score (PS) matching was performed. A subgroup analysis was also performed in patients with preoperative anemia. PS matching was possible in 4118 patients. During a mean follow-up of 4.05 years (range, 0.0-7.3 years), 140 patients (14.6%) died in the RBC- group and 173 (17.2%) died in the RBC+ group. The hazard ratio for the RBC+ group versus the RBC- group was 1.00 (95% confidence interval, 0.79-1.25; P = .969). The number of revascularizations was 96 (9.9%) and 125 (10.6%), respectively, with a hazard ratio of 1.21 (95% confidence interval, 0.92-1.58; P = .166) for the RBC+ group. Preoperative anemia was not a risk factor for postoperative mortality, even when patients were transfused. This PS-matched analysis does not provide evidence for an association of the transfusion of small volumes of leukocyte-depleted RBCs with an increased postoperative mortality in cardiac surgical patients. Moreover, preoperative anemia could not be identified as a risk factor for increased postoperative mortality.