Seigo Shindo

Morphologic Features of Carotid Plaque Rupture Assessed by Optical Coherence Tomography

BACKGROUND AND PURPOSE: Rupture of the plaque fibrous cap and subsequent thrombosis are the major causes of stroke. This study evaluated morphologic features of plaque rupture in the carotid artery by using optical coherence tomography in vivo. MATERIALS AND METHODS: Thirty-six carotid plaques with high-grade stenosis were prospectively imaged by optical coherence tomography. “Plaque rupture” was defined as a plaque containing a cavity that had overlying residual fibrous caps. The fibrous cap thickness was measured at its thinnest part for both ruptured and nonruptured plaques. The distance between the minimum fibrous cap thickness site and the bifurcation point was also measured. Optical coherence tomography identified 24 ruptured and 12 nonruptured plaques. RESULTS: Multiple ruptures were observed in 9 (38%) patients: Six patients had 2 ruptures in the same plaque, 2 patients had 3 ruptures in the same plaque, and 1 patient had 5 ruptures in the same plaque. Most (84%) of the fibrous cap disruptions were identified at the plaque shoulder and near the bifurcation point (within a 4.2-mm distance). The median thinnest cap thickness was 80 μm (interquartile range, 70–100 μm), and 95% of ruptured plaques had fibrous caps of <130 μm. Receiver operating characteristic analysis revealed that a fibrous cap thickness of <130 μm was the critical threshold value for plaque rupture in the carotid artery. CONCLUSIONS: Plaque rupture was common in high-grade stenosis and was located at the shoulder of the carotid plaque close to the bifurcation. A cap thickness of <130 μm was the threshold for plaque rupture in the carotid artery.

Drastic therapy for listerial brain abscess involving combined hyperbaric oxygen therapy and antimicrobial agents.

Background Listeria monocytogenes (L. monocytogenes) is a rare causative pathogen of brain abscess that is often found in immunocompromised patients. Although patients with supratentorial listerial abscesses showed a longer survival with surgical drainage, the standard therapy for patients with subtentorial lesions has not been established. Case Report We report herein a patient with supra- and subtentorial brain abscesses caused by L. monocytogenes infection. These abscesses did not respond to antibiotics, and his symptoms gradually worsened. Drainage was not indicated for subtentorial lesions, and the patient was additionally treated with hyperbaric oxygen therapy, which dramatically reduced the volume of abscesses and improved the symptoms. Conclusions This is the first report of drastic therapy for a patient with listerial brain abscesses involving combined antibiotics and hyperbaric oxygen therapy. The findings suggest that hyperbaric oxygen therapy is a good option for treating patients with deep-seated listerial abscesses and for who surgical drainage is not indicated.

Three-Dimensional Optical Frequency Domain Imaging Evaluation of Novel Dual-Layered Carotid Stent Implantation for Vulnerable Carotid Plaque.

Plaque prolapse through the cell stent has been suggested as one of the major causes of postprocedural distal embolization after carotid artery stenting. A CASPER stent (Terumo, Tokyo, Japan) is the latest-generation stent having the dual layers and expected to reduce the risk of embolization. A 76-year-old male asymptomatic patient with high-grade stenosis in the left internal carotid artery received carotid artery stenting. Preoperative magnetic resonance imaging demonstrated very high intensity signals on T1-weighted images. After a predilatation, a CASPER stent, which has a dual-layer design construction with an inner nitinol micromesh woven onto an external closed-cell stent, was deployed followed by postdilatation. Postprocedural optical frequency domain imaging revealed good apposition of the outer stent to the vascular wall and no significant prolapse of plaque materials between the struts of the inner micromesh. No ischemic lesions were identified on MRI and no abnormal neurological findings were noted after stenting.

