Long-term outcome of symptomatic severe ostial vertebral artery stenosis (OVAS)

Introduction  

The optimal management of patients with symptomatic severe ostial vertebral artery stenosis (OVAS) is currently unclear. We analyzed the long-term outcome of consecutive patients with OVAS who received either medical treatment (MT) or vertebral artery stenting (VAS).     

Flat-detector computed tomography in the assessment of intracranial stents: comparison with multi detector CT and conventional angiography in a new animal model

Objective  

Careful follow up is necessary after intracranial stenting because in-stent restenosis (ISR) or residual stenosis (RS) is not rare. A minimally invasive follow-up imaging technique is desirable. The objective was to compare the visualisation of stents in Flat Detector-CT Angiography (FD-CTA) after intravenous contrast medium injection (i.v.) with Multi Detector Computed Tomography Angiography (MD-CTA) and Digital Subtracted Angiography (DSA) in an animal model.     

Posterior Inferior Cerebellar Artery Patency after Flow-Diverting Stent Treatment

BACKGROUND AND PURPOSE:The rate of PICA occlusion after flow-diverting stent placement for vertebral and vertebrobasilar artery aneurysms is not known. The purpose of this study is to determine the medium-term rate of PICA patency and risk factors for occlusion after such aneurysm treatment.MATERIALS AND METHODS:Patients were identified who had vertebral or vertebrobasilar artery aneurysms and who were treated by placing a flow-diverting stent across the PICA ostium. Demographic and procedural factors associated with stent placement were recorded. Patency of the PICA was evaluated immediately after stent placement and on follow-up angiography.RESULTS:Thirteen patients with vertebral or vertebrobasilar artery aneurysms were treated in the study period, of whom 4 presented with subarachnoid hemorrhage. The average number of devices that spanned the PICA ostium was 1.77 (range, 1–3), with no immediate PICA occlusions. There were no postoperative strokes in the treated PICA territory, although there was 1 contralateral PICA-territory stroke of unclear etiology without clinical sequelae. In 11 patients with follow-up angiography at a mean of 10.6 months (range, 0.67–27.9 months), the PICA patency rate remained 100%.CONCLUSIONS:Flow-diverting stent placement across the PICA ostium in the treatment of vertebral and vertebrobasilar artery aneurysms may not result in immediate or midterm PICA occlusion.

The initial studies of safety and efficacy of flow-diverting stents (FDSs), such as the Pipeline Embolization Device (Covidien, Irvine, California), for the treatment of intracranial aneurysms primarily focused on anterior circulation aneurysms.¹ The application of an FDS in posterior circulation aneurysms remains controversial due to an increased risk of thrombotic and hemorrhagic complications.^2–4 The location of some vertebral and vertebrobasilar aneurysms in relation to the PICA often necessitates stent placement across the arterial ostium, theoretically risking PICA occlusion with resultant brain stem infarction. The immediate and midterm rate of branch occlusion of the PICA after FDS placement has not been described.     

球囊扩张支架成形术治疗椎动脉狭窄致后循环脑缺血的效果分析

目的总结因椎动脉狭窄致后循环脑缺血的患者行支架成形手术的经验体会。 方法47例因椎动脉狭窄致缺血性脑卒中的患者,于我科行椎动脉支架成形术,共留置支架52枚,其中椎动脉V1段为46枚,V4段6枚。所有患者行全脑血管造影或CT血管造影随访,平均随访6.3月。分析动脉狭窄改善及其他并发症情况。 结果所有患者均成功行支架成形术。术后患者症状缓解率为85.1%（40/47）;术前狭窄率（75.2±6.7）%,术后狭窄率为(7.6±6.1)%。发生支架内再狭窄（IRS）9处（17%）,8处为椎动脉起始部,1处为V4段。 结论支架成形术是治疗缺血性椎动脉狭窄安全有效的方法,但应尽量避免IRS等术后并发症。     

Use of Self-Expanding Stents for the Treatment of Vertebral Artery Ostial Stenosis: a Single Center Experience

Objective

To evaluate our early experience using self-expanding stents to treat atherosclerotic vertebral artery ostial stenosis (VAOS), with respect to technical feasibility and clinical and imaging follow-up results.

