4-factor prothrombin complex concentrate is not inferior to andexanet alfa for the reversal or oral factor Xa inhibitors: An Eastern Association for the Surgery of Trauma multicenter study.

BACKGROUND: Andexanet Alfa (AA) is the only FDA approved reversal agent for apixaban and rivaroxaban (DOAC). There are no studies comparing its efficacy with 4-Factor Prothrombin Complex Concentrate (PCC). This study aimed to compare PCC to AA for DOAC reversal, hypothesizing non-inferiority of PCC. METHODS: We performed a retrospective, non-inferiority multicenter study of adult patients admitted from July 1, 2018 to December 31, 2019 who had taken a DOAC within 12 hours of injury, were transfused red blood cells (RBCs) or had traumatic brain injury, and received AA or PCC. Primary outcome was PRBC unit transfusion. Secondary outcome with ICU length of stay. MICE imputation was used to account for missing data and zero-inflated poisson regression was used to account for an excess of zero units of RBC transfused. 2 Units difference in RBC transfusion was selected as non-inferior. RESULTS: Results: From 263 patients at 10 centers, 77 (29%) received PCC and 186 (71%) AA. Patients had similar transfusion rates across reversal treatment groups (23.7% AA vs 19.5% PCC) with median transfusion in both groups of 0 RBC. According to the Poisson component, PCC increases the amount of RBC transfusion by 1.02 times (95% CI: 0.79-1.33) compared to AA after adjusting for other covariates. The averaged amount of RBC transfusion (non-zero group) is 6.13. Multiplying this number by the estimated rate ratio, PCC is estimated to have an increase RBC transfusion by 0.123 (95% CI: 0.53-2.02) units compared to AA. CONCLUSION: PCC appears non-inferior to AA for reversal of DOACs for RBC transfusion in traumatically injured patients. Additional prospective, randomized trials are necessary to compare PCC and AA for the treatment of hemorrhage in injured patients on DOACs. LEVEL OF EVIDENCE: Therapeutic/Care Management, Level III.

MACROPHAGE SWITCHING: POLARIZATION AND MOBILIZATION AFTER TRAUMA.

ABSTRACT: Introduction: Trauma alters the immune response in numerous ways, affecting both the innate and adaptive responses. Macrophages play an important role in inflammation and wound healing following injury. We hypothesize that macrophages mobilize from the circulation to the site of injury and secondary sites after trauma, with a transition from proinflammatory (M1) shortly after trauma to anti-inflammatory (M2) at later time points. Methods: C57Bl6 mice (n = 6/group) underwent a polytrauma model using cardiac puncture/hemorrhage, pseudofemoral fracture, and liver crush injury. The animals were killed at several time points: uninjured, 24 h, and 7 days. Peripheral blood mononuclear cells, spleen, liver nonparenchymal cells, and lung were harvested, processed, and stained for flow cytometry. Macrophages were identified as CD68 + ; M1 macrophages were identified as iNOS + ; M2 macrophages as arginase 1 + . Results: We saw a slight presence of M1 macrophages at baseline in peripheral blood mononuclear cells (6.6%), with no significant change at 24 h and 7 days after polytrauma. In contrast, the spleen has a larger population of M1 macrophages at baseline (27.7%), with levels decreasing at 24 h and 7 days after trauma (20.6% and 12.6%, respectively). A similar trend is seen in the lung where at baseline 14.9% of CD68 + macrophages are M1, with subsequent continual decrease reaching 8.7% at 24 h and 4.4% at 7 days after polytrauma. M1 macrophages in the liver represent 14.3% of CD68 + population in the liver nonparenchymal cells at baseline. This percentage increases to 20.8% after trauma and decreases at 7 days after polytrauma (13.4%). There are few M2 macrophages in circulating peripheral blood mononuclear cells and in spleen at baseline and after trauma. The percentage of M2 macrophages in the lungs remains constant after trauma (7.2% at 24 h and 9.2% at 7 days). In contrast, a large proportion of M2 macrophages are seen in the liver at baseline (36.0%). This percentage trends upward and reaches 45.6% acutely after trauma and drops to 21.4% at 7 days. The phenotypic changes in macrophages seen in the lungs did not correlate with a functional change in the ability of the macrophages to perform oxidative burst, with an increase from 2.0% at baseline to 22.1% at 7 days after polytrauma ( P = 0.0258). Conclusion: Macrophage phenotypic changes after polytrauma are noted, especially with a decrease in the lung M1 phenotype and a short-term increase in the M2 phenotype in the liver. However, macrophage function as measured by oxidative burst increased over the time course of trauma, which may signify a change in subset polarization after injury not captured by the typical macrophage phenotypes.

