C. O'Kelly

Canadian Experience with the Pipeline Embolization Device for Repair of Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE: Flow-diverting stents, such as the PED, have emerged as a novel means of treating complex intracranial aneurysms. This retrospective analysis of the initial Canadian experience provides insight into technical challenges, clinical and radiographic outcomes, and complication rates after the use of flow-diverting stents for unruptured aneurysms. MATERIALS AND METHODS: Cases were compiled from 7 Canadian centers between July 2008 and December 2010. Each center prospectively tracked their initial experience; these data were retrospectively updated and pooled for analysis. RESULTS: During the defined study period, 97 cases of unruptured aneurysm were treated with the PED, with successful stent deployment in 94 cases. The overall complete or near-complete occlusion rate was 83%, with a median follow-up at 1.25 years (range 0.25–2.5 years). Progressive occlusion was witnessed over time, with complete or near-complete occlusion in 65% of aneurysms followed through 6 months, and 90% of aneurysms followed through 1 year. Multivariate analysis found previous aneurysm treatment and female sex predictive of persistent aneurysm filling. Most patients were stable or improved (88%), with the most favorable outcomes observed in patients with cavernous carotid aneurysms. The overall mortality rate was 6%. Postprocedural aneurysm hemorrhage occurred in 3 patients (3%), while ipsilateral distal territory hemorrhage was observed in 4 patients (3.4%). CONCLUSIONS: Flow-diverting stents represent an important tool in the treatment of complex intracranial aneurysms. The relative efficacy and morbidity of this treatment must be considered in the context of available alternate interventions.

Delayed ipsilateral parenchymal hemorrhage following flow diversion for the treatment of anterior circulation aneurysms.

Acute and subacute complications from the use of the Pipeline device are becoming evident. Here, the authors report delayed ipsilateral hemorrhage in 8.5% of patients with anterior circulation aneurysms treated with this device. All bleeds were distant from the treated aneurysms. All procedures were done without complications and when waking after the embolization all patients were normal. Despite this, hemorrhages occurred 1–6 days postprocedure, and were not related to aneurysm size, intraprocedural complications, or anticoagulation. BACKGROUND AND PURPOSE: The PED is a flow-diverting stent designed for the treatment of cerebral aneurysms. We report 4 cases of delayed ipsilateral IPH following the technically successful treatment of anterior circulation aneurysms with the PED. MATERIALS AND METHODS: Clinical and imaging data from all patients undergoing aneurysm treatment with the PED at 2 institutions were analyzed to assess the incidence of delayed IPH after treatment with the PED. RESULTS: A total of 66 patients (47 anterior circulation) with cerebral aneurysms underwent treatment with a PED between January 2008 and November 2010. Four patients experienced delayed periprocedural IPH, all after the treatment of anterior circulation aneurysms (8.5%, 4/47). The aneurysm size ranged from 5 to 21 mm. All IPHs occurred within the cerebral hemisphere, ipsilateral to the treated aneurysm, and were anatomically remote from the treated aneurysms. All procedures were uncomplicated, and patients emerged from general anesthesia at neurologic baseline. The hemorrhages became clinically evident between 1 and 6 days after the procedure. Two patients had unfavorable outcomes (mRS scores, 4 and 6). CONCLUSIONS: Delayed IPH may occur after the treatment of anterior circulation aneurysms with flow diverters. This complication does not seem to be restricted to a specific aneurysm subtype and does not seem to be related to an intraprocedural complication or solely attributable to DAT.

A Novel Grading Scale for the Angiographic Assessment of Intracranial Aneurysms Treated Using Flow Diverting Stents

Flow diverting stents are emerging as a treatment option for difficult intracranial aneurysms. Current grading scales for assessment of angiographic outcomes following aneurysm treatment do not apply to aneurysms treated by flow diversion. We propose a novel grading scale based on the degree of angiographic filling and contrast stasis. This scale will facilitate communication and standardize reporting of outcomes following flow diversion treatments.

