Succinate Activation of SUCNR1 Predisposes Severely Injured Patients to Neutrophil-mediated ARDS.

OBJECTIVES: Identify the metabolites that are increased in the plasma of severely injured patients that developed ARDS versus severely injured patients that did not, and assay if these increased metabolites prime pulmonary sequestration of neutrophils (PMNs) and induce pulmonary sequestration in an animal model of ARDS. We hypothesize that metabolic derangement due to advanced shock in critically injured patients leads to the PMNs, which serves as the first event in the ARDS. Summary of Background Data: Intracellular metabolites accumulate in the plasma of severely injured patients. METHODS: Untargeted metabolomics profiling of 67 critically injured patients was completed to establish a metabolic signature associated with ARDS development. Metabolites that significantly increased were assayed for PMN priming activity in vitro. The metabolites that primed PMNs were tested in a 2-event animal model of ARDS to identify a molecular link between circulating metabolites and clinical risk for ARDS. RESULTS: After controlling for confounders, 4 metabolites significantly increased: creatine, dehydroascorbate, fumarate, and succinate in trauma patients who developed ARDS ( P < 0.05). Succinate alone primed the PMN oxidase in vitro at physiologically relevant levels. Intravenous succinate-induced PMN sequestration in the lung, a first event, and followed by intravenous lipopolysaccharide, a second event, resulted in ARDS in vivo requiring PMNs. SUCNR1 inhibition abrogated PMN priming, PMN sequestration, and ARDS. Conclusion: Significant increases in plasma succinate post-injury may serve as the first event in ARDS. Targeted inhibition of the SUCNR1 may decrease ARDS development from other disease states to prevent ARDS globally.

Do not drink and lyse: alcohol intoxication increases fibrinolysis shutdown in injured patients.

INTRODUCTION: High alcohol consumption has been associated with decreased fibrinolysis and enhanced thrombosis risk in cardiovascular disease. In trauma, alcohol has been associated with poor clot formation; however, its effect on fibrinolysis has not been fully investigated. We assessed the association of blood alcohol levels and fibrinolysis in trauma activation patients. METHODS: We queried our prospective registry of trauma activations from 2014 to 2016. Associations between viscoelastic measurements [rapid thrombelastography (rTEG)] and blood alcohol level (BAL) were determined and adjusted for confounders by a multinomial logistic regression. Lysis phenotypes were defined by the % lysis in 30 min (LY30) as follows: hyperfibrinolysis ≥ 3%, physiologic 0.9-2.9%, and fibrinolysis shutdown < 0.9%. RESULTS: Overall, 191 (43.8%) had BAL measured. There were 65 (34%) patients that had no detectable BAL, 32 (16.8%) had BAL of 10-150 mg/dL, and 94 (49.2%) patients had BAL > 150 mg/dL. BAL had a moderate, but significant inverse correlation with LY30 (Rho = - 0.315, p < 0.001), while there were no significant correlations between BAL and other TEG values. The distribution of fibrinolysis phenotypes varied significantly by BAL levels (p < 0.009, with high BAL having more shutdown and less hyperfibrinolysis than the other two BAL level groups. Multinomial logistic regression showed that after adjustment for confounders, BAL levels > 150 mg/dL were independently associated with a threefold increase in the odds of shutdown compared to undetectable BAL (OR 3.37, 95% CI 1.04-8.05, p = 0.006). High BAL was also significantly associated with higher odds of shutdown compared to low BAL (OR 2.63, 95% CI 1.15-6.06). Compared to physiologic fibrinolysis, fibrinolysis shutdown was associated with increased mortality (OR 2.87, 95% CI 1.41-5.83) and VFD < 28 (OR 2.54, 95% CI 1.47-4.39). CONCLUSION: In the injured patient, high blood alcohol levels are associated with increased incidence of fibrinolysis shutdown. This finding has implications for postinjury hemostatic resuscitation as these patients may be harmed by anti-fibrinolytics. Further research is needed to assess whether the association with fibrinolysis is modified by the chronicity and type of alcohol consumed and whether anti-fibrinolytic therapy in intoxicated patients produces adverse effects.