High-Intensity Signal in Carotid Plaque on Routine 3D-TOF-MRA Is a Risk Factor of Ischemic Stroke

Background: Carotid atherosclerotic disease is recognized as an important risk factor for brain ischemic events. However, high-grade stenosis does not always cause ischemic strokes, whereas moderate-grade stenosis may often cause ischemic strokes. It has been reported that there is an association between carotid intraplaque hemorrhage (IPH) and new cerebral ischemic events. The purpose of this study was to elucidate the relationship between high-intensity signals (HIS) on maximum intensity projection (MIP) images from routine 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) and prior ischemic strokes in the patients with moderate carotid stenosis. Materials and Methods: Sixty-one patients with moderate carotid artery stenosis (50-69% stenosis based on North American Symptomatic Carotid Endarterectomy Trial criteria) were included. Carotid IPH was defined as the presence of HIS in carotid plaques on MIP images detected by 3D-TOF-MRA using criteria we previously reported. We analyzed the relationship between the presence of HIS in plaques and prior ischemic strokes defined as ischemic lesions on diffusion-weighted brain images. Results: HIS in carotid plaques were present in 27 (44%) of 61 patients. Prior ipsilateral ischemic strokes occurred more frequently in the HIS-positive group than the HIS-negative group (67 vs. 9%, p < 0.001). Furthermore, there were more smokers in the group with ischemic stroke than without it (62 vs. 25%, p = 0.005). In multivariate logistic regression analysis, HIS in carotid plaque (OR 23.4, 95% CI 4.62-118.3, p < 0.001) and smoking (OR 5.44, 95% CI 1.20-24.6, p = 0.028) were independent determinants of prior ischemic strokes after adjustment for age. Conclusions: HIS in carotid plaques on 3D-TOF-MRA MIP images are independent determinants of prior ischemic strokes in patients with moderate carotid artery stenosis, and they can potentially provide a reliable risk stratification of patients with moderate carotid artery stenosis.

Resolving Thrombus in the Left Atrial Appendage by Edoxaban Treatment after Acute Ischemic Stroke: Report of 2 Cases

Here we report first 2 cases of patients with nonvalvular atrial fibrillation with acute cardioembolic stroke in whom thrombi in the left atrial appendage (LAA) were resolved by edoxaban administration. Case 1 reports an 86-year-old woman who suddenly showed right hemiparesis and aphasia due to occlusion of the left middle cerebral artery. She received mechanical thrombectomy and recovered neurologically. Transesophageal echocardiography (TEE) performed on day 1 demonstrated thrombus in the LAA. The thrombus was resolved on day 13 after initiation of edoxaban (30 mg once daily) instead of warfarin, which was administered before stroke onset. Case 2 reports a 49-year-old man who was admitted because of the sudden onset of left hemiparesis and aphasia. TEE demonstrated thrombus in the LAA on day 4, and edoxaban therapy (60 mg once daily) was initiated. The thrombus resolution was observed on day 16, and no embolic stroke occurred.

Acute Embolic Cerebral Infarction and Coronary Artery Embolism in a Patient with Atrial Fibrillation Caused by Similar Thrombi

Although atrial fibrillation (AF) is one of the most frequent causes of ischemic stroke, coronary artery embolism (CE) from AF is rare, and 2.9% of all myocardial infarctions are caused by CE. We present a case of an 87-year-old female patient who suffered ischemic stroke and myocardial infarction at the same time and received intracranial and coronary thrombectomy. Pathological investigation revealed that thrombi were similar and both infarctions were considered as cardioembolism.

