[Show abstract][Hide abstract] ABSTRACT: Objective: This study was designed to develop a new hemodynamic parameter on the computational fluid dynamics (CFD) analysis using porous media modeling to predict the angiographic occlusion status after coil embolization of unruptured cerebral aneurysms preoperatively.Method: From September 2009 to June 2013, we treated 20 unruptured cerebral aneurysms with intra-aneurysm coil embolization. Aneurysms were classified into complete occlusion (n=11) or residual flow (n=9) groups based on the angiographic appearance performed at 6-12 months post-coiling. For each aneurysm, a preoperative patient-specific geometry was obtained after segmentation using the DICOM dataset of 3D rotation angiography or 3D CT angiography. With the assumption that coil fibers were randomly distributed in the dome, filtration of blood through a virtual coil-filled aneurysm was described by Darcy's law (porous media modeling), and a new hemodynamic parameter, residual flow volume (RFV), was calculated using CFD analyses. Other hemodynamic parameters such as wall shear stress (WSS) and inflow area (IFA) were also calculated by the CFD analysis. The CFD simulation was achieved using both pre-coiling aneurysm models and virtual coil-filled aneurysm models (porous media modeling). Morphological parameters, volume embolization ratio (VER), and hemodynamic parameters were compared between the complete occlusion and residual flow groups. The area under the receiver operating characteristic (ROC) curve (AUC) was used to examine the diagnostic accuracy to predict the 6-12-month post-coiling angiographic results of aneurysms.Result: There were no significant differences in VER and WSS between the two groups. Among morphological parameters, neck diameter (P=0.020) and neck area (P=0.025) were significantly larger in the residual flow group. Among hemodynamic parameters, IFA in the pre-coiling aneurysm model (P=0.014) and RFV in the coil-filled aneurysm model (P=0.011) were significantly larger in the residual flow group. The ROC analyses showed that RFV with an average flow velocity of more than 1.0 cm/sec in the aneurysm dome (RFV1.0) was useful to predict the post-coiling aneurysm occlusion status (AUC, 0.84 [95% confidence interval, 0.64-1.00]; cut-off value, 10.6 mm3; sensitivity, 100%; and specificity, 63.6%).Conclusion: CFD analysis using porous media simulation may be useful to predict the post-coiling aneurysm-occlusion status. This study proposed a new hemodynamic parameter, RFV1.0, on the CFD analysis, which potentially affects the treatment strategy because the parameter can be simulated before coiling of aneurysms.
[Show abstract][Hide abstract] ABSTRACT: Objectives:
Restenosis or neointimal hyperplasia remains an important complication after carotid artery stenting (CAS) for carotid artery stenosis. The purpose of this study was to examine if an anti-hypertensive drug, angiotensin receptor blocker (ARB), prevents post-CAS neointimal hyperplasia during the first 1-year period after CAS, and to clarify the possible mechanisms.
Hypertension had been treated with a calcium channel blocker (CCB) and/or an ARB, valsartan, by the preference of the neurosurgeon in charge in our department. At admission to perform CAS, patients were assigned to normotensive, valsartan (hypertensive patients treated with valsartan with/without any kind of CCBs), and non-valsartan (hypertensive patients treated with any kind of CCBs without ARBs) groups. Post-CAS neointimal hyperplasia was evaluated by carotid duplex ultrasound imaging in terms of intima-media thickening (IMT), which was performed at pre-CAS and at 90, 180, 270, and 360 days post-CAS. Biomarkers of oxidative stress (8-hydroxy-2'-deoxyguanosine), inflammation (C-reactive protein, tenascin-C) and endothelial cell injury (von Willebrand factor [vWF] antigen) were measured at pre-CAS and at 1, 7, and 180 days post-CAS.
The non-valsartan group (n = 8) had a higher incidence of maximum in-stent IMT ≧ 1.1 mm compared with the normotensive group (n = 6). Valsartan (n = 9) significantly suppressed plasma vWF levels at 7 days post-CAS and decreased the incidence of maximum in-stent IMT ≧ 1.1 mm compared with the non-valsartan group, although clinical parameters were similar between the two groups. Other biomarkers were not significantly different among the three groups.
These findings suggest that valsartan may prevent post-CAS neointimal hyperplasia possibly by suppressing endothelial cell injury.
