Establishment of a novel hemodynamic cerebral ischemia model of atherosclerotic rabbit.

BACKGROUND: Atherosclerosis is the most common cause of ischemic stroke. Until now, there has been no ideal animal model for studying the hemodynamic ischemia caused by atherosclerosis in posterior circulation. OBJECTIVE: This study was conducted to establish a cerebral ischemic model in an atherosclerotic rabbit by subclavian artery (SA) ligation or embolization, emphasizing the role of hemodynamics. MATERIALS AND METHODS: Thirty-two male New Zealand rabbits (weight, 3.5 to 4.0 kg; provided by Animal Laboratory of Tongji Hospital of Tongji University) were randomly divided into four groups. All the groups, except the controlled group, were fed with high lipid diet for three months and two of the groups were submitted for right SA ligation or left SA embolization and the remaining one group to non-operated group. RESULTS: A SA steal syndrome was established successfully with delayed visualization and prolonged circulation time in the posterior circulation. The circulation time was different when SA was ligated or embolized (P < 0.001), and also there was statistically significant difference between controlled and non-operated groups when angiography of either, left and right, VA was performed (P = 0.009, P = 0.003, respectively). However, there was no statistical significant difference between the ligation and embolization group either before or after the procedure (ligation or embolization) (P = 0.402, P = 0.068, respectively). In the control and non-operated group, angiography of either left or right VA showed no statistically significant difference (P = 0.285, P = 0.197, respectively). In the groups fed with high lipid diet for three months, atherosclerotic plaques were found in the common carotid arteries (CCAs), aortic arch (AAs) and variably in the internal carotid arteries (ICAs). CONCLUSIONS: This model could, to some extent, simulate the clinical hemodynamic state of atherosclerotic stroke. and it is an ideal model for studying the hemodynamic cerebral ischemia in posterior circulation.

Endovascular embolization of small ruptured intracranial aneurysms using a biplane angiographic system with three-dimensional rotational digital subtraction angiography.

Endovascular coiling of small, ruptured intracranial aneurysms is controversial because of technical difficulties. We analyzed the clinical and angiographic effects of endovascular treatment of 39 small (5mm) ruptured intracranial aneurysms (in 37 patients) at our institution between March 2004 and March 2007. Procedures were carried out on a biplane angiographic system with three-dimensional rotational digital subtraction angiography. Immediately after embolization, 30 aneurysms were completely occluded and nine had a residual neck. The volumetric percentage occlusion was 45.2+/-9.7%. Angiographic and clinical follow-up was at 6.1 months and 15.9 months, respectively. Delayed rebleeding was not observed. Complications directly related to the procedure were encountered in two patients (one coil migration and one intraoperative rupture). For 34 patients, the final outcome was excellent or good, one suffered a moderate disability, one a severe disability and one patient died. The results suggest that endovascular embolization is effective and safe for patients with small ruptured intracranial aneurysms.

Correlation between carotid intraplaque hemorrhage and clinical symptoms: systematic review of observational studies.

BACKGROUND AND PURPOSE: We sought to investigate the association between carotid intraplaque hemorrhage (IPH) and ipsilateral symptoms of cerebral ischemia. METHODS: A search was performed for clinical observational studies comparing the incidence of IPH between symptomatic and asymptomatic patients. Odds ratios (ORs) for IPH as a factor in the pathogenesis of neurologic events were calculated and combined by a meta-analysis. Interstudy heterogeneity, estimated effects, and methodologic quality of the studies were assessed. RESULTS: Thirty-one studies were included for analysis. The reported ORs varied widely. Overall, the incidence of IPH in the symptomatic groups was significantly higher than in the asymptomatic group. However, there was an apparent trend for heterogeneity (P<0.00001) between studies. The random-effects summary estimator of ORs was 2.25 (95% CI, 1.57 to 3.22; P<0.00001). To identify potential sources of heterogeneity, subgroup analyses were performed. The pooled ORs varied greatly by stratification. Major heterogeneity was found among studies with low quality, microscopic methods of examination, significant effects, small sizes, early publication, and unequal severity of carotid stenosis in both groups. Large, recent, macroscopic, or high-quality studies, as well as studies with equal degrees of stenosis, tended to yield insignificant associations. The methods in defining and evaluating hemorrhage were very heterogeneous. Characterizations of the age, size, number, and location of hemorrhages were poorly reported and highly variable. In addition, a lack of control of confounders and selection bias were frequently identified among studies. CONCLUSIONS: Statistical inferences have suggested a plausible role in the production of cerebral ischemia; however, reliable interpretation was strongly undermined by poor methodologic quality, substantial heterogeneity, and suspicious publication bias. To preciously estimate the underlying correlation, a well-designed study with uniformity in definition and evaluation for IPH might be warranted.