Variability in international normalized ratio and activated partial thromboplastin time after injury are not explained by coagulation factor deficits.

BACKGROUND: Conventional coagulation assays (CCAs), prothrombin time (PT)/international normalized ratio (INR) and activated partial thromboplastin time (aPTT), detect clotting factor (CF) deficiencies in hematologic disorders. However, there is controversy about how these CCAs should be used to diagnose, treat, and monitor trauma-induced coagulopathy. Study objectives were to determine whether CCA abnormalities are reflective of deficiencies of coagulation factor activity in the setting of severe injury. METHODS: Patients without previous CF deficiency within a prospective database at an ACS-verified Level I trauma center had CF activity levels, PT/INR, aPTT, and fibrinogen levels measured upon emergency department arrival from 2014 to 2017. Linear regression assessed how CF activity explained the aPTT and PT/INR variation. Prolonged CCA values were set as INR greater than 1.3 and aPTT greater than 34 seconds. CF deficiency was defined as less than 30% activity, except for fibrinogen, defined as less than 150 mg/dL. RESULTS: Sixty patients with a mean age of 35.8 (SD, 13.6) years and median New Injury Severity Score of 32 (interquartile range, 12-43) were included; 53.3% sustained blunt injuries, 23.3% required massive transfusion, and mortality was 11.67%. Overall, 44.6% of the PT/INR variance and 49.5% of the aPTT variance remained unexplained by CF activity. Deficiencies of CFs were: common pathway, 25%; extrinsic pathway, 1.7%; and intrinsic pathway, 6.7%. The positive predictive value for CF deficiencies were: (1) PT/INR greater than 1.3:4.4% for extrinsic pathway, 56.5% for the common pathway; (2) aPTT greater than 34 seconds:16.7% for the intrinsic pathway, 73.7% for the common pathway. CONCLUSION: Almost half of the variances of PT/INR and aPTT were unexplained by CF activity. Prolonged PT/INR and aPTT were poor predictors of deficiencies in the intrinsic or extrinsic pathways; however, they were indicators of common pathway deficiencies. LEVEL OF EVIDENCE: Prognostic, level III.

Discrepancies between conventional and viscoelastic assays in identifying trauma-induced coagulopathy.

BACKGROUND: Trauma-induced coagulopathy can present as abnormalities in a conventional or viscoelastic coagulation assay or both. We hypothesized that patients with discordant coagulopathies reflect different clinical phenotypes. METHODS: Blood samples were collected prospectively from critically injured patients upon arrival at two urban Level I trauma centers. International normalized ratio (INR), partial thromboplastin time (PTT), thromboelastography (TEG), and coagulation factors were assayed. RESULTS: 278 patients (median ISS 17, mortality 26%) were coagulopathic: 20% with isolated abnormal INR and/or PTT (CONVENTIONAL), 49% with isolated abnormal TEG (VISCOELASTIC), and 31% with abnormal INR/PTT and TEG (BOTH). Compared with VISCOELASTIC, CONVENTIONAL and BOTH had higher ISS, lower GCS, larger base deficit, and decreased factor activities (all p < 0.017). They received more blood products and had more ICU/ventilation days (all p < 0.017). Mortality was higher in CONVENTIONAL (40%) and BOTH (49%) than VISCOELASTIC (6%, p < 0.017). CONCLUSIONS: Although TEG-guided resuscitation improves survival after injury, INR and PTT identify coagulopathic patients with highest mortality regardless of TEG and likely represent distinct mechanisms independent of biochemical clot strength.

Redefining postinjury fibrinolysis phenotypes using two viscoelastic assays.

