Acute interventional recanalisation of vertebrobasilar stenoses by angioplasty: complications and 12 months follow up

Introduction

In acute symptomatic vertebrobasilar artery stenosis, the use of mechanical recanalisation remains controversial. The complication rate of acute interventional recanalisation (aIR) has to be considered, as evidence from randomised trials is lacking. In a single centre retrospective case series, we here describe complications and outcome after aIR.

Methods

We retrospectively assessed aIR in a tertiary care centre and included the following parameters: indication for aIR, national institute of health stroke scale (NIHSS) score on admission, recanalisation by thrombolysis in myocardial infarction score (TIMI) grades, post-interventional complications, mortality, NIHSS and modified Rankin scale at follow-up and rate of restenosis.

Results

We identified 14 aIR (14 percutaneous transluminal angioplasty with or without stent implantation in 12 patients; 6/12 with thrombolysis; n?=?6 vertebral artery, n?=?8 basilar artery; 4 women, mean age 67 years). Mortality was 25 % (3/12) after 7 days and 42 % (5/12) after 12 months. In 12/14, interventions are complete (TIMI 3, 86 %), in 2/14, a partial recanalisation (TIMI 2, 14 %) was achieved. In one case, a peri-interventional fatal intracerebral haemorrhage occurred (1/12, 8 %). At late follow-up (mean 342 days), one re-occlusion (1/7, 14 %) and one recurrent stroke (1/12, 8 %) were observed.

Conclusions

In our single centre series of vertebrobasilar aIR recanalisation rate was high. However, procedural safety and clinical outcome varied considerably. The results of aIR need to be assessed in multicentric registers to define the procedural risk and outcome in the clinical setting.     

Complication rates using balloon-expandable and self-expanding stents for the treatment of intracranial atherosclerotic stenoses

Introduction

Using balloon-expandable stents (BES) for treatment of intracranial stenoses, high inflation pressures and rigidity of the device are regarded as major drawbacks limiting feasibility and safety of the procedure. Self-expanding stents (SES) were developed to facilitate lesion access and to allow for less aggressive dilatation. We analyzed data of the INTRASTENT multicentric registry to assess whether self-expanding stents significantly reduced peri-interventional complication rates.

Methods

Records of intracranial stent procedures were entered consecutively into the registry. Datasets were divided into two groups according to the type of stent used. For outcome measurement, we chose three categories: TIA/minor stroke [modified Rankin score (mRS) <2], disabling stroke, and patient death. Clinical outcome was compared between BES and SES. We analyzed types of adverse events occurring in each group in addition.

Results

Of 409 atherosclerotic lesions, 254 were treated with BES and 155 with SES. Technical success rates were 97.6% and 98.7%, respectively. Adverse event rates were 4.9%, 3.7%, and 0.8% for TIA/nondisabling stroke, disabling stroke, and death in the BES group compared with 5.3%, 6.0%, and 4.0% in the SES group. The differences were not statistically significant. We observed more perforator strokes after use of BES, but thromboembolic events occurred more often in the SES treatment group.

Conclusion

Data of the INTRASTENT registry do not support the hypothesis that introduction of SES lowered the overall complication rate of intracranial stent procedures. There might be an advantage using self-expanding stents in vessel segments with important perforating arteries.     

Karotisstents – eine Standortbestimmung

Clinical/methodical issue

Therapy of carotid stenosis should be based on an accurate assessment of the stenosis and a differentiation between symptomatic and asymptomatic patients.

Standard radiological methods

According to current guidelines carotid artery stenting (CAS) can be considered as an established therapeutic alternative to carotid endarterectomy (CEA).

Methodical innovations

For the therapy of carotid stenosis CAS has become established as a minimally invasive alternative to CEA because the complication rate has been reduced due to growing experience, technical innovations and external quality assessment.

Performance

The CAS procedure should be performed in centers with documented complication rates of <?3?% for asymptomatic and <?6?% for symptomatic stenoses.

Achievements

Overall there are no significant differences between CAS and CEA in the treatment of carotid stenosis concerning the secondary prophylactic effect.

Practical recommendations

Ideally an interdisciplinary approach should be chosen for the therapy regime. Revascularization of asymptomatic stenoses should be considered critically as these patients might profit from optimized conservative medicinal therapy.     

