# Association between hemostatic changes and contusion volume in traumatic brain injury: an observational cohort study

## TL;DR

This study investigates whether changes in blood clotting after traumatic brain injury are linked to the growth of brain bruises, finding no strong independent connection.

## Contribution

The study provides new evidence that hemostatic changes are not independently associated with contusion expansion in traumatic brain injury.

## Key findings

- Hemostatic disturbances were common after TBI but not independently linked to contusion volume.
- Univariable models showed associations between coagulation markers and contusion volume, but these lost significance after adjusting for age and injury time.
- Contusion volumes increased over time, but this was not directly driven by hemostatic marker changes.

## Abstract

Contusion expansion is a key determinant of outcome after traumatic brain injury (TBI). Because many patients develop acute coagulopathy, it has been proposed that hemostatic changes may drive this expansion, but the link remains uncertain.

In this retrospective single-center cohort, we included adults with isolated moderate-to-severe TBI and no pre-injury antithrombotic therapy. The hemostatic markers activated partial thromboplastin time (APTT), prothrombin time (PT, reported as INR), platelet count (PLT), and fibrinogen were measured on admission and during the first 72 h. Contusion volumes were derived from serial CT scans. Associations between hemostatic markers and contusion volumes over time were analyzed using generalized additive mixed models (GAMMs), adjusting for confounders.

Among 109 patients, median admission values were fibrinogen 2.4 g/L, PT-INR 1.0, APTT 29 s, and PLT 233 × 109/L. After admission, fibrinogen and PLT declined, whereas PT-INR and APTT increased modestly. Contusion volume increased from a median of 0.7 ml at baseline to 4.6 ml on the third CT. In univariable models, higher APTT and PT-INR values and lower platelet counts were associated with larger contusion volumes, but these associations lost significance after adjustment for age and time from injury.

Hemostatic disturbances, as measured by standard coagulation assays, were common after TBI but not independently associated with contusion volume over time.

The online version contains supplementary material available at 10.1007/s00701-026-06768-9.