Contrast-enhanced time-resolved MRA for follow-up of intracranial aneurysms treated with the pipeline embolization device.

BACKGROUND AND PURPOSE: Endovascular reconstruction and flow diversion by using the Pipeline Embolization Device is an effective treatment for complex cerebral aneurysms. Accurate noninvasive alternatives to DSA for follow-up after Pipeline Embolization Device treatment are desirable. This study evaluated the accuracy of contrast-enhanced time-resolved MRA for this purpose, hypothesizing that contrast-enhanced time-resolved MRA will be comparable with DSA and superior to 3D-TOF MRA. MATERIALS AND METHODS: During a 24-month period, 37 Pipeline Embolization Device-treated intracranial aneurysms in 26 patients underwent initial follow-up by using 3D-TOF MRA, contrast-enhanced time-resolved MRA, and DSA. MRA was performed on a 1.5T unit by using 3D-TOF and time-resolved imaging of contrast kinetics. All patients underwent DSA a median of 0 days (range, 0-68) after MRA. Studies were evaluated for aneurysm occlusion, quality of visualization of the reconstructed artery, and measurable luminal diameter of the Pipeline Embolization Device, with DSA used as the reference standard. RESULTS: The sensitivity, specificity, and positive and negative predictive values of contrast-enhanced time-resolved MRA relative to DSA for posttreatment aneurysm occlusion were 96%, 85%, 92%, and 92%. Contrast-enhanced time-resolved MRA demonstrated superior quality of visualization (P = .0001) and a higher measurable luminal diameter (P = .0001) of the reconstructed artery compared with 3D-TOF MRA but no significant difference compared with DSA. Contrast-enhanced time-resolved MRA underestimated the luminal diameter of the reconstructed artery by 0.965 ± 0.497 mm (27% ± 13%) relative to DSA. CONCLUSIONS: Contrast-enhanced time-resolved MRA is a reliable noninvasive method for monitoring intracranial aneurysms following flow diversion and vessel reconstruction by using the Pipeline Embolization Device.

Angiographic and clinical outcomes in 200 consecutive patients with cerebral aneurysm treated with hydrogel-coated coils.

BACKGROUND AND PURPOSE: Denser coil packing in intracranial aneurysms is believed to result in lower recanalization rates. Hydrogel-coated expandable coils (HydroCoil) improve volumetric packing of aneurysms in animal models and clinical studies, but data from large clinical series are limited. The objective of this retrospective analysis was to analyze immediate and follow-up angiographic results as well as complications in a large consecutive series of patients treated with HydroCoils at a single institution. MATERIALS AND METHODS: Retrospective analysis was performed of periprocedural complications, immediate and follow-up angiograms, and retreatments of the first 200 consecutive intracranial aneurysms treated at Emory University Hospital. RESULTS: One hundred eighty-seven patients with 200 intracranial aneurysms were treated with HydroCoils during a 3-year period. Immediate angiograms showed complete aneurysmal obliteration in 58.4% of small aneurysms and 42.7% of large aneurysms. Periprocedural complications included early rebleeding and thromboembolic events resulting in permanent neurologic morbidity and mortality in 6% of cases. Follow-up angiography during an average of 16.3 months demonstrated recanalization in 17.7% of small aneurysms and 28.6% of large aneurysms, requiring retreatment in 6.3% and 19.0% of cases, respectively. During the same time period, there was delayed angiographic improvement in aneurysm obliteration in 26.6% of small aneurysms and 26.2% of large aneurysms. CONCLUSIONS: First-generation HydroCoil treatment of intracranial aneurysms has a favorable rate of recanalization compared with most large series of pure platinum coils with similar complication rates.

Transorbital puncture for the treatment of cavernous sinus dural arteriovenous fistulas.