CT angiography after carotid artery stenting: assessment of the utility of adaptive statistical iterative reconstruction and model-based iterative reconstruction

Introduction

Follow-up CT angiography (CTA) is routinely performed for post-procedure management after carotid artery stenting (CAS). However, the stent lumen tends to be underestimated because of stent artifacts on CTA reconstructed with the filtered back projection (FBP) technique. We assessed the utility of new iterative reconstruction techniques, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR), for CTA after CAS in comparison with FBP.

Methods

In a phantom study, we evaluated the differences among the three reconstruction techniques with regard to the relationship between the stent luminal diameter and the degree of underestimation of stent luminal diameter. In a clinical study, 34 patients who underwent follow-up CTA after CAS were included. We compared the stent luminal diameters among FBP, ASIR, and MBIR, and performed visual assessment of low attenuation area (LAA) in the stent lumen using a three-point scale.

Results

In the phantom study, stent luminal diameter was increasingly underestimated as luminal diameter became smaller in all CTA images. Stent luminal diameter was larger with MBIR than with the other reconstruction techniques. Similarly, in the clinical study, stent luminal diameter was larger with MBIR than with the other reconstruction techniques. LAA detectability scores of MBIR were greater than or equal to those of FBP and ASIR in all cases.

Conclusion

MBIR improved the accuracy of assessment of stent luminal diameter and LAA detectability in the stent lumen when compared with FBP and ASIR. We conclude that MBIR is a useful reconstruction technique for CTA after CAS.     

Interventional Exclusion of Iliac Artery Aneurysms Using the Flow-Diverting Multilayer Stent

Purpose

This study was designed to evaluate retrospectively the results of complex iliac artery aneurysm (IAA) exclusion using the Cardiatis-Multilayer-Stent.

Methods

Between October 2010 and August 2012, ten IAAs were treated in eight males (mean age 75 (59–91) years) using the Multilayer Stent. All IAA exceeded a diameter of 3 cm or were symptomatic. Follow-up (FU) examinations included CT or MR angiography, sonography, and clinical assessment up to 2 years.

Results

Primary stent placement was technically successful in eight of ten cases. In two cases, severe stent retraction during deployment necessitated placement of an additional stent. Immediately after stent placement, a marked reduction of flow within the sac was observed in all cases (peri-interventional mortality 0 %). During FU, there were two thrombotic stent occlusions, making reintervention necessary (primary patency rate 80 %, secondary patency 100 %). Four IAA were completely occluded at FU, whereas the original vessel and covered branches (n = 8) were patent. In four IAA, there was still residual perfusion. In one patient, IAA diameter decreased slightly, while it remained constant in seven (mean imaging FU 195 (range 1–695) days). There were no adverse events on clinical FU (mean FU 467 (range 101–695) days).

Conclusions

Other studies showed the Cardiatis-Multilayer-Stent to be a technically relatively simple treatment option for complex IAA with inadequate landing zones, especially in patients with multiple comorbidities to avoid ipsilateral IIA obstruction. However, in our series complication rate was high. Incomplete sac exclusion, stent-shortening, and thrombotic occlusion can complicate treatment, making meticulous patient selection necessary. Close imaging surveillance is mandatory especially in the early postinterventional period.     

Fragmentation of calcified plaque after carotid artery stenting in heavily calcified circumferential stenosis

Introduction

We assessed the morphological change of calcified plaque after carotid artery stenting (CAS) in vessels with heavily calcified circumferential lesions and discuss the possible mechanisms of stent expansion in these lesions.

Methods

We performed 18 CAS procedures in 16 patients with severe carotid artery stenosis accompanied by plaque calcification involving more than 75% of the vessel circumference. All patients underwent multidetector-row computed tomography (MDCT) to evaluate lesion calcification before and within 3 months after intervention. The angiographic outcome immediately after CAS and follow-up angiographs obtained 6 months post-CAS were examined.

