Tissue Protrusion With Attenuation Is Associated With Ischemic Brain Lesions After Carotid Artery Stenting.

Background and Purpose- Tissue protrusion between stent struts is frequently observed on optical frequency domain imaging evaluation after carotid artery stenting, but its clinical relevance is unclear. We aimed to investigate the association between the characteristics of tissue protrusion assessed by optical frequency domain imaging and brain lesions identified by diffusion-weighted imaging after carotid artery stenting. Methods- Sixty-five consecutive patients who underwent optical frequency domain imaging after protected carotid artery stenting were enrolled in the study. Cross-sectional optical frequency domain images within the stented segments were evaluated at 0.125-mm intervals. Magnetic resonance imaging was performed 1 to 10 days after treatment. The characteristics of tissue protrusion were compared between patients with and without new ipsilateral brain lesions on posttreatment magnetic resonance imaging. Results- Tissue protrusion was observed in 62 patients (95%). New brain lesions were observed in 24 patients (37%). In the multivariate analysis, the presence of protrusion with attenuation (odds ratio, 2.94 [95% CI, 1.05-8.68] P=0.04) was associated with new brain lesions after carotid artery stenting. Conclusions- The presence of protrusion with attenuation assessed by optical frequency domain imaging was associated with ipsilateral brain lesions after carotid artery stenting. Prevention or treatment of protrusions with attenuation may reduce ischemic brain lesions after carotid artery stenting.

Pathologic Findings of Symptomatic Carotid Artery Stenosis Several Decades after Radiation Therapy: A Case Report.

Improved long-term survival of malignancy has drawn increased attention to late cerebrovascular toxicity after neck radiotherapy. Recently, neck radiotherapy has been found as a significant risk factor of carotid artery stenosis and ischemic stroke; however, long-term adverse effects of radiation in large arteries remain unknown. Here, we described an autopsied case with recurrent ischemic stroke associated with ipsilateral carotid artery stenosis several decades after neck radiation therapy. Pathologically, there were intima-media fibrosis, endothelial cell loss, and decreased expression of thrombomodulin in irradiated carotid artery stenosis. Our findings support the hypothesis that long-term radiation-induced vascular injury in large arteries is morphologically different from atherosclerotic change. Furthermore, endothelial cell injury may promote fibrin thrombus formation through decreased expression of thrombomodulin, which may cause ischemic stroke associated with radiation-induced carotid artery stenosis.

Histopathologic Analysis of Retrieved Thrombi Associated With Successful Reperfusion After Acute Stroke Thrombectomy.

BACKGROUND AND PURPOSE: Histopathologic evaluation of occlusive thrombi retrieved from cerebral arteries using endovascular therapy is possible. We investigated the relationship between successful reperfusion after thrombectomy and histopathologic characteristics of retrieved thrombi. METHODS: Among consecutive patients with acute ischemic stroke treated with endovascular therapy at our institute from December 2010 to July 2015, we retrospectively reviewed those with acute major arterial occlusion from which retrieved thrombi were evaluated histopathologically. Obtained thrombi were assessed for the existence of atheromatous gruel, organization, and the ratios of erythrocyte and fibrin/platelet components. Successful reperfusion was defined as the modified Treatment in Cerebral Ischemia grade of 2b to 3. RESULTS: Of 83 patients studied, 58 (70%) underwent successful reperfusion. Atheromatous gruel was less frequently identified (3% versus 20%; P=0.024), and the proportion of erythrocyte components was higher (57±23% versus 47±24%; P=0.042) in thrombi retrieved from the reperfused than the unreperfused group. On multivariate logistic regression analysis, atheromatous gruel was inversely related (odds ratio, 0.062; 95% confidence interval, 0.002-0.864), and >64% erythrocyte components (cutoff obtained from receiver operating characteristic curve) were positively related (odds ratio, 4.352; 95% confidence interval, 1.185-19.363) to successful reperfusion. CONCLUSIONS: Successful reperfusion could be associated with the histopathology of occlusive thrombi, including the existence of atheromatous gruel and proportion of erythrocyte components. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02251665.

STA-MCA/STA-PCA Bypass Using Short Interposition Vein Graft.

BACKGROUND AND AIMS: Superficial temporal artery (STA) is the mainstay of donor vessels for extra-intracranial bypass (EC-IC bypass) in cerebral revascularization. However, the typically used STA frontal or parietal branch is not always adequate in its flow-carrying capacity. In the present study, we provide an update on an alternative strategy: the use of the STA main trunk as a donor vessel, with a short vein interposition graft. METHODS: Seven patients in whom the STA main trunk was used as a donor site for anastomosis of a short interposition vein graft were included. The grafts were implanted into the M2 of the middle cerebral artery for adjunctive treatment of IC anterior wall blood-blister aneurysms in two patients, for revascularization of an internal carotid artery occlusion in one patient, into the P2/3 of the posterior cerebral artery (PCA) for adjunct treatment of complex PCA aneurysms in three patients and into the P3 of PCA for adjunct treatment of basilar artery (BA) trunk giant aneurysm in one patient. RESULTS: All the bypasses were patent. Intraoperative flow measurements confirmed a moderate flow-carrying capacity of the STA main trunk-interposition short vein graft (20-50 ml; mean 43 ml/min). CONCLUSION: The STA main trunk has a larger diameter than the distal branch; therefore, it would be expected to have a significantly higher flow capacity than its branches. STA main trunk to proximal MCA/PCA bypass using short interposition vein grafts can provide sufficient blood flow, and may be a reasonable alternative to ECA to MCA/PCA bypass using long vein grafts.

