Abstract

IMPORTANCE It is not clear which severely injured patients with hemorrhagic shock may benefit most from a 1:1:1 vs 1:1:2 (plasma:platelets:red blood cells) resuscitation strategy. Identification of trauma molecular endotypes may reveal subgroups of patients with differential treatment response to various resuscitation strategies. OBJECTIVE To derive trauma endotypes (TEs) from molecular data and determine whether these endotypes are associated with mortality and differential treatment response to 1:1:1 vs 1:1:2 resuscitation strategies. DESIGN, SETTING, AND PARTICIPANTS This was a secondary analysis of the Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized clinical trial. The study cohort included individuals with severe injury from 12 North American trauma centers. The cohort was taken from the participants in the PROPPR trial who had complete plasma biomarker data available. Study data were analyzed on August 2, 2021, to October 25, 2022. EXPOSURES TEs identified by K-means clustering of plasma biomarkers collected at hospital arrival. MAIN OUTCOMES AND MEASURES An association between TEs and 30-day mortality was tested using multivariable relative risk (RR) regression adjusting for age, sex, trauma center, mechanism of injury, and injury severity score (ISS). Differential treatment response to transfusion strategy was assessed using an RR regression model for 30-day mortality by incorporating an interaction term for the product of endotype and treatment group adjusting for age, sex, trauma center, mechanism of injury, and ISS. RESULTS A total of 478 participants (median [IQR] age, 34.5 [25-51] years; 384 male [80%]) of the 680 participants in the PROPPR trial were included in this study analysis. A 2-class model that had optimal performance in K-means clustering was found. TE-1 (n = 270) was characterized by higher plasma concentrations of inflammatory biomarkers (eg, interleukin 8 and tumor necrosis factor α) and significantly higher 30-day mortality compared with TE-2 (n = 208). There was a significant interaction between treatment arm and TE for 30-day mortality. Mortality in TE-1 was 28.6% with 1:1:2 treatment vs 32.6% with 1:1:1 treatment, whereas mortality in TE-2 was 24.5% with 1:1:2 treatment vs 7.3% with 1:1:1 treatment (P for interaction = .001). CONCLUSIONS AND RELEVANCE Results of this secondary analysis suggest that endotypes derived from plasma biomarkers in trauma patients at hospital arrival were associated with a differential response to 1:1:1 vs 1:1:2 resuscitation strategies in trauma patients with severe injury. These findings support the concept of molecular heterogeneity in critically ill trauma populations and have implications for tailoring therapy for patients at high risk for adverse outcomes.

Abstract

OBJECTIVES Determine associations between biomarkers of endotheliopathy, 24-hour fibrinolysis phenotypes and clinical outcomes after trauma. BACKGROUND The vascular endothelium is a critical regulator of hemostasis and organ function. The relationship between markers of endotheliopathy and fibrinolysis following trauma has not been evaluated. METHODS We performed a secondary analysis of prospectively collected biomarker data in the Pragmatic Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized controlled trial. We stratified subjects by 24-hour thromboelastography (TEG) percent clot lysis (LY30) and plasma D-dimer (DD) levels and evaluated differences in endotheliopathy biomarkers and clinical outcomes between subjects with one of four 24-hour fibrinolysis phenotypes: LY30 0.9-2.9% (LY30(norm)), LY30 >2.9% (LY30(high)), LY30 <0.9% and low DD (LY30(low)+DD(low)), and LY30 <0.9% and high DD (LY30(low)+DD(high)). RESULTS The analysis included 168 subjects with LY30(norm), 32 with LY30(high), 147 with LY30(low)+DD(low) and 124 with LY30(low)+DD(high). LY30(low)+DD(high) subjects had greater injury severity and a higher incidence of severe head injury, multiorgan failure (MOF), and mortality than the other phenotypes. All endotheliopathy biomarkers were significantly higher in the LY30(low)+DD(high) phenotype. Adjusting for injury severity, mechanism and head trauma, 24-hour angiopoietin-2 and soluble thrombomodulin were independently associated with the LY30(low)+DD(high) phenotype. Both endothelial biomarkers were discriminating for MOF. Subjects with thrombomodulin level >9.5 ng/mL and angiopoietin-2 level >3.6 ng/mL accounted for 64% of subjects who developed MOF. CONCLUSIONS In a multicenter trauma cohort, subjects with a fibrinolysis phenotype characterized by low TEG lysis and elevated DD 24 hours after injury have significantly worse endotheliopathy and clinical outcomes. Our findings support mechanistic evaluations of the role of the endothelium in fibrinolysis dysregulation that may drive late-stage organ injury.