Results

The preoperative mean arc of the calcifications was 320.1?±?24.5° (range 278–360°). In all lesions, CAS procedures were successfully carried out; excellent dilation with residual stenosis ≤30% was achieved in all lesions. Post-CAS MDCT demonstrated multiple fragmentations of the calcifications in 17 of 18 lesions (94.4%), but only cracks in the calcified plaque without fragmentation in one (5.6%). Angiographic study performed approximately 6 months post-CAS detected severe restenosis in one lesion (5.6%) without fragmentation of calcified plaque.

Conclusions

Excellent stent expansion may be achieved and maintained in heavily calcified circumferential carotid lesions by disruption and fragmentation of the calcified plaques.     

Role of interventional radiology in treating obstetric haemorrhages

Purpose

The aim of this study was to evaluate the efficacy and the safety of selective uterine artery embolisation in patients with a high risk of haemorrhage due to obstetric issues.

Materials and methods

We retrospectively reviewed the angiographic examinations of 63 patients (average age ± SD, 32.6 years ± 4.8), affected by an obstetric disease with a high risk of haemorrhage (22 cases of ectopic pregnancy, 41 of postpartum haemorrhage) and treated with an interventional approach. In particular, we considered the rate of second treatment with interventional technique or conservative or radical surgery, the incidence of postprocedural complications, and the absorbed radiation dose.

Results

Immediate technical success, defined as the cessation of active bleeding, was achieved in all cases. Uterine artery embolisation was able alone to control the haemorrhage in 95.24 % of cases. Three patients required a second treatment to achieve haemostasis. No peri- or postprocedural complications were observed. At the 12-month follow-up after embolisation, 22/49 conservatively treated patients were found to be pregnant and successfully completed their pregnancy.

Conclusions

Selective uterine artery embolisation allows for safe and complete control of haemorrhage in patients with obstetric disease, with a very low incidence of complications and preservation of fertility.     

Radial Artery Approach to Salvage Nonmaturing Radiocephalic Arteriovenous Fistulas

Purpose

To evaluate the usefulness of an approach through the radial artery distal to the arteriovenous anastomosis for salvaging nonmaturing radiocephalic arteriovenous fistulas.

Methods

Procedures that fulfilled the following criteria were retrospectively reviewed: (1) autogenous radiocephalic fistulas, (2) fistulas less than 3 months old, (3) distal radial artery approach for salvage. From 2005 to 2011, a total of 51 patients fulfilling the above criteria were enrolled. Outcome variables were obtained from angiographic, clinical and hemodialysis records, including the success, complication, and primary and secondary patency rates.

Results

The overall anatomical and clinical success rates for the distal radial artery approach were 96 and 94 %, respectively. The average procedure time was 36 ± 19 min. Six patients (12 %) experienced minor complications as a result of extravasations. No arterial complication or puncture site complication was noted. The postinterventional 6-month primary patency rate was 51 %, and the 6-month secondary patency rate was 90 %. When the patients were divided into a stenosed group (20 patients) and an occluded group (31 patients), there were no differences in the success rate, complication rate, or primary and secondary patency rates.

Conclusion

An approach through the radial artery distal to the arteriovenous anastomosis is an effective and safe alternative for the salvage of nonmaturing radiocephalic arteriovenous fistulas, even for occluded fistulas.     

How to design the optimal self-expandable oesophageal metallic stents: 22 years of experience in 645 patients with malignant strictures

Objectives

To evaluate the clinical efficacy and safety of self-expandable metallic stent (SEMS) placement for malignant oesophageal strictures and their relationship with stent designs.

Methods

Seven generations of SEMS were used to treat 645 consecutive patients with oesophageal strictures. Logistic regression models were constructed to identify predictive factors associated with complications.

Results

Stent placement was technically successful in 641 of 645 patients (99.4%). The clinical success rate was 95.5%. There were 260 (40.3%) complications after stent placement. Due to complications, 68 stents were removed; 66 of 68 stents (97.1%) were removed successfully. Stainless steel (SS) stents (odds ratio [OR] 4.18; 95% confidence interval [CI] 2.10, 8.32) and radiation therapy (RT) before stent placement (OR 4.23; CI 2.02, 8.83) were significantly associated with severe pain. Flared ends (OR 9.63; CI 3.38, 27.43), stricture length <6 cm (OR 2.01; CI 1.13, 3.60), and a stent diameter <18 mm (OR 3.00; CI 1.32, 6.84) were predictive factors of stent migration. Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene (PTFE) membranes (P?=?0.002).

