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Reversal of trauma-induced coagulopathy using first-line coagulation factor concentrates or fresh frozen plasma (RETIC): a single-centre, parallel-group, open-label, randomised trial
Innerhofer P, Fries D, Mittermayr M, Innerhofer N, von Langen D, Hell T, Gruber G, Schmid S, Friesenecker B, Lorenz IH, et al
The Lancet. Haematology. 2017;4((6):):e258-e271.. e258
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Abstract
BACKGROUND Effective treatment of trauma-induced coagulopathy is important; however, the optimal therapy is still not known. We aimed to compare the efficacy of first-line therapy using fresh frozen plasma (FFP) or coagulation factor concentrates (CFC) for the reversal of trauma-induced coagulopathy, the arising transfusion requirements, and consequently the development of multiple organ failure. METHODS This single-centre, parallel-group, open-label, randomised trial was done at the Level 1 Trauma Center in Innsbruck Medical University Hospital (Innsbruck, Austria). Patients with trauma aged 18-80 years, with an Injury Severity Score (ISS) greater than 15, bleeding signs, and plasmatic coagulopathy identified by abnormal fibrin polymerisation or prolonged coagulation time using rotational thromboelastometry (ROTEM) were eligible. Patients with injuries that were judged incompatible with survival, cardiopulmonary resuscitation on the scene, isolated brain injury, burn injury, avalanche injury, or prehospital coagulation therapy other than tranexamic acid were excluded. We used a computer-generated randomisation list, stratification for brain injury and ISS, and closed opaque envelopes to randomly allocate patients to treatment with FFP (15 mL/kg of bodyweight) or CFC (primarily fibrinogen concentrate [50 mg/kg of bodyweight]). Bleeding management began immediately after randomisation and continued until 24 h after admission to the intensive care unit. The primary clinical endpoint was multiple organ failure in the modified intention-to-treat population (excluding patients who discontinued treatment). Reversal of coagulopathy and need for massive transfusions were important secondary efficacy endpoints that were the reason for deciding the continuation or termination of the trial. This trial is registered with ClinicalTrials.gov, number NCT01545635. FINDINGS Between March 3, 2012, and Feb 20, 2016, 100 out of 292 screened patients were included and randomly allocated to FFP (n=48) and CFC (n=52). Six patients (four in the FFP group and two in the CFC group) discontinued treatment because of overlooked exclusion criteria or a major protocol deviation with loss of follow-up. 44 patients in the FFP group and 50 patients in the CFC group were included in the final interim analysis. The study was terminated early for futility and safety reasons because of the high proportion of patients in the FFP group who required rescue therapy compared with those in the CFC group (23 [52%] in the FFP group vs two [4%] in the CFC group; odds ratio [OR] 25.34 [95% CI 5.47-240.03], p<0.0001) and increased needed for massive transfusion (13 [30%] in the FFP group vs six [12%] in the CFC group; OR 3.04 [0.95-10.87], p=0.042) in the FFP group. Multiple organ failure occurred in 29 (66%) patients in the FFP group and in 25 (50%) patients in the CFC group (OR 1.92 [95% CI 0.78-4.86], p=0.15). INTERPRETATION Our results underline the importance of early and effective fibrinogen supplementation for severe clotting failure in multiple trauma. The available sample size in our study appears sufficient to make some conclusions that first-line CFC is superior to FFP. FUNDING None.
Clinical Commentary
What is known?
The management of major trauma haemorrhage has changed significantly over the last two decades, and the use of haemostatic resuscitation (the transfusion of red cells and FFP early and in high ratio to mitigate/treat clotting abnormalities that arise from severe trauma haemorrhage) is now standard practice. There are attendant risks from the transfusion of blood components (TRALI, TACO, increased rates of multiple organ failure (MOF) in trauma) and the potential to use clotting factor concentrates (CFCs) such as prothrombin complex concentrate, factor XIII and fibrinogen in place of FFP may confer advantages.
What did this paper set out to examine?
The RETIC study was a single centre, open-label, RCT evaluating the effects of FFP vs. coagulation factor concentrates (CFCs) as treatment for major bleeding after injury in adult trauma patients (age 18 80). The primary endpoint was the development of MOF during ICU stay, as defined by the SOFA score. Secondary endpoints were numerous and included transfusion use, changes to clotting parameters, thromboembolic complications and mortality. The study was designed to detect a difference in MOF between groups notably the publication did not specify the difference expected and 292 patients were required for 80% power.
What did they show?
The study recruited 100 patients (48 FFP and 52 CFC) between March 2012 Feb 2016. Six patients were later excluded. 44FFP and 50 CFC patients were analysed. The baseline characteristics in each arm were balanced. The study was terminated early for safety 52% patients in FFP arm required rescue therapy (double dose therapy followed by switching to the other treatment to stop the bleeding) compared to 4% CFC group (OR: 25.34 [95% CI 5.47 240.03], p < 0.0001). Additionally more FFP patients received massive transfusion; OR 3.04 [0.95 10.87], p = 0.042.
Primary endpoint results were provided using a modified ITT population (patients randomised but did not complete therapy were removed). The study showed no significant difference in MOF between arms: 66% FFP arm vs. 50% CFC arm; OR 1.92 [95%CI 0.78 4.86], p = 0.15. Post-hoc logistic regression analysis showed a significant difference in MOF development in the FFP arm for patients who had higher injury severity and worse brain injury; OR 3.13 [1.19-8.88], p = 0.025. The CFC patients were more likely to have coagulopathy reversed OR 25.34 [5.47-240.03], p <0.0001. (Defined by: FIBTEM A10 >8mm, EXTEM CT < 78 secs and no clinical bleeding). Seven patients died 5 CFC and 2 FFP, most due to severe brain injury and no patient died from exsanguination.