The Height and Mobility of Protruding Plaque After Carotid Artery Stenting Are Associated with Postoperative Ischemic Lesions.

BACKGROUND: Tissue protrusion (TP) is a possible cause of cerebral infarction after carotid artery stenting (CAS). Using optical frequency domain imaging (OFDI) and angioscopy, we investigated the relationship between the morphological features of TP and postoperative new ischemic lesions on magnetic resonance imaging (MRI)-diffusion weighted imaging (DWI) after CAS. METHODS: Fifty patients who underwent CAS and subsequent poststenting intravascular evaluation using both OFDI and angioscopy were included. CAS was performed for proximal protection via the femoral artery approach, and intravascular evaluation with OFDI and angioscopy were performed after stent placement. We compared the background and poststenting intravascular findings between patients with and without postoperative new ischemic lesions on MRI-DWI. RESULTS: TP was observed in 42 patients (84%), and postoperative new ischemic lesions on MRI-DWI were observed in 32 patients (64%). The frequency of TP did not differ between the 2 groups, but the height of TP was higher in the DWI-positive group (0.62 mm vs. 0.29 mm, P = 0.0028), and mobile TP was observed only in the DWI-positive group. The height of TP (P = 0.023) was an independent predictor of new periprocedural ischemic brain lesions after CAS, and its cut-off value for mobility was 0.55 mm on the receiver operating characteristic curve (area under the curve, 0.93). CONCLUSIONS: The height of TP on OFDI and mobile-TP on angioscopy after CAS were associated with postoperative new ischemic lesions on MRI-DWI. The intravascular evaluation using OFDI and angioscopy could be helpful for a detailed evaluation of TP.

The Effect of Stent Design on Plaque Protrusion after Carotid Artery Stenting.

Objective: The association between stent design and post-stent intravascular findings after carotid artery stenting (CAS) was evaluated. Methods: Among the 79 patients who underwent CAS between March 2016 and June 2020 at our institution, we retrospectively analyzed 65 patients with full post-stent intravascular evaluation by both optical frequency domain imaging and angioscopy. All CAS procedures were performed under the flow reversal method, and the stent selection was determined by each operator's discretion, depending on the vessel anatomy or plaque characteristics. The patient's characteristics, plaque characteristics, ischemic complication, and post-stent intravascular findings (plaque protrusion, vessel wall apposition of stent) were compared between the closed-cell and open-cell stent groups. Results: The closed-cell group (n = 34) had more high-risk plaques, such as symptomatic lesions or intraplaque hemorrhages, on MRI compared with the open-cell group (n = 31). There was no difference in the rate of ischemic complications between the groups. Although there was no difference in the frequency of plaque protrusion between the two, the maximum height of the protruded plaque was higher in the open-cell group (320 vs. 612 µm, p = 0.003) and incomplete apposition was higher in the closed-cell group (85.3 vs. 6.5%, p <0.0001). Conclusion: The open-cell stent provided better apposition but had larger plaque protrusion. The need for a new hybrid stent that combines the merits of both open- and closed-cell stents was suggested.

Vascular wall components in thrombi obtained by acute stroke thrombectomy: clinical significance and related factors.

BACKGROUND AND PURPOSE: Vascular wall components (VWCs) are sometimes identified as collagen fibers in specimens retrieved by thrombectomy from acute stroke patients. However, their clinical significance and associated factors remain unclear. The purpose of this study was to clarify the factors associated with VWCs in retrieved thrombi. METHODS: Consecutive acute stroke patients treated endovascularly using the Penumbra aspiration catheter or stent retrievers (SRs) at our institute from November 2013 to April 2016 were retrospectively reviewed, and the retrieved thrombi were evaluated histopathologically. VWCs were defined as banded collagen fibers with a distinct boundary observed at the rim or outside of the retrieved thrombi. Factors associated with the presence of VWCs were studied. RESULTS: A total of 150 specimens (76 specimens retrieved by the Penumbra, 74 by SRs) from 101 patients (47 women, age 74.9±11.1 years) were investigated. Applied thrombectomy devices were aspiration catheters in 42 patients, SRs in 21 patients, and both in 38 patients. VWCs were observed in 24 specimens (16%) from 22 patients. A low proportion of erythrocyte components (41.7±24.8% vs 55.0±26.3%, P=0.01), a high frequency of the devices reaching the M2/P2 (75% vs 50%, P=0.02), and a high number of device passages (P for trend=0.02) were associated with VWC positive thrombi. Successful recanalization (Treatment in Cerebral Ischemia ≥2b) tended to be less frequent in patients with VWC positive thrombi than in those without (73% vs 89%, P=0.06). CONCLUSIONS: The histopathology of occlusive thrombi, arterial sites where devices reached, and number of device passages, might affect the presence of VWCs in retrieved thrombi.