Conclusions

Despite the relatively high complication rate, retrievable self-expandable PTFE-covered nitinol stents equipped with a head and a tail appeared to be an effective treatment for malignant oesophageal strictures.

Key Points

? Self-expandable metallic stents are now widely used for palliating unresectable oesophageal strictures ? Stents equipped with a head and a tail showed decreased stent migration rate ? Stainless steel stents and radiation therapy before stenting can cause severe pain ? Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene membranes ? Considering the high complication rate, stent retrievability is important for safety reasons     

Treatment of lacrimal stenoses obstructions with interventional radiology: immediate and 5-year follow-up results

Purpose

This study was undertaken to evaluate the effectiveness of the Song stent in patients with nasolacrimal duct obstruction.

Materials and methods

Between 2003 and 2007, we treated 76 consecutive nasolacrimal obstructions in 73 patients (mean age 56 years; range 19–81) with implantation of polyurethane stents. Indications were epiphora in 46 patients, dacryocystitis in 18 and recurrent conjunctivitis in three. Average follow-up was 1 year (3 months to 5 years).

Results

Technical success was achieved in 73 procedures (96%). Complications included pain in three cases, eyelid inflammation in four cases and severe bleeding in one case. Postprocedural mucocele was observed in five patients. Mean time without symptoms was 31 weeks. There were 24 cases of stent obstruction: 15 were treated with high-pressure 5% N-acetyl-cysteine and saline flush, achieving resolution in two cases; in three cases, attempts to recanalise the obstruction with a guidewire failed. The occluded stents were rsemoved in 22 patients: seven remained asymptomatic, 15 had recurrence of epiphora, nine received a new stent after dacryocystography and six underwent dacryocystorhinostomy.

Conclusions

Advantages of the procedure include the lack of anatomical alterations to the lacrimal ducts and a low short-term complication rate, whereas limitations include restricted duration of stent patency. The pathophysiological causes of stent obstruction should be clarified in order to relate them to stent morphology.     

Percutaneous Intraductal Radiofrequency Ablation for Clearance of Occluded Metal Stent in Malignant Biliary Obstruction: Feasibility and Early Results

Purpose

The major complication occurring with biliary stents is stent occlusion, frequently seen because of tumour in-growth, epithelial hyperplasia, and sludge deposits, resulting in recurrent jaundice and cholangitis. We report a prospective study with the results of first in man percutaneous intraductal radiofrequency (RF) ablation to clear the blocked metal stents in patients with malignant biliary obstruction using a novel bipolar RF catheter.

Methods

Nine patients with malignant biliary obstruction and blocked metal stents were included. These patients underwent intraductal biliary RF ablation through the blocked metal stent following external biliary decompression with an internal–external biliary drainage.

Results

All nine patients had their stent patency restored successfully without the use of secondary stents. Following this intervention, there was no 30-day mortality, haemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the nine patients, six are alive and three patients are dead with a median follow-up of 122 (range 50–488) days and a median stent patency of 102.5 (range 50–321) days. Six patients had their stent patent at the time of last follow-up or death. Three patients with stent blockage at 321, 290, and 65 days postprocedure underwent percutaneous transhepatic drain insertion and repeat ablation.

Conclusions

In this selective group of patients, it appears that this new approach is safe and feasible. Efficacy remains to be proven in future, randomized, prospective studies.     

Novel 3D-CT evaluation of carotid stent volume: greater chronological expansion of stents in patients with vulnerable plaques

Introduction

Although self-expanding carotid stents may dilate gradually, the degrees of residual stenosis have been quantified by the NASCET criteria, which is too simple to reflect the configuration of the stented artery. We measured the volumes of the stent lumens chronologically by 3D-CT in patients after carotid artery stenting (CAS), and analyzed the correlations between the volume change and medical factors.

Methods

Fourteen patients with carotid artery stenosis were treated using self-expanding, open-cell stents. All patients underwent preoperative plaque MRI (magnetization-prepared rapid acquisition gradient-echo, MPRAGE) and chronological 3D-CT examinations of their stents immediately after their placement and 1 day, 1 week, and 1 month after the procedure. The volume of the stent lumen was measured using a 3D workstation. The correlations between stent volume and various factors including the presence of underlying diseases, plaque characteristics, and the results of the CAS procedure were analyzed.