This report describes a series of patients for whom dural arteriovenous fistulae (DAVFs) of the cavernous sinus were successfully embolized using a percutaneous, transorbital technique to directly cannulate the cavernous sinus. A vascular access needle and catheter are percutaneously advanced along the inferolateral aspect of the orbit to access the cavernous sinus via the superior orbital fissure. Safe and effective embolization is achieved without the need for a surgical cut-down.

Basilar artery stent angioplasty for symptomatic intracranial athero-occlusive disease: complications and late midterm clinical outcomes.

BACKGROUND AND PURPOSE: After an initial series of basilar artery stent angioplasty indicated a high technical success rate and minimal morbidity, subsequent reports suggested significant procedural risks. We retrospectively reviewed our experience with basilar artery stent placement to assess complications and clinical outcomes. MATERIALS AND METHODS: Ten consecutive patients with symptomatic intracranial athero-occlusive disease underwent stent placement of the basilar artery at our institution (1999-2003). We collected clinical data by chart review and determined outcomes (modified Rankin Scale [mRS]) by telephone interview. Angiographic data were analyzed by 2 blinded investigators. Clinical and angiographic variables were tested for correlation with outcome and complications using the Pearson correlation test. RESULTS: Of 10 patients (mean follow-up time, 31 months), 4 patients suffered 6 ischemic complications that were immediate in 1, early delayed (<2 weeks) in 4, and late delayed (>2 weeks) in 1. Complications included basilar artery rupture in 1 patient, access site complications in 1 patient, and other non-neurologic complications in 5. Symptomatic restenosis occurred in 1 patient. Outcomes (mRS) were excellent (0-2) in 5 patients, good (3) in 4, and poor (4-6) in 1 patient, who died. Ischemic complications were associated with lesion lumen 45 degrees (P<.05). Less favorable clinical outcomes were associated with few ischemic complications and the presence of fewer than 2 patent vertebral arteries (P<.05). CONCLUSIONS: Despite a significant incidence of ischemic and nonischemic complications after basilar artery stent placement, most patients in this small series achieved freedom from vertebrobasilar ischemia and good to excellent clinical outcomes at late midterm follow-up (12-46 months). Ischemic complications usually had an early delayed presentation and procedural risks correlated with lesion characteristics.

Effects of endothelial injury on the rate of thrombus organization in canine carotid arteries occluded with microcoils.

SUMMARY: Thrombus organization in canine carotid arteries occluded with platinum microcoils was studied to determine if endothelial injury created with a Xenon Chloride Excimer Laser (XEL) could acclerate endovascular fibrosis. Ten common carotid artery stumps were created in ten dogs. Each of four stumps were schematically divided into four longitudinally contiguous injury zones (thermal ablation injury, non-ablative injury, proximal and distal non-injury zones) to test the effects of ablative and non-ablative injury and to establish a set of internal controls that would account for proximity to circulating blood at the ostium of the occluded artery. Following XEL irradiation of the endothelium through an arteriotomy, each stump was embolized with microcoils. Four control stumps were subjected to sham laser procedures, and embolized in an identical fashion. Two additional stumps were embolized in the absence of sham surgery. Angiographic, gross and histologic analysis was performed after four weeks. Specimens of freshly clotted whole blood mixed with microcoils were used as an additional control. In irradiated stumps and non-irradiated stumps (sham and embolization only), angiography revealed no evidence of coil compaction or recanalization. In all irradiated stumps the thermal ablation zone contained fibrous tissue and neovascularity without unorganized thrombus. The other zones in the irradiated stumps were indistingnishable from each other and from all zones in the non-irradiated sham stumps, containing primarily unorganized thrombus. Stumps embolized in the absence of sham surgery were filled with material that was grossly and microscopically identical to specimens of freshly clotted whole blood containing microcoils. The results indicate that thermal ablation injury of the endothelium accelerates thrombus organization in canine carotid arteries occluded with platinum microcoils.

Treatment of Trapped CCF by Direct Puncture of the Cavernous Sinus by Infraocular Trans-SOF Approach. Case Report and Anatomical Basis.

