Single center experience with pipeline stent: feasibility, technique, and complications

Flow diverter stents for unruptured saccular anterior circulation perforating artery aneurysms: safety, efficacy, and short-term follow-up

BACKGROUND

Anterior circulation perforating artery aneurysms including anterior choroidal artery and lenticulostriate artery aneurysms are rare. Injury to these vessels can lead to severe debilitating symptoms.

OBJECTIVE

To present a new approach to treatment using flow diversion technology.

METHODS

Patients treated with a Pipeline embolization device (PED) for perforator artery aneurysms at our institution between June 2012 and May 2013 were identified and included in our retrospective analysis. We evaluated patient vascular risk factors; family history of aneurysms; aneurysm characteristics; National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) on admission; and angiography follow-up and patient clinical outcome at discharge, 6 months, and 1 year.

RESULTS

We included four patients with a mean age of 59.8 years. Two patients had a positive family history of aneurysms. Patient vascular risk factors included smoking, dyslipidemia, and hypertension. All patients presented with a NIHSS and mRS of 0 on admission. Aneurysms were located at the anterior choroidal (n=2) or lenticulostriate artery (n=2) and were treated with a single PED. No periprocedural or postprocedural complications occurred. The patients were discharged with no change in NHISS or mRS score. Six-month and 1-year follow-up angiography showed complete aneurysm occlusion. Mild intimal hyperplasia was seen in 2 cases at 6 months, but was resolved at the 1-year follow-up. No re-treatment was necessary. NIHSS and mRS remained 0 at follow-up time points.

CONCLUSIONS

Our preliminary results show that flow diversion technology is an effective and safe therapy for complex, hard-to-treat aneurysms in perforating arteries. Larger studies with long-term follow-up are needed to validate our promising results.

Microsurgical clipping of large and giant cerebral aneurysms: a single-center contemporary experience

Several treatment strategies are available to manage large and giant cerebral aneurysms, including surgical, endovascular and combined approaches. We present our experience with microsurgical clipping of large and giant aneurysms. A total of 138 patients with 139 aneurysms of which 128 were large (≥10mm) and 11 were giant (≥25mm) were treated at our institution between 2004 and 2011. Data were collected from a prospectively maintained neurovascular database. Of 138 patients, 53 (38.4%) patients presented with subarachnoid hemorrhage (SAH). Peri-operative complications occurred in 16.7% of patients causing permanent morbidity in 4.4% and death in 0.7%. Complete occlusion, as evident on intra-operative angiography, was achieved in all clipped aneurysms (100%). Long-term follow-up angiography showed no recurrence (mean follow-up time, 43.9 months; range: 1-72 months). Favorable outcomes at discharge (Glasgow Outcome Scale score 4 or 5) were noted in 64.1% of SAH patients and 93% of non-SAH patients. Favorable outcomes at follow-up (mean follow up time, 42.5 months) were seen in 96% of patients. In our experience, microsurgical clipping of large and giant aneurysms carries low rates of morbidity and mortality with high rates of favorable outcomes. The excellent durability of surgical treatment stands in stark contrast with the high recurrence rates observed with coiling for this subset of aneurysms. These data suggest that microsurgical clipping continues to be a viable option that can be offered for patients with large and giant aneurysms.

Radiation dose analysis of large and giant internal carotid artery aneurysm treatment with the pipeline embolization device versus traditional coiling techniques

BACKGROUND

Flow diversion is an effective and increasingly accepted method for endovascular treatment of cerebral aneurysms. Additionally, the public has heightened concerns regarding radiation exposure from medical procedures. This study analyzes radiation dose and fluoroscopy time during treatment of large and giant proximal internal carotid artery (ICA) aneurysms with the pipeline embolization device (PED) versus traditional coiling techniques.

METHODS

Radiation dose, fluoroscopy time, and contrast dye administration were retrospectively analyzed in 55 patients undergoing endovascular treatment of aneurysms ≥ 10 mm from petrous to superior hypophyseal ICA segments. Patients were treated by either PED (37 patients) or traditional coiling techniques (18 patients). Aortic arch type and proximal ICA tortuosity were also assessed as markers of access difficulty.

RESULTS

Average radiation dose with PED treatment was 2840 ± 213 mGy and 4010 ± 708 mGy with traditional coiling techniques (p=0.048; 29% decrease with PED). Mean fluoroscopy time for PED was 56.1 ± 5.0 min and 85.9 ± 11.9 min for coiling cases (p=0.0087; 35% decrease with PED). These benefits existed despite more difficult arch anatomy and a trend towards greater proximal vessel tortuosity in PED cases. Contrast dye amounts were also reduced by 37.5% in PED cases (75 ± 6 mL) versus coiling cases (120 ± 13 mL, p=0.0008).