Materials and Methods

A total of 20 lesions in 20 patients underwent stenting of the VAOS using a self-expanding stent (Precise RX; Cordis Neurovascular, Miami Lakes, FL). Two patients were asymptomatic. We analyzed the technical success rate, causes of technical failure, occurrence of any vascular or neurological event, and the occurrence of any neurological abnormality or in-stent restenosis (ISR) seen on follow-up. The imaging follow-up was performed with Doppler ultrasound (DUS) as a primary screening modality.

Results

One instance of technical failure was caused by failure of the guidewire passage. The stent diameter was 5 mm, and post-stenting balloon dilatations were necessary in all cases. Stent misplacement requiring placement of an additional stent occurred in four cases. Following a 14.8 month average clinical follow-up time, two patients showed anterior circulation ischemia, which was not attributed to the VAOS we treated. Following a 13.7 month average DUS follow-up, five patients showed a mild degree of diffuse or focal intimal thickening in the stent lumen; however, none of the stenosis showed luminal loss of more than 50% and no stent fracture was noted.

Conclusion

The use of self-expanding stents for treating VAOS was technically feasible and helped to improve artery patency during our limited follow-up interval.     

Retrograde stenting through the posterior cerebral artery in coil embolization of the posterior communicating artery aneurysm

Introduction

Protection techniques using stents or balloons are occasionally limited in coil embolization of wide-necked posterior communicating artery (PcomA) aneurysms in which the PcomA originated from the aneurysm neck at an acute angle. Here, we present two cases undergoing retrograde stenting through the posterior cerebral artery in coil embolization of the PcomA aneurysms.

Methods

To perform retrograde stenting, a microcatheter used for stent delivery was advanced from the vertebral artery (VA) to the terminal internal carotid artery (ICA) via the ipsilateral P1 and the PcomA. The aneurysm sac was selected with another microcatheter for coil delivery through the ipsilateral ICA. Coil embolization was performed under the protection of a stent placed from the terminal ICA to the PcomA.

Results

Deployment of the stent was successful in both aneurysms treated using retrograde stenting by the VA approach. Coil deployment was performed through the jailed microcatheter at first. The microcatheter was repositioned through the stent struts later in one case and another microcatheter was inserted into the sac through the stent struts in the other case. Both aneurysms were occluded properly with the coils without procedure-related complications.

Conclusion

By providing complete neck coverage, retrograde stenting for coil embolization in wide-necked PcomA aneurysms seems to be a good alternative treatment strategy, when the aneurysms are incorporating extended parts of the PcomA, and the PcomA and P1 are big enough to allow passage of the microcatheter for delivery of the stent. However, this technique should be reserved for those cases with the specific vascular anatomy.     

Are Carotid Stent Fractures Clinically Significant?

Purpose  

Late stent fatigue is a known complication after carotid artery stenting (CAS) for cervical carotid occlusive disease. The purpose of this study was to determine the prevalence and clinical significance of carotid stent fractures.     

Vertebral artery ostial stent placement for atherosclerotic stenosis in 72 consecutive patients: clinical outcomes and follow-up results

Introduction  The study’s purpose is to report the technical and clinical outcomes of a patient cohort that underwent vertebral artery ostium stent placement for atherosclerotic stenosis. Methods  We retrospectively analyzed a prospectively collected database of neurointerventional procedures performed at a single center from 1999 to 2005. Outcome measures included recurrent transient neurological deficits (TNDs), stroke, and death. Kaplan–Meier analysis was used to estimate stroke- and/or death-free survival at 12 months. Cox proportional hazard was used to identify risk factors for recurrent vertebrobasilar ischemic events. Results  Seventy-two patients with 77 treated vertebral ostial lesions were included. The 30-day stroke and/or death rate was 5.2% (n = 4), although no event was directly related to the vertebral ostium stent placement. Three procedure-related strokes were secondary to attempted stent placement at other sites (one carotid artery and two basilar arteries), and the one death was secondary to the presenting stroke severity. The mean clinical follow-up time available for 66 patients was 9 months. There were 14 TNDs (21%), two strokes (3%), and two deaths (3%) recorded in the follow-up. Recurrent vertebrobasilar ischemic events occurred in nine patients (seven TNDs and two strokes). No recurrent stroke and/or deaths were related to the treated vertebral ostium. Stroke- and/or death-free survival rate (including periprocedural stroke and/or death) was 89 ± 5% at 12 months. No vascular risk factor was significantly associated with recurrent vertebrobasilar ischemic events. Conclusions  Vertebral artery ostium stent placement can be safely and effectively performed with a low rate of recurrent stroke in the territory of the treated vessel. Patients who also underwent attempted treatment of a tandem intracranial stenosis appeared to be at highest risk for periprocedure stroke.     

