Yoshikazu Nakahara

Effect of Guglielmi Detachable Coils on Experimental Carotid Artery Aneurysms in Primates

BACKGROUND AND PURPOSE Clinical experience has established that intravascularly placed metal coils can be a useful treatment for cerebral vascular aneurysms. However, the mechanism by which the coils induce occlusion of the aneurysm is unclear. Appropriate use of this promising treatment modality requires basic understanding of the occlusive process. We used an animal model system of experimentally induced carotid aneurysms to investigate the initial events induced by Guglielmi detachable coils (GDCs), as well as the subsequent vascular changes induced by the coils over time. METHODS We induced 23 aneurysms in the carotid arteries of 16 Japanese monkeys. Nineteen aneurysms were then occluded with GDCs placed via endovascular surgery; 4 aneurysms served as controls. We then used gross and microscopic pathological examination, angiography, and scanning electron microscopy to assess the effects of the GDC. RESULTS In the first few hours after placement of the GDC in the experimental aneurysms, we observed leukocyte attachment and deposition of fibrinlike materials and other proteins. By 4 days after coil placement, leukocytes and fibroblasts were observed in the thrombus. By 2 weeks after coil placement, there was evidence of an endothelial-like covering of the coils. At 3 months after coil placement, we observed development of an arterial media in the occluded aneurysms. CONCLUSIONS The GDCs initiated a cellular response within several hours of aneurysm occlusion. By 2 weeks after coil placement, endothelialization was proceeding, and by 3 months after occlusion, remodeling of the aneurysm had progressed to produce a media-like structure in the former aneurysm.

Mucinous adenocarcinoma arising from supratentorial intramedullary neuroenteric cyst with broncho-pulmonary differentiation.

Neuroenteric cysts are benign intradural endoderm cysts lined by gastrointestinal (GI) or tracheobronchial epithelial cells. Their malignant transformation is extremely rare and only six cases have been reported. In these cases, tissue lineage of the cystic endoderm cells giving rise to carcinoma was not clearly identified either as respiratory or as GI type. Herein, we report a case of mucinous adenocarcinoma arising from the neuroenteric cyst with broncho‐pulmonary differentiation in the right cerebral hemisphere of a Japanese woman in her late 50s. The cyst wall was entirely lined by the following respiratory epithelial components: stratified bronchial ciliated columnar epithelium with basal cells positive for CK5 and p63, terminal bronchiolar Clara cells positive for thyroid transcription factor (TTF)‐1, surfactant B and negative for surfactant C, type I pneumocytes positive for TTF‐1, negative for surfactant B and C, and type II pneumocytes positive for TTF‐1 and surfactant B and C. In addition, nests of hyperplastic single layered mucinous epithelial cells with bronchial goblet cell phenotype were also demonstrated, and histologic features were almost the same as the pulmonary type I congenital adenomatoid malformation (CCAM) with mucinous epithelial proliferation. The mucinous epithelial nests of type I CCAM are liable to develop mucinous adenocarcinoma and frequently accompany K‐ras mutation and expression of p16. However, K‐ras mutation and p‐16 expression were not detected in this case.

Factors for Achieving Safe and Complete Treatment for Unruptured Saccular Aneurysm Smaller Than 10 mm by Simple Clipping or Simple Coil Embolization

OBJECTIVE Reducing complications from unruptured aneurysms (UAs) treatment is important. We clarify the criteria for achieving safe and complete treatment for UAs ≤10 mm by clipping or coil embolization. METHODS This study included 59 newly treated UAs in the past 2 years. We prospectively decided on criteria to recommend active treatment. UAs ≤10 mm and in ≤75 year-olds, located at in the internal carotid artery at the paraclinoid portion and the posterior circulation aneurysms except for a vertebral artery-inferior posterior cerebellar artery aneurysm were mainly treated by coil embolization, and those in the internal carotid artery except at the paraclinoid portion, in the anterior or middle cerebral artery, and in the vertebral artery-inferior posterior cerebellar artery were treated preferably by clipping. UAs with a height/neck ratio or a dome/neck ratio ≤1.4 were treated preferentially by clipping. Specific preoperative imaging and careful manipulation were adopted for clipping. RESULTS Fifty-seven (96.6%) achieved modified Rankin scale (mRS) 0-1, 2 (3.4%) mRS 2-5, and 0 had mRS 6. Fifty-three UAs (89.8%) achieved complete occlusion (CO) and 7 (10.1%) had neck remnants (NR). Forty-one UAs (100%) within the criteria achieved mRS 0-1, 40 (98%) achieved CO, and 1 (2%) NR. The odds ratio of NR for those outside the criteria was 18.5 (95% confidence interval, 1.83-186.6) (P < 0.05). CO treated within the criteria was 39 and NR was 1. CO treated outside the criteria was 14 and NR was 5 (P < 0.05). The mRS 0-1 with age ≤75 years was 55 and the mRS 2-6 was 0. The mRS 0-1 with age ≥76 years was 2 and the mRS 2-6 was 2 (P < 0.01). CONCLUSIONS The treatment for UAs within the criteria, with the most recent points of concern, can lead to safe and complete results.