SUMMARY: We present a case of recurrent carotid-cavernous fistula after prior ipsilateral carotid artery ligation. Due to lack of endovascular access, embolization was performed by direct puncture of the cavernous sinus via a transorbital approach. Operative technique and an anatomical basis for treatment are described.

Early intracerebral hemorrhage complicating the successful occlusion of a carotid-cavernous fistula.

SUMMARY: A 74-year-old woman with a direct carotidcavernous fistula secondary to aneurysm rupture was treated by endovascular balloon occlusion of the fistula. Two days later, she suffered an intracerebral hemorrhage ipsilateral to the treated carotid cavernous fistula, perhaps due to normal perfusion pressure breakthrough. Normal perfusion pressure breakthrough has been described as a cause of hemorrhage following treatment of arteriovenous malformations (1) and carotid stenosis (2,3). We report an unusual case of therapeutic endovascular occlusion of a direct carotid-cavernous fistula complicated by hemorrhage presumably caused by normal pressure perfusion breakthrough.

Use of abciximab for mediation of thromboembolic complications of endovascular therapy.

We describe four cases in which abciximab was used as a thrombolytic rescue agent in the setting of thrombotic events complicating interventional neuroradiologic procedures. After IV administration of abciximab, the thrombus resolved within 30 min in three cases, whereas no thrombolysis occurred in the fourth case despite the addition of intraarterial tissue plasminogen activator. Further evaluation of glycoprotein IIb-IIIa inhibitors in patients with cerebral thromboembolic events is necessary to prove clinical efficacy.

In vitro effects of transcatheter injection on structure, cell viability, and cell metabolism in fibroblast-impregnated alginate microspheres.

PURPOSE: To determine if microsphere-encapsulated cell preparations can be delivered through a microcatheter without compromising microsphere structure, cell viability, or metabolism. MATERIALS AND METHODS: Fibroblast-impregnated microspheres were fabricated by using 1.0% alginate and rabbit synovial fibroblasts. Fibroblast-impregnated alginate microspheres injected through microcatheters were analyzed in parallel with identical noninjected microspheres. The effects of transcatheter injection on structure and cell viability (percentage of viable cells per microsphere) were correlated with microsphere size. Structural effects were analyzed by using light microscopy, and 7-day percentage (ratio of live cells to dead cells) cell viability was assessed with confocal microscopy and fluorescent staining. In a second series of experiments, the metabolism of small microspheres was studied during a course of 7 days by using a spectrophotometric bioanalyzer. RESULTS: Transcatheter injection caused fracturing and/or fragmentation of large (800-1,000 microm) and medium (500-750 microm) microspheres, while small (250-400 microm) microspheres were structurally unaffected by transcatheter injection. Fracturing and fragmentation were associated with cell release from the alginate matrix. Although transcatheter injection reduced cell viability by 17%-23% in all size categories, it did not cause a detectable alteration in the rate of glucose metabolism. CONCLUSION: Transcatheter injection was physiologically well tolerated by fibroblasts encapsulated in alginate microspheres; however, when microsphere diameter exceeded the catheter diameter, fracturing and fragmentation of microspheres compromised the sequestration function of the microsphere vector.

Endoluminal stent placement and coil embolization for the management of carotid artery pseudoaneurysms.

PURPOSE: To present a series of carotid artery pseudoaneurysms treated successfully using an endovascular approach. METHODS: From April 1995 to November 1999, 5 patients with neurological symptoms not explained by computed tomography of the head were identified by carotid angiography as having internal carotid artery (ICA) pseudoaneurysms. Three patients had sustained blunt trauma, and 2 had previous elective carotid endarterectomies for atherosclerotic disease. The time between injury and treatment ranged from 3 days to 10 years. The patients were treated with endovascular stent placement for exclusion of the pseudoaneurysm, followed by filling of the cavity with multiple detachable coils. Patients were maintained on oral antiplatelet agents or anticoagulant therapy after the procedure. RESULTS: Primary technical success was 100%. No patient suffered permanent neurological sequelae. Postprocedure angiography demonstrated a patent ICA in all cases, with complete obliteration of the pseudoaneurysm. At a mean 8.4-month follow-up (range 2-21), all patients remained symptom free; angiograms in 3 patients at a mean 11.7 months demonstrated continued ICA patency. One patient had a 60% focal narrowing of the distal common carotid artery, which was treated successfully with balloon dilation and stenting. CONCLUSIONS: Endovascular treatment of carotid artery pseudoaneurysms is a useful alternative to standard surgical repair. This modality avoids the necessity for surgical exposure at the skull base with its inherent morbidity.