Influence of Residual Stenosis on Clinical Outcome and Restenosis After Middle Cerebral Artery Stenting

Background  

The purpose of this study was to assess whether the residual stenosis has effect on restenosis after stenting for atherosclerotic stenosis in the middle cerebral artery.     

Initial and Long-Term Results of Endovascular Therapy for Chronic Total Occlusion of the Subclavian Artery

Purpose  

To study the initial and long-term results of angioplasty and primary stenting for the treatment of chronic total occlusion (CTO) of the subclavian artery (SA).     

Angiographically confirmed stent over expansion in the internal carotid artery during stenting: incidence,predictors, and outcomes

Introduction  

Selection of the appropriate diameter of stent is difficult in patients with the size mismatch between the internal carotid artery (ICA) and the common carotid artery (CCA). Although stent overexpansion (SOE) in the ICA after carotid artery stenting (CAS) is suspected of producing restenosis, SOE has not been well established. We discuss its incidence, predictors, and outcomes.     

Risk Factors and Complications Associated with Difficult Retrieval of Embolic Protection Devices in Carotid Artery Stenting

Purpose  

This study was designed to investigate the risk factors and complications of difficult retrieval (DR) of embolic protection devices (EPDs) in carotid artery stenting (CAS).     

Diagnostic performance of computed tomography angiography in the detection of coronary artery in-stent restenosis: evidence from an updated meta-analysis

Objectives

To evaluate the performance of computed tomography angiography (CTA) ≥64 slices for detecting coronary in-stent restenosis (ISR) and determine the influence of separate characteristics on diagnostic accuracy.

Methods

We searched the PubMed, EMBASE and Cochrane databases for studies of CTA ≥64 slices in diagnosing ISR. We pooled data on bivariate modelling, and subgroup analysis was also performed.

Results

A total of 35 studies involving 4131 stents were included. The pooled positive likelihood ratio (LR⁺) and the negative likelihood ratio (LR^–) were 14.0 and 0.10, for CTA in diagnosis-significant ISR ≥50%. LR⁺ and LR^– were similar between CTA >64 slices versus 64 slices (both P > 0.99). LR^– (0.10) was good for ruling out suspected ISR for <3-mm diameter. Time between CTA and stent implantation >6 months did not affect the ability of CTA for the high LR⁺ (12.3) and the LR^– (0.10). Thick-strut stents ≥100 μm or bifurcation stenting demonstrated inferior accuracy, which was unfavourable for stent imaging.

Conclusions

With the high LR⁺ and LR^– of CTA, patients with ISR may be appropriate for non-invasive angiographic follow-up. However, CTA imaging seems unsuitable for patients with characteristics unfavourable for stent imaging, such as thick-strut stents or bifurcation stenting.

Key points

? CTA may provide accurate information on characteristics of in-stent restenosis lesions. ? Using CTA, ISR patients may be appropriate for non-invasive angiographic follow-up. ? Stent diameter and the number of slices do not influence CTA. ? CTA seems unsuitable for patients with thick-strut stents or bifurcation stenting.

     

Anomalous origin of the occipital artery diagnosed by magnetic resonance angiography

Introduction  

It is well known that the occipital artery (OA) can arise from the internal carotid artery (ICA) or vertebral artery (VA). However, the incidence of an anomalously originating OA has not been reported. We investigate its incidence and characteristic features on magnetic resonance angiography (MRA).     

Peri-stent aneurysm formation following a stent implant for stenotic intracranial vertebral artery dissection: a technical report of two cases successfully treated with coil embolization

Introduction

Although stenting for stenotic vertebral artery dissection (VAD) improves compromised blood flow, subsequent peri-stent aneurysm (PSA) formation is not well-known. We report two cases with PSA successfully treated with coil embolization.

Methods

Three patients with stenotic intracranial VAD underwent endovascular angioplasty at our institution because they had acute infarction in posterior circulation territory and clinical evidence of hemodynamic insufficiency. In two of three patients balloon angioplasty at first session failed to relieve the stenosis, and a coronary stent was implanted. Angiography immediately after stenting showed no abnormality in case 1 and minimal slit-like projection at proximal portion of the stent in case 2.