CONCLUSIONS

Treatment of large and giant proximal ICA aneurysms using PED requires less radiation, less fluoroscopy time, and less contrast administration than standard coiling techniques. This further demonstrates the benefits of flow diversion for treatment of these aneurysms.

Patient selection for endovascular treatment of intracranial aneurysms

With recent advancement in medical imaging, techniques, and endovascular tools more patients are diagnosed with unruptured intracranial aneurysms. The main aim of offering aneurysm treatment is to ameliorate the risk of future aneurysm bleeding, while not posing additional risks on the patient from the treatment itself. We discuss in this paper our approach of selecting patients for treatment (simple coiling, balloon-assisted, stent-assisted, vessel sacrifice, or flow-divertion stents). Our decision-making is based on the published data and our center experience. Risks of all option are compared to each other and weighed against natural history of intracranial aneurysms. In this paper, literature is cited and case illustrations are presented to support this approach. Factors that affect our decision-making are aneurysm location, presentation, size, aneurysm geometry, parent vessel anatomy, and relevant co-morbidities.

Endovascular treatment of middle cerebral artery aneurysms with flow modification with the use of the pipeline embolization device

BACKGROUND AND PURPOSE

The Pipeline Embolization Device was reported to be safe and effective in the treatment of sidewall aneurysms, preserving the patency of the vessels covered by the construct. However, to date, the safety and efficacy of this device in treating bifurcation aneurysms remains unknown. We report our preliminary experience with the use of the Pipeline Embolization Device in the management of MCA aneurysms located at the bifurcations, including mid- and long-term follow-up data.

MATERIALS AND METHODS

Wide-neck MCA aneurysms, which give rise to a bifurcating or distal branch in which other endovascular techniques are thought to be unfeasible or more risky, were included. Data including demographics, aneurysm features, antiplatelet therapy, complications, and angiographic follow-up results for up to 30 months were recorded.

RESULTS

Twenty-five aneurysms located at the MCA bifurcation (n = 21) or distal (n = 4) were treated. Of these, 22 were small and 3 were large. A single device was used in all but 2. No deaths occurred in the series. All patients had at least 1 control angiographic study, 21 of which were DSA (3-30 months), which showed that 12 of the rising branches were patent whereas 6 were filling in reduced caliber and 3 were occluded asymptomatically. According to the last angiographic follow-up, complete occlusion was revealed in 21 of 25 aneurysms (84%).

CONCLUSIONS

The Pipeline Embolization Device provides a safe and effective treatment alternative for wide-neck MCA aneurysms that give rise to a bifurcating or distal branch when other endovascular techniques are thought to be unfeasible or more risky.

Flow-diversion panacea or poison?

Endovascular therapy is now the treatment of choice for intracranial aneurysms (IAs) for its efficacy and safety profile. The use of flow diversion (FD) has recently expanded to cover many types of IAs in various locations. Some institutions even attempt FD as first line treatment for unruptured IAs. The most widely used devices are the pipeline embolization device (PED), the SILK flow diverter (SFD), the flow redirection endoluminal device (FRED), and Surpass. Many questions were raised regarding the long-term complications, the optimal regimen of dual antiplatelet therapy, and the durability of treatment effect. We reviewed the literature to address these questions as well as other concerns on FD when treating IAs.

Treatment of Blister-Like Aneurysms With the Pipeline Embolization Device

BACKGROUND:

Endovascular vessel reconstruction with the pipeline embolization device (PED) has become common practice. Data on the safety and efficacy of the PED in blister-like aneurysms (BLAs) are limited.

OBJECTIVE:

To retrospectively present our experience with use of the PED in BLAs.

METHODS:

A total of 8 patients harboring 8 BLAs were treated with the PED at our institution between November 2011 and April 2013.

RESULTS:

Aneurysm size was 2.5 mm on average. Five patients had sustained a subarachnoid hemorrhage (SAH), 1 patient presented with sentinel headaches, and in 2 patients the aneurysm was incidentally discovered. Seven aneurysms arose from the ICA and 1 from the basilar artery. Placement of the PED was successful in all 8 patients. There were no procedural or perioperative complications in any of the patients. At the latest follow-up, all 8 patients achieved a favorable outcome (mRS 0-2). Angiographic follow-up was available for 6 patients at a mean time point of 3.9 months. Follow-up angiography showed 100% aneurysm occlusion in 5 patients and marked decrease in aneurysm size in 1 patient.

CONCLUSION:

The findings of this study suggest that the PED may be a safe and effective treatment for BLAs. Given the limitations of other treatment modalities and the challenging nature of BLAs, flow diversion may be a valuable option for these lesions.

