Platelet transfusion does not improve outcomes in patients with brain injury on antiplatelet therapy.
Jeremy L Holzmacher, Cassandra Reynolds, Mayur Patel and 11 others
PMID 29341793WHAT IT FOUND
Platelet transfusion did not improve CT bleeding scores or clinical outcomes in adults with traumatic brain injury taking antiplatelet drugs, although it reduced lab measures of aspirin-like platelet inhibition.
Key findings
01Platelet transfusion significantly reduced arachidonic acid pathway platelet inhibition from 76.0 ± 30.2 to 52.7 ± 31.5 (p < 0.01), while ADP pathway inhibition decreased from 64.5 ± 28.0 to 48.4 ± 31.1 but not significantly (p = 0.07).
02Marshall CT score changes over time were not significant in transfused patients (0.21 ± 0.60, p = 0.10) or non-transfused patients (0.07 ± 0.37, p = 0.32).
03Transfused patients had more surgery (26.1% vs 0%) and longer ICU and hospital stays (3.9 ± 2.6 vs 0.73 ± 1.1 days; 7.8 ± 4.8 vs 3.5 ± 2.8 days), but they also had higher injury severity scores (ISS 23 ± 9 vs 17 ± 10; AIS TBI 4.0 ± 0.37 vs 3.5 ± 0.67).
STILL TO COME
How it was doneWhat they found
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What it does not show
The study was observational, not randomised, so treatment decisions and outcomes could be mixed together. Patients who received transfusion were more severely injured at baseline, so the study cannot separate the effect of transfusion from injury severity. Transfusion practice varied widely between centers and was left to clinician discretion. Repeat CT scans were done at the treating team's discretion, so bleeding progression may have been missed in some patients. The sample was small and underpowered, and a multivariate model could not be made. Marshall CT scores were assigned by researchers, not radiologists, and were not validated within or between institutions. Patients on warfarin or direct oral anticoagulants were excluded, so the results do not address those groups. Many higher severity injuries may have been excluded because confirming home antiplatelet use was difficult.
Declared interests
The authors declared no conflicts of interest. The article is tagged as NIH and non-U.S. government supported.
The easy way to misread this
Do not conclude that platelet transfusion worsened recovery or caused longer stays. The study was observational, transfusion was chosen by clinicians, and transfused patients had more severe brain injury at baseline, so the treatment cannot be separated from the injury.