Retrieval of migrated coils with stent retrievers: an animal study

Results of Temporary Stent-assisted Coil Embolization (CATS) for the Treatment of Wide-neck Aneurysms : A 10-year Single Center Experience

PURPOSE

In intracranial wide-neck aneurysms, simple coil embolization is often not a feasible treatment option. Balloon-assisted coiling comes with the drawback of blood flow impairment, whereas permanent stent placement requires long-term antiplatelet therapy. Temporary stent-assisted coiling (coiling assisted by temporary stenting, CATS) is an alternative that eliminates both disadvantages. Because prior studies included only small numbers of patients, it was our aim to analyze the safety and effectiveness of this technique in a larger cohort of patients.

METHODS

We retrospectively evaluated all endovascular aneurysm treatments at our institution from 2011 to 2020. Out of a total of 688 aneurysm treatments, we intended to perform 95 (14%) with temporary stent-assisted coiling and included them in our study.

RESULTS

Sixty-four (64)% of aneurysms were acutely ruptured, 3% were symptomatic but unruptured, and 33% were incidental. Successful stent recovery was possible in 93% of treatments. Initial complete and adequate occlusion rate were 53% and 82%, respectively. Long-term follow-up at 6 and 12 months was available for 71% and 44% of cases. Aneurysm recurrence was observed in 10% of cases after 6 months, and in 17% after 1 year or later. Periprocedural complications were noted in 12 cases (13%), of which only 1 complication was definitely associated with temporary stent-assisted coiling (1%). One of the periprocedural complications resulted in neurological damage, the other complications were asymptomatic.

CONCLUSION

Temporary stent-assisted coiling appears to be a safe and effective treatment method in intracranial wide-neck aneurysms. Procedural safety appears to be comparable with balloon remodeling or permanent stent-assisted coiling, but it comes with the further benefit of diminished need for posttreatment antiplatelet therapy, which may improve the outcome of patients. However, to define the true value and potential benefit of this technique, further prospective studies are required.

Comparison of porcine and human vascular diameters for the optimization of interventional stroke training and research

The branches of the porcine subclavian artery are frequently used in endovascular stroke training and research. This study aimed to determine a porcine weight group, in which the arterial diameters most closely match human cerebral artery diameters, and thus optimize the porcine in-vivo model for neuroendovascular purposes. A group of 42 German Landrace swine (45–74 kg) was divided into four subgroups according to their weight. Angiographic images of the swine were used to determine the arterial diameter of the main branches of the subclavian artery: axillary artery, brachial artery, external thoracic artery, subscapular artery (at two different segments), suprascapular artery, caudal circumflex humeral artery, thoracodorsal artery, and circumflex scapular artery. The porcine arterial diameters were correlated with animal weight and compared to luminal diameters of human arteries which are commonly involved in stroke: internal carotid artery, basilar artery, vertebral artery, middle cerebral artery and M2 branches of the middle cerebral artery. Swine weight was positively correlated with porcine arterial diameter. The most conformity with human arterial diameters was found within the two heavier porcine groups (55–74 kg). We suggest the use of swine with a weight between 55–59.7 kg, as lighter animals show less similarity with human arterial diameters and heavier animals could cause more problems with manipulation and handling.

Disturbed flow's impact on cellular changes indicative of vascular aneurysm initiation, expansion, and rupture: A pathological and methodological review

Aneurysms are malformations within the arterial vasculature brought on by the structural breakdown of the microarchitecture of the vessel wall, with aneurysms posing serious health risks in the event of their rupture. Blood flow within vessels is generally laminar with high, unidirectional wall shear stressors that modulate vascular endothelial cell functionality and regulate vascular smooth muscle cells. However, altered vascular geometry induced by bifurcations, significant curvature, stenosis, or clinical interventions can alter the flow, generating low stressor disturbed flow patterns. Disturbed flow is associated with altered cellular morphology, upregulated expression of proteins modulating inflammation, decreased regulation of vascular permeability, degraded extracellular matrix, and heightened cellular apoptosis. The understanding of the effects disturbed flow has on the cellular cascades which initiate aneurysms and promote their subsequent growth can further elucidate the nature of this complex pathology. This review summarizes the current knowledge about the disturbed flow and its relation to aneurysm pathology, the methods used to investigate these relations, as well as how such knowledge has impacted clinical treatment methodologies. This information can contribute to the understanding of the development, growth, and rupture of aneurysms and help develop novel research and aneurysmal treatment techniques.