Treatment of ophthalmic segment carotid aneurysms using the pipeline embolization device: clinical and angiographic follow-up

OBJECTIVES

Aneurysms of the ophthalmic segment of the internal carotid artery (ICA) often present unique challenges to endovascular treatment due to their proximity to or involvement of the ophthalmic artery, and the subsequent risk of post-operative visual complications. The pipeline embolization device (PED) represents a paradigm shift and promising new therapy in the treatment of intracranial aneurysms. We reviewed the ophthalmic segment ICA aneurysms treated with the PED at Barrow Neurological Institute (BNI) to report outcome data, including patency of the ophthalmic artery and visual complications.

METHODS

The prospectively maintained BNI endovascular database was reviewed for all patients with ophthalmic segment ICA aneurysms treated with the PED since May 2011. Patient charts and digital subtraction angiograms were reviewed to report angiographic outcomes and visual complications. Only patients with at least 6 months of follow-up were included in the analysis.

RESULTS

Of 30 patients treated with ophthalmic segment aneurysms during the study period, sufficient follow-up was available for 29 patients with 38 aneurysms, all of which were treated electively. The PED was successfully deployed for all lesions, with 92·1% complete or near-complete obliteration rate at angiographic follow-up. All but one patient were found to have a patent ophthalmic artery at short-term follow-up and 100% of patients retained intact vision. Five patients had minor periprocedural hemorrhagic complications but no permanent morbidities. There were no intracranial hemorrhages, thromboembolic phenomena, vessel dissections, or mortalities.

CONCLUSION

Treatment of ophthalmic segment ICA aneurysms with the PED is safe and effective at short-term follow-up.

Sole stenting with large cell stents for very small ruptured intracranial aneurysms

A flow-diverting stent such as the Pipeline embolization device (PED, ev3 Endovascular, Plymouth, MN, USA) and Silk flow-diverting stent (Balt Extrusion, Montmorency, France) offers an acceptable alternative for the treatment of difficult aneurysms according to their morphologies, including giant, wide-necked, fusiform, and blister types. However, complications arising from the use of these stents have frequently been reported including several cases of branch artery occlusion and delayed occlusion of the stented parent vessel shortly after antiplatelet medications were discontinued, highlighting the potential need for long-term antiplatelet therapy, and disastrous bleeding complications in unruptured aneurysm. In addition, these microcell stents are difficult to use in distal aneurysms located over the ICA bifurcation and basilar tip because of the stiffness of the device, and perforating vessel occlusion is more likely to occur due to the characteristics of the stent. Before the era of flow-diverting microcell stents, large cell intracranial stents like the Neuroform stent (Boston Scientific/Target Therapeutic, Fremont, CA, USA) and Enterprise stent (Cordis Neurovascular, Miami, FL, USA) without coiling were used to provide flow-diverting effects for complex intracranial aneurysms. Sole stenting has been used even in cases of ruptured aneurysm, with patients on different antiplatelet medications. However, no single endovascular institute has embraced sole stenting using large cell intracranial stents as a systemized treatment for ruptured intracranial aneurysms. Here we designed this study to evaluate the possibility of safely treating very small aneurysms using one or two stents without coiling during the period of subarachnoid hemorrhage (SAH). This retrospective study was conducted with eight patients who had rupture of very small intracranial aneurysms (less than 3 mm in size). All were treated using the Neuroform and the Enterprise stents; there was single stenting in five, in-stent telescopic stenting in two, and Y-configured stenting in one. The angiographic results with clinical outcomes were collected and analyzed. Complete aneurysm obliteration was observed in three cases, and size reduction or stable angiographic findings was found in five cases on the last follow-up angiography. No growing aneurysm or rebleeding was found on any follow-up angiography. Thromboembolic complications were found in one patient. It is difficult to make conclusions on the long-term efficacy of this technique with such a small number of cases, however sole stenting with a large cell intracranial stent for the treatment of very small aneurysms may be used safely as an alternative treatment even during an episode of SAH.

Endovascular treatment of fusiform cerebral aneurysms with the Pipeline Embolization Device

OBJECT

Despite advances in surgical and endovascular techniques, fusiform aneurysms remain a therapeutic challenge. Introduction of flow-diverting stents has revolutionized the treatment of aneurysms with wide necks and of complex morphology. The authors report their experience with the endovascular treatment of fusiform aneurysms using the Pipeline Embolization Device.

METHODS

A retrospective review of 146 patients with cerebral aneurysms treated with the Pipeline Embolization Device between June 2011 and January 2013 was performed. Twenty-four patients were identified as having fusiform aneurysms. Twenty-four aneurysms in these 24 patients were treated. The mean patient age was 59 years. There were 9 men and 15 women. Angiographic and clinical data (including the modified Rankin Scale [mRS] score) were recorded at the time of treatment and at follow-up. The aneurysms were located in the internal carotid artery in 8 patients (33.3%), middle cerebral artery in 8 patients (33.3%), anterior cerebral artery in 1 patient (4%), and vertebrobasilar circulation in 7 patients (29%). The aneurysms were smaller than 10 mm in 3 patients, 10-25 mm in 16 patients, and larger than 25 mm in 5 patients. The mean largest dimension diameter was 18 mm.