Neurological Research 06/2014; 37(1):1743132814Y0000000408. DOI:10.1179/1743132814Y.0000000408 · 1.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inflammation is crucially involved in the development of carotid plaques. We examined the relationship between plaque vulnerability and inflammatory biomarkers using intraoperative blood and tissue specimens. We examined 58 patients with carotid stenosis. Following carotid plaque magnetic resonance imaging, 41 patients underwent carotid artery stenting (CAS) and 17 underwent carotid endarterectomy (CEA). Blood samples were obtained from the femoral artery (systemic) and common carotid artery immediately before and after CAS (local). Seventeen resected CEA tissue samples were embedded in paraffin, and histopathological and immunohistochemical analyses for IL-6, IL-10, E-selectin, adiponectin, and pentraxin 3 (PTX3) were performed. Serum levels of IL-6, IL-1β, IL-10, TNFα, E-selectin, VCAM-1, adiponectin, hs-CRP, and PTX3 were measured by multiplex bead array system and ELISA. CAS-treated patients were classified as stable plaques (n = 21) and vulnerable plaques (n = 20). The vulnerable group showed upregulation of the proinflammatory cytokines (IL-6 and TNFα), endothelial activation markers (E-selectin and VCAM-1), and inflammation markers (hs-CRP and PTX3) and downregulation of the anti-inflammatory markers (adiponectin and IL-10). PTX3 levels in both systemic and intracarotid samples before and after CAS were higher in the vulnerable group than in the stable group. Immunohistochemical analysis demonstrated that IL-6 was localized to inflammatory cells in the vulnerable plaques, and PTX3 was observed in the endothelial and perivascular cells. Our findings reveal that carotid plaque vulnerability is modulated by the upregulation and downregulation of proinflammatory and anti-inflammatory factors, respectively. PTX3 may thus be a potential predictive marker of plaque vulnerability.
PLoS ONE 06/2014; 9(6):e100045. DOI:10.1371/journal.pone.0100045 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Stent-assisted coil embolization has enabled the endovascular treatment of wide-necked cerebral aneurysms. Moreover, recent reports demonstrated that stent-assisted coil embolization was associated with a significant decrease in angiographic recurrences of coiled cerebral aneurysms. One of the possible explanations for this adjunctive effect of stent-assisted coil embolization is changes in the local hemodynamics caused by placing intracranial stents. This study investigated the hemodynamic effect of intracranial stents using computational fluid dynamics (CFD) analysis. The geometry of the intracranial stent, Enterprise(TM) VRD, was acquired by using micro computed tomography and virtually placed across the aneurysm orifice of a saccular aneurysm model (saccular model) and a blister-like aneurysm model (blister-like model) constructed from patient-specific three-dimensional (3D) rotational angiography data. Transient CFD analysis was performed with these models with and without stents. Stent placement induced no significant changes in the 3D streamline in the saccular model and slight changes in the blister-like model. Both saccular and blister-like models with stents had lower wall shear stress (WSS) and flow velocity, and higher oscillatory shear index, WSS gradient, and relative residence time than the equivalent models without stents, indicating the possibility that stent placement induced stagnant and disturbed blood flow. Cross-sectional vector velocity around the stent strut revealed complex blood flow patterns with variable direction and velocity. Although this study was a simulation under limited conditions, similar hemodynamic changes might be induced in the neck remnants treated with stent-assisted coil embolization.
[Show abstract][Hide abstract] ABSTRACT: Background and purpose:
Preventing cerebral embolisms is a major concern with carotid artery stenting (CAS). This study evaluated 3-dimensional T1-weighted gradient echo (3D T1GRE) sequence to predict cerebral embolism related to CAS.
We performed quantitative analyses of the characteristics of 47 carotid plaques before CAS by measuring the signal intensity ratio (SIR) and plaque volume using 3D T1GRE images. We used T1-weighted turbo field echo sequence to obtain 3D T1GRE images. We also evaluated diffusion-weighted images (DWI) of the brain before and after CAS to detect ischemic lesions (DWI lesions) from cerebral emboli.
SIR (2.17 [interquartile range 1.50-3.07] versus 1.35 [interquartile range 1.08-1.97]; P=0.010) and plaque volume (456 mm(3) [interquartile range 256-696] versus 301 mm(3) [interquartile range 126-433]; P=0.008) were significantly higher in the group of patients positive for DWI lesions (P-group: n=26) than DWI lesion-negative patients (N-group: n=21). In multivariate logistic regression analysis, SIR (P=0.007) and plaque volume (P=0.042) were independent predictors of DWI lesions with CAS. Furthermore, SIR (rs=0.42, P=0.005) and plaque volume (rs=0.36, P=0.012) were positively correlated with the number of DWI lesions. From analysis of a receiver-operating characteristic curve, the most reliable cutoff values of SIR and plaque volume to predict DWI lesions related to CAS were 1.80 and 373 mm(3), respectively.
