Avi Setton

Treatment of distal anterior cerebral artery aneurysms with the Pipeline Embolization Device

Aneurysms of the anterior cerebral artery (ACA) located distal to the anterior communicating artery complex (ACOM) remain challenging to treat with surgical clip reconstruction as well as with endovascular coil-embolization strategies. We have treated five complex geometry distal ACA aneurysms with endoluminal reconstruction using the Pipeline Embolization Device (PED). Two aneurysms were of the dysplastic fusiform type. Three aneurysms were of complex saccular configuration. Three aneurysms were treated electively at the outset with PED. One patient had previously undergone aborted clip reconstruction, and one was treated for recurrent aneurysm growth after coil embolization. The mean diameter of the ACA in this cohort was 1.96mm proximal to the aneurysm and 1.79mm distal to the aneurysmal segment. A single PED of 2.5mm inner diameter was the sole treatment in four cases. Two PEDs, telescopically overlapped across the aneurysm, were used in the remaining case. All devices were deployed successfully. No parent artery occlusion or stenosis was observed. In all cases an associated branch vessel arising from the vicinity of the aneurysm or incorporated into its neck was covered by the endoluminal construct. At follow-up angiography, robust antegrade flow was maintained in the jailed branch. One patient experienced asymptomatic, delayed occlusion of the jailed branch. Complete aneurysm occlusion was seen in all patients. We confirm that PED can be deployed in parent vessels smaller than 2mm diameter, and that endoluminal reconstruction with the PED may be a safe and effective treatment alternative for selected distal ACA aneurysms.

Iatrogenic dural arteriovenous fistula and aneurysmal subarachnoid hemorrhage

The authors present the case of a patient who presented acutely with aneurysmal subarachnoid hemorrhage (SAH) and a contralateral iatrogenic dural arteriovenous fistula (DAVF). Diagnostic angiography was performed, revealing a right-sided middle cerebral artery (MCA) aneurysm and a left-sided DAVF immediately adjacent to the entry of the ventriculostomy and bur hole site. A craniotomy was performed for clipping of the ruptured MCA aneurysm, and the patient subsequently underwent endovascular obliteration of the DAVF 3 days later. The authors present their treatment of an iatrogenic DAVF in a patient with an aneurysmal SAH, considerations in management options, and a literature review on the development of iatrogenic DAVFs.

Modifying flow in the ICA bifurcation: Pipeline deployment from the supraclinoid ICA extending into the M1 segment-clinical and anatomic results.

BACKGROUND AND PURPOSE: Utility of the Pipeline Embolization Device extending to the M1 and its clinical and flow consequences at the ICA bifurcation have not been characterized. We analyzed flow modification in cases where a single Pipeline Embolization Device was deployed from the M1 to the distal supraclinoid ICA, covering the A1, for aneurysm treatment. MATERIALS AND METHODS: A1 flow modifications and size regression in postprocedure and follow-up angiography were analyzed. Vessel diameters and ratios of the proximal A1 and M1 segments and the distal ICA were assessed. Relationships between Pipeline Embolization Device nominal diameter and the vessel diameters at landing zones were obtained. Clinical assessments after flow modification were documented. RESULTS: Six of 7 patients demonstrated no change of flow in the anterior cerebral artery/anterior communicating artery complex at immediate postembolization angiography. All patients who underwent follow-up angiography demonstrated size regression of the ipsilateral A1. Midterm follow-up angiography revealed complete reversal of flow in the ipsilateral A1 in 4 of 5 patients. One patient did not demonstrate flow modification. This patient had a dominant ipsilateral A1. Vessel ratios in this case demonstrated a unique configuration in favor of maintaining patency of the ipsilateral A1. There were no clinical or radiographic signs of ischemia. One patient experienced asymptomatic angiographic in-stent stenosis at the M1. CONCLUSIONS: We found that deployment of a Pipeline Embolization Device from the distal supraclinoid ICA to the M1 may result in reversal of flow in the anterior cerebral artery/anterior communicating artery complex and regression of the ipsilateral A1. Preoperative anatomic quantitation and sizing of the Pipeline Embolization Device may predict flow modification results.