What are the implications for practice and for future work?
Overall, given these limitations, there will be debate about the implications of this trial for practice. The findings regarding reversal of coagulopathy are intriging there is a clear agreement between reversal of coagulopathy i.e. a FIBTEM A10 >8mm, and an EXTEM CT < 78 secs and reduced bleeding. This is the first time, in an RCT setting, that improved ROTEM parameters have been linked to clinical reduction of bleeding and these findings are important. One particular area for further research might be to validate whether the ROTEM parameters are effective thresholds for bleeding treatment and importantly linking the thresholds with hard clinical outcomes such as mortality or significant reduction in transfusion therapy.
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Mechanism of action of tranexamic acid in bleeding trauma patients: an exploratory analysis of data from the CRASH-2 trial
Roberts I, Prieto-Merino D, Manno D
Critical Care (London, England). 2014;18((6):):685.
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Abstract
INTRODUCTION To investigate the mechanism of action of tranexamic acid (TXA) in bleeding trauma patients, we examined the timing of its effect on mortality. We hypothesised that if TXA reduces mortality by decreasing blood loss, its effect should be greatest on the day of the injury when bleeding is most profuse. However, if TXA reduces mortality via an anti-inflammatory mechanism its effect should be greater over the subsequent days. METHODS Exploratory analysis, including per-protocol analyses, of data from the CRASH-2 trial, a randomised placebo controlled trial of the effect of TXA on mortality in 20,211 trauma patients with, or at risk of, significant bleeding. We examined hazard ratios (HR) and 95% confidence intervals for all-cause mortality, deaths due to bleeding and non-bleeding deaths, according to the day since injury. The CRASH-2 trial is registered as ISRCTN86750102 and ClinicalTrials.gov NCT00375258. RESULTS The effect of TXA on mortality is greatest for deaths occurring on the day of the injury (HR all-cause mortality = 0.83, 0.73 to 0.93). This survival benefit is only evident in patients in whom treatment is initiated within 3 hours of their injury (HR <3 hours = 0.78, 0.68 to 0.90; HR >3 hours = 1.02, 0.76 to 1.36). Initiation of TXA treatment within 3 hours of injury reduced the hazard of death due to bleeding on the day of the injury by 28% (HR = 0.72, 0.60 to 0.86). TXA treatment initiated beyond 3 hours of injury appeared to increase the hazard of death due to bleeding, although the estimates were imprecise. CONCLUSIONS Early administration of tranexamic acid appears to reduce mortality primarily by preventing exsanguination on the day of the injury.
Clinical Commentary
What is known?
The CRASH-2 trial, an international, multicentre randomized controlled trial involving over 20 000 patients published in Lancet in 2010, has shown that administration of tranexamic acid (TXA), an antifibrinolytic, to bleeding trauma patients within 3 hours of injury significantly reduces death due to bleeding (p = 0.0077), as well as all-cause mortality (20% reduction)(p = 0.0035) as compared to placebo. TXA is a synthetic derivative of lysine that inhibits fibrinolysis by blocking the lysine binding sites on plasminogen as well as by interfering with the binding of plasmin to fibrin.
What did this paper set out to examine?
The authors set out to investigate the mechanism of action of TXA in bleeding in trauma patients by examining the timing of its effect on mortality in patients evaluated via the CRASH-2 trial. There is debate in the literature as to whether TXA functions by reducing inflammation by reducing plasmin, a pro-inflammatory mediator, or if TXA functions by simply reducing blood loss. The authors hypothesized that if TXA reduces mortality by decreasing blood loss, its effect should be greatest on the day of injury when bleeding should be most profuse. Their belief was that if TXA reduces mortality by an anti-inflammatory mechanism its effect should be greater in the days following the injury.
What did they show?
It is clear that for tranexamic acid to be most beneficial in bleeding trauma patients, it should be given within 3 hours of injury. The effect of TXA on mortality is greatest for deaths occurring on the day of injury and for deaths due to exsanguination. It is still unclear if TXA reduces mortality by an anti-inflammatory mechanism as well as by reducing blood loss. The authors merely used data from CRASH-2 and examined hazard ratios and 95% confidence intervals for all-cause mortality, deaths due to bleeding and non-bleeding deaths according to the day since injury; markers of inflammation were not measured. Future RCTs looking at specific inflammatory mediators measured in bleeding trauma patients receiving TXA versus placebo may be informative.
What are the implications for practice and for future work?
It is clear that for tranexamic acid to be most beneficial in bleeding trauma patients, it should be given within 3 hours of injury. The effect of TXA on mortality is greatest for deaths occurring on the day of injury and for deaths due to exsanguination. It is still unclear if TXA reduces mortality by an anti-inflammatory mechanism as well as by reducing blood loss. The authors merely used data from CRASH-2 and examined hazard ratios and 95% confidence intervals for all-cause mortality, deaths due to bleeding and non-bleeding deaths according to the day since injury; markers of inflammation were not measured. Future RCTs looking at specific inflammatory mediators measured in bleeding trauma patients receiving TXA versus placebo may be informative.