Plaque neovascularization detected with contrast-enhanced ultrasound predicts ischaemic stroke recurrence in patients with carotid atherosclerosis.

BACKGROUND AND PURPOSE: Plaque neovascularization is a hallmark of carotid plaque vulnerability. With contrast-enhanced ultrasound (CEUS) it is possible to visualize plaque neovessels in vivo. Our aim was to determine if CEUS-detected neovessels were associated with stroke recurrences in patients with a recent stroke and carotid atherosclerosis. METHODS: We conducted a prospective study of consecutive patients with a recent stroke and at least one atherosclerotic plaque in the internal carotid artery on the side consistent with symptoms. All of our patients underwent a carotid ultrasound examination including a CEUS study. Neovascularization was graded into three categories according to the extent of neovessels. During the follow-up, we recorded stroke recurrences. A multivariable Cox regression analysis was performed to evaluate predictors of recurrence. RESULTS: We included 78 patients whose mean age was 74.3 ± 10.4 years. There were 29 (37.2%) patients with a low-grade stenosis (<50%). The remainder presented moderate (50%-69%) or high-grade (≥70%) stenosis. CEUS was not interpretable in 35.9% of the patients, mainly due to calcium shadows. We detected neovascularization in 80% of the plaques. After a median follow-up of 14.1 (interquartile range, 9.5-19.6) months, there were 15 (19.2%) stroke recurrences. In the Cox regression analysis, CEUS-detected neovascularization was independently associated with the risk of stroke recurrence, even after adjusting for the degree of stenosis (hazard ratio, 6.57; 95% confidence interval, 1.66-26.01). CONCLUSION: In patients with an anterior circulation ischaemic stroke and carotid atherosclerosis, plaque neovascularization detected with CEUS was an independent predictor of stroke recurrence.

Proliferation in the human ipsilateral subventricular zone after ischemic stroke.

BACKGROUND: It is uncertain whether neurogenesis occurs in humans after stroke. We studied the morphologic changes that occurred in the subventricular zone (SVZ) in patients who died following an acute ischemic stroke. METHODS: We examined coronal brain slices from patients who died after a first-ever cerebral nonlacunar infarction in the middle cerebral artery territory. We evaluated the morphologic changes in the ipsilateral and contralateral SVZ by light and electron microscopy. Using immunochemistry with Ki-67 and PCNA, we detected cell proliferation. We used Tuj-1 for immature neurons and PSA-NCAM for migrating cells. RESULTS: The study included 7 patients with a mean age of 82 +/- 5 (mean +/- SD) years; 4 were men. They died a mean of 10 +/- 5 days after the ischemic stroke. Brain samples were obtained a mean of 4 +/- 2 hours after death. In comparison with the contralateral SVZ, the following changes were observed in the ipsilateral SVZ: an increase in the width of the gap and ribbon layers, as well as in the cell density of the ribbon layer, an enlargement of the cytoplasmic volume of astrocytes, and an increase of Ki-67-positive cells. In the ipsilateral SVZ, mitoses and cells that stained for either Tuj-1 or PSA-NCAM markers were observed more frequently than in the contralateral SVZ. CONCLUSION: We found unequivocal evidence of active cell proliferation in the ipsilateral subventricular zone following an acute ischemic stroke in our patients.