Intracranial thrombectomy using the Solitaire stent: a historical vignette.

INTRODUCTION: The endovascular treatment of acute ischemic stroke has been revolutionized in the past years by the introduction of new devices for mechanical thrombectomy. Several tools were already available in 2008. The majority allowed the recanalization of acutely occluded intracranial arteries with acceptable levels of safety and efficacy, and with occasional failures. CASE PRESENTATION: On 3 March 2008, a 67-year-old woman was treated 3.5 h after the clinical onset of a right hemispheric stroke due to an embolic middle cerebral artery (MCA) M1 occlusion. The National Institutes of Health Stroke Scale (NIHSS) score prior to treatment was 10. Mechanical thrombectomy with a microbrush yielded a significant amount of thrombotic material without recanalization. Given the urgency of the situation, the uncertain outcome in the case of a persistent occlusion of the right M1 segment and the fact that no other device was available, a Solitaire stent was deployed within the occluded right M1 segment. After several minutes of incubation, the expanded stent was slowly withdrawn under continuous aspiration with instantaneous removal of the entire thrombus and complete recanalization of the right MCA with reperfusion of the whole MCA supply territory. Digital subtraction angiography showed neither peripheral emboli nor vasospasm. The patient made a complete clinical recovery with an NIHSS score of 0 at the 30 day follow-up. CONCLUSION: The Solitaire stent was initially developed for the endovascular treatment of wide necked intracranial aneurysms but has been demonstrated to be safe and efficacious for intracranial thrombectomy. This was the first successful human clinical use of a Solitaire stent for this purpose and the ignition spark for the development of a whole generation of new devices, now called stent retrievers.

Treatment of intracranial atherosclerotic arterial stenoses with a balloon-expandable cobalt chromium stent (Coroflex Blue): procedural safety, efficacy, and midterm patency.

INTRODUCTION: We evaluated the coronary balloon-expandable cobalt chromium stent Coroflex Blue for the treatment of intracranial atherosclerotic arterial stenoses (IAAS). METHODS: Between March 2007 and October 2007, a total of 25 patients (20 male, age median 67 years) with 30 IAAS underwent endovascular treatment using Coroflex Blue stents (B. Braun, Germany). Location and degree of target stenoses before and after treatment and at follow-up and adverse clinical sequelae of treatment were registered. Angiographic follow-up was scheduled for 6, 12, 26, and 52 weeks after the treatment. RESULTS: The 30 treated lesions were located as follows: nine in intracranial-extradural internal carotid artery (ICA), three in intradural ICA, five in middle cerebral artery, eight in intradural vertebral artery, and five in basilar artery. The technical success rate was 100%. The degree of stenoses prior to and after treatment was 61 +/- 2% and 26 +/- 3% (mean +/- SE), respectively. A residual stenosis of <50% was achieved in 29 (97%) procedures. Treatment was uneventful in 28 out of 30 procedures (93%); one patient suffered a transient and one patient a permanent neurological deficit. Angiographic follow-up was available in all of the patients (100%) after 15.2 months (median) and showed significant (i.e., more than 50%) degree of recurrent stenosis in 11 (37%) of the lesions. Retreatment was performed in 11 (37%) lesions. CONCLUSION: The Coroflex Blue stent is easily inserted and safely deployed into intracranial arteries. The incidence of recurrent stenoses remains a concern. Stringent angiographic and clinical follow-up and retreatment are therefore mandatory.

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.

Angiographic and clinical results in 316 coil-treated basilar artery bifurcation aneurysms.

OBJECT: The aim of this study was to analyze the effect of the endovascular treatment of basilar artery (BA) bifurcation aneurysms and to compare the results with those published by other neuroendovascular teams. METHODS: The authors performed a retrospective analysis of 316 aneurysms of the BA bifurcation that had been treated using endovascular coil occlusion between November 6, 1992, and February 12, 2005. After the initial embolization procedure, a 90 to 100% occlusion rate was achieved in 86% of the aneurysms. No complication was evident in 80% of the lesions, although periprocedural aneurysm rupture (3.2%) and thromboembolic events (12.3%) were the most frequent complications. Clinical outcome according to the Glasgow Outcome Scale (GOS) was a score of 5 or 4 in 77%, 3 in 11%, 2 in 5%, and 1 in 7% of patients. Initial follow-up angiography studies were obtained in 56% of patients at a mean of 19 months posttreatment and demonstrated a 90 to 100% occlusion rate in 70%. No recurrence was seen on 65% of the aneurysms. Coil compaction was evident on 24% of the follow-up angiograms. A second treatment was performed on 48 aneurysms (15%) a mean of 27 months after the first therapeutic session and resulted in 90 to 100% occlusion in 83% of the lesions. Complications were encountered in 19% of the aneurysms. Rupture did not occur during any of the procedures. Clinical outcome was rated as GOS Score 5 or 4 in 83% of the patients and Grade 3 in 17%. During a cumulative clinical follow up of 821 years in 237 patients, 182 patients (81%) were independent (GOS Score 5 or 4), 33 (14%) were dependent (GOS Score 3), eight (3%) were in a vegetative state, and two (1%) had died. Clinical outcome was significantly worse after previous aneurysm rupture and following procedural complications. CONCLUSIONS: These results are within the range of published data for coil treatment of BA tip aneurysms and confirm both the safety and efficacy of this endovascular treatment method.

