Repeated endovascular coil occlusion in 350 of 2759 intracranial aneurysms: safety and effectiveness aspects.

OBJECTIVE: Evaluation of the safety and effectiveness of endovascular retreatment of intracranial aneurysms with detachable coils. METHODS: Retrospective analysis of clinical outcome as well as angiographic studies both before and after coil retreatment. The indication for retreatment was based on either inadequate occlusion after previous treatment or recurrent perfusion of the aneurysm. RESULTS: A total of 2759 intracranial aneurysms in 2360 patients were treated by endovascular coil occlusion. Of those, 350 (12.3%) aneurysms underwent a second treatment, and 94 (3.4%) aneurysms underwent three or more treatment sessions. The second treatment sessions were performed an average of 27.2 months after the previous procedure. The third and following treatment sessions were conducted an average of 25.3 months after the previous procedure. Initial treatment resulted in 100% occlusion in 63.7% of aneurysms. One hundred percent occlusion was achieved in only 46.9% of the second and 35.2% of the third and following sessions. Stent-assisted coil treatment was used in 5.6% of initial, 28.0% of second, and 20.7% of third and following sessions. Initial treatment sessions were uneventful in 83.2% of cases, second sessions in 86.9% of cases, and third and following sessions in 87.6% of cases. The morbidity-mortality rate for 495 retreatment sessions was 2.2% (n = 11). CONCLUSION: The natural course of aneurysm remnants or recurrent aneurysm perfusion after coil treatment is not completely understood. The low risk of bleeding from partially filled aneurysms must be balanced against the procedure-related risks of retreatment. Great caution is recommended for the treatment of asymptomatic recurrent aneurysms.

Comparative in vitro study of five mechanical embolectomy systems: effectiveness of clot removal and risk of distal embolization.

INTRODUCTION: We report an in vitro study comparing the effectiveness of clot removal and clot fragmentation of five embolectomy systems. METHODS: A flow model was embolized with fresh and old thrombi, occluding an inner diameter of 2-5 mm simulating internal carotid artery (ICA), basilar artery (BA) and middle cerebral artery (MCA) branch occlusion. Embolectomy was performed using five retrieval systems: CATCH (Balt), Merci retriever (Concentric), InTime and Attracter (Boston Scientific), and the Phenox Clot Retriever (Phenox). Clot removal and evidence and type of thrombus fragmentation and distal embolization were recorded. RESULTS: There were no observable differences attributable to thrombus age. The Merci, CATCH and Phenox Clot Retriever were equally able to mobilize and remove thrombi with the exception of one particularly firm clot. There were marked differences in terms of thrombus fragmentation and distal embolization. All devices produced micro- and macrofragments during penetration and retrieval. The Phenox Clot Retriever was able to filter fragments. The InTime and Attracter devices failed to retrieve thrombi in this model and achieved partial removal at best with a tendency towards thrombus displacement and fragmentation. CONCLUSION: Within limits, the experimental setup was appropriate for generating occlusions of diameter 2-5 mm of various lengths, simulating ICA, BA and MCA thromboembolism. In this model, thrombus mobilization appeared to be less dependent upon the individual design of the retrieval system than on thrombus fragmentation. The ability to prevent distal embolization is, however, strongly dependent on the ability of a thrombectomy device to capture fragments that are generated during removal of the device.

A device for fast mechanical clot retrieval from intracranial arteries (Phenox clot retriever).

INTRODUCTION: To describe a new device meant for rapid endovascular thrombectomy of intracranial arteries of various sizes and its first clinical use. METHODS: A device with oriented microfilaments was constructed that consists of a core wires compound surrounded by a dense palisade of perpendicular-oriented stiff polyamid microfilaments (phenox clot retriever). The device is introduced into the target vessel through a 0.021- or 0.027-inch microcatheter, deployed distally to the thrombus, and slowly pulled back under continuous aspiration via the guiding catheter. RESULTS: The clinical use of the phenox clot retriever in two successive patients is described. Case 1: In a 78-year-old patient with acute posterior circulation ischemia not eligible for intravenous or intraarterial thrombolysis, endovascular recanalization of the occluded left V4 segment was possible using the phenox clot retriever within a few minutes. Case 2: A 70-year-old patient presented after the sudden onset of a left upper extremity paresis 1 day after abdominal surgery. Angiography revealed a thromboembolic occlusion of two cortical branches of the right middle cerebral artery. The rolandic artery was recanalized by a single passage of the phenox clot retriever, with complete neurological recovery. CONCLUSION: The phenox clot retriever, a flexible microfilament pattern, might be a useful supplement to the repertoire of currently available devices for endovascular intracranial thrombectomy.

