Written by Clay Smith
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TXA administration for trauma patients in a U.S. level 1 trauma center was associated with similar overall mortality but higher risk for thromboembolic events than the original CRASH-2 cohort.
Why does this matter?
CRASH-2 showed lower mortality when TXA was given to adult patients with traumatic hemorrhage. Most sites in the original study were in countries where transfusion practices and capability to identify adverse events differ from U.S. trauma centers. How would use of TXA fare in a U.S. trauma center context?
A CRASH trip into the real world
This was a retrospective review of implementation of TXA at U.C. Davis, a U.S. level 1 trauma center. They gave TXA 1g over 10 minutes and 1g over the next 8h to trauma patients with either hypotension, massive transfusion, or those who went straight from the ED to OR and presented under 3h from injury. Over a three year period, 273 patients received TXA at this facility, with a 12.3% mortality rate – similar to the original CRASH-2 cohort, 14.5% mortality; 84% of the time TXA was given within 3 hours. However, the rate of thromboembolic events was much higher (6.6%), compared to CRASH-2 (2%). Patients in this study received blood transfusions and surgery more often, were older, and had higher percentage of female patients than the CRASH-2 cohort. They also had high severity of injury. Injury severity score was not recorded in CRASH-2, so it cannot be compared directly. TXA was also given earlier than in CRASH-2. However, authors noted, “only 61% of patients in our study cohort received both bolus and maintenance TXA doses, while 94% received both TXA doses in the CRASH-2 trial.” One would think this would bias results toward fewer thromboembolic events. The difference in thromboembolic events may have been due to older age of patients, greater comorbidities, higher rate of surgery and transfusion, and enhanced screening for thromboembolism compared to CRASH-2. This study shows that use of TXA in another setting may produce different results from the original study population. More research is needed to sort out the safety of TXA in a U.S. trauma center setting.
Source
Mortality and Complication Rates in Adult Trauma Patients Receiving Tranexamic Acid: A Single-center Experience in the Post-CRASH-2 Era. Acad Emerg Med. 2020 May;27(5):358-365. doi: 10.1111/acem.13883. Epub 2020 Mar 19.
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Hello. These are valuable data, but the "angle" is misleading. These data do not suggest any signal of increased VTE risk with TXA. The reported VTE incidence is normal for trauma patients with or without TXA treatment. Moreover, the CRASH-2 trial was designed with an expectation that the incidences of VTE would be under-reported, but that the comparison to placebo would be unbiased – that is, the actual percentages were meaningless, but the RR vs placebo showed a lack of increased risk. From the original report: "In the context of outcome assessment in clinical trials, estimates of the RR are unbiased even when the sensitivity of diagnosis is imperfect, provided that there are few false positives (high specificity). […] As a result, we might have under-reported the frequency of these events. However, our estimates of the RR of non-fatal occlusive events should be unbiased."
That is an excellent point. Thanks for clarifying this.
Thank you for your wonderful service in sharing and summarizing EM literature.