Pipeline Embolization Device in Aneurysmal Subarachnoid Hemorrhage

The authors used the Pipeline device to treat 20 patients with acutely ruptured intracranial aneurysms. The most common types of aneurysms treated were blister and dysplastic/dissecting. Procedure-related morbidity/mortality overall was 15%, and 1 death directly related to the procedure occurred. Occlusion rates were 75% and 94% at 6 months and 12 months, respectively. The authors concluded that the Pipeline device offers a feasible treatment option in acute or subacute ruptured aneurysms, especially the blister type. Ruptured giant aneurysms remain challenging for both surgical and endovascular techniques; at this stage, the Pipeline device should be used with caution in this aneurysm subtype. BACKGROUND AND PURPOSE: The PED is an FDS designed for the treatment of intracranial aneurysms. Data regarding the use of this device in acute or subacute aSAH is limited to a few case reports or small series. We aimed to demonstrate the feasibility of using an FDS, the PED, for the treatment of ruptured intracranial aneurysms with challenging morphologies. MATERIALS AND METHODS: We conducted a retrospective review of all known patients treated with the PED for aSAH at 4 institutions between June 2008 and January 2012. Pertinent clinical and radiologic information was submitted by individual centers for central collation. The decision to treat with the PED was made on a case-by-case basis by a multidisciplinary team under compassionate use. RESULTS: Twenty patients (15 women; median age, 54.5 years; IQR, 8.0 years) were found. There were 8 blister, 8 dissecting or dysplastic, 2 saccular, and 2 giant aneurysms. Median time to treatment was 4 days (range, 1–90 days; IQR, 12.75 days) from rupture. Three patients had previous failed treatment. Procedure-related symptomatic morbidity and mortality were 15%, with 1 (5%) procedure-related death. Two patients died relative to medical complications, and 1 patient was lost to follow-up. Sixteen patients were available for follow-up, 81% had a GOS of 5, and 13% had a GOS of 4 attributed to a poorer initial clinical presentation. One patient died of urosepsis at 4 months. Occlusion rates were 75% and 94% at 6 months and 12 months, respectively. There were 3 delayed complications (1 silent perforator infarct, 2 moderate asymptomatic in-stent stenoses). No symptomatic delayed complications or rehemorrhages occurred. CONCLUSIONS: The FDS may be a feasible treatment option in the acute or subacute setting of selected ruptured aneurysms, especially blister aneurysms. Ruptured giant aneurysms remain challenging for both surgical and endovascular techniques; at this stage, FDSs should be used with caution in this aneurysm subtype.

Delayed Spontaneous Rupture of a Posterior Inferior Cerebellar Artery Aneurysm Following Treatment with Flow Diversion: A Clinicopathologic Study

SUMMARY: In this report, we present the fatal spontaneous delayed rupture of a previously unruptured large PICA aneurysm following treatment with the PED. Pathology at postmortem examination has supported the theory that intra-aneurysmal thrombus may acutely destabilize the aneurysm wall. Aneurysms with an anatomic arrangement that promote continued flow into the neck may not be optimal candidates for the flow-diversion treatment strategy.

Enhancing Brain Lesions after Endovascular Treatment of Aneurysms

These authors present MR images in 7 patients who developed enhancing lesions after endovascular therapy for intracranial aneurysms, 3 of which were symptomatic. The number of lesions increased in 2, was stable in 1, decreased in 3, and disappeared in 1 patient. The authorsput forward that the imaging and clinical characteristics suggested a foreign body reaction. They found no correlation to a specific device, but a possible source may be the generic hydrophilic coating. SUMMARY: Complications of endovascular therapy of aneurysms mainly include aneurysm rupture and thromboembolic events. The widespread use of MR imaging for follow-up of these patients revealed various nonvascular complications such as aseptic meningitis, hydrocephalus, and perianeurysmal brain edema. We present 7 patients from 5 different institutions that developed MR imaging–enhancing brain lesions after endovascular therapy of aneurysms, detected after a median time of 63 days. The number of lesions ranged from 4–46 (median of 10.5), sized 2–20 mm, and were mostly in the same vascular territory used for access. Three patients presented with symptoms attributable to these lesions. After a median follow-up of 21.5 months, the number of lesions increased in 2, was stable in 1, decreased in 3, and disappeared in 1. The imaging and clinical characteristics suggested a foreign body reaction. We could find no correlation to a specific device, but a possible source may be the generic hydrophilic coating.

Randomized clinical trials: the double edged sword

> “Evidence based medicine has contributed to the development of a rigid hierarchy of research design that underestimates the limitations of randomized controlled trials”1 > J Concato In May 2013, the Data Safety Monitoring Board of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) halted enrollment due to excess morbidity in the interventional group. This result was not surprising to the medical community, as prior editorials attest.2 Until complete trial data are available, it is impossible to determine why interventional treatment was deemed inferior to medical management. However, the trial had major inherent limitations that portended failure from the outset. Brain arteriovenous malformations (AVMs) are congenital lesions, which frequently present in young patients. The goal of treatment is a complete and durable cure, with limited neurological morbidity and mortality, and a better quality of life, for the rest of that patients life. Unfortunately, the logistics of any trial, particularly a National Institutes of Health funded trial, initially will only accommodate follow-up for a finite period of time—5 years in the case of ARUBA. With this study design, patients allocated to intervention were exposed to the entire upfront risk of the interventional procedure(s) to achieve curative treatment of the lesion. While most patients allocated to intervention presumably underwent definitive treatment and were cured of the AVM during the trial, the benefit of this curative treatment was only realized for the relatively brief period of follow-up. At the same time, patients allocated to the medical management arm, who remain at a lifelong risk for neurological morbidity, were only tracked for a small fraction of their ‘at risk’ period. For this reason, the study design heavily favored medical management. In other words, patients undergoing treatment face the full risk posed by that treatment during the study while those allocated to medical management are …

