Tomonori Iwata

Predictors of hyperperfusion syndrome before and immediately after carotid artery stenting in single-photon emission computed tomography and transcranial color-coded real-time sonography studies.

BACKGROUND:Hyperperfusion syndrome (HPS) is a critical complication after carotid artery stenting (CAS) and carotid endarterectomy (CEA). OBJECTIVE:To identify predictors of HPS before and immediately after CAS. METHODS:We analyzed patients who underwent elective CAS from 2005 to 2008, and underwent single-photon emission computed tomography (SPECT) and transcranial color-coded real-time sonography before and immediately after CAS. HPS was defined as post-CAS deteriorating neurological conditions with headache not secondary to cerebral ischemia. We assessed the measures of blood flow between the two cortical hemispheres by taking the ratio of cerebral blood flow (CBF) of the affected to unaffected hemisphere excluding any ischemic/infarcted areas (asymmetry index); the measures of blood flow within each cortical hemisphere by comparing the CBF in the affected cortical hemispheric area to the CBF in the ipsilateral cerebellar hemisphere (middle cerebral artery [MCA]-to-cerebellar activity ratio); cerebral vasoreactivity (CVR); MCA mean blood flow velocity in the affected hemisphere; and MCA mean blood flow velocity ratio (preoperative to postoperative). RESULTS:Sixty-four patients were analyzed retrospectively. Nine patients presented with HPS. Logistic regression analysis showed that CVR (P < .01) and MCA mean blood flow velocity (P < .05) were the significant predictors among the pre-CAS variables, and that MCA mean blood flow velocity ratio (P < .05) and MCA-to-cerebellar activity ratio change (P < .05) were significant predictors among the post-CAS variables. CONCLUSION:SPECT and transcranial color-coded real-time sonography studies are useful in predicting HPS.

Initial experience of a novel sheath guide for transbrachial carotid artery stenting: technical note

Background The transfemoral approach has been a common technique for carotid artery stenting (CAS). When aortic or peripheral arterial conditions limit the transfemoral approach, the transbrachial approach may be used as an alternative. The purpose of our study was to report initial experiences of CAS with a novel sheath guide specifically designed for transbrachial carotid cannulation. Methods Patients who underwent transbrachial CAS with a novel sheath guide between May 2011 and July 2012 were analyzed. The sheath guide has an internal diameter of 6 Fr (2.24 mm, 0.088 inch) and is 90 cm long with a soft distal part and a particular distal shape like a modified Simmons catheter. Results Sixty-two patients underwent transbrachial CAS with the sheath guide. Transbrachial carotid cannulation was easy and successful and CAS procedures were performed easily through the sheath guide in every case. No sheath-related periprocedural complications occurred. Conclusions The sheath guide specifically designed for transbrachial carotid cannulation is useful for transbrachial CAS.

Long-term angiographic and clinical outcome following stenting by flow reversal technique for chronic occlusions older than 3 months of the cervical carotid or vertebral artery.

BACKGROUND Long-term angiographic and clinical outcome following stenting by flow reversal technique (FRT) for chronic occlusions (COs) of the cervical internal carotid artery (ICA) or vertebral artery (VA) is unknown. OBJECTIVE The aim of our retrospective study was to investigate the feasibility, safety, and long-term outcome of stenting by FRT for COs of the cervical ICA or VA. METHODS Included for analysis were patients (1) who underwent stenting for COs of the ICA or VA older than 3 months by FRT, and (2) who finished at least 1-year follow-up angiographic and clinical investigation. Criteria of stenting for CO in the ICA or VA were patients (1) who experienced minor strokes, a transient ischemic attack, or transient symptoms probably due to hemodynamic compromise or insufficiency, (2) angiographic complete occlusion of the ICA or VA, and (3) occlusion limited in the cervical area of the affected artery. RESULTS During the study period, 6 patients underwent stenting by FRT for cervical COs successfully, ICAs in 4 cases and VAs in 2 cases. The prestenting angiographically estimated occlusion length ranged from 50 to 130 mm. Total length of the deployed stents ranged from 30 to 108 mm. No complications occurred during the periprocedural period. Neither transient ischemic events nor restenosis has occurred during the follow-up period. CONCLUSION COs of the cervical carotid or vertebral arteries older than 3 months can be opened safely with FRT, and 1-year angiographic and long-term clinical outcome is favorable.