EFFECT OF IRRIGATION FLUID COMPOSITION ON HEMOSTASIS IN MOUSE BLEEDING MODELS.

ABSTRACT: Introduction: Intraoperative irrigation, usually with normal saline (NS), aids in bleeding identification and management. We investigated the effect of different irrigation fluids, with additives, on hemostasis using two bleeding models. Methods: C57BL/6 J mice were subjected to a tail bleed model or uncontrolled abdominal hemorrhage via liver laceration followed by abdominal cavity irrigation. We compared NS, lactated Ringer's (LR), and PlasmaLyte. We examined NS and LR at different temperatures. Normal saline or LR with calcium (Ca 2+ ) or tranexamic acid (TXA) was studied. Results: Compared with room temperature (RT), increasing the temperature of the irrigation fluid to 37°C and 42°C reduced tail vein bleeding times substantially in both NS and LR (all P < 0.001), with no significant differences between the two fluids. At RT, LR, but not PlasmaLyte, substantially reduced bleeding times in comparison to NS ( P < 0.0001). Liver injury blood loss was lower with LR ( P < 0.01). Normal saline supplemented with 2.7 mEq/L of Ca 2+ decreased bleeding time and blood loss volume ( P < 0.001 and P < 0.01, respectively) to similar levels as LR. Normal saline with 150 mg/mL of TXA markedly reduced bleeding time ( P < 0.0001), and NS with 62.5 mg/mL TXA decreased blood loss ( P < 0.01). Conclusion: Whereas Ca 2+ - and TXA-supplemented NS reduced bleeding, LR remained superior to all irrigation fluid compositions. As LR contains Ca 2+ , and Ca 2+ -supplemented NS mirrored LR in response, Ca 2+ presence in the irrigation fluid seems key to improving solution's hemostatic ability. Because warming the fluids normalized the choice of agents, the data also suggest that Ca 2+ -containing fluids such as LR may be more suitable for hemostasis when used at RT.

Prehospital synergy: Tranexamic acid and blood transfusion in patients at risk for hemorrhage.

BACKGROUND: Growing evidence supports improved survival with prehospital blood products. Recent trials show a benefit of prehospital tranexamic acid (TXA) administration in select subgroups. Our objective was to determine if receiving prehospital packed red blood cells (pRBC) in addition to TXA improved survival in injured patients at risk of hemorrhage. METHODS: We performed a secondary analysis of all scene patients from the Study of Tranexamic Acid during Air and ground Medical Prehospital transport trial. Patients were randomized to prehospital TXA or placebo. Some participating EMS services utilized pRBC. Four resuscitation groups resulted: TXA, pRBC, pRBC+TXA, and neither. Our primary outcome was 30-day mortality and secondary outcome was 24-hour mortality. Cox regression tested the association between resuscitation group and mortality while adjusting for confounders. RESULTS: A total of 763 patients were included. Patients receiving prehospital blood had higher Injury Severity Scores in the pRBC (22 [10, 34]) and pRBC+TXA (22 [17, 36]) groups than the TXA (12 [5, 21]) and neither (10 [4, 20]) groups (p < 0.01). Mortality at 30 days was greatest in the pRBC+TXA and pRBC groups at 18.2% and 28.6% compared with the TXA only and neither groups at 6.6% and 7.4%, respectively. Resuscitation with pRBC+TXA was associated with a 35% reduction in relative hazards of 30-day mortality compared with neither (hazard ratio, 0.65; 95% confidence interval, 0.45-0.94; p = 0.02). No survival benefit was observed in 24-hour mortality for pRBC+TXA, but pRBC alone was associated with a 61% reduction in relative hazards of 24-hour mortality compared with neither (hazard ratio, 0.39; 95% confidence interval, 0.17-0.88; p = 0.02). CONCLUSION: For injured patients at risk of hemorrhage, prehospital pRBC+TXA is associated with reduced 30-day mortality. Use of pRBC transfusion alone was associated with a reduction in early mortality. Potential synergy appeared only in longer-term mortality and further work to investigate mechanisms of this therapeutic benefit is needed to optimize the prehospital resuscitation of trauma patients. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.

