(688) Arteriovenous Uncoupling in Moderate-to-Severe Traumatic Brain Injury: Perfusion CT Study

Introduction: In healthy people, cerebral arterial inflow and venous outflow are in equilibrium, which reflects the maintenance of a constant oxygen brain supply. Many studies have examined venous and arterial cerebral blood flow velocities (CBFV) in TBI patients. At the same time, the changes between arterial and venous blood volume in moderate-to-severe traumatic brain injury (TBI) remain understudied. The aim was to assess the relationship between cerebral arterial inflow and venous outflow at moderate-to-severe TBI based on the comparison of supratentorial arterial and venous cerebral blood flows using dynamic multiphase perfusion computed tomography (PCT).

Methods: 107 moderate-to-severe TBI patients (women 33; men 74) were undergoing PCT on 2–5 days after hospital admission and stratified into 3 groups as follows: group 1 (moderate TBI, 18 to 59 years old); group 2 (severe diffuse TBI without the intracranial surgery, 19 to 56 years old); group 3 (severe TBI after the surgery, 19 to 58 years old). The cerebral blood flows (CBF) were measured by PCT in both the middle cerebral arteries (CBFmca) and the posterior upper sagittal sinus (CBFuss). The relationship between cerebral arterial inflow and venous outflow was assessed based on the correlations between CBF in these cerebral arteries and the sinus. There were no significant demographic differences between the groups in any of the parameters.

Results: In group 1, CBFmca on the left and right sides were significantly correlated between themselves (R = 0.769, P < 0.0001) and CBFuss (R = 0.359, P =0.027; R = 0.332, P =0.042) . We found a correlation between CBFmca in group 2 (R = 0.76, P < 0.0001), but there was no correlation between CBFmca and CBFuss (P > 0.05). There was no correlation (CBFmca vs. CBFuss) in group 3 (on the side of the removed hematoma, R = 0.025, P =0.89; on the opposite side, R = 0.029, P =0.87; R = 0.113, P =0.529 between MCA).

Conclusions: The increasing severity of TBI is accompanied by an increase in a mismatch between the arterial inflow and venous outflow, reflecting the impaired autoregulation of cerebral blood flow. The study was funded by RSF 24-45-00010.