Double Microcatheter Single Vascular Access Embolization Technique for Complex Peripheral Vascular Pathology

The authors describe an embolization technique that allows safe, controllable exclusion of complex vascular pathologies using a single vascular access and 2 microcatheters. This technique is particularly useful in situations where high flow increases the risk of coil migration and nontarget embolization and in large aneurysms. It affords precise placement and repositioning of coils. This method was used to treat patients with pulmonary arteriovenous malformations, renal arteriovenous fistulae and aneurysms, visceral arterial aneurysms and pseudoaneurysms, an aortic pseudoaneurysm, and occlusion of native parent vessels. The technique facilitated safe and successful endovascular closure in all cases.

Treatment of posttraumatic aortic pseudoaneurysms using detachable hydrogel-coated coils.

Several percutaneous and endovascular alternatives to open surgical repair for the treatment of pseudoaneurysms have been described. Nevertheless, treatment of pseudoaneurysms of large size, with wide necks, and adjacent to vessels or branches that must be preserved is challenging. Filling a large volume appropriately using traditional coils requires tight packing of the coils to prevent shift of the embolic material over time and subsequent failure of treatment due to recanalization. This often requires a large number of coils with associated increased expense and procedure time. In addition, the last few coils to be placed often meet resistance and are apt to bulge into the parent vessel, or worse, fail to deploy in the already dense nest of coils and embolize downstream. It may also be difficult to retreat initially incompletely treated pseudoaneurysms with coils for the same reason. Several potential solutions to these problems each have limitations of their own. Stent-graft exclusion requires an adequate landing zone to minimize the risk of occluding the origin of important adjacent vessels. Adjacent vessels also create a relative contraindication to another described technique, namely using a bare stent and placing coils through the interstices into the pseudoaneurysm. Nontarget embolization or migration of embolic material into the parent vessel with percutaneous or transcatheter administration of liquid embolics or thrombin, even with protective devices, remains a limitation of their use and the risk may be increased in wide-necked pseudoaneurysms. Percutaneous thrombin treatment is effective even for fairly large pseudoaneurysms in the periphery, if adequate visualization with color duplex ultrasound is available, but may require repeat treatment. Detachable balloons have been removed from the US market. Detachable coils, such as Guglielmi detachable coils (GDC), allow for precise placement, but are costly, particularly if used to fill large volumes and have been demonstrated to recanalize in aneurysms of the intracerebral circulation approximately 21% of the time. Hydrogel-coated detachable Hydrocoils (MicroVention, Aliso Viejo, CA) have been described in the successful treatment of intracranial aneurysms. The fact that they can be repositioned before deployment, a characteristic shared with other detachable coils and balloons, as well as their expansion to up to 107% of the original coil diameter, make them appealing for use in large-volume pseudoaneurysms with large necks that predispose to incomplete treatment and nontarget embolization, respectively. This was demonstrated in the following case of posttraumatic aortic pseudoaneurysm repair.

Modifying flow in the ACA–ACoA complex: endovascular treatment option for wide-neck internal carotid artery bifurcation aneurysms

Background Treatment of selected wide-neck internal carotid artery (ICA) bifurcation aneurysms remains challenging for clip reconstruction and for endovascular options. Objective To describe a new endovascular treatment technique for wide-neck ICA bifurcation (ICAb) aneurysms. Methods We have employed a treatment approach that uses both complete proximal occlusion and reversal of flow in the ipsilateral A1 segment, using different endovascular modalities such as coils, stent-assisted coiling, or flow diverters (FDs) plus coiling concomitantly. This endovascular technique may overcome the challenges of current treatments and high recanalization rates for coiled ICAb aneurysms. Results We treated four patients in whom we redirected the pre-existing flow in the supraclinoid ICA into the ipsilateral A1 and M1 segments, to a new unilateral, linear flow from the supraclinoid ICA solely into the ipsilateral M1 segment. This resulted in the establishment of flow from the contralateral A1 segment into the ipsilateral A1 segment, allowing supply of only demanding perforating arteries on this specific (ipsilateral) segment. This technique was not associated with any new neurological deficits or radiographic ischemia. The four patients reviewed were all treated using coils. One was treated with a standard stent. The other two were treated with a FD. Conclusions We found that the proposed technique of flow modification can allow for hemodynamic conversion of ICAb to ‘side-wall’ aneurysm. In patients with good collateral flow through the anterior communicating complex, this treatment paradigm is safe and effective.