Optical Frequency Domain Imaging Evaluation of Progressive Carotid Plaque and In-Stent Restenosis Lesion with Multiple Neovascularizations

BACKGROUND Neovascularization (NV) plays an important role in plaque progression and plaque vulnerability. However, visualization of NV is difficult using standard imaging tools. Recently, optical frequency domain imaging (OFDI) has provided images of intraplaque microstructure that could not be visualized by previous imaging modalities. Here we report a rare case of NV in the carotid plaque detected both before carotid artery stenting (CAS) and in an in-stent restenotic lesion using OFDI. CASE DESCRIPTION A 71-year-old man with asymptomatic severe left carotid artery stenosis was scheduled for CAS. The degree of stenosis had progressed during short-term follow-up. Preoperative magnetic resonance imaging suggested vulnerable plaque. We performed OFDI to evaluate plaque morphology before and after the CAS procedure. Before CAS, OFDI revealed multiple NVs in the carotid plaque, localized around the most stenotic lesion. After CAS, OFDI showed good apposition of the stent to the vascular wall. At 5 months after CAS, in-stent restenosis was detected, which was treated by CAS. Before CAS of the restenotic lesion, OFDI revealed multiple NVs in the restenotic lesion inside the stent struts. After stenting, no ischemic lesions were detected, and restenosis did not occur again over the 1-year follow-up period. CONCLUSIONS In carotid artery plaque, NV might correlate with plaque progression and in-stent restenosis. OFDI enables advanced evaluation of NVs in the carotid artery plaque.

Cerebral infarction related to varicella zoster virus vasculopathy

A 14-year-old girl developed transient disturbance of consciousness, dysarthria, and clumsiness of the right upper limb 4 months after herpes zoster ophthalmicus. Brain MRI showed acute cerebral infarction in the left middle cerebral artery (MCA) territory. CT angiography demonstrated mild stenosis in the top of the left internal carotid artery and the proximal side of the MCA. Cerebrospinal fluid (CSF) examination showed slightly mononuclear pleocytosis (6/μl). Titer of the anti-varicella zoster virus (VZV) IgG antibodies in CSF was increased, and gadolinium-enhanced brain MRI (T1-weighted imaging) revealed enhancement of the vessel walls at the stenotic lesions. Based on the diagnosis of VZV vasculopathy, methylprednisolone and valacicrovir were administered, followed by acyclovir, in addition to antithrombotic therapy using aspirin and warfarin. After these treatment, her right upper clumsiness was resolved and gadolinium-enhancement of the vessel walls was disappeared on MRI. VZV vasculopathy may cause ischemic stroke in young patients, especially in children. A careful history-taking about herpes is necessary to detect the disease as a potential cause in young stroke patients.

Relationship between Hemorrhagic Complications and Target Vessels in Acute Thrombectomy

PURPOSE Intracranial hemorrhage after thrombectomy using a catheter to treat acute major cerebral artery occlusion is known to exacerbate patient outcomes. This study was performed to determine the relationship between middle cerebral artery (MCA) tortuosity and postoperative hemorrhage. METHODS We examined 111 consecutive patients who underwent acute thrombectomy for major intracranial artery occlusion in the anterior circulation at our hospital between September 2013 and June 2016. Patients in whom intracranial hemorrhage or subarachnoid hemorrhage was seen on head computed tomography 12-24 hours after surgery were assigned to the hemorrhagic group, whereas all the other patients were assigned to the nonhemorrhagic group. The groups were compared for tortuosity of the MCA, which was evaluated by finding the top-to-bottom (TB) distance of the M1 segment on anterior-posterior view angiograms. A modified Rankin scale score of 0-2 at 3 months after onset was considered a favorable prognosis. RESULTS The hemorrhagic group comprised 28 patients (25.2%) and the nonhemorrhagic group comprised 83 patients (74.8%). No significant difference in patient characteristics was seen between the groups. The hemorrhagic group displayed significantly fewer patients with a favorable prognosis (17.9% versus 43.4%, P = .016). The TB distance was significantly greater in the hemorrhagic group (hemorrhagic group, 9.7 mm; nonhemorrhagic group, 7.6 mm; P = .002); multivariate analysis also identified a TB distance over 8.8 mm as a factor independently associated with postoperative intracranial hemorrhage (P = .001). CONCLUSIONS Post-thrombectomy hemorrhage was significantly correlated with TB distance. A solution is needed for selecting and combining devices used in patients with a TB distance over 8.8 mm.