The correlation of carotid plaque pathohistologic features and neurological symptoms: a meta-analysis of observational studies.

OBJECTIVE: To investigate the association between the pathological features of carotid plaque and ipsilateral symptoms of cerebral ischemia. MATERIALS AND METHODS: We sought to identify clinical observational studies comparing the incidence of pathological features between symptomatic and asymptomatic carotid plaques in terms of ulceration, thrombosis and intraplaque hemorrhage (IPH), published between 1996 and 2006. A search on, PubMed was supplemented by a review of bibliographies of relevant articles and lists of references in it. Odds ratios (OR) for the presence of each feature as a role in the pathogenesis of neurological events were calculated and combined by a meta-analysis. RESULTS: We integrated 16 clinical studies totaling 2839 plaques harvested at endarterectomy procedures. The reported incidence for each feature was highly variable. The methods in defining ulceration, thrombosis and IPH were very heterogeneous. The time intervals between the latest onset of ischemic symptoms and pathological examinations varied greatly. Overall, the incidence of ulcerated plaques in the symptomatic group were significantly higher than that in the asymptomatic group (study number, n=10; OR, 2.32; 95% CI, 1.90-2.83. A random-effect model was performed among studies regarding surface thrombosis because an apparent trend for heterogeneity was observed (n=6; OR, 1.57; 95% CI, 0.68-3.64). There was no difference with respect to IPH between the two groups (n=11; OR, 1.09; 95% CI, 0.91-1.32). CONCLUSIONS: Ulcerated carotid plaque is significantly correlated with the production of neurological events, whereas thrombosis fails to correlate with ischemic symptoms because of the presence of substantial heterogeneity. The association between IPH and clinical presentations is less clear.

[Treatment of dural arteriovenous fistula by transarterial embolization with low dose of N-butyl-2-cyanoacrylate].

OBJECTIVE: To evaluate the efficacy of treatment of dural arteriovenous fistula (DAVF) by transarterial embolization with low dose of N-butyl-2-cyanoacrylate (NBCA). METHODS: Eighteen patients, 6 males and 12 females, aged 47.5 (23-72), with DAVF, 12 with carotid cavernous fistula and 6 with fistula in parietal lobe, underwent transarterial embolization with low dose of NBCA (10%-20%). The key point of transarterial embolization with low dose of NBCA was that low dose NBCA was injected and embolized the veins and then was reversed into the other supplying arteries. RESULTS: Seventeen patients with DAVF in cavernous region and 6 patients with DAVF in parietal lobe were cured anatomically, with the clinical syndromes disappearing. In 1 patient with DAVF in cavernous region the clinical syndrome were moderately improved after transarterial embolization, however, worsened 2 days later. Cerebrovascular angiography demonstrated that the vein was not completely embolized and the draining vein was broadened, and the clinical syndromes were moderately improved again after carotid artery compression therapy for 10 days. CONCLUSION: Convenient and fast, and with low cost and satisfying efficacy, transarterial embolization with low dose of NBCA is a better choice for treatment of DAVF in some cases. The key point of this approach is that the tip of microcatheter is close as much as possible to the fistulae, and NBCA is injected into the fistulae and make the vein diffused well. Attention should be paid to avoid dangerous anastomosis.