A novel self-expanding fully retrievable intracranial stent (SOLO): experience in nine procedures of stent-assisted aneurysm coil occlusion.

INTRODUCTION: The endovascular treatment of large and broad-necked aneurysms may require the use of a remodelling balloon or a stent system to achieve proper occlusion while maintaining the patency of the parent vessel. With the advent of self-expanding stents that can be delivered through a microcatheter, this kind of treatment has improved and problems with the previously used balloon expandable stents have largely been overcome. However, rigidity, insufficient track-ability, and limited or non-existent retrieve-ability may still restrict the application of self-expanding stents in some situations. METHODS: Recently, a stent system with a new and different design has been introduced. This stent is highly flexible, fully retrievable, and can be delivered through a standard 0.021-inch microcatheter without a wire. We describe the first nine cases of stent-assisted coil occlusion of intracranial aneurysms with the use of this stent system. Between May and June of 2004, nine patients with large or broad-necked aneurysms were treated in two endovascular centres. The anatomy of the aneurysms and parent vessels, technical details of the procedure, performance of the stent system, and follow-up results were evaluated. RESULTS: In all procedures, the SOLO stent could be introduced without difficulty, in one procedure after positioning of a different self-expanding stent system had failed due to vessel tortuosity. Overlapping stents were placed in one patient and stent retrieval or repositioning was successfully performed in two procedures. There was no interference or limitation of subsequent coil occlusion after stenting. With regard to the stent, immediate post-procedure and follow-up angiograms were unremarkable in terms of thromboembolic events and signs of intimal hyperplasia. CONCLUSION: From our experience, we conclude that the SOLO stent shows satisfactory performance overall. Its unique design gives the stent properties that may help overcome some of the difficulties experienced with other self-expanding intracranial stent systems.

Repeated endovascular coil occlusion in 350 of 2759 intracranial aneurysms: safety and effectiveness aspects.

OBJECTIVE: Evaluation of the safety and effectiveness of endovascular retreatment of intracranial aneurysms with detachable coils. METHODS: Retrospective analysis of clinical outcome as well as angiographic studies both before and after coil retreatment. The indication for retreatment was based on either inadequate occlusion after previous treatment or recurrent perfusion of the aneurysm. RESULTS: A total of 2759 intracranial aneurysms in 2360 patients were treated by endovascular coil occlusion. Of those, 350 (12.3%) aneurysms underwent a second treatment, and 94 (3.4%) aneurysms underwent three or more treatment sessions. The second treatment sessions were performed an average of 27.2 months after the previous procedure. The third and following treatment sessions were conducted an average of 25.3 months after the previous procedure. Initial treatment resulted in 100% occlusion in 63.7% of aneurysms. One hundred percent occlusion was achieved in only 46.9% of the second and 35.2% of the third and following sessions. Stent-assisted coil treatment was used in 5.6% of initial, 28.0% of second, and 20.7% of third and following sessions. Initial treatment sessions were uneventful in 83.2% of cases, second sessions in 86.9% of cases, and third and following sessions in 87.6% of cases. The morbidity-mortality rate for 495 retreatment sessions was 2.2% (n = 11). CONCLUSION: The natural course of aneurysm remnants or recurrent aneurysm perfusion after coil treatment is not completely understood. The low risk of bleeding from partially filled aneurysms must be balanced against the procedure-related risks of retreatment. Great caution is recommended for the treatment of asymptomatic recurrent aneurysms.