Quantitative evaluation of carotid plaques using 3D T1GRE images may be useful in predicting cerebral embolism related to CAS.
[Show abstract][Hide abstract] ABSTRACT: Slow-flow phenomenon is frequently observed during carotid artery stenting (CAS) with a filter embolic protection device. It results in technical difficulties and can lead to adverse neurological events. Flow impairment is thought to be caused by plaque entrapped by the filter and/or blood coagulation on the filter. Characteristics of heparin- or urokinase-treated polyurethanes were analyzed by surface plasmon resonance, and the fibrinolytic activity of the urokinase-treated filter of Angioguard XP was estimated by the fibrin plate assay. A filter membrane of Angioguard XP protection device was treated with a heparin or urokinase solution. In clinical studies, six and nine patients were treated by CAS using Angioguard XP modified with heparin and urokinase, respectively. Filter membranes were examined by scanning electron microscopy (SEM). From in vitro studies, it appeared that urokinase adsorbed and remained on the Angioguard XP filter, and its fibrinolytic activity was demonstrated even after washing with saline; heparin, however, was easily washed out from the surface. From clinical study, some filter pores were obstructed in all six patients in the heparin group and in three patients in the urokinase group. Fibrin net was found on the filter in five of six patients in the heparin group and in one of nine patients in the urokinase group. Treatment of an Angioguard XP filter with a urokinase solution is effective in preventing pore occlusion and may reduce occurrence of the slow-flow phenomenon.
Journal of Biomedical Materials Research Part B Applied Biomaterials 10/2010; 95(1):171-6. DOI:10.1002/jbm.b.31699 · 2.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Management of Vertebral Artery (VA) dissections remains controversial. The clinical and angiographic variables of VA dissections were evaluated to demonstrate the safety and efficacy of endovascular intervention in treatment of VA dissecting aneurysms. MATERIAL and
25 patients with 27 VAdissecting aneurysms were treated with endovascular intervention during the last 10 years.17 patients were admitted with subarachnoid hemorrhage. 23 aneurysms treated using destructive endovascular trapping, while reconstructive techniques were used in 3 aneurysms treated with stent-assisted coiling and one aneurysm treated with false lumen embolization.
The right VA was involved in 14 patients, the left VA in 9 patients, while 2 patients had bilateral VA dissection. The pearl and string sign was the commonest angiographic sign in 12 aneurysms. Perioperative complications included; rebleeding in one patient, symptomatic brain stem infarction in two patients and silent cerebellar ischemic lesion in one patient. Afavorable outcome was evident more in patients with unruptured VA dissection (100%) versus (76.5%) in patients presented with SAH.
The endovascular technique should be individualized according to the clinical status of the patient, angiographic variables, condition of the posterior circulation and the available supplies.
[Show abstract][Hide abstract] ABSTRACT: Distal embolism is an important periprocedural technical complication with carotid angioplasty and carotid artery stenting (CAS). We evaluated the safety and efficacy of protection devices used during CAS by detecting new cerebral ischemic lesions using diffusion-weighted magnetic resonance imaging in 95 patients who underwent 98 CAS procedures: 34 using single PercuSurge GuardWire, 31 using double balloon protection, 15 using proximal flow reverse protection devices, 14 using Naviballoon, and 4 using filter anti-embolic devices. Diffusion-weighted imaging was performed preoperatively and postoperatively to evaluate the presence of any new embolic cerebral lesions. Postoperative diffusion-weighted imaging revealed 117 new ischemic lesions. Three patients had new ischemic stroke, two minor and one major, all ipsilateral to the treated carotid artery. The remaining patients had clinically silent ischemia. The incidence of new embolic lesions was lower using the proximal flow reverse protection device than with the double balloon protection (33% vs. 48.4%), but the volume of ipsilateral new ischemic lesions per patient was 136.6 mm(3) vs. 86.9 mm(3), respectively. Neuroprotection with Naviballoon yielded ipsilateral lesions of large volume (86.6 mm(3)) and higher number (5.7 lesions per patient) than using the filter anti-embolic device (34.8 mm(3) and 1 lesion per patient). New cerebral ischemic lesions after neuroprotected CAS are usually silent. The lower incidence of distal ischemia using proximal flow reverse and double balloon protection devices is limited by the larger volume and higher number of ischemic lesions.