Angiographic Evidence of a Purely Pial Bihemispheric Intracranial Hemangiopericytoma

Background. Classification of hemangiopericytoma (HPC) has evolved to a mesenchymal, nonmeningothelial grade two or three neoplasm according to the World Health Organization; however its blood supply has always been defined by dual origin, pial and dural contribution. Case Description. We present the case of a patient with an intracranial HPC with only pial vascular supply. Angiography confirmed the lack of dural supply to this bihemispheric intracranial mass. Subsequent histologic examination confirmed the diagnosis of hemangiopericytoma. Angiographic evidence here is atypical of the natural history of hemangiopericytomas with dual vascular supply and was critical in the decision-making towards surgical resection without tumor embolization. Conclusion. Data presented suggests the lack of dural vascular supply alone does not rule out the diagnosis of hemangiopericytoma.

O-020 Modifying Flow in the ICA Bifurcation: Pipeline Deployment from the supraclinoid ICA Extending into the M1 Segment: Clinical and Anatomical Results

Background Utility of the pipeline embolization device (PED) extending to the M1 segment as well as its clinical and flow consequences at the ICA bifurcation, has not clearly described. We describe clinical and anatomical flow modifications results at the ICA bifurcation. Methods In this retrospective analysis of patients treated for distal supraclinoid carotid aneurysms, a single PED was deployed from the proximal M1 segment to the distal supraclinoid carotid. Flow assessment prior to the procedure, to predict the competence of the ACA/AcomA complex, was achieved by formal DSA angiography and occasional manual cross compression. In all cases a single PED was deployed over the ostium of the A1, while treating a single or multiple aneurysms. Anatomical vessels diameters and ratios between the size of the proximal segments of the A1 and M1 as well as the distal ICA were assessed. Relationships between the PED nominal diameter and the diameters of the vessels at the landing zones were obtained. All measurements were evaluated in respect to flow modifications and size regression of the A1 in the immediate postoperative images, at 3 month MRI/MRA and at 6–9 month formal DSA angiography. Immediate and mid-term clinical results were assessed. Results We treated seven patients using this technique. Median age was 62. Four patients were treated for multiple aneurysms. The following aneurysms were treated: 3 posterior communicating artery aneurysms, 3 anterior choroidal artery aneurysms, 4 ICA bifurcation aneurysms and one A1 segment aneurysm. 6/7 patients demonstrated no change of flow in ACA/AComA complex at the immediate post embolization angiography. One patient demonstrated immediate antegrade flow retardation in the ipsilateral A1 segment. Five patients underwent 3–4 month MRA follow up. All demonstrated size regression of the ipsilateral A1 segment and occlusion of the neurysms. Five patients underwent mid-term follow-up angiography (5.5–12 month). Complete reversal of flow in the ipsilateral A1, was noted in 4/5 patients (Figure 1). One patient did not demonstrate any flow modification. This patient had a dominant ipsilateral A1 segment. Interestingly, ratios of the vessels participating in this bifurcation demonstrated a unique configuration of a higher A1/M1, A1/ICA ratios and a lower M1/ICA ratio, possibly in favor of maintaining patency of the ipsilateral A1. In this specific patient, a minimal length (0.97 mm) of PED was deployed in the M1 segment. This was the most oversized PED in respect to the M1 segment. All patients were stable in the post-procedural period and with no new neurological deficits. There were no clinical nor radiographic signs of ischemia. One patient experienced asymptomatic angiographic in-stent stenosis at the M1 segment. Conclusions We found that the deployment of PED from the distal supraclinoid carotid to the M1 segment may result in reversal of flow in the ACA/AcomA complex as well as regression of the ipsilateral A1 segment. Preoperative anatomical disposition and sizing of the PED may predict the flow modification results. This modification of flow is safe and effective, based on pre-embolization flow assessments, and may be useful in treating distal ICA aneurysm by a flow diverter. Disclosures E. Nossek: None. D. Chalif: None. S. Chakraborty: None. A. Setton: None.