Hydatid Disease of the Liver in the Middle East: A Single Center Experience.

Background: Human cystic echinococcosis (CE), most commonly caused by echinococcosis granulosis, is the most common presentation of hydatid disease of the liver and is considered endemic in the Middle East region. Patients and Methods: This study is a retrospective single-center analysis of all patients with hepatic hydatid disease presenting for surgical management from 2001 to 2019. Results: From 2001 to 2019, 100 patients (54 males, 46 females) were diagnosed with hydatid disease of the liver with a mean age of 45 years (range, 19-82). The most common presenting symptom was right upper quadrant abdominal pain followed by incidental finding of cyst on imaging. Thirteen patients (13%) presented with signs and symptoms of obstructive jaundice. Of the 100 patients, 39 underwent laparoscopic surgery and 61 underwent open surgery. The most common complications were as follows: 16 bile leaks (16%), 14 intra-abdominal fluid collections (14%), 8 wound infections (8%), and 3 patients had biliary strictures (3%). Of the 100, 8 patients(8%) had recurrence of their hepatic hydatid disease. Conclusions: Hydatid disease of the liver is not a common disease, and its management can include medical, surgical, and interventional radiology. The decision depends on the size and complexity of the cyst and its location. Bile leak is a common complication and should be managed conservatively or through intervention by radiology or endoscopic retrograde cholangiopancreatography (ERCP).

Reduced cleavage of von willebrand factor by ADAMTS13 is associated with microangiopathic acute kidney injury following trauma.

Acute kidney injury (AKI) is common after trauma, but contributory factors are incompletely understood. Increases in plasma von Willebrand Factor (vWF) with concurrent decreases in ADAMTS13 are associated with renal microvascular thrombosis in other disease states, but similar findings have not been shown in trauma. We hypothesized that molecular changes in circulating vWF and ADAMTS13 promote AKI following traumatic injury. VWF antigen, vWF multimer composition and ADAMTS13 levels were compared in plasma samples from 16 trauma patients with and without trauma-induced AKI, obtained from the Prehospital Air Medical Plasma (PAMPer) biorepository. Renal histopathology and function, vWF and ADAMTS13 levels were assessed in parallel in a murine model of polytrauma and haemorrhage. VWF antigen was higher in trauma patients when compared with healthy controls [314% (253-349) vs. 100% (87-117)] [median (IQR)], while ADAMTS13 activity was lower [36.0% (30.1-44.7) vs. 100.0% (83.1-121.0)]. Patients who developed AKI showed significantly higher levels of high molecular weight multimeric vWF at 72-h when compared with non-AKI counterparts [32.9% (30.4-35.3) vs. 27.8% (24.6-30.8)]. Murine plasma cystatin C and vWF were elevated postpolytrauma model in mice, with associated decreases in ADAMTS13, and immunohistologic analysis demonstrated renal injury with small vessel plugs positive for fibrinogen and vWF. Following traumatic injury, the vWF-ADAMTS13 axis shifted towards a prothrombotic state in both trauma patients and a murine model. We further demonstrated that vWF-containing, microangiopathic deposits were concurrently produced as the prothrombotic changes were sustained during the days following trauma, potentially contributing to AKI development.

The Pathobiological Basis for Thrombotic Complications in COVID-19: a Review of the Literature.

Purpose of Review: COVID-19 has rapidly evolved into a global pandemic infecting over two hundred and forty-four million individuals to date. In addition to the respiratory sequelae and systemic infection that ensues, an alarming number of micro and macrovascular thrombotic complications have been observed. This review examines the current understanding of COVID-19-associated thrombotic complications, potential mechanisms, and pathobiological basis for thromboses development. Recent Findings: The endothelium plays a major role in the process due to direct and indirect injury. The immune system also contributes to a pro-thrombotic environment with immune cell dysregulation leading to excessive formation of cytokines, also called cytokine storm, and an eventual promotion of a hypercoagulable environment, known as immunothrombosis. Additionally, neutrophils play an important role by forming neutrophil extracellular traps, which are shown to be pro-thrombotic and further enhanced in COVID-19 patients. A disruption of the fibrinolysis system has also been observed. Summary: Multiple pathways likely contribute synergistically to form a pro-thrombotic milieu. A better understanding of these factors and the complex interplay between them will lead to the improvement of diagnostic and therapeutic interventions.