Abstract

BACKGROUND Massive transfusion protocols to treat post-injury hemorrhage are based on pre-defined blood product transfusion ratios followed by goal-directed transfusion based on patient's clinical evolution. However, it remains unclear how these transfusion ratios impact patient outcomes over time from injury. METHODS The Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) is a phase 3, randomized controlled trial, across 12 level-I trauma centers in North America. From 2012 to 2013, 680 severely injured patients required massive transfusion. We used semi-parametric machine learning techniques and causal inference methods to augment the intent-to-treat analysis of PROPPR, estimating the dynamic relationship between transfusion ratios and outcomes: mortality and hemostasis at different time-points during the first 24 hours after admission. RESULTS In the intention-to-treat analysis, the 1:1:1 group tended to have decreased mortality, but with no statistical significance. For patients in whom hemostasis took longer than 2 hours, the 1:1:1 ratio was associated with a higher probability of hemostasis, statistically significant from the 4 hour on. In the per-protocol, actual-transfusion-ratios-received analysis, during four successive time intervals, no significant association was found between the actual ratios and mortality. When comparing patient groups who received both high plasma:PRBC and high platelet:PRBC ratios to the group of low ratios in both, the relative risk of achieving hemostasis was 2.49 (95% CI = 1.19-5.22) during the 3 hour after admission, suggesting a significant beneficial impact of higher transfusion ratios of plasma and platelets on hemostasis. CONCLUSIONS Our results suggest that the impact of transfusion ratios on hemostasis is dynamic. Overall, the transfusion ratios had no significant impact on mortality over time. However, receiving higher ratios of platelets and plasma relative to red blood cells hastens hemostasis in subjects who have yet to achieve hemostasis within 3 hours after hospital admission. LEVEL OF EVIDENCE Prognostic, level III.

Abstract

BACKGROUND No FDA-approved medication improves outcomes following traumatic brain injury (TBI). A forthcoming clinical trial that evaluated the effects of two prehospital tranexamic acid (TXA) dosing strategies compared with placebo demonstrated no differences in thromboelastography (TEG) values. We proposed to explore the impact of TXA on markers of coagulation and fibrinolysis in patients with moderate to severe TBI. METHODS Data were extracted from a placebo-controlled clinical trial in which patients ≥15 years old with TBI (Glascow Coma Scale 3-12) and systolic blood pressure ≥90 mmHg were randomized prehospital to receive placebo bolus/placebo infusion (Placebo), 1 gram (g) TXA bolus/1g TXA infusion (Bolus Maintenance [BM]); or 2g TXA bolus/placebo infusion (Bolus Only [BO]). TEG was performed and coagulation measures including prothrombin time (PT), activated partial thromboplastin time (aPTT), international ratio (INR), fibrinogen, D-dimer, plasmin anti-plasmin (PAP), thrombin anti-thrombin (TAT), tissue plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) were quantified at admission and six hours later. RESULTS Of 966 patients receiving study drug, 700 had labs drawn at admission and six hours later. There were no statistically significant differences in TEG values, including LY30, between groups (p>0.05). No differences between PT, aPTT, INR, fibrinogen, TAT, tPA, and PAI-1 were demonstrated across treatment groups. Concentrations of D-dimer in TXA treatment groups were less than placebo at six hours (p<0.001). Concentrations of PAP were less in TXA treatment groups than placebo on admission (p<0.001) and six hours (p=0.02). No differences in D-dimer and PAP were observed between BM and BO. CONCLUSION While D-dimer and PAP levels reflect a lower degree of fibrinolysis following prehospital administration of TXA when compared to placebo in a large prehospital trial of patients with TBI, TEG obtained on admission and six hours later did not demonstrate any differences in fibrinolysis between the two TXA dosing regimens and placebo. LEVEL OF EVIDENCE III; Diagnostic.