RESULTS

Stent deployment was successful in all cases. The minor procedural morbidity was 4% (1 case). Morbidity and mortality related to aneurysm treatment were 4.2% and 4.2%, respectively. The mean mRS scores preoperatively and at clinical follow-up (median 6.0 months, mean 6.9 months) were 0.71 and 1.2, respectively (91.7% presented with an mRS score of 2 or better, and 79.2% had an mRS score of 2 or better at the 6.0-month follow-up). At clinical follow-up, 82.6% of patients were stable or had improved, 13.0% worsened, and 4.2% had died. Twenty-two (91.7%) of 24 patients had follow-up angiography available (mean follow-up time 6.3 months); 59% had excellent angiographic results (> 95% or complete occlusion), 31.8% had complete aneurysm occlusion, 27.3% had greater than 95% aneurysm occlusion, 18.2% had a moderate decrease in size (50%-95%), 4.5% had a minimal decrease in size (< 50%), 13.6% had not changed, and 4.5% had an increase in size.

CONCLUSIONS

This series demonstrates that endovascular treatment of fusiform cerebral aneurysms with flow diversion was a safe and effective treatment. Procedural complications were low. Long-term morbidity and mortality rates were acceptable given the complex nature of these lesions.

The Pipeline Embolization Device: learning curve and predictors of complications and aneurysm obliteration

BACKGROUND

The Pipeline Embolization Device (PED) has emerged as a promising treatment for intracranial aneurysms.

OBJECTIVE

To assess the safety and efficacy of the PED, to analyze the effect of operator experience on the complication rate, and to identify predictors of complications and obliteration.

METHODS

A total of 109 patients with 120 aneurysms were treated with PED at our institution. The patient population was divided into 3 consecutive equal groups to assess whether overall and major complication rates decreased over time: group 1, patients 1 through 37; group 2, patients 38 through 73; and group 3, patients 74 through 109.

RESULTS

The number of PEDs used was 1.40 per aneurysm. Symptomatic and major procedure-related complications occurred in 11% and 3.7% of patients, respectively. The rate of complications decreased from 16.2% in group 1 to 5.6% in group 3, and the rate of major complications fell dramatically from 10.8% in group 1 to 0% in groups 2 and 3 (P < .05). Procedure time significantly decreased over time (P = .04). In multivariate analysis, previously treated aneurysms were predictive of procedural complications (P = .02). At the latest follow-up, 65.8% of aneurysms were completely occluded, 9.6% were nearly completely occluded, and 24.6% were incompletely occluded. In multivariate analysis, fusiform aneurysms (P = .05) and shorter angiographic follow-up (P = .03) were negative predictors of aneurysm obliteration.

CONCLUSION

PED therapy may have an acceptable safety-efficacy profile. The risk of complications appears to decrease dramatically with physician experience, supporting the existence of a learning curve. Patients with previously treated aneurysms have higher complication rates, whereas fusiform aneurysms achieve lower obliteration rates.

Treatment of posterior circulation aneurysms with the pipeline embolization device

BACKGROUND

Treatment of complex intracranial aneurysms with the pipeline embolization device (PED) has become common practice in neurovascular centers. Very few studies have assessed the safety and efficacy of PED treatment for posterior circulation aneurysms.

OBJECTIVE

To retrospectively present our experience with use of the PED in the posterior circulation.

METHODS

A total of 7 patients harboring 7 posterior circulation aneurysms were treated with the PED at our institution between November 2011 and July 2012.

RESULTS

Aneurysm size was 14.1 mm on average. All patients had unruptured aneurysms. Three aneurysms arose from the vertebral artery, 2 from the basilar artery, and 2 from the vertebrobasilar junction. A single stent was used in 4 patients, 2 stents in 2 patients, and 3 stents in 1 patient. Treatment was successful in all 7 patients. No procedural complications or perforator infarcts were noted in the series. No patient experienced new neurological symptoms related to PED treatment during the follow-up period. Angiographic follow-up was available for 6 patients at a mean time point of 5.5 months. Follow-up angiography showed 100% aneurysm occlusion in 3 patients, marked decrease in aneurysm size in 2 patients, and no change in 1 patient.

CONCLUSION

In our initial experience, it appears that PED treatment in select patients with vertebrobasilar aneurysms may have a reasonable safety-efficacy profile. Larger studies are needed to confirm our findings.

Extending the Indications of Flow Diversion to Small, Unruptured, Saccular Aneurysms of the Anterior Circulation

Background and Purpose—

Flow diverters are currently indicated for treatment of large and complex intracranial aneurysms. The purpose of this study was to determine whether the indications of flow diversion can be safely extended to unruptured, small, saccular aneurysms (<10 mm) of the anterior circulation.