Periprocedural Outcomes of Carotid Artery Stenting in Elderly Patients

BACKGROUND Carotid artery stenting has emerged as an alternative to carotid endarterectomy especially in patients with high risk of carotid endarterectomy. Older age (≥80 years old) was recognized as one of the high risk factors of carotid endarterectomy. However, the association between older age and increased risk of adverse events for carotid artery stenting has been reported. The purpose of this study was to evaluate the association between age and periprocedural outcomes after carotid artery stenting. METHODS A total of 126 symptomatic and asymptomatic cases of carotid artery stenosis were treated with tailored carotid artery stenting. The type of stents and embolic protection devices were chosen according to clinical and morphologic characteristics of the patients. Procedural, imaging, and clinical outcomes were retrospectively assessed and compared between the elderly patients group (≥80 years old) and the non-elderly patients group (<80 years old). RESULTS Clinical and morphologic characteristics except for dyslipidemia were not significantly different between the 2 groups. Periprocedural neurologic complications were not significantly different between the 2 groups (P = .095). Minor stroke occurred more frequently in the elderly patients group (P = .021). However, the frequency of major stroke was not significantly different between the 2 groups (P = 1). Presence of new ischemic lesions on postprocedural examination was not significantly different between the 2 groups (P = .84). Myocardial infarction and death did not occur in either group. CONCLUSIONS Carotid artery stenting can be performed safely in elderly patients, comparable with non-elderly patients.

Complications and Predictors of Hypotension Requiring Vasopressor after Carotid Artery Stenting

A significant controversy exists regarding the clinical impact of hemodynamic depression on major adverse events after carotid artery stenting (CAS). The purpose of this study was to evaluate the incidence, predictors, and clinical significance of hypotension after CAS. A total of 118 cases of carotid artery stenosis were treated with CAS. Hypotension was defined as sustained systolic blood pressure <80 mmHg and requiring intravenous administration of vasopressor to maintain adequate systolic blood pressure after the procedure. Baseline characteristics, procedural characteristics, and periprocedural major adverse events were retrospectively compared between postprocedural hypotension group and non-hypotension group. Morphological and procedural characteristics were not significantly different between the two groups. Periprocedural major adverse events, presence of new ischemic lesions, and number of new ischemic lesions were not significantly different between the two groups (P = 1, P = 0.36, P = 0.68). Hypertension was an independent protective factor (P = 0.037), and use of proximal protection and the distance from carotid bifurcation to maximum stenotic lesion ≤ 10 mm were independent risk factors for developing hypotension after CAS (P = 0.034, P = 0.027). There was no significant relationship between hypotension after CAS and major adverse events in this study. Maintenance of periprocedural adequate cerebral perfusion is thought to be important to prevent ischemic complications due to hypotension after CAS, especially in these cases.

Progress in the Treatment of Unruptured Aneurysms

Recent technological progress has reduced the complication rate of unruptured aneurysm. We treated 128 unruptured aneurysms between April 2006 and March 2012. Seventy-six aneurysms (59 %) were clipped and 52 (41 %) were coil embolized. After 2010, we applied new instruments, i.e., near-infrared indocyanine-green videoangiography (ICG), an intraoperative endoscope, preoperative detailed MRI, and a stent-assisted coil embolization. In the results: (1) In 60 aneurysms treated before 2009, three patients showed a deterioration of more than two points in mRS (5 %). In 68 aneurysms treated after 2010, no patients showed deterioration (0 %) (p: n.s.). (2) No patients died and 126 patients (98 %) were discharged to home directly. (3) No patients showed rupture after treatment. In conclusion, the appropriate selection of treatment and recent technological progress have facilitated sophisticated treatment of unruptured aneurysms. Recently, the complication rate in surgery and endovascular surgery for unruptured aneurysms has become acceptably low.