Abstract

BACKGROUND No Food and Drug Administration-approved medication improves outcomes following traumatic brain injury (TBI). A forthcoming clinical trial that evaluated the effects of two prehospital tranexamic acid (TXA) dosing strategies compared with placebo demonstrated no differences in thromboelastography (TEG) values. We proposed to explore the impact of TXA on markers of coagulation and fibrinolysis in patients with moderate to severe TBI. METHODS Data were extracted from a placebo-controlled clinical trial in which patients 15 years or older with TBI (Glasgow Coma Scale, 3-12) and systolic blood pressure of ≥90 mm Hg were randomized prehospital to receive placebo bolus/placebo infusion (placebo), 1 g of TXA bolus/1 g of TXA infusion (bolus maintenance), or 2 g of TXA bolus/placebo infusion (bolus only). Thromboelastography was performed, and coagulation measures including prothrombin time, activated partial thromboplastin time, international ratio, fibrinogen, D-dimer, plasmin-antiplasmin (PAP), thrombin antithrombin, tissue plasminogen activator, and plasminogen activator inhibitor 1 were quantified at admission and 6 hours later. RESULTS Of 966 patients receiving study drug, 700 had laboratory tests drawn at admission and 6 hours later. There were no statistically significant differences in TEG values, including LY30, between groups (p > 0.05). No differences between prothrombin time, activated partial thromboplastin time, international ratio, fibrinogen, thrombin antithrombin, tissue plasminogen activator, and plasminogen activator inhibitor 1 were demonstrated across treatment groups. Concentrations of D-dimer in TXA treatment groups were less than placebo at 6 hours (p < 0.001). Concentrations of PAP in TXA treatment groups were less than placebo on admission (p < 0.001) and 6 hours (p = 0.02). No differences in D-dimer and PAP were observed between bolus maintenance and bolus only. CONCLUSION While D-dimer and PAP levels reflect a lower degree of fibrinolysis following prehospital administration of TXA when compared with placebo in a large prehospital trial of patients with TBI, TEG obtained on admission and 6 hours later did not demonstrate any differences in fibrinolysis between the two TXA dosing regimens and placebo. LEVEL OF EVIDENCE Diagnostic test, level III.

Abstract

BACKGROUND The mortality of trauma patients requiring massive transfusion to treat hemorrhagic shock approaches 17% at 24 hours and 26% at 30 days. The use of stored RBCs is limited to less than 42 days, so older RBCs are delivered first to rapidly bleeding trauma patients. Patients who receive a greater quantity of older RBCs may have a higher risk for mortality. METHODS AND MATERIALS Characterizing blood age exposure requires accounting for the age of each RBC unit and the quantity of transfused units. To address this challenge, a novel Scalar Age of Blood Index (SBI) that represents the relative distribution of RBCs received is introduced and applied to a secondary analysis of the Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized controlled trial (NCT01545232, https://clinicaltrials.gov/ct2/show/NCT01545232). The effect of the SBI is assessed on the primary PROPPR outcome, 24-hour and 30-day mortality. RESULTS The distributions of blood storage ages successfully maps to a parameter (SBI) that fully defines the blood age curve for each patient. SBI was a significant predictor of 24-hour and 30-day mortality in an adjusted model that had strong predictive ability (odds ratio, 1.15 [1.01-1.29], p = 0.029, C-statistic, 0.81; odds ratio, 1.14 [1.02-1.28], p = 0.019, C-statistic, 0.88, respectively). CONCLUSION SBI is a simple scalar metric of blood age that accounts for the relative distribution of RBCs among age categories. Transfusion of older RBCs is associated with 24-hour and 30-day mortality, after adjustment for total units and clinical covariates.