Results

Stent volume gradually increased in each case and had increased by 1.04–1.55 (mean, 1.25)-fold at 1 postoperative month. The presence of underlying medical diseases, plaque length, the degree of residual stenosis immediately after CAS, and plaque calcification did not have an impact on the change in stent volume. On the other hand, the stent volume increase was significantly larger in the patients with vulnerable plaques that demonstrated high MPRAGE signal intensity (P?<?0.05).

Conclusions

A 3D-CT examination is useful for precisely measuring stent volume. Self-expanding stents in carotid arteries containing vulnerable plaques expand significantly more than those without such plaques in a follow-up period.     

The Effect of Stent Cell Geometry on Carotid Stenting Outcomes

Purpose

The aim of this study was to investigate the effect of stent cell geometry on midterm results of carotid artery stenting (CAS).

Materials and Method

One hundred fifty-five patients underwent CAS between February 2010 and December 2012. Ninety-one open- and 84 closed-cell stents were used in this non-randomized, retrospective study. Periprocedural complications were defined as the ones happened during the procedure or within 30 days afterwards. Starting from the 6th month after the procedure, in-stent restenosis was detected with multidetector computed tomography angiography and classified into four groups from focal restenosis to occlusion.

Results

Eleven complications were encountered in the periprocedural period (four on the open- and seven on the closed-cell group). Total complication rate was 6.3 % (11/175). No significant difference was detected in terms of periprocedural complications between two groups (p = 0.643). There was statistically significant difference between stent design groups in regard to radiological findings (p = 0.002). Sixteen of open-cell stents and three of closed-cell stents had focal restenosis. One closed-cell stent had diffuse proliferative restenosis and one open-cell stent had total occlusion.

Conclusion

In-stent restenosis was more common in open-cell stent group, which have larger free cell area than closed-cell stents. Although our radiologic findings promote us to use closed-cell design if ‘possible’, no difference was detected in terms of clinical outcomes.

     

Evaluation of stent visibility by flat panel detector CT in patients treated for intracranial aneurysms

Introduction

This study aimed to evaluate the visibility of stents using high-resolution computed tomography (CT) acquisitions acquired with flat panel detector (XperCT, Allura series, Philips Healthcare, The Netherlands) for endovascular treatment of intracranial aneurysms.

Methods

On a 24-month period, 48 patients endovascularly treated by coiling and stenting (59 stents) for intracranial aneurysms were explored by flat panel detector CT technique. A sequence of 620 2D images was acquired over an angle of 240° using a 1,024?×?1,024 pixel matrix detector within a 48-cm field of view. The images were retrospectively analyzed independently by two neuroradiologists. Evaluation criteria were percentage of visualization of the stents and stent deployment (kinking or unsatisfactory deployment of the stent).

Results

Evaluation of the stent was feasible for all the patients. Stent visibility by XperCT was overall estimated at 76% of the stent length. Difficulties to analyze the stents were related to coil artifacts but not to packing density or aneurysm location. Stent length visualization was higher when the acquisition was performed before additional coiling (P?Conclusion XperCT technique provides multiplanar and 3D reconstructions that allows for a satisfying visualization of intracranial stents. This CT-like acquisition should be performed after the stent deployment and before coiling, in order to obtain better stent visualization.     

Carotid artery stenting: findings based on 8 years’ experience

Purpose

Carotid artery stenting (CAS) may be an alternative to surgical endarterectomy not only in high-risk patients. Few data are available regarding the long-term clinical efficacy of CAS with the use of cerebral protection devices and the incidence of restenosis. Our experience demonstrates that if certain requirements are fulfilled, CAS can be considered a safe and effective treatment with high short-and long-term success rates.

Materials and methods

In the past 8 years, we treated 1,003 patients (1,096 arteries) affected by internal carotid artery stenosis, 93 with bilateral stenosis. Of these, 567 (51.74%) were symptomatic and 529 (48.26%) asymptomatic lesions. The preprocedural evaluation was performed with Doppler ultrasound (US), magnetic resonance (MR) angiography/computed tomography (CT) angiography and a neurological evaluation. Antiplatelet therapy was administered before and after the procedure.