Bilateral type 1 proatlantal arteries with absence of vertebral arteries.

The persistent proatlantal artery is a well-described communication between the carotid and vertebrobasilar system. However, persistence of bilateral proatlantal arteries is exceptionally rare. Although usually noted as an incidental finding, the presence of a proatlantal artery, particularly when bilateral, may result in unusual symptoms or may have implications for therapy. We report a case of bilateral proatlantal arteries, describe their embryology, and consider potential clinical implications of this finding.

Percutaneous vertebroplasty in the treatment of osteoporotic compression fractures.

Percutaneous vertebroplasty is an innovative and successful approach to the treatment of painful osteoporotic compression fractures refractory to medical therapy. We encourage all neuroradiologists to take an active interest in bringing this exciting technology to their patients and their practices.

Preoperative and palliative embolization of vertebral tumors.

Embolization of vertebral tumors is useful as an adjunct to surgery because it can minimize blood loss. Embolization also may decrease surgical operating time and reduce complications by improving visualization in the operative field. It also is occasionally useful as a palliative measure to relieve pain or neurologic compromise in patients with unresectable tumors. Spinal embolization is a relatively safe procedure when performed with proper technique by experienced operators.

Abciximab rescue in acute carotid stent thrombosis.

Occlusion of an internal carotid artery stent was identified immediately post placement in a patient who had restenosis after prior angioplasty. An IV dose of abciximab was administered, and serial angiograms were performed. This resulted in partial resolution of the thrombus at 10 minutes and complete resolution at 20 minutes.

Use of three-dimensional Guglielmi detachable coils in the treatment of wide-necked cerebral aneurysms.

A three-dimensional Guglielmi detachable coil (3D-GDC) has been developed that is designed specifically to bridge the neck of an aneurysm with coil loops, thereby facilitating retention of additional coils placed within the aneurysm. Nine wide-necked cerebral aneurysms were successfully embolized using the 3D-GDC, provided that the dome-to-neck ratio was 1.5 or greater.

Endovascular treatment of intracranial aneurysms with Guglielmi Detachable Coils: emphasis on new techniques.

Endovascular therapy for intracranial aneurysms has evolved since Serbinenko pioneered embolisation with latex balloons in the 1970s. The focus of modern endovascular therapy has shifted to the use of Guglielmi Detachable Coils (GDC; Boston Scientific Corporation, Natick, MA, USA) which are retrievable until the operator is satisfied with placement and they are detached. GDC therapy has been shown to be most efficacious in smaller aneurysms with relatively large dome:neck ratios which allow maximal coil packing within the aneurysm lumen. Wide neck aneurysms with dome:neck ratios of less than 2.0 and large aneurysms have a significantly lower incidence of complete treatment, with higher rates of repeat rupture following GDC therapy. The geometry of wide neck aneurysms is less favourable for retention of coils within the aneurysm lumen, resulting in greater risk of parent vessel compromise from coil herniation and difficulty obtaining maximal coil packing. This chapter will summarise GDC therapy for intracranial aneurysms including newer techniques designed to address the problem of wide neck aneurysms.

Adjuvant use of epsilon-aminocaproic acid (Amicar) in the endovascular treatment of cranial arteriovenous fistulae.