Abstract

BACKDROP Clinicians intuitively recognize that faster time to hemostasis is important in bleeding trauma patients, but these times are rarely reported. METHODS Prospectively collected data from the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial were analyzed. Hemostasis was predefined as no intraoperative bleeding requiring intervention in the surgical field or resolution of contrast blush on interventional radiology (IR). Patients who underwent an emergent (within 90 minutes) operating room (OR) or IR procedure were included. Mixed-effects Poisson regression with robust error variance (controlling for age, Injury Severity Score, treatment arm, injury mechanism, base excess on admission [missing values estimated by multiple imputation], and time to OR/IR as fixed effects and study site as a random effect) with modified Bonferroni corrections tested the hypothesis that decreased time to hemostasis was associated with decreased mortality and decreased incidence of acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), multiple-organ failure (MOF), sepsis, and venous thromboembolism. RESULTS Of 680 enrolled patients, 468 (69%) underwent an emergent procedure. Patients with decreased time to hemostasis were less severely injured, had less deranged base excess on admission, and lower incidence of blunt trauma (all p < 0.05). In 408 (87%) patients in whom hemostasis was achieved, every 15-minute decrease in time to hemostasis was associated with decreased 30-day mortality (RR, 0.97; 95% confidence interval [CI], 0.94-0.99), AKI (RR, 0.97; 95% CI, 0.96-0.98), ARDS (RR, 0.98; 95% CI, 0.97-0.99), MOF (RR, 0.94; 95% CI, 0.91-0.97), and sepsis (RR, 0.98; 95% CI, 0.96-0.99), but not venous thromboembolism (RR, 0.99; 95% CI, 0.96-1.03). CONCLUSION Earlier time to hemostasis was independently associated with decreased incidence of 30-day mortality, AKI, ARDS, MOF, and sepsis in bleeding trauma patients. Time to hemostasis should be considered as an endpoint in trauma studies and as a potential quality indicator. LEVEL OF EVIDENCE Therapeutic/care management, level III.

Abstract

BACKGROUND Women are underrepresented in trauma research, and aggregated results of clinical trials may mask effects that differ by sex. It is unclear whether women respond differently to severe hemorrhage compared with men. We sought to evaluate sex-based differences in outcomes after severe trauma with hemorrhage. METHODS We performed a secondary analysis of the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Trauma patients predicted to require massive transfusion were randomized to a 1:1:1 vs 1:1:2 plasma to platelet to red blood cell transfusion ratio. Analysis was performed according to sex, controlling for clinical characteristics and transfusion arm. RESULTS A total of 134 women and 546 men were analyzed. In multivariable analysis, there was no difference in mortality at 24 hours (hazard ratio for women 0.64, 95% confidence interval 0.34-1.23, P = .18) or in time to hemostasis (hazard ratio 1.10, 95% confidence interval 0.84-1.42, P = .49) by sex. We observed no difference between sexes in volume of blood products transfused during active hemorrhage. However, after anatomic hemostasis, women received lower volumes of all products, with a 38% reduction in fresh frozen plasma (mean ratio 0.62 (95% confidence interval 0.43-0.89, P = .01), 49% reduction in platelets (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01) and 49% reduction in volume of red blood cells (mean ratio 0.51, 95% confidence interval 0.33-0.79, P < .01). CONCLUSION Mortality and time to hemostasis of trauma patients with hemorrhage did not differ by sex. Although there was no difference in transfusion requirement during active hemorrhage, once hemostasis was achieved, women received fewer units of all blood products than men. Further research is required to determine whether women exhibit differences in coagulation during and after severe traumatic hemorrhage.