INTRODUCTION: Fibrinolysis was initially defined using rapid thrombelastography (rTEG). The cutoffs for the pathologic extremes of the fibrinolytic system, hyperfibrinolysis and shutdown, were both defined based on association with mortality. We propose to redefine these phenotypes for both TEG and for rotational thrombelastometry, the other commonly used viscoelastic assay. METHODS: Rotational thrombelastometry, rTEG, and clinical data were prospectively collected on trauma patients admitted to an urban Level I trauma center from 2010 to 2016. Hyperfibrinolysis was defined as the Youden index from EXTEM-clot lysis index 60 minutes after clotting time (CLI60) and rTEG-fibrinolysis 30 minutes after achieving MA (LY30) for predicting massive transfusion (>10 red blood cell units, or death per 6 hours after injury) as a surrogate for severe bleeding. Patients identified as having hyperfibrinolysis were then removed from the data set, and the cutoff for fibrinolysis shutdown was derived as the optimal cutoff for predicting mortality in the remaining patients. RESULTS: Overall, 216 patients (median age, 36 years (interquartile range, 27-49 years), 82% men, 58% blunt injury) were included. Of these, 16% required massive transfusion, and 12.5% died. Rapid thrombelastography phenotypes were redefined as hyperfibrinolysis: rTEG-LY30 greater than7.7%, physiologic rTEG-LY30 0.6% to7.6%, and shutdown rTEG-LY30 less than 0.6%. EXTEM-CLI60 fibrinolysis phenotypes were hyperfibrinolysis CLI60 less than 82%, physiologic (CLI60, 82-97.9%), and shutdown (CLI60 > 98%). Weighted kappa statistics revealed moderate agreement between rotational thrombelastometry- and rTEG-defined fibrinolysis (k = 0.51; 95% confidence interval, 0.39-0.63), with disagreement mostly in the shutdown and physiologic categories. CONCLUSION: We confirmed the U-shaped distribution of death related to fibrinolysis system abnormalities. Both rTEG LY30 and EXTEM CLI60 can identify the spectrum of fibrinolytic phenotypes, have moderate agreement, and can be used to guide hemostatic resuscitation. LEVEL OF EVIDENCE: Diagnostic study, level III.

Citrated kaolin thrombelastography (TEG) thresholds for goal-directed therapy in injured patients receiving massive transfusion.

INTRODUCTION: Goal-directed hemostatic resuscitation based on thrombelastography (TEG) has a survival benefit compared with conventional coagulation assays such as international normalized ratio, activated partial thromboplastin time, fibrinogen level, and platelet count. While TEG-based transfusion thresholds for patients at risk for massive transfusion (MT) have been defined using rapid TEG, cutoffs have not been defined for TEG using other activators such as kaolin. The purpose of this study was to develop thresholds for blood product transfusion using citrated kaolin TEG (CK-TEG) in patients at risk for MT. METHODS: CK-TEG was assessed in trauma activation patients at two Level 1 trauma centers admitted between 2010 and 2017. Receiver operating characteristic (ROC) curve analyses were performed to test the predictive performance of CK-TEG measurements in patients requiring MT, defined as >10 units of red blood cells or death within the first 6 hours. The Youden Index defined optimal thresholds for CK-TEG-based resuscitation. RESULTS: Of the 825 trauma activations, 671 (81.3%) were men, 419 (50.8%) suffered a blunt injury, and 62 (7.5%) received a MT. Patients who had a MT were more severely injured, had signs of more pronounced shock, and more abnormal coagulation assays. CK-TEG R-time was longer (4.9 vs. 4.4 min, p = 0.0084), angle was lower (66.2 vs. 70.3 degrees, p < 0.0001), maximum amplitude was lower in MT (57 vs. 65.5 mm, p < 0.0001), and LY30 was greater (1.8% vs. 1.2%, p = 0.0012) in patients with MT compared with non-MT. To predict MT, R-time yielded an area under the ROC curve (AUROC) = 0.6002 and a cut point of >4.45 min. Angle had an AUROC = 0.6931 and a cut point of <67 degrees. CMA had an AUROC = 0.7425, and a cut point of <60 mm. LY30 had an AUROC = 0.623 with a cut point of >4.55%. CONCLUSION: We have identified CK-TEG thresholds that can guide MT in trauma. We propose plasma transfusion for R-time >4.45 min, fibrinogen products for an angle <67 degrees, platelet transfusion for MA <60 mm, and antifibrinolytics for LY30 >4.55%. LEVEL OF EVIDENCE: Therapeutic study, level V.

Empiric transfusion strategies during life-threatening hemorrhage.