Rescue Maneuver of Migrated Coil Using the ERIC Device after Previous Attempts with Conventional Stentrievers

Coil prolapse or migration is a rare but potentially serious complication that may occur during aneurysm embolization, with no standard management currently described. Here we describe our experience with the Embolus Retriever with Interlinked Cages (ERIC) device^® (Microvention, Aliso Viejo, CA, USA) for the retrieval of prolapsed or migrated coils in a case series and Flow-Model analysis. First, a retrospective review was performed using our institution database for patients in which coil prolapse or migration occurred during aneurysm embolization, and data was collected and analyzed. Second, an in vitro Flow-Model analysis was performed comparing the ERIC device^® with other stent retrievers for coil retrieval. In 2 cases, the ERIC device^® successfully retrieved the displaced coil from intracranial circulation in 1 pass, after failure with other devices. In the Flow-Model, again the ERIC device^® achieved success for retrieving a detached coil, whereas 2 other different stent retrievers failed to capture the coil after 2 attempts. The ERIC device^® appears to be a safe and effective tool for retrieving a prolapsed or migrated coil from the intracranial circulation.

Endovascular retrieval of a dislocated pushable coil in the common hepatic artery using a cerebral stent retriever

BACKGROUND

This is case of removing a dislocated pushable coil from the common hepatic artery (CHA) as a possible complication of using pushable coils in the embolization of an upper gastrointestinal bleeding (UGIB) from the gastroduodenal artery (GDA) by using a pRESET stent retriever (Phenox, Bochum, Germany) which is utilized mainly for treatment of endovascular stroke.

CASE PRESENTATION

An 88-year-old female patient was referred to our hospital to get an emergency embolization of the GDA causing an UGIB with a relevant drop of the hemoglobin level. During the routine embolization of the GDA using pushable coils, a complete dislocation of the last coil into the CHA took place leading to a relevant slowing down of the arterial blood flow to the liver. A decision was thereby made to remove the dislocated coil to avoid further possible complications which was successfully achieved.

CONCLUSIONS

Various stent retrievers have been proven to be effective in removing dislocated coils during intracerebral coiling of different pathologies. This case report is to our knowledge the first case report proving the high efficacy and safety of using yet another stent retriever, namely a pRESET stent retriever in removing a fully dislocated coil in the abdominal vessels, namely in this case the CHA.

Solitaire Stentectomy Using a Stent-Retriever Technique in a Porcine Model

PURPOSE

Mechanical thrombectomy using the Solitaire device has become a standard treatment of ischemic stroke due to large vessel occlusions. Inadvertent detachment is a feared complication, which is associated with poor clinical outcome. The aim of this experimental study was to assess in a porcine model the feasibility and effectiveness of rescuing detached Solitaire devices using different stent retrievers.

METHODS

Solitaire FR devices (4 × 15/20 mm and 6 × 20/30 mm) were placed in the axillary artery of pigs. By means of 3 different stent retrievers (Trevo ProVue; EmboTrap II revascularization device; 3D revascularization device) a total of 24 rescue maneuvers (8 per retriever) were performed by deploying the retrievers within the deployed Solitaire devices and trapping parts of the Solitaire within the microcatheter. Rescue rates, rescue time and complications were assessed.

RESULTS

Overall stentectomy of the Solitaire devices was successful in all cases (100%). Time of rescue was comparable using the applied stent retrievers (Trevo ProVue; EmboTrap II revascularization device; 3D revascularization device). Complications, such as entrapment of the Solitaire-retriever complex at the intermediate catheter, Solitaire migration, vasospasm, perforation, or dissection were not observed.

CONCLUSION

Stentectomy of inadvertently detached Solitaire devices using different stent retrievers is a feasible and effective method. Rescue rates and times with the Trevo ProVue, EmboTrap II and 3D revascularization device were comparable.