Results

Technical success was achieved in 1,092 cases (99.6%), and a cerebral protection device was successfully used in 1,019 procedures (92.9%). The 30-day transient ischaemic attack (TIA)/stroke/death rate was 2.16%: death (0.18%) major stroke (0.45%) and minor stroke/TIA (1.53%). During a follow-up up to 8 years, restenoses occurred in 39 cases (3.57%), of which 28 were post-CAS (2.57%) and 11 post-CAS performed for restenosis after carotid endarterectomy (1%). Only five symptomatic restenoses >80% were treated with a repeated endovascular procedure.

Conclusions

A retrospective analysis of our experience suggests that CAS is a safe and effective procedure with better results than endarterectomy. In up to 8 years of follow-up, CAS seems to be effective in preventing stroke, with a low restenosis rate.     

Biodegradable biliary stent implantation in the treatment of benign bilioplastic-refractory biliary strictures: preliminary experience

Objectives

To evaluate feasibility, safety, and outcome of patients treated with biodegradable biliary stents for benign biliary stenosis refractory to other treatments.

Methods

Between March 2011 and September 2012, ten patients (seven men, three women; age 59?±?7 years) with recurrent cholangitis due to postsurgical biliary stricture, previous multiple unsuccessful (two to five) bilioplasties, and unsuitability for surgical/endoscopic repair underwent percutaneous implantation of a biodegradable biliary stent. Patients were followed-up clinically and with ultrasound at 1, 3 and 6 months, and then at 6-month intervals.

Results

Stent implantation was always feasible. No immediate major or minor complications occurred. In all patients, 48-h cholangiographic control demonstrated optimal stent positioning and stenosis resolution. In a median follow-up time of 16.5 months (25th–75th percentiles = 11–20.25 months) no further invasive treatment was needed. Three patients experienced transient episodes of cholangitis. Neither re-stenosis nor dilatation of the biliary tree was documented during follow-up. No stent was visible at the 6-month follow-up.

Conclusions

Percutaneous placement of biodegradable biliary stents represents a new option in treating benign biliary stenoses refractory to treatment with bilioplasty. This technique seems to be feasible, effective and free from major complications. Further investigations are warranted to confirm our preliminary results.

Key Points

? Percutaneous biodegradable stents can be used to treat benign biliary stenosis. ? They can be used in patients refractory to bilioplasty. ? The procedure for insertion appears free from major complication. ? Biodegradable stents may represent an alternative device to covered expandable stents.     

The Use of Biodegradable Stents in Malignant Oesophageal Strictures for the Treatment of Dysphagia Before Neoadjuvant Treatment or Radical Radiotherapy: A Feasibility Study

Purpose

To evaluate the clinical results of the use of biodegradable oesophageal stents in malignant strictures.

Methods

Eleven patients were included in this prospective analysis in which a woven polydioxanone biodegradable oesophageal stent was used. The inclusion criterion was that the patient underwent neoadjuvant treatment or radical radiotherapy after the stent insertion. Primary end points were dysphagia score at discharge, stent patency, and complication rate. Secondary end points were overall survival and surgical outcome of surgery.

Results

There was a 100 % procedure technical success rate. Early complications occurred in three patients resulting in failure to restore oral nutrition. In the remaining eight patients, dysphagia was significantly improved at discharge. Mean stent patency rate in this group was 71.5 days. Stent dysfunction occurred in five of eight patients (62.5 %); in two of five patients this was due to local inflammatory reaction, and in three of five patients it was due to tumour growth after a mean time of 97.8 days, and a new metallic stent was consequently placed in four of five patients. One patient was successfully treated with esophagectomy. At the end of follow-up (mean time 102.1 days), three of eight stents were patent. The overall patient survival rate was 81.8 %.

Conclusion

Although short-term dysphagia scores improved, biodegradable stents do not appear to offer a clear beneficial effect in most cases of malignant strictures, particularly due to a local inflammatory reaction that may be induced. Technical improvement of the device and delineation of the patient group that would benefit from its use is necessary if further studies are to be conducted in the future.     