Treatment of extracranial and intracranial aneurysms and arteriovenous fistulae using stent grafts.

OBJECTIVE: Treatment of 11 patients with aneurysms or arteriovenous fistulae of the craniocervical arteries with stent grafts. METHODS: Peripheral stent grafts were deployed in two extracranial internal carotid arteries. Coronary stent grafts were used to treat two giant aneurysms, five direct carotid-cavernous fistulae, one vertebrojugular fistula, and two dissecting aneurysms of the vertebral artery (V2 and V4). RESULTS: Stent grafts were used successfully in two extracranial internal carotid and two extracranial vertebral arteries, one dissecting aneurysm of the intracranial vertebral artery, one giant aneurysm and one pseudoaneurysm of the cavernous internal carotid artery, and five direct carotid-cavernous sinus fistulae. Angiographic follow-up examinations (available in nine patients; obtained at 3 mo to 5 yr; average, 24 mo) revealed normal vessel caliber, and the stent grafts in all 9 of 11 initial patients were patent. There was a recurrent saccular aneurysm adjacent to the stent graft in the patient with the intracranial vertebral artery aneurysm. The following five complications were encountered: transient hemiparesis (n = 2), increased hemiparesis, postprocedural management-related fatality, and ICA dissection. In six patients, stent graft deployment was accomplished without any technical or clinical complication. There were no permanent neurological deficits consequent to stent graft placement. CONCLUSION: Stent grafts are a useful tool for the endovascular treatment of head and neck aneurysms and direct arteriovenous fistulae in selected patients. The major disadvantage of the currently available stent grafts is their lack of mechanical flexibility. Maneuvering stent grafts in the intracranial arteries carries the risk of iatrogenic vessel dissection and may require supportive measures and protection of the target site by conventional stents.

Endovascular coil occlusion of 1811 intracranial aneurysms: early angiographic and clinical results.

OBJECTIVE: We sought to evaluate the early angiographic and clinical outcomes of the first session of endovascular coil occlusion of a large number of patients with intracranial aneurysms treated by five neurointerventionalists during a decade at a single center. METHODS: We performed retrospective analyses of pre- and postprocedural angiographic studies and early clinical outcomes. Enrolled patients underwent endovascular treatment of intracranial aneurysms with detachable coils. RESULTS: A total of 1811 aneurysms in 1579 patients were treated with coil occlusion. Of these, 90 to 100% occlusion of 86.5% of the aneurysms was achieved. In 82.3% of the procedures, no complications occurred. The clinical outcome profile at primary discharge according to the Glasgow Outcome Scale was as follows: Grade V, 74.6%; Grade IV, 6.7%; Grade III, 11.1%; Grade II, 3.1%; and Grade I, 4.5%. In patients with large aneurysms with wide necks, a lower occlusion rate and an increased complication rate were encountered. The use of three-dimensional and fibered coils resulted in higher occlusion rates. Balloon remodeling and stent deployment increased the complication rate. Previous aneurysm rupture, procedural complications, and vasospasm correlated with poor outcome. Of the patients in poor grade after aneurysm rupture, 42% recovered to Glasgow Outcome Scale Grade IV or V, as opposed to 90% of patients who were treated for unruptured aneurysms. The ischemic complication rate was 9%, and the hemorrhagic complication rate was 3%. The early procedural morbidity rate was 5.3%, and the procedural mortality rate was 1.5%. The management mortality rate was 4.4%. CONCLUSION: These data confirm the safety and efficacy of endovascular coil occlusion for patients with intracranial aneurysms.