Safety and effectiveness of emergency carotid artery stenting for a high-grade carotid stenosis with intraluminal thrombus under proximal flow control in hyperacute and acute stroke

Background A study was undertaken to investigate the feasibility, safety and effectiveness of emergency carotid artery stenting (eCAS) for a high-grade carotid stenosis with intraluminal thrombus (ILT) with or without proximal flow control (PFC). Methods Patients with acute ischemic stroke included in the analysis were those who were admitted between 2001 and 2010 with serious neurological symptoms, without a large high-intensity area of diffusion-weighted images and who underwent eCAS for a high-grade carotid stenosis with ILT. Patients underwent eCAS without PFC until 2004 (group C) and under PFC after 2004 (group P). The National Institutes of Health Stroke Scale (NIHSS) score on admission, just before CAS and 7 days after CAS as well as the 3-month modified Rankin Scale were investigated. Results Fifty-six patients underwent eCAS, eight of whom had a high-grade stenosis with ILT. Four of the eight patients were in group C and four were in group P. Probable distal embolism associated with eCAS occurred in two cases in group C and in none in group P. In groups C and P the median 7-day NIHSS scores were 15 and 5, respectively (p<0.05) and the median 3-month modified Rankin Scale scores were 4 and 2, respectively (p<0.05), but there were no significant differences between the two groups in the NIHSS scores on admission and just before CAS. Conclusion In stroke patients with a high-grade carotid stenosis with ILT, eCAS under PFC is safer and more effective in achieving a favorable clinical outcome than eCAS without PFC.

Successful stenting by combination technique of reverse flow and downstream filtering for long chronic total occlusion of the cervical vertebral artery: technical case report.

OBJECTIVETo report a case of successful recanalization using the combination technique of reverse flow and downstream filtering in chronic total occlusion of the bilateral vertebral artery (VA). CLINICAL PRESENTATIONA 59-year-old man had experienced attacks consisting of vertigo and/or dysarthria more than 1 year before presentation. He experienced symptoms despite the administration of antiplatelet drugs and presented to our institution. Diagnostic cerebral angiography demonstrated that the right VA was not occluded at the ostium but, rather, along its midcervical portion and that the left VA ended in the left posterior inferior cerebellar artery. INTERVENTIONLong chronic total occlusion of the right cervical VA was recanalized successfully and safely by reverse flow and downstream filtering with proximal flow blockade and a distal filter device positioned in the right brachial artery. Follow-up angiography at 1 year demonstrated no re-occlusion. The patients symptoms disappeared after recanalization and did not recur. To our knowledge, there are no reports describing successful angioplasty and/or stenting for long chronic total occlusion of the cervical VA. CONCLUSIONStenting using the combination technique of reverse flow and downstream filtering can safely open even long chronic cervical VA occlusion and may be effective in the treatment of patients experiencing vertebrobasilar insufficiency due to bilateral chronic VA occlusion.

Continuous daily use of cilostazol prevents in-stent restenosis following carotid artery stenting: serial angiographic investigation of 229 lesions

Background Several studies have reported that cilostazol (CLS) may reduce in-stent restenosis (ISR) after carotid artery stenting (CAS). However, it is not known for how long CLS must be continued to prevent ISR. Methods We retrospectively reviewed a prospectively collected database of patients who underwent elective CAS and follow-up angiography at 3 months and 1 year after the procedure. ISR was defined as stenosis of 50% or greater on digital subtraction angiography. The cumulative incidence rates of angiographic ISR were compared between the three groups, divided according to duration of CLS use : (1) patients who were maintained on CLS for 12 months or more after CAS (12M CLS group, n=70), (2) patients who were treated with CLS for the first 3 months after CAS (3M CLS group, n=23), and (3) patients who did not receive CLS (no CLS group, n=136). Results A total of 229 lesions in 199 patients were included in our analysis. During a median follow-up of 365 days, ISR was detected in 15 lesions. The cumulative ISR rates overall and in the 12M CLS, 3M CLS, and no CLS groups were 5.6%, 0%, 5.0%, and 8.4%, respectively, at 1 year, and the log rank test showed that there was a significant difference between the three groups (p<0.05). Cox regression analysis demonstrated that the 12M CLS group had a significantly lower risk of ISR than the 3M CLS group (adjusted relative risk (aRR) 3.06e-10, 95% CI 0 to 0.51, p<0.05) and the no CLS group (aRR 1.41e-10, 95% CI 0 to 0.15, p<0.001), whereas no difference was found between the 3M CLS group and the no CLS group. Conclusions An overall cumulative ISR rate of 5.6% was documented angiographically at 1 year after CAS. Continuous daily use of CLS (for at least 1 year) may have a beneficial effect on long term prevention of ISR.

Global oxygen extraction fraction by blood sampling to anticipate cerebral hyperperfusion phenomenon after carotid artery stenting.

BACKGROUND Cerebral hyperperfusion syndrome sometimes occurs after carotid revascularization in patients with severe hemodynamic failure. To prevent cerebral hyperperfusion syndrome, cerebral hyperperfusion phenomenon (CHP) must be detected early. Single-photon emission computed tomography (SPECT) is useful for detecting CHP, but it is impractical on a daily basis. A tool with high availability to find CHP is desired. OBJECTIVE To investigate whether global oxygen extraction fraction (OEF) by a blood sampling method is useful for indicating CHP after carotid artery stenting (CAS). METHODS When patients underwent elective CAS from September 2010 to August 2012, we performed blood sampling for OEF calculation and SPECT before and immediately after elective CAS. Data were collected prospectively. OEF was calculated from the cerebral arteriovenous oxygen difference. Cerebral blood flow was measured in the affected middle cerebral artery (MCA) territory and in the ipsilateral cerebellum by SPECT. The ratio of MCA to cerebellar activity was defined as cerebral blood flow in the affected MCA territory divided by cerebral blood flow in the ipsilateral cerebellar hemisphere. Probable CHP was defined as ≥10% increase in the ratio of MCA to cerebellar activity after CAS. The relationship between peri-CAS OEF and probable CHP was evaluated. RESULTS Of the 96 patients enrolled, 92 patients were analyzed. Probable CHP occurred in 17 patients. Post-CAS OEF was related to probable CHP (P < .01), but pre-CAS OEF was not. The receiver-operating characteristic curve showed that the cutoff value was 45% for probable CHP (P < .001). CONCLUSION An increase in blood sampling OEF immediately after CAS was related to probable CHP; then the oxygen demand should be reduced.