Results

Angiography obtained 16 months after the stenting revealed PSA in case 1. In case 2, angiography performed 3 months later showed that the projection at proximal portion enlarged and formed an aneurysm outside the stent. Because follow-up angiographies showed growth of the aneurysm in both cases, endovascular aneurysmal embolization was performed. We advanced a microcatheter into the aneurysm through the strut of existing stent and delivered detachable coils into the aneurysm lumen successfully in both cases. The post-procedural course was uneventful, and complete obliteration of aneurysm was confirmed on angiography in both cases.

Conclusion

Stenting for stenotic intracranial VAD may result in delayed PSA; therefore, follow-up angiographies would be necessary after stenting for stenotic intracranial arterial dissection. Coil embolization through the stent strut would be a solution for enlarging PSA.     

Transfemoral subclavian artery stenting through a shaped guiding catheter without pull-through technique: A case report

Transfemoral subclavian artery stenting can be challenging unless the placement of the guiding catheter is secured. Herein, we present a patient with subclavian artery stenosis treated with endovascular stenting using a shaped guiding catheter. A 79-year-old woman was admitted to our department because of a cold sensation and numbness of her left arm. Computed tomography revealed stenosis of the left subclavian artery (SA), located just proximal to the ostium of the left vertebral artery (VA). Doppler ultrasound showed reverse flow in the left VA. We planned to stent for the SA stenosis under the balloon protection of the left VA. The balloon protection device was easily navigated into the left VA through brachial access. After that, a self-expandable stent was successfully placed from just proximal to the VA origin to the ostium of the SA using a highly stable shaped guiding catheter. The patient recovered from the symptoms and was discharged 4 days after the procedure. The high stability of the shaped guiding catheter is advantageous during endovascular treatment of the subclavian artery.     

Vertebral artery variations at the C1–2 level diagnosed by magnetic resonance angiography

Introduction  

The craniovertebral junction is clinically important. The vertebral artery (VA) in its several variations runs within this area. We report the prevalence of these VA variations on magnetic resonance angiography (MRA).     

Carotid Stenting for Restenosis after Endarterectomy

Introduction  

Restenosis after carotid endarterectomy (CEA) has been described in 8–19% of patients, 14–23% of whom become symptomatic. This study analyzes our experience with carotid artery stenting (CAS) for post-CEA recurrent stenoses.     

Association between carotid plaque composition assessed by multidetector computed tomography and cerebral embolism after carotid stenting

Introduction  

We aimed to assess the relationship between atherosclerotic carotid plaque composition analyzed using multidetector computed tomography (MDCT) and the appearance of new ischemic lesions detected by diffusion-weighted images (DWI) after carotid artery stenting (CAS).     

Carotid artery stenting and follow-up: value of 64-MSCT angiography as complementary imaging method to color-coded duplex sonography

Purpose

To compare 64-multi-slice-CT angiography (64-MSCTA) to color-coded duplex sonography (CCDS) in the follow-up after carotid artery stenting (CAS).

Methods

Thirty patients who had an MSCTA and CCDS examination prior and after CAS were included. Twelve closed-cell and 24 open-cell stents were implanted. Neointimal surface, in-stent-restenosis (ISR), stent expansion, and fracture were evaluated. In addition, the occurrence of atherosclerotic lesions leading to a > 50% stenosis in supraaortic vessels was assessed.

Results

With MSCTA, >50% ISR was found in 5.6% of cases during a mean follow-up of 41.7 months. Comparing MSCTA and CCDS, grading of ISR and absolute diameters of neointimal surface correlated moderately (Spearman = 0.402, p = 0.015; Pearson = 0.404, p = 0.03). Assessment of the neointimal surface was significantly better with MSCTA (100% vs. 80.6%; p = 0.011). Stent expansion was significant, compared to the basic value, with both modalities and stent types (p < 0.001). Of 237 additionally assessed vessel segments, a > 50% stenosis was detected in 38 (16.0%) vessel segments. Findings were stable in 25 (10.5%) and progressed in 11 (4.6%) vessel segments. Five small intracranial aneurysms were detected in four (13.3%) patients. Of 21 incidental findings in 16 (51.6%) patients there was one with malignancy (4.8%).

Conclusion

With regard to ISR and stent expansion, no significant difference was found, when MSCTA and CCDS were compared. CTA is quite applicable as a complementary imaging method for the follow-up of patients with carotid artery stents. Additional advantages are the detection of supraaortic vessel pathologies and incidental findings.