Blood flow velocities in the basal vein after subarachnoid haemorrhage. A prospective study using transcranial duplex...

Early recognition of emerging delayed neurological deficits (DND) 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 veins can predict DND in these patients b) the correlation of venous flow velocity to cerebral blood flow (CBF).

a) We prospectively investigated the mean flow velocity in the basal vein (VBVR), in the middle cerebral artery (VMCA) and in the extracranial internal carotid artery (VICA) in 66 patients after spontaneous SAH. Examinations were performed daily during the first 10 days, using transcranial duplex sonography. Thirty-seven patients had VMCA exceeding 120 cm/s. They were categorised in three groups: 1: 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 blood flow (CBF) measured by the Kety-Schmidt-method were correlated with variations in VBVR, VMCA, and VICA.

a) In patients without deficit, VBVR was significantly elevated above normal values the first day (p < 0.05), and days 5 and 6 (p < 0.1) after VMCA exceeding 120 cm/s. In group III (permanent deficit), flow velocities in the BVR were significantly below normal on day 5 (p < 0.05) and 9 (p < 0.1). b) The correlation between changes in VBVR to changes in CBF (r = 0.78, p < 0.001) was closer than between changes in VMCA to the changes in CBF (r = 0.54, p < 0.05).

In case of elevated VMCA, patients with higher VBVR seem to have a better outcome. Changes in CBF correlate better with VBVR than with arterial flow velocities.