We report our experience with the use of the antifibrinolytic agent epsilon-aminocaproic acid (EACA), Amicar, as an adjuvant to endovascular treatment of cranial arteriovenous fistulae. We also review applications of antifibrinolytic agents to neurovascular disorders and discuss the mechanism of action, dosing strategy, contraindications, and possible complications associated with the use of EACA. We identified 13 patients with cranial arteriovenous fistulae (five direct carotid cavernous fistulae [CCF], seven dural arteriovenous fistulae [DAVF], and one vein of Galen malformation) who received EACA as an adjunct to endovascular treatment. In all cases embolic coils were the primary embolic agent. We reviewed the modes of initial endovascular therapy and angiographic findings immediately thereafter and the response to EACA. Two direct CCF and two DAVF were completely thrombosed on follow-up angiography, and two DAVF demonstrated diminished flow after EACA therapy. Seven fistulae did not respond to EACA. Four of eight tightly coiled fistulae thrombosed, while none of five loosely coiled fistulae thrombosed. None of four cases with a residual fistula separate from the coil mass underwent thrombosis with EACA, while four of nine cases without a separate fistula thrombosed. There was no morbidity related to EACA therapy. EACA may thus be useful as an adjunct to endovascular treatment of cranial arteriovenous fistulae. Loose or incomplete coil packing of the fistula predicts a poor response to EACA therapy.

Arterial dissections complicating cerebral angiography and cerebrovascular interventions.

BACKGROUND AND PURPOSE: Iatrogenic dissections are an uncommon complication of cerebral angiography. We retrospectively reviewed 12 cases of arterial dissections complicating cerebral angiography and cerebrovascular interventions to evaluate the clinical course of these dissections. METHODS: Cases from a large tertiary center performing a large number of neurovascular procedures were collected retrospectively. The patients' medical records and imaging studies were reviewed, with particular attention given to the cause of the dissection, the development of ischemic events resulting from the dissection, and the treatment used. RESULTS: Each of nine dissections affected a vertebral artery, each of two affected an internal carotid artery, and one affected a common carotid artery. The prevalence of iatrogenic dissections was 0.4%. Seven of the dissections were noted at the time of contrast material injection for the filming of cerebral angiograms. The other five dissections occurred during catheter or wire manipulations for interventional neuroradiologic procedures. Five of the patients in our series were treated with IV administered heparin for 24 to 48 hours. The other seven patients had recently suffered acute intracranial hemorrhage or undergone neurosurgery and could not undergo anticoagulant therapy. None of the patients developed symptoms of ischemia, but one was later found to have an asymptomatic infarct in the territory supplied by the dissected artery. CONCLUSION: Arterial dissections are an uncommon complication of cerebral angiography and cerebrovascular interventions and usually have a benign clinical course.

Bovine type I collagen as an endovascular stent-graft material: biocompatibility study in rabbits.

PURPOSE: To study the biocompatibility of a bovine type I collagen preparation as a material for small-vessel stent-grafts in rabbits. MATERIALS AND METHODS: A composite nitinol-collagen endovascular stent-graft with a 4-mm inner diameter was deployed in the abdominal aorta in nine rabbits. Angiography was performed, and the rabbits were sacrificed at 1, 2, and 7 days and at 1 and 3 months. The portion of the aorta containing the stent-graft was excised and was histologically evaluated. RESULTS: All stent-grafts were patent at all time points. On days 1, 2, and 7 after implantation, scattered red and white blood cells adhered to the stent-graft. At 1 month, the stent-graft was endothelialized and was infiltrated with fibroblasts that deposited collagen within the interstices of the implanted collagen material. At 3 months, there was additional collagen deposition within the interstices of the stent-graft that did not narrow the lumen of the stent-grafts. CONCLUSION: Type I collagen as a intravascular stent-graft material is biocompatible for at least 3 months in rabbits. It is rapidly endothelialized and does not cause reactive stenosis. As a versatile and biocompatible polymer, collagen is potentially useful in the construction of endovascular stent-grafts for use in human arteries.