Blood flow velocities in the basal vein after subarachnoid haemorrhage a prospective study using transcranial duplex sonography

Background. Early recognition of emerging delayed neurological deficits (DN D) in patients after subarachnoid haemorrhage (SAH) is not always possible by transcranial Doppler sonography. Aim of this study was to investigate a) whether determination of blood flow velocities in deep cerebral basal ve ins can predict DND in these patients b) the correlation of venous flow velocity to cerebral blood flow (CBF). Methods, a) We prospectively investigated the mean flow velocity in the bas al vein (V-BVR), in the middle cerebral artery (V-MCA) and in the extracran ial internal carotid artery (V-ICA) in 66 patients after spontaneous SAH. E xaminations were performed daily during the first 10 days, using transcrani al duplex sonography. Thirty-seven patients had VMCA exceeding 120 cm/s. Th ey were categorised in three groups: I: no delayed neurological deficit; II : transient DND; III: permanent DND or death associated with vasospasm. b) In another group of 14 patients, interdiane variations in global cerebral b lood flow (CBF) measured by the Kety-Schmidt-method were correlated with va riations in V-BVR, V-MCA, and V-ICA. Findings. a) In patients without deficit, V-BVR was significantly elevated above normal values the first day (p < 0.05), and days 5 and 6 (p < 0.1) af ter V-MCA exceeding 120 cm/s. In group III (permanent deficit), flow veloci ties in the BVR were significantly below normal on day 5 (p < 0.05) and 9 ( p < OA). b) The correlation between changes in VBVR to changes in CBF (r = 0.78, p < 0.001) was closer than between changes in V-MCA to the changes in CBF (r = 0.54, p < 0.05). Interpretation. In case of elevated V-MCA, patients with higher V-BVR seem to have a better outcome. Changes in CBF correlate better with V-BVR than w ith arterial flow velocities.