Rescue of migrated Woven Endobridge devices using a stent-retriever-technique in a porcine model

PURPOSE

The Woven Endobridge device (WEB) has become widely applied for the treatment of intracranial aneurysms. Complications are rare, however, especially dislocations and migrations can potentially increase poor clinical outcome. The aim of this study was to assess the feasibility and effectiveness of rescuing migrated Woven Endobridges using different stent retrievers.

METHODS

In a porcine model, Woven Endobridges of different sizes (SLS 4, SLS 7, SL 5 × 3, SL 4 × 3) were placed into the axillary arteries. By means of two different stent retrievers (Solitaire Platinum and 3D Revascularization Device), a total of 20 rescue maneuvers were performed. For this purpose, the retrievers were deployed distally of the migrated Woven Endobridges. After retracting the stent retrievers partially, the Woven Endobridges were trapped within the microcatheter. Rescue rates, time, attempts and complications were assessed.

RESULTS

Successful rescue of the migrated Woven Endobridges was observed in all cases (100%). Rescue was slightly faster (177.8 ± 72.8 s vs. 223.4 ± 104.1 s) with fewer attempts (1.5 ± 0.8 vs. 1.8 ± 0.9) when using the 3D Revascularization Device compared to the Solitaire Platinum. However, there were no significant differences (p = 0.327; p = 0.554). Migration of the Woven Endobridges during rescue was seen with both stent retrievers in a comparable frequency (p = 0.642). Further complications, such as entrapment of the stent-retriever-WovenEndobridge-complex at the intermediate catheter, vasospasm, perforation or dissection, were not observed.

CONCLUSIONS

Rescue of migrated Woven Endobridges using stent retrievers is a feasible and effective method. Rescue rates, times and attempts with the Solitaire Platinum and 3D Revascularization Device are comparable with each other.

Different Rescue Approaches of Migrated Woven Endobridge (WEB) Devices: an Animal Study

Purpose

Treatment of wide-necked intracranial aneurysms using the Woven Endobridge (WEB) device has become broadly accepted. Feared complications with the potential of increased poor clinical outcome include dislocations and migration of the device. This study was carried out to determine the effectiveness of a variety of different strategies to rescue migrated WEB devices.

Methods

In a porcine model, WEB devices of different sizes (SL [single layer] 3.5 × 2mm and SL 4.0 × 3 mm, SL 8 × 5 mm and SLS 8 mm [single layer spherical]) were placed into both the subclavian and axillary arteries. A total of 32 rescue maneuvers (8 per rescue device) were performed. Small WEBs were rescued using reperfusion catheters (RC) (SOFIA Plus and JET 7), larger WEBs were rescued using dedicated rescue devices (Microsnare and Alligator). Rescue rates, times, attempts and complications were assessed.

Results

Rescue attempts of migrated WEBs were successful in all cases (100%). Rescue time (p = 0.421) and attempts (p = 0.619) of small WEBs using RCs were comparable without significant differences. Aspiration alone was not successful for larger WEBs. Rescue of larger WEBs was slightly faster (122.75 ± 41.15 s vs. 137.50 ± 54.46 s) with fewer attempts (1 vs. 1.37) when using the Microsnare compared to the Alligator device. Complications such as entrapment of the WEB in the RCs, vasospasm, perforation, or dissection were not observed.

Conclusion

Rescue of migrated WEB devices is a feasible and effective method and 100% successful rescue rates and appropriate rescue times can be achieved for small WEBs using RCs and for larger WEBs using dedicated rescue devices (Microsnare and Alligator).

Large animals in neurointerventional research: A systematic review on models, techniques and their application in endovascular procedures for stroke, aneurysms and vascular malformations

Neuroendovascular procedures have led to breakthroughs in the treatment of ischemic stroke, intracranial aneurysms, and intracranial arteriovenous malformations. Due to these substantial successes, there is continuous development of novel and refined therapeutic approaches. Large animal models feature various conceptual advantages in translational research, which makes them appealing for the development of novel endovascular treatments. However, the availability and role of large animal models have not been systematically described so far. Based on comprehensive research in two databases, this systematic review describes current large animal models in neuroendovascular research including their primary use. It may therefore serve as a compact compendium for researchers entering the field or looking for opportunities to refine study concepts. It also describes particular applications for ischemic stroke and aneurysm therapy, as well as for the treatment of arteriovenous malformations. It focuses on most promising study designs and readout parameters, as well as on important pitfalls in endovascular translational research including ways to circumvent them.