Initial experience of a novel sheath guide for transbrachial coil embolization of cerebral aneurysms in the anterior cerebral circulation.

BACKGROUND: The transfemoral approach is a common technique for coil embolization of cerebral aneurysms in the anterior cerebral circulation. However, it is difficult to advance a guiding catheter into the carotid artery via the femoral route in patients with a tortuous aortic arch, an unfavorable supra-aortic takeoff, aortic diseases, or occlusion of the femoral artery. OBJECTIVE: To report our initial experiences of coil embolization of cerebral aneurysms in the anterior cerebral circulation with a novel sheath guide for transbrachial carotid cannulation. METHODS: A sheath guide designed specifically for transbrachial carotid cannulation was developed; transbrachial coil embolization for cerebral aneurysms began in May 2011. Included for analysis were patients who underwent transbrachial coil embolization for cerebral aneurysms in the anterior cerebral circulation from May 2011 to January 2012. Adjuvant techniques, angiographic results, procedural success, and periprocedural complications were investigated. RESULTS: Ten patients underwent transbrachial coil embolization of cerebral aneurysms in the anterior cerebral circulation. All procedures were successful using the brachial route. No periprocedural complications occurred. Patients were permitted to get seated immediately after coil embolization even during hemostasis. CONCLUSION: The sheath guide specifically designed for transbrachial carotid cannulation was useful for coil embolization of cerebral aneurysms in the anterior cerebral circulation. ABBREVIATIONS: CAS, carotid artery stenting ICA, internal carotid artery

Anatomical features of the vertebral artery for transbrachial direct cannulation of a guiding catheter to perform coil embolization of cerebral aneurysms in the posterior cerebral circulation

Background Transbrachial approach is an alternative technique for coil embolization of posterior circulation aneurysms. The purpose of our study was to investigate the anatomical features of the vertebral artery (VA) for transbrachial direct VA cannulation of a guiding catheter (GC) to perform coil embolization of posterior circulation aneurysms. Methods Included in retrospective analysis were patients who underwent transbrachial coil embolization of cerebral aneurysms in the posterior cerebral circulation by direct VA cannulation of a GC from 2007 to 2013. Investigated were patient characteristics, preoperative sizes of aneurysms, aneurysms location, the angle formed by the target VA and the subclavian artery (AVS), and the VA diameter at the level of the fourth cervical vertebral body (VAD) in the side of the transbrachial access route. Results Thirty-one patients with 32 aneurysms met our criteria. The locations of aneurysms were the VA (n = 16), basilar artery (BA) tip (n = 10), BA trunk (n = 3), BA superior cerebellar artery (n = 1), BA anterior inferior cerebellar artery (n = 1), and VA posterior inferior cerebellar artery (n = 1). The right brachial artery was punctured in 27 cases with 28 aneurysms as transbrachial direct cannulation of a GC, and left was in 4 cases with 4 aneurysms. The average AVS, ranging from 45° to 95°, was 77°, and the average VAD, ranging from 3.18 to 4.45 mm, was 3.97 mm. Conclusion For transbrachial direct cannulation of a GC, it seems required that the AVS is about 45° or more and the VAD is about 3.18 mm or more.

Iatrogenic Ascending Pharyngeal Artery Injury by Predilation Balloon Inflation During Carotid Artery Stenting with Flow Reversal

BACKGROUND The ascending pharyngeal artery (APA) may rarely arise from the common carotid artery bifurcation. We report an injury to the APA as an unusual complication of predilation balloon inflation during carotid artery stenting (CAS) with flow reversal. CASE DESCRIPTION A 73-year-old man presented with symptomatic severe left cervical internal carotid artery stenosis. The left APA arose from the common carotid artery bifurcation. We performed CAS with flow reversal to decrease the risk of distal embolization. When we attempted to catheterize the internal carotid artery under roadmap guidance for predilation, we did not notice that the balloon catheters had advanced into the APA owing to the absence of an anterograde angiogram, and the APA was injured when the balloon catheters were inflated. CONCLUSIONS Our case emphasizes the importance of performing a detailed anatomic assessment before CAS and ensuring adequate angiographic visualization during the procedure under flow reversal when the origin of the APA is in the vicinity of the origin of the internal carotid artery.