Methods—

Forty patients treated with the pipeline embolization device (PED) were matched in a 1:4 fashion with 160 patients treated with stent-assisted coiling based on patient age, sex, aneurysm location, and aneurysm size. Procedural complications, angiographic results, and clinical outcomes were analyzed and compared.

Results—

The rate of periprocedural complications was 5% in the PED group and 3% in the stent-coil group ( P =0.7). In multivariable analysis, increasing age was the only predictor of complications. At follow-up, a higher proportion of aneurysms treated with PED (80%) achieved complete obliteration compared with stent-coiled aneurysms (70%) but the difference did not reach statistical significance ( P =0.2). In multivariable analysis, increasing aneurysm size and aneurysm location were predictors of nonocclusion. The rate of favorable outcome (modified Rankin Scale, 0–2 and modified Rankin Scale, 0–1) was similar in the PED group and the coil group.

Conclusions—

The PED was associated with similar periprocedural risks, clinical outcomes, and angiographic results compared with stent-assisted coiling. These findings suggest that the indications of PED can be safely extended to small intracranial aneurysms that are amenable to conventional endovascular techniques. Larger studies with long-term follow-up are necessary to determine the optimal treatment that leads to the highest rate of obliteration and best clinical outcomes.

Delayed migration of a pipeline embolization device

BACKGROUND

Giant and complex aneurysms are increasingly treated with the Pipeline Embolization Device (PED). However, clinical experience with the device remains preliminary.

OBJECTIVE

To report the first case of a delayed migration of an intracranial PED.

METHODS

A 61-year-old woman with a known large right cavernous internal carotid artery aneurysm had a 3-month history of increasing retro-orbital pain. She underwent uneventful treatment of her aneurysm with the PED.

RESULTS

Five months after the procedure, the patient's pain recurred. On the routine 6-month follow-up angiography, there was proximal PED migration, with the distal end of the device projecting directly into the aneurysm and creating a jet of contrast against the aneurysm sac. The migration distance was more than 1 cm, and there was significant foreshortening of the device. A second, overlapping PED was successfully deployed within the first PED to bridge the neck of the aneurysm and redirect the flow jet away from the aneurysm sac. Complete resolution of the patient's symptoms was noted 4 weeks later.

CONCLUSION

Delayed proximal migration may occur after placement of a PED. Accurate stent sizing and adequate apposition to the vessel wall may minimize the occurrence of this undesirable phenomenon. If there is any concern regarding the position of the PED, early imaging follow-up may be indicated.

Endovascular management of cerebral aneurysm : review of the literature

Management of intracranial aneurysms remains controversial. For unruptured aneurysms, many factors should be taken into account before deciding the type of treatment and whether to treat or not. Ruptured aneurysms on the other hand are almost always treated. Still, the question remains what are the indicators that one must rely on to decide what treatment suits the patient best. We present a review on the management of intracranial aneurysm while focusing on endovascular aspects.

Molecular imaging of cerebrovascular lesions

Inflammation is a key component in the pathogenesis of cerebrovascular lesions. Two agents have emerged as promising possibilities for imaging cerebrovascular lesions. These agents are ferumoxytol and myeloperoxidase (MPO)-specific paramagnetic magnetic resonance (MR) contrast agent. Ferumoxytol is an iron oxide nanoparticle coated by a carbohydrate shell that is used in MRI studies as an inflammatory marker as it is cleared by macrophages. Ferumoxytol-enhanced MRI allows noninvasive assessment of the inflammatory status of cerebral aneurysms and arteriovenous malformations and, possibly, may differentiate "unstable" lesions that require early intervention from "stable" lesions that can be safely observed. Several pilot studies have also suggested that MPO-specific paramagnetic MR contrast agent, di-5-hydroxytryptamide of gadopentetate dimeglumine, may allow imaging of inflammation in the wall of saccular aneurysms in animal models. However, studies in human subjects have yet to be performed. In this paper, we review current data regarding ferumoxytol-enhanced MRI and MPO-specific paramagnetic MR contrast agent and discuss current and future applications.

Treatment of unruptured intracranial aneurysms with the pipeline embolization device

The pipeline embolization device (PED; ev3 Endovascular, Plymouth, MN, USA) is a flow-diverter used in the endovascular treatment of intracranial aneurysms, particularly those with unfavorable configurations. It causes progressive flow redirection leading to aneurysm thrombosis. This study aimed to present a systematic review of the published literature on the clinical outcomes of PED. A Medline search of the English language literature was performed using the keywords "intracranial aneurysms" and "pipeline embolization device" or "flow diverters". The inclusion criteria were: n>10 patients; unruptured aneurysms; documentation of complications; and at least 3 months of follow-up. A total of 13 studies, with 905 patients and 1043 aneurysms, were included. The mean age was 53.8 years, with women comprising 76.3% of patients. The mean aneurysm diameter was 11.1mm with 37% classed as large aneurysms and 10% classed as giant. The cumulative mortality rate was 2.3%. Seventeen patients had a stroke (1.9%), while 19 (2.0%) had a transient ischemic attack and 21 patients (2.3%) had an intracranial hemorrhage. The two outcome measures were the cumulative event rate (16.7%) and the 6 month aneurysm occlusion rate (79.7%). A funnel plot with study size plotted against the two outcome measures revealed publication bias. Data from recent studies suggest that complication and mortality rates associated with PED may be similar to other contemporary endovascular techniques, with a better 6 month aneurysm occlusion rate. More prospective clinical trials are warranted to further validate these results.

