Reduction of flow velocities in patients with ischemic events in the middle cerebral artery--long-term follow-up with ultrasound.

Data concerning the persistent reduction of flow velocities measured by transcranial color-coded sonography (TCCS) in relation to the clinical and radiological outcome among patients with ischemic events in middle cerebral artery (MCA) territory is scarce. Patients with > or = 50% reduction of peak systolic velocities (PSV-MCA) as compared to the contralateral MCA were prospectively included in follow-up by TCCS (mean 404 days). Out of 849 patients with stroke admitted to our stroke unit, 25 patients showed reduced PSV-MCA and included in the analyses of this study. Ten (40%) survivors showed persistent reduction of PSV-MCA. None of the patients with normalized PSV-MCA suffered an ischemic event compared with three patients with persistent reduction of PSV-MCA (all had ipsilateral occlusion of the internal carotid artery caused by dissection). Patients with persistently reduced PSV-MCA exhibited significantly (Mann-Whitney test, p = 0.02) larger infarct volumes on CT (mean +/- SD 38 +/-50 cm3) compared to those with normalized PSV-MCA (6 +/- 7 cm3). The functional outcome were, however, similar in patients with normalized and those with persistently reduced PSV-MCA. We found that a relatively high percentage (40%) of patients suffered ischemic event in the MCA territory with initial reduction of flow velocity on TCCS showed persistent reduction on long term follow-up.