Mechanische Revaskularisation beim Schlaganfall

Clinical/methodical issue

Stroke is the third most common cause of death in the developed world and the leading cause of disability worldwide. The present demographic development will lead to increased numbers of stroke patients in the future.

Standard radiological methods

Patient selection takes place by using various computer tomographic (CT) or magnetic resonance (MR) imaging modalities. For endovascular stroke treatment a modern biplane angiography suite is recommended.

Methodical innovations

Intra-arterial chemical thrombolysis was shown to be effective in achieving recanalization and improving clinical outcome. Mechanical devices were introduced in the late 1990s and the highly effective stent retriever was recently included.

Performance

Mechanical devices allows a recanalization rate of up to 90?% of affected brain vessels.

Achievements

The advantage of a stent retriever compared to other mechanical devices seems to be an improvement in good clinical outcome.

Practical recommendations

Currently, the stent retriever seems to be the definitive first choice in the use of mechanical devices for intra-arterial recanalization treatment in acute ischemic stroke.     

Haemorrhagic Complications and Symptomatic Venous Thromboembolism in Interventional Tumour Ablations: The Impact of Peri-interventional Thrombosis Prophylaxis

Aim

The aim of this study was to assess the rates of haemorrhagic and thrombotic complications in patients undergoing interventional tumour ablation with and without peri-interventional low-molecular-weight heparin (LMWH) thrombosis prophylaxis.

Methods

Patients presented with primary and secondary neoplastic lesions in the liver, lung, kidney, lymph nodes and other locations. A total of 781 tumour ablations (radiofrequency ablation, n = 112; interstitial brachytherapy, n = 669) were performed in 446 patients over 22 months; 260 were conducted under peri-interventional thrombosis prophylaxis with LMWH (H-group;) and 521 without this (NH-group, in 143 of these, LMWH was given post-interventionally).

Results

Sixty-three bleeding events occurred. There were significantly more bleedings in the H-group than in the NH-group (all interventions, 11.66 and 6.26 %, p = 0.0127; liver ablations, 12.73 and 7.1 %, p = 0.0416). The rate of bleeding events Grade ≥ III in all procedures was greater by a factor of >2.6 in the H-group than in the NH-group (4.64 and 1.73 %, p = 0.0243). In liver tumour ablations, the corresponding factor was about 3.3 (5.23 and 1.54 %, p = 0.028). In uni- and multivariate analyses including covariates, the only factor constantly and significantly associated with the rate of haemorrhage events was peri-interventional LMWH prophylaxis. Only one symptomatic lung embolism occurred in the entire cohort (NH-group). The 30- and 90-day mortalities were significantly greater in the H-group than in the NH-group.

Conclusions

Peri-interventional LMWH thrombosis prophylaxis should be considered with caution. The rate of clinically relevant thrombotic events was extremely low.

     

Treatment of carotid siphon aneurysms by use of the Willis stent graft: an angiographic and histopathological study

Objective

We designed a carotid siphon (CS) aneurysm model in dogs to test a new stent graft (the Willis covered stent) and compared tissue reaction over 12-month follow-up versus a comparison group with stents implanted in straight vessels.

Methods

Twenty-four saccular sidewall aneurysms (group A) and 12 CS aneurysms (group B) were created surgically. A Willis stent graft was implanted in each aneurysm. Angiography was performed immediately and at 1-, 3-, 6- and 12-month post-implantation to investigate aneurysm isolation, endoleak, stent angulation, parent artery (PA) patency and restenosis. Light and scanning electron microscopy were used to identify aneurysmal sac thrombi, intima hyperplasia and endothelial progress.

Results

Immediate angiography demonstrated mild endoleak in two aneurysms and three stent angulations in group B. Follow-up at 12 months revealed resolved endoleaks, occlusion in one PA and mild stenosis in three in group B. In group A, occlusion occurred in one PA and mild stenosis in two. Light microscopy revealed new intima, and all aneurysm sacs were filled with thrombi. In group B, endothelial progress was complete at 12 months, and closely correlated with haemodynamic changes.

Conclusions

Application of a Willis stent graft is a feasible method of treating CS aneurysms, and it exhibits a prolonged endothelial progress compared with that in straight vessels.