The emerging role of ferumoxytol-enhanced MRI in the management of cerebrovascular lesions

Inflammation is increasingly being understood to be a key component to the pathophysiology of cerebrovascular lesions. Ferumoxytol, an iron oxide nanoparticle coated by a carbohydrate shell, has been used in MRI studies as an inflammatory marker because it is cleared by macrophages. Ferumoxytol-enhanced MRI has emerged as an important tool for noninvasive assessment of the inflammatory status of cerebrovascular lesions, namely aneurysms and arteriovenous malformations. Moreover, preliminary evidence suggests that ferumoxytol-enhanced MRI could be applied as a non-invasive tool to differentiate “unstable” lesions that require early intervention from “stable” lesions in which observation may be safe. Assessment of the effects of anti-inflammatory pharmacological interventions on cerebrovascular lesions is also a potentially crucial application of the technique. Future improvements in technique and MRI signal quantification will certainly pave the way for widespread and efficient use of ferumoxytol-enhanced MRI in clinical practice. In this paper, we review current data regarding ferumoxytol-enhanced MRI and discuss its current/potential applications and future perspectives.

Last-recorded P2Y12 reaction units value is strongly associated with thromboembolic and hemorrhagic complications occurring up to 6 months after treatment in patients with cerebral aneurysms treated with the pipeline embolization device

BACKGROUND AND PURPOSE

A recent study identified a preprocedural P2Y12 reaction units value of <60 or >240 as a strong independent predictor of perioperative thromboembolic and hemorrhagic complications after treatment of cerebral aneurysms with the Pipeline Embolization Device. This study aimed to determine whether a last-recorded P2Y12 reaction units value of <60 or >240 predicts thromboembolic and hemorrhagic complications up to 6 months after treatment of cerebral aneurysms with the Pipeline Embolization Device in the same patient cohort.

MATERIALS AND METHODS

We recorded patient and aneurysm characteristics, P2Y12 receptor antagonist administered, P2Y12 reaction units value with VerifyNow, procedural variables, and thromboembolic and hemorrhagic complications up to 6 months after Pipeline Embolization Device procedures at our institution during an 8-month period. Complications causing a permanent disabling neurologic deficit or death were considered major. Multivariate regression analysis was performed to identify independent predictors of thromboembolic and hemorrhagic complications.

RESULTS

Forty-four patients underwent 48 Pipeline Embolization Device procedures at our institution during the study period. There were 11 thromboembolic and hemorrhagic complications up to 6 months after treatment in our cohort (22.9%), 5 of which were major (10.4%). A last-recorded P2Y12 reaction units value of <60 or >240 was the only independent predictor of all (P = .002) and major (P = .03) thromboembolic and hemorrhagic complications in our cohort. Most patients (71%) required, on average, 2 adjustments to the dose or type of P2Y12 receptor antagonist to remain within the 60-240 target P2Y12 reaction units range.

CONCLUSIONS

In our cohort, a last-recorded P2Y12 reaction units value of <60 or >240 was the only independent predictor of all and major thromboembolic and hemorrhagic complications up to 6 months after Pipeline Embolization Device procedures.

Spontaneous delayed migration/shortening of the pipeline embolization device: report of 5 cases

Five patients were found to have spontaneous delayed migration/shortening of their Pipeline Embolization Devices on follow-up angiography. The device migrated proximally in 4 patients and distally in 1 patient. One patient had a subarachnoid hemorrhage and died as a result of migration of the Pipeline Embolization Device, and another patient presented with complete MCA occlusion and was left severely disabled. Mismatch in arterial diameter between inflow and outflow vessels was a constant finding. Migration of the Pipeline Embolization Device was managed conservatively, with additional placement of the device, or with parent vessel occlusion. Obtaining complete expansion of the embolization device by using a longer device, increasing vessel coverage, using adjunctive aneurysm coiling, and avoiding dragging and stretching of the device are important preventive measures. Neurointerventionalists should be aware of this potentially fatal complication and take all necessary preventive measures.