[Show abstract][Hide abstract] ABSTRACT: Out-of-hospital cardiopulmonary arrest (OHCPA) because of aneurysmal subarachnoid hemorrhage (SAH) is almost always fatal, because devastating SAH causes OHCPA and the brain damage is aggravated by OHCPA. We report a rare case of a 63-year-old female patient who survived SAH-induced ventricular fibrillation OHCPA without neurologic sequelae. Early brain computed tomography scans were needed for the diagnosis, as most of SAH seemingly disappeared within 7 h after the onset and was associated with acute coronary syndrome-like findings. This case shows that even less severe SAH can cause ventricular fibrillation OHCPA and takotsubo cardiomyopathy, and that early diagnosis and appropriate treatment following immediate, successful resuscitation may lead to a surprisingly favorable outcome.
European Journal of Emergency Medicine 07/2009; 17(1):42-4. DOI:10.1097/MEJ.0b013e32832d3bde · 1.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Carotid angioplasty and stenting is used for treatment of carotid stenosis. Stent deployment may induce HDI and thereby cause systemic or neurologic deficits. This study defines characteristics and predictors of HDI with CAS.
A total of 132 patients who had undergone CAS were evaluated for periprocedural and postprocedural HDI (hypertension, systolic blood pressure >160 mm Hg; hypotension, systolic blood pressure <90 mm Hg; or bradycardia, heart rate <60 beats per minute).
Frequencies of HDI were 6.8% for hypertension, 32.6% for hypotension, and 15.9% for bradycardia. In addition, CAS of the right side (P < .01), carotid bulb lesions (P < .05), eccentric posterior carotid plaque (P < .0001), and general anesthesia (P < .05) were associated significantly with postprocedural HDI. Male sex (OR, 3.4; 95% CI, 1.8-67.2; P < .001), age of 80 years or older (OR, 0.4; 95%CI, 0.1-1.4; P = .011), and plaque ulceration (OR, 0.5; 95% CI, 0.1-9.5; P = .008) independently predicted postprocedural hypertension. Male sex (OR, 2.5; 95% CI, 1.3-24.9; P < .001), preprocedural major stroke (OR, 0.1; 95% CI, 0.01-0.8; P = .002), carotid bulb lesions (OR, 1.6; 95% CI, 1.1-25.9; P = .024), and contralateral carotid occlusion (OR, 0.6; 95% CI, 0.2-4.9; P = .040) all predicted postprocedural hypotension. Bradycardia was associated with diabetes mellitus (OR, 0.7; 95% CI, 0.3-2.4; P = .033), preprocedural TIA (OR, 1.7; 95% CI, 1.4-17.9; P = .020), and minor stroke (OR, 1.5; 95% CI, 1-10.9; P = .037). In 5 patients, HDI predisposed neurologic or systemic deterioration.
Hemodynamic instability is common with CAS; hypotension and bradycardia are more frequent than hypertension. Some clinical, angiographic, and procedural variables can predict these HD changes.
[Show abstract][Hide abstract] ABSTRACT: Carotid angioplasty and stenting is a relatively new therapeutic alternative to CEA for treatment of carotid stenosis. The percutaneous transfemoral approach, the standard technique for angioplasty and stent deployment, may not be feasible in all patients. We present our experience with access site complications that occurred with CAS.
One hundred thirty-two CAS procedures were performed at our institution in the past 5 years for symptomatic (62.1%) or asymptomatic (37.9%) carotid stenosis. Mean age of patients was 70.72 +/- 6.53 years and the mean degree of stenosis of the treated carotids was 80.74% +/- 11.83%. The transfemoral approach was the access route in 126 CAS, the transbrachial approach was used in 2 CAS procedures, and direct carotid exposure was used in 5 patients.
All CAS procedures were done successfully; 4 (3%) access site complications were detected, 3 (2.4%) groin hematomas with transfemoral approach and 1 hematoma on the left side of the neck, in patients treated with direct carotid cutdown. Surgical repair of FSA was successfully performed for the patients with groin hematoma, whereas surgical wound exploration in the neck for the remaining patient revealed no identifiable cause. All patients received blood transfusion for correction of associated hypovolemia or hemorrhagic anemia. No patients had experienced access site-related additional cardiac, systemic, or neurologic events.
The authors' experience demonstrates that access site complications are rare events with CAS despite the large diameter of implantable devices and liberal anticoagulant and antiplatelet therapy. Transbrachial and direct carotid approaches are relatively safe, accepted alternatives in the setting of contraindicated femoral access.
[Show abstract][Hide abstract] ABSTRACT: The goal of this study was to evaluate the usefulness of a recently developed image fusion of three-dimensional digital subtraction angiography (3D DSA) and magnetic resonance (MR) images, DSA-MR fusion, in the pre-treatment assessment of cerebral aneurysm.