Intra-arterial pulse wave analysis during thrombectomy for the assessment of collateral status - A feasibility study

Purpose

Knowledge of the collateralization of an occluded vessel is important for the risk-benefit analysis of difficult revascularization maneuvers during mechanical thrombectomy. If the territory behind a clot is well perfused, one could desist from performing a risky thrombectomy maneuver. The arterial pulse pressure curve may serve as an indicator for the collateralization of an occluded target vessel. We investigated the feasibility of arterial pulse measurements with a standard microcatheter.

Methods

We measured the intra-arterial blood pressure proximal and distal to the clot in 40 thrombectomy maneuvers in a porcine stroke model. We used a microcatheter (Trevo Pro 18, Stryker, Kalamazoo, CA, USA), a pressure transducer (MEMSCAP SP844), an AdInstruments Powerlab 16/35 workstation, and LabChart 8 Software (AdInstruments, Dunedin, New Zealand).

Results

Median arterial blood pressure proximal and distal to the clot was 96.0 mmHg (IQR, 23.8 mmHg) and 47.5 mmHg (IQR, 43.5 mmHg), respectively (p < .001). The median difference between systolic maximum and diastolic minimum proximal and distal to the clot decreased significantly from 1.8 mmHg (IQR, 3.6 mmHg) to 0.0 mmHg (IQR, 0.5 mmHg) (p < .001). There was loss of the curve in 26 of 40 cases and loss of pressure in 23 of 40 cases (p = .008). There was no significant correlation between vessel diameter and either loss of the pulse pressure curve (p = .20) or overall pressure loss (p = .31).

Conclusion

It is possible to measure the pulse pressure proximal and distal to the clot with a standard microcatheter used during mechanical thrombectomy.

Endovascular Retrieval of Dislodged Neurovascular Devices with a Stentriever: Case Series and Technical Review

PURPOSE

Endovascular treatment of neurovascular disorders is now well established as effective and safe; however, the nature of the intracranial vasculature poses unique challenges. The unintentional dislodgement or fracture of a device and its migration within cerebral vessels is a complication with serious potential morbidity that must be managed urgently. In this series, the authors describe 7 cases of a stentriever being used to remove foreign objects from within the cerebral vasculature.

METHODS

A retrospective search of all interventional neurovascular procedures performed in 2017 at a tertiary metropolitan hospital was performed to identify cases of dislodged devices.

RESULTS

Five dislodged endovascular coils, 1 microcatheter, and 1 fractured stentriever were technically successfully retrieved. In 6 of the cases, the foreign object was successfully removed with a stentriever alone, whereas 1 case used a J-tip wire and a "J-tip flick" to manipulate the coil and facilitate retrieval. Stentrievers, particularly when used alone, confer the advantages of speed, cost, as well as being tailor-made for cerebral vessels. They also allow continuous blood flow when deployed, a critical advantage when considering cerebral perfusion. Critical techniques include the gradual deployment of the stentriever alongside the foreign object to allow its entanglement and partial resheathing, so that the foreign object can become pinned within the microcatheter. Stentrievers do remain limited by vessel caliber and are less able to entangle larger, stiffer devices.

CONCLUSION

The migration of foreign devices during neurointerventional procedures is a serious complication requiring urgent treatment. This case series highlights the efficacy and advantages of using a stentriever and suggests its consideration as a first-line technique in recovering dislodged foreign bodies in the cerebral vasculature.

Balloon-Guide Catheters Are Needed for Effective Flow Reversal during Mechanical Thrombectomy

BACKGROUND AND PURPOSE

Blood flow management in the carotid artery during mechanical thrombectomy is crucial for safety and effectiveness. There is an ongoing discussion about whether balloon-guide catheters or large-bore sheaths are needed for effective flow management. We compared general flow characteristics of proximal aspiration through a large-bore sheath and a balloon-guide catheter in a porcine in vivo model.