Flow diversion versus traditional aneurysm embolization strategies: analysis of fluoroscopy and procedure times

BACKGROUND AND OBJECTIVE

Flow diverters are increasingly used for treatment of complex intracranial aneurysms. The purpose of this study was to compare the pipeline embolization device (PED) and traditional embolization strategies in terms of fluoroscopy and procedure time.

MATERIAL AND METHODS

Fluoroscopy and procedure times (in minutes) were retrospectively analyzed and compared between 127 patients treated with the PED, 86 patients treated with single stage stent assisted coiling (SAC), and 16 patients treated with Onyx HD 500 at our institution. A multivariate logistic regression analysis was performed to determine independent predictors of fluoroscopy and procedure time.

RESULTS

The three groups were comparable with respect to patient age, gender, and ruptured/unruptured aneurysm status. Aneurysms treated with the PED were significantly larger than stent coiled aneurysms, and aneurysm location distribution differed significantly between the three groups. Mean fluoroscopy time was significantly increased in the SAC (55±31 min, p<0.001) and Onyx HD 500 (91±36 min, p<0.001) groups relative to the PED group (34±23 min). Likewise, mean procedure time was significantly longer in SAC (155±50 min, p<0.001) and Onyx HD 500 (176±65 min, p<0.001) patients compared with PED patients (131±36 min). In multivariate analysis, SAC/Onyx HD 500 versus PED independently predicted longer procedure and fluoroscopy times.

CONCLUSIONS

PED treatment requires significantly shorter fluoroscopy and procedure times compared with SAC and Onyx HD 500. The results of this study may be used by advocates of flow diverters as an additional argument for using this treatment modality to treat intracranial aneurysms.

Cerebrovascular neurosurgery in 2012

Considerable advances in our understanding of the natural history and treatment of cerebrovascular disease were made in 2012. The landmark Unruptured Cerebral Aneurysm Study in Japan was published, illustrating a significantly greater rupture risk than previously reported for small anterior and posterior communicating artery aneurysms, those with daughter domes, and giant aneurysms. Results from the Cerecyte (DePuy Synthes, West Chester, PN, USA) coil trial did not demonstrate a statistically significant positive impact of these bioactive coils on angiographic occlusion rates or outcome. The Clazosentan to Overcome Neurological Ischemia and Infarct Occurring after Subarachnoid Hemorrhage study was also published and unfortunately did not demonstrate an overall favorable long-term functional outcome rate for patients with aneurysmal subarachnoid hemorrhage receiving clazosentan. Studies furthering our understanding of the natural history and treatment of vascular malformations were also published, including large prospective natural history studies of cavernous malformations from the Mayo Clinic and the Scottish Audit of Intracranial Vascular Malformations database. Although pregnancy was found to be a significant risk factor for arteriovenous malformation hemorrhage, several studies did not demonstrate pregnancy as a significant risk factor for cavernous malformation hemorrhage. Finally, prospective randomized control trials illustrated significantly improved angiographic and clinical outcome results for both the Solitaire (ev3 Endovascular, Plymouth, MN, USA; SWIFT trial) and Trevo (Concentric Medical, Mountainview, CA, USA; TREVO 2 trial) stent retrievers as compared to the Merci (Concentric Medical) clot retriever.

Developments on the horizon in the treatment of neurovascular problems

The field of Interventional Neuroradiology and Endovascular Neurosurgery has seen much technical advancement in the past two decades, which has brought the specialty from its infancy as an alternative therapy to the current standing as near standard of care for many complex neurovascular pathologies. This past year is no exception with flow diverting stents and stent retriever devices aiming to make their mark on advanced treatments for intracranial aneurysms and ischemic stroke, respectively. This review article will focus on the development of these technologies, current data supporting their advantages and limitations, and a brief expert opinion on where these technologies may take the field in the next few years.

Balloon-assisted guide catheter positioning to overcome extreme cervical carotid tortuosity: technique and case experience

BACKGROUND AND SIGNIFICANCE

We describe a method by which to efficiently and atraumatically achieve distal positioning of a flexible guiding catheter beyond extreme cervical tortuosity using a hypercompliant temporary occlusion balloon.

METHODS

A retrospective review of a prospective neuroendovascular database was used to identify cases in which a hypercompliant balloon catheter (Hyperform or Hyperglide, ev3/Covidien, Irvine, California, USA; Scepter or Scepter XC, Alisa Viejo, California, USA) was used to achieve distal positioning of a flexible guiding catheter (Navion, ev3/Covidien, Irvine, California, USA; Neuron, Penumbra Inc, Alameda, California, USA). After achieving a stable guiding sheath position within the proximal cervical carotid artery, a hypercompliant balloon catheter was manipulated beyond the tortuous cervical internal carotid segment into the distal carotid artery. The balloon was then inflated to anchor it distally within an intracranial (cavernous or petrous) segment of the internal carotid artery. The guiding catheter was then advanced beyond the tortuous cervical segment, over the balloon catheter, as gentle counter traction was applied to the balloon.