Eighteen patients with 21 unruptured anterior or posterior circulation aneurysms underwent pre-treatment DSA-MR fusion. The authors independently assessed whether DSA-MR fusion images provided any useful additional information compared with analysing 3D DSA and MR images separately, and if this had an impact on the therapeutic decision-making of unruptured aneurysms.
DSA-MR fusion images were obtained within 30 minutes for all patients. In 19 of 21 aneurysms, it provided the following additional information to the findings of 3D DSA, MR images or both: the passing course in the brain tissues of perforating arteries near or originating from an aneurysm, and/or the spatial relationship between an aneurysm and an oculomotor nerve. This information from DSA-MR fusion images was useful for diagnosis, therapeutic decision-making and the risk assessment associated with the treatment, as well as patient education regarding cerebral aneurysm.
DSA-MR fusion images were useful for the pre-treatment evaluation of unruptured cerebral aneurysms as a supplement to DSA and MR images.
Neurological Research 01/2007; 29(1):58-63. DOI:10.1179/174313206X153806 · 1.44 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Distal embolism during carotid angioplasty with stent (CAS) can be protected by a flow-reversal device. Diffusion-weighted MR imaging was used to evaluate this protective procedure and perform a comparison with the control.
Cases of CAS with protection procedures were included in this study. Sixty-five men (68 procedures) and 5 women (5 procedures), with an average age of 68.8 years, having severe carotid stenosis were treated in our department between 2002 and 2004. Eleven cases were treated with the Parodi Anti-Emboli System, with which the internal carotid blood flow is reversed by simultaneous occlusion of the proximal common carotid artery and external carotid artery. Diffusion-weighted MR imaging was performed within 1-3 days after CAS. As controls, data from diffusion-weighted MR imaging in 26 patients who had diagnostic angiography were included.
Diffusion-weighted MR imaging in diagnostic angiography showed 11.5% appearance of ischemic spots after procedures. In the Parodi Anti-Emboli System, this value was 18.2%. In the CAS group, ischemic lesions appeared only in the hemisphere ipsilateral to carotid stenosis. There were no ischemic lesions in the opposite carotid or vertebrobasilar territory. The appearance rate of new ischemic spots was not significantly different between the control group and the group of CAS with Parodi Anti-Emboli System (chi2 test, P = .6227, Fisher exact method).
Protection results obtained with the Parodi system were excellent and comparable with conventional angiography.
American Journal of Neuroradiology 05/2006; 27(4):753-8. · 3.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We compared the results of two procedures to protect against distal embolism caused by embolic debris from carotid angioplasty with stent deployment (CAS) using diffusion-weighted magnetic resonance imaging (MRI). The study group comprised 39 men and 3 women (42 and 3 CAS procedures, respectively) with severe carotid stenosis (average age 70.0 +/- 6.6 years). During 20 CAS procedures the internal carotid artery was protected with a single balloon. A PercuSurge GuardWire was used for temporary occlusion. During 25 CAS procedures the internal and external carotid arteries were simultaneously temporarily occluded with a PercuSurge GuardWire and a Sentry balloon catheter, respectively. Diffusion-weighted MRI was performed 1 to 3 days after CAS. Data from 26 patients undergoing conventional angiography for diagnosis of cerebral ischemic disease, cerebral aneurysm or brain tumors were included as controls. Diffusion-weighted MRI after conventional diagnostic angiography showed ischemic spots in 3 of the 26 controls (11.5%). Ischemic spots were observed during 11 of 20 CAS procedures with the internal carotid artery protected with a single balloon (55.0%), and were observed during 9 of 25 CAS procedures with both the internal and external carotid arteries protected (36.0%). This difference was significant (P = 0.0068). Ischemic lesions appeared not only ipsilateral to the carotid stenosis but also in the contralateral carotid artery (31.9%) and vertebrobasilar territory (25.3%). Better protection was obtained with simultaneous double occlusion of both the internal and external carotid artery than with single protection of the internal carotid artery during CAS.
[Show abstract][Hide abstract] ABSTRACT: This clinical report is the first to describe angioscopy during carotid angioplasty with stent placement. The average observation time was 3 minutes 43 seconds in 18 cases. The view was clear in 67% of cases. Lesions in the endothelium, rupture of the fibrous cap, clots, debris detaching from plaque, and stent struts were observed. No symptomatic ischemic complications occurred. Diffusion-weighted MR imaging after angioscopy showed asymptomatic ischemic lesions in 47% of cases.
American Journal of Neuroradiology 10/2005; 26(8):1943-8. · 3.59 Impact Factor