Abstract

INTRODUCTION Administration of tranexamic acid (TXA) in coagulopathy of trauma gained popularity after the CRASH-2 trial. The aim of our analysis was to analyze the role of TXA in severely injured trauma patients with admission hyperfibrinolysis. METHODS We reviewed the prospectively collected Pragmatic, Randomized Optimal Platelet and Plasma Ratios database. We included patients with admission hyperfibrinolysis (Ly30 >3%) on thromboelastography. Patients were stratified into two groups (TXA and No-TXA) and were matched in 1:2 ratio using propensity score matching for demographics, admission vitals, and injury severity. Primary outcome measures were 6-, 12-, and 24-hour and 30-day mortality; 24-hour transfusion requirements; time to achieve hemostasis; and rebleeding after hemostasis requiring intervention. Secondary outcome measures were thrombotic complications. RESULTS We analyzed 680 patients. Of those, 118 had admission hyperfibrinolysis, and 93 patients (TXA: 31 patients; No-TXA: 62 patients) were matched. Matched groups were similar in age (p = 0.33), gender (p = 0.84), race (p = 0.81), emergency department (ED) Glasgow Coma Scale (p = 0.34), ED systolic blood pressure (p = 0.28), ED heart rate (p = 0.43), mechanism of injury (p = 0.45), head Abbreviated Injury Scale score (p = 0.68), injury severity score (p = 0.56), and blood products ratio (p = 0.44). Patients who received TXA had a lower 6-hour mortality rate (34% vs. 13%, p = 0.04) and higher 24-hour transfusion of plasma (15 vs. 10 units, p = 0.03) compared with the No-TXA group. However, there was no difference in 12-hour (p = 0.24), 24-hour (p = 0.25), and 30-day mortality (p = 0.82). Similarly, there was no difference in 24-hour transfusion of RBC (p = 0.11) or platelets (p = 0.13), time to achieve hemostasis (p = 0.65), rebleeding requiring intervention (p = 0.13), and thrombotic complications (p = 0.98). CONCLUSION Tranexamic acid was associated with increased 6-hour survival but does not improve long-term outcomes in severely injured trauma patients with hemorrhage who develop hyperfibrinolysis. Moreover, TXA administration was not associated with thrombotic complications. Further randomized clinical trials will identify the subset of trauma patients who may benefit from TXA. LEVEL OF EVIDENCE Therapeutic study, level III.

Abstract

Transfusing platelets during massive hemorrhage is debated because of a lack of high-quality evidence concerning outcomes in trauma patients. The objective of this study was to examine the effect of platelet transfusions on mortality in severely injured trauma patients. This work analyzed PROPPR (Pragmatic, Randomized Optimal Platelet and Plasma Ratios) trial patients who received only the first cooler of blood products, which either did or did not contain platelets. Primary outcomes were all-cause mortality at 24 hours and 30 days and hemostasis. Secondary outcomes included cause of death, complications, and hospital-, intensive care unit (ICU)-, and ventilator-free days. Continuous variables were compared using Wilcoxon rank sum tests. Categorical variables were compared using Fisher's exact tests. There were 261 PROPPR patients who achieved hemostasis or died before receiving a second cooler of blood products (137 received platelets and 124 did not). Patients who received platelets also received more total plasma (median, 3 vs 2 U; P < .05) by PROPPR intervention design. There were no differences in total red blood cell transfusions between groups. After controlling for plasma volume, patients who received platelets had significantly decreased 24-hour (5.8% vs 16.9%; P < .05) and 30-day mortality (9.5% vs 20.2%; P < .05). More patients in the platelet group achieved hemostasis (94.9% vs 73.4%; P < .01), and fewer died as a result of exsanguination (1.5% vs 12.9%; P < .01). Patients who received platelets had a shorter time on mechanical ventilation (P < .05); however, no differences in hospital- or ICU-free days were observed. In conclusion, early platelet administration is associated with improved hemostasis and reduced mortality in severely injured, bleeding patients. This trial was registered at www.clinicaltrials.gov as # NCT01545232.