MATERIALS AND METHODS

We investigated blood flow in a porcine common carotid artery with and without aspiration (VacLok syringe and Penumbra pump, Pump MAX) through an 8F-long sheath and an 8F balloon-guide catheter. Blood hemodynamics were assessed via continuous duplex sonography.

RESULTS

Average vessel diameter and baseline blood flow were 4.4 ± 0.2 mm and 244 ± 20 mL/min, respectively. For the 8F sheath, pump aspiration resulted in a significant flow reduction (225 ± 25 mL/min, P < .001), but with a persisting antegrade stream. Manual aspiration resulted in collapse of the vessel in 2 of 7 measurements and oscillatory flow with antegrade systolic and retrograde diastolic components in the remaining 5 measurements. Net flow was antegrade (52 ± 44 mL/min) in 3 and retrograde (-95 ± 52 mL/min) in the remaining 2 measurements. For balloon-guide catheters, balloon inflation always resulted in flow arrest. Additional pump or manual aspiration resulted in significant flow reversal of -1100 ± 230 and -468 ± 46 mL/min, respectively (both, P < .001).

CONCLUSIONS

Only balloon-guide catheters allow reliable blood flow arrest and flow reversal in combination with aspiration via syringes or high-flow pump systems. Aspiration through an 8F sheath results in either collapse of the vessel or oscillatory flow, which can result in a net antegrade or retrograde stream.

Delayed Coil Migration After Treatment of Traumatic Pseudoaneurysm

A teenager with epistaxis after head trauma was diagnosed with pseudoaneurysm of the internal carotid artery. Three years after the first aneurysm embolization, delayed coil migration was detected. Then the migrated coil was removed through nasal endoscopy.

Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT

BACKGROUND AND PURPOSE

Large-bore catheters allow mechanical thrombectomy in ischemic stroke by engaging and retrieving clots without additional devices (direct aspiration first-pass technique [ADAPT]). The purpose of this study was to establish a model for minimal catheter diameters needed for ADAPT.

MATERIALS AND METHODS

We established a theoretic model for the calculation of minimal catheter diameters needed for ADAPT. We then verified its validity in 28 ADAPT maneuvers in a porcine in vivo model. To account for different mechanical thrombectomy techniques, we factored in ADAPT with/without a hypothetic 0.021-inch microcatheter or 0.014-inch microwire inside the lumen of the aspiration catheter and aspiration with a 60-mL syringe versus an aspiration pump.

RESULTS

According to our calculations, catheters with an inner diameter of >0.040 inch and >0.064 inch, respectively, are needed to be effective in the middle cerebral artery (2.5-mm diameter) or in the internal carotid artery (4 mm) in an average patient. There was a significant correlation between predicted and actual thrombectomy results (P = .010). Our theoretic model had a positive and negative predictive value of 78% and 79%, respectively. Sensitivity and specificity were 88% and 64%, respectively.

CONCLUSIONS

Our theoretic model allows estimating the minimal catheter diameters needed for successful mechanical thrombectomy with ADAPT, as demonstrated by the good agreement with our animal experiments. Our model will be helpful to interventionalists in avoiding selecting catheters that are likely too small to be effective.

Delayed asymptomatic coil migrations toward different arteries after aneurysmal embolization: case report

Delayed coil migration after endovascular treatment with detachable coils, particularly several months after treatment, is extremely rare. In this report, the authors describe a 77-year-old female in whom delayed coil migration to the anterior cerebral artery and posterior communicating artery (PCoA) developed 3 months after an uncomplicated aneurysm embolization. The patient was successfully retreated with a closed-cell stent. Computational fluid dynamics (CFD) revealed high wall shear stress (WSS) and multiple vortices in the residual cavity of the initially treated aneurysm. CFD could be useful to detect and predict this complication, and a stent-assisted technique could be an important treatment option.

Endovascular retrieval of a dislocated coil in the peroneal artery with a stent retriever

We present a patient who underwent successful removal of a fully detached platinum coil from the peroneal artery using a Solitaire^™ stent retriever (Covidien, Irvine, CA) that is usually used in endovascular stroke treatment.