BACKGROUND: Resuscitation guided by thrombelastography improves survival after injury. If bleeding is rapid, however, or if no thrombelastography data are available, the optimal strategy remains controversial. Our current practice gives fresh frozen plasma and red blood cells (1:2) empirically in patients with life-threatening hemorrhage, with subsequent administration based on rapid thrombelastography. We identified patients at risk of massive transfusion at 1 hour, examined their initial rapid thrombelastography, and used this value to provide empiric recommendations about transfusions. METHODS: Massive transfusion was defined as >4 units of red blood cells in the first hour. Patients managed by a trauma activation (2014-2017) had an admission rapid thrombelastography analyzed to determine what proportion met thresholds for administration of cryoprecipitate or platelets. RESULTS: Overall, 35 patients received >4 units of red blood cells in the first hour. Based on the admission rapid thrombelastography, 37% met criteria for both platelets and cryoprecipitate, 35% for either platelets or cryoprecipitate and 29% for neither. Kaplan-Meier analysis showed a significant delay in the administration of cryoprecipitate and platelets compared to fresh frozen plasma. CONCLUSION: Patients who require >4 units of red blood cells within the first hour should receive cryoprecipitate and platelets if thrombelastography results are not available. Point-of-care devices are needed for optimal care of trauma-induced-coagulopathy, but these data offer guidance in their absence.

Fibrinolysis shutdown is associated with a fivefold increase in mortality in trauma patients lacking hypersensitivity to tissue plasminogen activator.

BACKGROUND: Fibrinolysis shutdown (SD) is an independent risk factor for increased mortality in trauma. High levels of plasminogen activator inhibitor-1 (PAI-1) directly binding tissue plasminogen activator (t-PA) is a proposed mechanism for SD; however, patients with low PAI-1 levels present to the hospital with a rapid TEG (r-TEG) LY30 suggestive SD. We therefore hypothesized that two distinct phenotypes of SD exist, one, which is driven by t-PA inhibition, whereas another is due to an inadequate t-PA release in response to injury. METHODS: Trauma activations from our Level I center between 2014 and 2016 with blood collected within an hour of injury were analyzed with r-TEG and a modified TEG assay to quantify fibrinolysis sensitivity using exogenous t-PA (t-TEG). Using the existing r-TEG thresholds for SD (<0.9%), physiologic (LY30 0.9-2.9%), and hyperfibrinolysis (LY30 > 2.9%) patients were stratified into phenotypes. A t-TEG LY30 greater than 95th percentile of healthy volunteers (n = 140) was classified as t-PA hypersensitive and used to subdivide phenotypes. A nested cohort had t-PA and PAI-1 activity levels measured in addition to proteomic analysis of additional fibrinolytic regulators. RESULTS: This study included 398 patients (median New Injury Severity Score, 18), t-PA-Sen was present in 27% of patients. Shutdown had the highest mortality rate (20%) followed by hyperfibinolysis (16%) and physiologic (9% p = 0.020). In the non-t-PA hypersensitive cohort, SD had a fivefold increase in mortality (15%) compared with non-SD patients (3%; p = 0.003) which remained significant after adjusting for Injury Severity Score and age (p = 0.033). Overall t-PA activity (p = 0.002), PAI-1 (p < 0.001), and t-PA/PAI-1 complex levels (p = 0.006) differed between the six phenotypes, and 54% of fibrinolytic regulator proteins analyzed (n = 19) were significantly different. CONCLUSION: In conclusion, acute fibrinolysis SD is not caused by a single etiology, and is clearly associated with PAI-1 activity. The differential phenotypes require an ongoing investigation to identify the optimal resuscitation strategy for these patients. LEVEL OF EVIDENCE: Prognostic, level III.

Platelet adenosine diphosphate receptor inhibition provides no advantage in predicting need for platelet transfusion or massive transfusion.