RESULTS

Balloon-assisted guiding catheter placement was used to perform endovascular treatments of 12 anterior circulation aneurysms. One patient underwent coiling alone. Five patients underwent balloon-assisted coiling. One patient underwent balloon and stent assisted coil embolization. Four patients with five carotid aneurysms (one with bilateral carotid aneurysms) underwent vascular reconstruction with the pipeline embolization device. All patients had severe tortuosity of the extracranial carotid system. Three patients had findings consistent with cervical carotid fibromuscular dysplasia. The technique was successful each time it was attempted. No parent artery dissections or catheter induced vasospam were noted in any case.

DISCUSSION

Hypercompliant balloon catheters can be reliably used to facilitate safe and rapid distal positioning of flexible guiding catheters beyond severe cervical tortuosity.

Treatment of large and giant intracranial aneurysms: cost comparison of flow diversion and traditional embolization strategies

OBJECTIVE

Flow diversion has emerged as a promising strategy for management of intracranial aneurysms. The purpose of this study was to determine whether treatment of large and giant aneurysms with the pipeline embolization device (PED) is more economical than traditional embolization strategies.

METHODS

We identified 30 consecutive aneurysms larger than 10 mm that were treated with PED at our institution. For each aneurysm treated with PED, theoretical coil embolization was performed by filling volume in a consistent, stepwise fashion until a packing density of 25% was reached. Prices of all equipment and implants were taken from price lists provided by each manufacturer.

RESULTS

Median aneurysm volume was 0.90 cm(3). Overall procedure cost was lower with the PED (mean, $23,911) vs. coiling ($30,522, P = .06). Above the median aneurysm volume, PED treatment was significantly less expensive than coiling even if multiple PEDs were used (P = .006). However, below the median aneurysm volume, PED treatment was significantly more expensive than coiling (P = .009). Treatment with multiple PEDs was not cost-beneficial compared with coiling, even above the median aneurysm volume. Potential savings associated with the PED were highly dependent on the type of embolic agent used.

CONCLUSIONS

The cost of initial treatment of large and giant aneurysms with PED is economically favorable compared to traditional embolization techniques. However, any potential cost benefit depends on aneurysm volume, coil type, and number of PEDs used. Accordingly, PED therapy is more expensive than coiling in aneurysms <0.9 cm(3) or when multiple devices are used.

Treatment of recurrent intracranial aneurysms with the Pipeline Embolization Device

BACKGROUND

The treatment of recurrent aneurysms after previous surgery or embolization is challenging. Little is known regarding the use of the Pipeline Embolization Device (PED) for recurrent aneurysms.

OBJECTIVE

To analyze the safety and results of PED therapy for recurrent aneurysms.

METHODS

Fifteen patients with recurrent intracranial aneurysms after previous embolization or surgical clipping were treated with the PED at our institution between 2011 and 2012. Procedural complications and clinical and angiographic outcomes were analyzed.

RESULTS

Median aneurysm size was 12 mm. Previous aneurysm treatment consisted of coiling in eight patients, stent coiling in four, a telescoping stent technique in two and surgical clipping in one. Major procedural complications (leaving significant morbidity) occurred in one patient (6.7%) and minor procedural or technical complications (no or minor morbidity) occurred in four patients (26.7%). Fourteen of the 15 patients (93.3%) had a favorable outcome (modified Rankin Scale score 0-2). Of 14 patients with angiographic follow-up, nine (64.3%) had complete aneurysm occlusion (100%), four (28.6%) had near-complete occlusion (≥90%) and only one (7.1%) had incomplete occlusion (<90%). Four of the five patients with less than 100% occlusion at follow-up had a previous stent in situ.

CONCLUSIONS

Treatment of recurrent aneurysms with the PED appears to be effective, but patients with a previous stent in situ may achieve lower obliteration rates. The morbidity rate associated with PED therapy may be higher than with more standard endovascular techniques using historical data. Larger studies are needed to assess this question better.

Successful treatment of a traumatic carotid pseudoaneurysm with the Pipeline stent: Case report and review of the literature

BACKGROUND

Traumatic intracranial pseudoaneurysms remain one of the most difficult vascular lesions to treat. In the case of traumatic pseudoaneurysms that may not be treated with parent vessel sacrifice, some flow diversion strategy such as stent-assistance or use of a flow diversion device is usually necessary.

CASE DESCRIPTION

In this study we describe endovascular parent vessel wall-remodeling/endoluminal reconstruction and traumatic pseudoaneurysm thrombosis through the use of the Pipeline stent and review recent reports concerning indications, safety, and efficacy for alternative pathology.

CONCLUSION

Although currently not routinely employed in the treatment of traumatic pseudoaneurysms, the Pipeline stent may represent a safe and effective treatment alternative achieving complete endoluminal reconstruction of the damaged vessel wall.