EBQ:MATTERs Study

Complete Journal Club Article

Morrison J. et al. "Military Application of Tranexamic Acid in Trauma Emergency Resuscitation (MATTERs) Study". JAMA Surgery. 2012. 147(2):113-119.
PubMed Full text PDF

Clinical Question

Does administration of Tranexamic (TXA) acid in trauma patients with hemorrhage improve mortality in a wartime setting?

Conclusion

The use of TXA with blood component-based resuscitation following combat injury results in improved measures of coagulopathy and survival, a benefit that is most prominent in patients requiring massive transfusion

Major Points

Similar to the CRASH-2 Trial, the MATTERs Study assessed the outcomes of trauma patients who received Tranexamic acid (TXA). However, unlike CRASH-2, which was a randomized controlled trial, MATTERs was a retrospective observational study of trauma patients at Camp Bastion, a British military base between Jan 1, 2009 an Dec 31, 2010. Only patients who received a transfusion were flagged for review in the retrospective analysis. During the two year period, for the 1st year, TXA was administered at the discretion of the surgeon or anesthetist on the basis of clinical judgment or if hyperfibrinolysis was demonstrated. For the second year TXA was part of a major hemorrhage protocol.

In addition to the administration of TXA (IV bolus of 1g with repeat dosing per clinician) all patients recieved blood transfusions and had similar ratios of PRBC:FFP (1:0.87 in TXA group and 1:0.88 in non-TXA group).

Overall patients who receive TXA in coordination with blood transfusions during resucitation following combat trauma, experience improved survival. The survival benefit is greatest in those requiring massive transfusions.

Study Design

• Retrospective cohort study
• N=896 patients
  • TXA group: 293 patients
  • Non-TXA group: 603 patients
    • Massive Transfusion TXA group: 125 patients
    • Massive Transfusion Non-TXA group: 196 patients
• Time period: January 1, 2009 - December 31, 2010
• Setting: Camp Bastion surgical hospital in southern Afghanistan
• In-hospital followup
• Primary end point: 24, 48hr, and in-hospital mortality

Population

Inclusion Criteria

• Trauma patients receiving at least 1 unit of PRBCs within 24 hours of admission following combat-related injury were identified using the UK Joint Theatre Trauma Registry

Patient Characteristics

• Age:23yrs old
• Male: 96%
• Mechanism of Injury:
  • Gunshot wound: 31%
  • Explosion:68.6%
• Injury Severity Score: 23.9

Interventions

• 1gm TXA IV bolus (with re-dosing at provider discretion)
• Massive transfusion transfusion patients were defined as receiving 10+ units PRBC within 24hrs

Outcome

Primary Outcomes

Overall TXA vs. Non-TXA

Mortality	TXA	No TXA	P Value
<24 hr	9.60%	12.40%	0.2
<48hrs	11.30%	18.90%	0.004
In Hospital Mortality	17.40%	23.90%	0.03

Secondary Outcomes

TXA vs Non-TXA (Massive Transfusion subgroup)

Mortality	TXA	No TXA	P Value
<24 hr	9.6%	14.8%	.17
<48hrs	10.4%	23.5%	0.003
In Hospital Mortality	14.4%	28.1%	0.004

Subgroup analysis

• 24-hr transfusion mean:
• PRBCs:
  • TXA: 11.8 (21 in Massive Transfusion)
  • Non-TXA: 9.8 (22.5 in Massive Transfusion)
• FFP:
  • TXA: 10.3 (11.5 in Massive Transfusion)
  • Non-TXA: 8.6 (14.3 in Massive Transfusion)
• Pulmonary Embolism:
  • TXA: 8
  • Non-TXA: 2
• Deep Venous Thrombosis:
  • TXA: 7
  • Non-TXA: 1

Criticisms

• For the first year of the study there was no clear protocol for administration of TXA to patients and was under discretion of the treating physician, which potentially introduces a selection bias.
• The MATTERs study offers much more insight into the mortality risk of bleeding patients than did the CRASH-2 Trial since everyone in MATTERs received a transfusion. However this was a single center military trauma hospital and the treatment setting may not be generalizable to all trauma centers.
• Although some patients were treated on the basis of the degree of fibrinolysis there was not quantitative degree or response to treatment demonstrated as well as no information provided regarding timing of TXA administration.
• The addition of cryoprecipitate to the resuscitation efforts may independently add to the survival benefit of tranexamic acid in the seriously injured requiring transfusion

Funding

The study was supported by the Office of the US Air Force Surgeon General and was created in the performance of a contract with the Air Force Medical Support Agency.

Further Reading

CRASH-2 Trial

Sources

Authors

Daniel Ostermayer, Jeffrey Siegler