BACKGROUND: Thrombelastography platelet mapping is a useful assay to assess antiplatelet therapy. Inhibited response to the adenosine diphosphate receptor on platelets occurs early after injury, but recent work suggests this alteration occurs even with minor trauma. However, the utility of thrombelastography platelet mapping, specifically the percent of adenosine diphosphate receptor inhibition, in predicting outcomes and guiding platelet transfusion in trauma-induced coagulopathy remains unknown We assessed the role of percent of adenosine diphosphate-inhibition in predicting survival, requirement for massive transfusion or platelet transfusion in patients at risk for trauma-induced coagulopathy. METHODS: Thrombelastography platelet mapping was assessed in 303 trauma activation patients from 2014-2016 and in 89 healthy volunteers. Percent of adenosine diphosphate-inhibition is presented as median and interquartile range. We compared the area under the receiver operating characteristic curve of percent of adenosine diphosphate-inhibition, platelet count, and rapid thrombelastography maximum amplitude for in-hospital mortality, massive transfusion (>10 red blood cells or death/6 hours), and platelet transfusion (>0 platelet units or death/6 hour). RESULTS: Overall, 35 (11.5%) patient died, 27 (8.9%) required massive transfusion and 46, platelet transfusions (15.2%). Median percent of adenosine diphosphate-inhibition was 42.5% (interquartile range: 22.4-69.1%), compared with 4.3 % (interquartile range: 0-13.5%) in healthy volunteers (P < .0001). Patients that died, had a massive transfusion, or platelet transfusion had higher percent of adenosine diphosphate-inhibition than those that did not (P < .05 for all). However, percent of adenosine diphosphate-inhibition did not add significantly to the predictive performance of maximum amplitude or platelet count for any of the 3 outcomes, after adjustment for confounders. Subgroup analyses by severe traumatic brain injury, severe injury and requirement of red blood cells showed similar results. CONCLUSION: Adenosine diphosphate receptor inhibition did not add predictive value to predicting mortality, massive transfusion, or platelet transfusion. Thus, the role of thrombelastography platelet mapping as a solitary tool to guide platelet transfusions in trauma requires continued refinement.

The hypercoagulability paradox of chronic kidney disease: The role of fibrinogen.

BACKGROUND: Chronic kidney disease (CKD) patients have increased rates of bleeding as well as thrombosis. Fibrinogen and platelets combine to generate a mature clot, but in CKD platelets are dysfunctional. Therefore, we hypothesize that CKD patients have increased clot strength due to elevated fibrinogen levels. METHODS: Retrospective review of CKD patients (n = 84) who had rTEG and fibrinogen levels measured. They were compared to healthy controls (n = 134). RESULTS: CKD patients had statistically significant increases in ACT, angle, MA and decreases in LY30 compared to controls. Fibrinogen levels were increased in CKD patients compared to reference range. Fibrinogen levels had a positive correlation with MA (rho = 0.709, p < 0.0001) in CKD patients. CONCLUSIONS: Patients with CKD manifest a coagulopathy consisting of delayed clot formation, but increased final clot strength and decreased clot breakdown. Furthermore, the elevated clot strength is mediated by increased fibrinogen levels in CKD patients.

Hemorrhagic shock and tissue injury drive distinct plasma metabolome derangements in swine.

BACKGROUND: Tissue injury and hemorrhagic shock induce significant systemic metabolic reprogramming in animal models and critically injured patients. Recent expansions of the classic concepts of metabolomic aberrations in tissue injury and hemorrhage opened the way for novel resuscitative interventions based on the observed abnormal metabolic demands. We hypothesize that metabolic demands and resulting metabolic signatures in pig plasma will vary in response to isolated or combined tissue injury and hemorrhagic shock. METHODS: A total of 20 pigs underwent either isolated tissue injury, hemorrhagic shock, or combined tissue injury and hemorrhagic shock referenced to a sham protocol (n = 5/group). Plasma samples were analyzed by UHPLC-MS. RESULTS: Hemorrhagic shock promoted a hypermetabolic state. Tissue injury alone dampened metabolic responses in comparison to sham and hemorrhagic shock, and attenuated the hypermetabolic state triggered by shock with respect to energy metabolism (glycolysis, glutaminolysis, and Krebs cycle). Tissue injury and hemorrhagic shock had a more pronounced effect on nitrogen metabolism (arginine, polyamines, and purine metabolism) than hemorrhagic shock alone. CONCLUSION: Isolated or combined tissue injury and hemorrhagic shock result in distinct plasma metabolic signatures. These findings indicate that optimized resuscitative interventions in critically ill patients are possible based on identifying the severity of tissue injury and hemorrhage.