Small Pipes: Preliminary Experience with 3-mm or Smaller Pipeline Flow-Diverting Stents for Aneurysm Repair prior to Regulatory Approval

SUMMARY: Flow diversion has become an established treatment option for challenging intracranial aneurysms. The use of small devices of ≤3-mm diameter remains unapproved by major regulatory bodies. A retrospective review of patients treated with Pipeline Embolization Devices of ≤3-mm diameter at 3 Canadian institutions was conducted. Clinical and radiologic follow-up data were collected and reported. Twelve cases were treated with ≥1 Pipeline Embolization Device of ≤3-mm diameter, including 2 with adjunctive coiling, with a median follow-up of 18 months (range, 4–42 months). One patient experienced a posttreatment minor complication (8%) due to an embolic infarct. No posttreatment hemorrhage or delayed complications such as in-stent stenosis/thrombosis were observed. Radiologic occlusion was seen in 9/12 cases (75%) and near-occlusion in 2/12 cases (17%). Intracranial aneurysm treatment with small-diameter flow-diverting stents provided safe and effective aneurysm closure in this small selected sample. These devices should be further studied and considered for regulatory approval.

The second-generation eCLIPs Endovascular Clip System: initial experience

OBJECTIVE Treatment of wide-necked intracranial aneurysms is associated with higher recanalization and complication rates; however, the most commonly used methods are not specifically designed to work in bifurcation lesions. To address these issues, the authors describe the evolution in the design and use of the eCLIPs (Endovascular Clip System) device, a novel hybrid stent-like assist device with flow diverter properties that was first described in 2008. METHODS A registry was established covering 13 international centers at which patients were treated with the second-generation eCLIPs device. Aneurysm morphology and rupture status, device neck coverage, coil retention, and procedural and late morbidity and mortality were recorded. For those patients who had undergone successful implantation more than 6 months earlier, the final imaging and clinical follow-up results and need for re-treatment were recorded. RESULTS Thirty-three patients were treated between June 2013 and September 2015. Twenty-five (76%) patients had successful placement of an eCLIPs device; 23 (92%) of these 25 patients had complete data. Eight cases of nondeployment occurred during the 1st year of use, consistent with a learning curve; no failures of deployment occurred thereafter. Two periprocedural transient ischemic attacks and 2 asymptomatic thrombotic events occurred. Twenty-one (91%) of 23 patients underwent follow-up at an average of 8 months (range 3-18 months); 9 (42.9%) of these 21 patients demonstrated an improvement in Raymond grade at follow-up; no cases of worsening Raymond grade were recorded, and 17 (81.0%) patients sustained a modified Raymond-Roy Classification class of I or II angiographic result at follow-up. Two delayed ruptures were recorded, both in previously coiled, symptomatic giant aneurysms where the device was used as a part of a salvage strategy. CONCLUSIONS The second-generation eCLIPs device is a viable treatment option for bifurcation aneurysms. The aneurysm occlusion rates in this initial clinical series are comparable to the initial experience with other bifurcation support devices.

Arteriovenous fistula and pseudoaneurysm of the anterior spinal artery caused by an epidural needle in a 5-year-old patient

Authors present the case of a 5-year-old patient with a spinal arteriovenous fistula (AVF) and pseudoaneurysm of the anterior spinal artery (ASA) caused by a traumatic epidural needle stick injury. A discussion and relevant review of the literature follow. The boy had a remote history of a liver transplant and required neuraxial blockade for an unrelated abdominal surgical procedure. Initial insertion of the epidural needle at the T9-10 interspace yielded blood. A second attempt at T10-11 was successful. Delayed left leg weakness developed on postoperative Day 8, with an MR image showing a track injury through the cord and a ventral subarachnoid hematoma. Laminectomies from T-9 to T-11were performed emergently to decompress the spinal cord. The dura mater was opened, the ventral hematoma was evacuated, and brisk venous bleeding was controlled with cauterization. Postoperative spinal angiography demonstrated an AVF and pseudoaneurysm of the ASA. Repeat angiography at postoperative Week 4 demonstrated complete resolution of the AVF and pseudoaneurysm, probably due to intraoperative cauterization of the draining vein. The patient underwent a short course of rehabilitation and had no clinical or electrophysiological evidence of spinal cord damage at the 20-month follow-up. One should be cognizant of the possibility of a cord injury in a patient with new-onset neurological deficits following an interventional spine procedure. Neuroimaging is essential for prompt diagnosis and treatment.