Transient Prosopometamorphopsia Restricted to the Left Eye Caused by Ischemia at the Right Splenium of the Corpus Callosum.

We herein report a patient who developed transient prosopometamorphopsia restricted to the left eye caused by ischemia of the right splenium of the corpus callosum. A 66-year-old right-handed woman suddenly noticed that the left eyes of people she encountered appeared markedly adducted to their noses. On emergent admission, neurological and ophthalmological examinations revealed no abnormalities. Diffusion-weighted magnetic resonance imaging showed a small, hyperintense lesion at the right splenium of the corpus callosum. In this case, information on the right visual field projected to the left occipital lobe might have been obstructed on transmission to the right hemisphere through the splenium of the corpus callosum.

Binding of 11C-Pittsburgh compound-B correlated with white matter injury in hypertensive small vessel disease.

OBJECTIVE: 11C-Pittsburgh compound-B (11C-PIB) positron emission tomography (PET) is used to visualize and quantify amyloid deposition in the brain cortex in pathological conditions such as Alzheimer's disease (AD). Intense 11C-PIB retention is also observed in the white matter (WM) of both healthy individuals and AD patients. However, the clinical implications of this retention in brain WM have not been clarified. We investigated the relationship between the extent of white matter lesions (WMLs) and the binding potential of 11C-PIB (BPND) in the WM in patients with hypertensive small vessel disease. We further examined the relationship between the extent of WMLs and BPND in WML and in normal-appearing white matter (NAWM). METHODS: Twenty-one hypertensive vasculopathy patients, without AD and major cerebral arterial stenosis and/or occlusion, were enrolled (9 women, 68 ± 7 years). Regions of WML and NAWM were extracted using magnetization-prepared rapid gradient-echo and fluid-attenuated inversion recovery of magnetic resonance images. Volumes of interest (VOIs) were set in the cortex-subcortex, basal ganglia, and centrum semiovale (CS). BPND in the cortex-subcortex, basal ganglia, CS, WML, and NAWM were estimated on 11C-PIB PET using Logan graphical analysis with cerebellar regions as references. The relationships between WML volume and BPND in each region were examined by linear regression analysis. RESULTS: BPND was higher in the CS and basal ganglia than in the cortex-subcortex regions. WML volume had a significant inverse correlation with BPND in the CS (Slope = -0.0042, R 2 = 0.44, P < 0.01). For intra WM comparison, BPND in NAWM was significantly higher than that in WML. In addition, although there were no correlations between WML volume and BPND in WML, WML volume was significantly correlated inversely with BPND in NAWM (Slope = -0.0017, R 2 = 0.26, P = 0.02). CONCLUSIONS: 11C-PIB could be a marker of not only cortical amyloid-ß deposition but also WM injury accompanying the development of WMLs in hypertensive small vessel disease.

Continuous growth of remote intracerebral haematoma following angiographically successful endovascular embolisation of ruptured cerebral aneurysms.

We describe a poorly recognised and rare complication following the endovascular embolisation of ruptured cerebral aneurysms. Three patients with dense focal subarachnoid haemorrhage (SAH) developed continuous growth of remote intracerebral haematoma (ICH) following endovascular embolisation of a ruptured aneurysm. All endovascular procedures were conducted within less than 6 hours after the onset of SAH with systemic anticoagulation and were completed uneventfully; external ventricular drainage was subsequently inserted. Repeated CT scans revealed continuous growth of ICH remote from the aneurysm without aneurysmal rebleeding. The authors suggest that endovascular embolisation for a ruptured aneurysm under systemic anticoagulation within 6 hours after SAH onset may increase the risk of expanding haematomas, especially in patients with dense focal SAH.

Viral cell-to-cell movement requires formation of cortical punctate structures containing Red clover necrotic mosaic virus movement protein.

Movement protein (MP) of Red clover necrotic mosaic virus (RCNMV) forms punctate structures on the cortical endoplasmic reticulum (ER) of Nicotiana benthamiana cells, which are associated with viral RNA1 replication (Kaido et al., Virology 395, 232-242. 2009). We investigated the significance of ER-targeting by MP during virus movement from cell to cell, by analyzing the function of a series of MPs with varying length deletions at their C-terminus, either fused or not fused with green fluorescent protein (GFP). The C-terminal 70 amino acids were crucial to ER-localization of MP-GFP and cell-to-cell movement of the recombinant virus encoding it. However, C-terminal deletion did not affect MP functions, such as increasing the size exclusion limit of plasmodesmata, single-stranded RNA binding in vitro, and MP interacting in vivo. We discuss the possible role of this MP region in virus movement from cell to cell.