Kiffon M. Keigher

Thromboembolic complications with Pipeline Embolization Device placement: impact of procedure time, number of stents and pre-procedure P2Y12 reaction unit (PRU) value.

Background Thromboembolic events after Pipeline Embolization Device (PED) placement remain a feared complication among neuroendovascular surgeons. This study aimed to investigate potential risk factors for thromboembolic events in patients undergoing PED placement. Methods Medical records of patients who underwent PED placement from April 2011 to August 2013 were reviewed. Variables including pre-procedure P2Y12 reaction unit (PRU) value, procedure time, number of PEDs deployed and perioperative neurovascular complications were recorded. Multivariate analysis was performed to identify risk factors for perioperative thromboembolic complications. Results Seventy-four patients were identified. Six patients (8.1%) had changes in neurological status after PED placement including five (6.8%) thromboembolic complications and one (1.4%) delayed intracranial hemorrhage; 50.9% of patients had diffusion-weighted imaging (DWI) changes on post-procedural MRI. Longer procedure time (>116 min) and multiple PED placements (>1) were statistically significant risk factors for symptomatic thromboembolic events (p<0.01). A pre-procedural PRU value >208 had an OR of 11.32 (95% CI 0.06 to 212.57) for symptomatic thromboembolic complications, but the result was not statistically significant. Conclusions DWI changes on MRI occurred at a much higher rate than new neurological symptoms following PED placement. Longer procedure time and multiple PED deployment are associated with higher risks of new neurological changes due to thromboembolic events. There was a trend for an increased risk of a symptomatic thromboembolic event in patients with pre-procedural PRU values >208. Reloading (clopidogrel 600 mg) patients with preoperative PRU >208 was safe and may have a protective effect on thromboembolic events.

Utilization of Pipeline embolization device for treatment of ruptured intracranial aneurysms: US multicenter experience

Objective Utilization of the Pipeline embolization device (PED) in complex ruptured aneurysms has not been well studied. We evaluated the safety and effectiveness data from five participating US centers. Methods Records of patients with ruptured cerebral aneurysms who underwent PED treatment between 2011 and 2013 were retrospectively reviewed. Results 26 patients with ruptured aneurysms underwent PED treatment (mean age 51.4±13.2 years;16 women). At presentation, 8 patients (30.8%) had a Hunt–Hess grade of IV or above; 11 required extraventricular drain placement. Aneurysm morphologies were: 8 dissecting, 8 blister-like, 6 fusiform, and 4 saccular. There were 22 anterior circulation and 4 posterior circulation aneurysms. PED deployment was successful in all patients, with adjunctive coiling utilized in 12. Periprocedural complications occurred in 5 (19.2%), including 3 inhospital deaths. 23 patients (88.5%) had postoperative angiography at a mean of 5.9 months: 18 aneurysms (78.3%) were completely occluded, 3 (13.0%) had residual neck filling, and 2 (8.7%) had residual dome filling. All blister-type aneurysms were completely occluded at follow-up. Clinical follow-up was available for an average of 10.1 months (range 2–21 months), with one asymptomatic in-stent stenosis and one asymptomatic thromboembolic stroke noted. Good outcome (modified Rankin Scale (mRS) score of 0–2) was achieved in 20 patients (76.9%), fair (mRS 3–4) in 3 (11.5%), and 3 died (11.5%). Conclusions The PED can be utilized for ruptured aneurysms and is a good option for blister-type aneurysms. However, due to periprocedural complications, it should be reserved for lesions that are difficult to treat by conventional clipping or coiling.

The Pipeline Embolization Device for the treatment of posterior circulation fusiform aneurysms: lessons learned at a single institution

OBJECT Vertebrobasilar fusiform aneurysms (VFAs) are rare lesions characterized by abnormal dilation and tortuosity of the vertebral and/or basilar arteries. Untreated, these aneurysms have a tendency to progress, often resulting in neurological symptoms or rupture leading to subarachnoid hemorrhage. The microsurgical treatment of these lesions can be difficult due to their location and the circumferential involvement of the arteries. These features make microsurgical treatment prone to high morbidity. The Pipeline Embolization Device (PED) has gained popularity for the treatment of aneurysms of the internal carotid artery. Its use in the posterior circulation has been limited, likely due to a fear of perforating artery occlusion. METHODS The authors retrospectively reviewed their database of patients treated with the PED and identified 12 patients who had VFAs. The clinical features, complications, and outcomes of these patients were analyzed. RESULTS At an average follow-up of 11 months, the mean modified Rankin Scale score was 1.9. Complete aneurysm occlusion was seen in 90% of the patients with radiographic follow-up. Three patients suffered new neurological deficits postoperatively. One of these patients died, while the remaining 2 demonstrated significant clinical improvement at follow-up. CONCLUSIONS With attention to the anatomy of perforating arteries, staged contralateral vertebral artery sacrifice, and adequate platelet inhibition, PED may be an effective treatment option-alone or in a hybrid construct with stents of less coverage for VFAs-with an acceptable complication rate.

Long-term radiographic results of stent-assisted embolization of cerebral aneurysms.

BACKGROUND Aneurysmal subarachnoid hemorrhage is a disabling disease. Endovascular coiling provides minimally invasive, effective, and safe treatment of both ruptured and unruptured intracranial aneurysms. Intracranial stents have improved the endovascular treatment of complex aneurysms, but the long-term durability of this treatment modality needs clarification. OBJECTIVE To elucidate the long-term success of intracranial stent use in the treatment of aneurysms. METHODS Four hundred ten patients were treated with stent-assisted endovascular management of 464 aneurysms. Treatment of 363 small aneurysms, 88 large aneurysms, and 13 giant aneurysms was analyzed with respect to both long-term anatomic results with digital subtraction angiography and magnetic resonance angiography over the follow-up period. RESULTS The 6-month angiographic results of 387 aneurysm treatments revealed complete aneurysm occlusion in 282 (72.9%), residual aneurysm neck in 50 (12.9%), and residual aneurysm filling in 55 (14.2%). Long-term radiographic follow-up, performed in 262 patients (mean, 3.63 years), showed significant recurrence of only 3 aneurysms after 6-month follow-up imaging. Forty-eight aneurysms (11.9%) were considered radiographic failures during the follow-up period. CONCLUSION The aneurysm recurrence rate after stent-assisted embolization in this series was similar to published data using only coil embolization for the period between treatment and the initial follow-up imaging. For aneurysms that do not initially recur, the presented data suggest improved durability in the subsequent long-term follow-up period. ABBREVIATIONS DSA, digital subtraction angiographyMRA, magnetic resonance angiography.

Complication analysis in nitinol stent-assisted embolization of 486 intracranial aneurysms.

OBJECT Stent-assisted embolization (SAE) has broadened the scope of endovascular cerebral aneurysm treatment. The risks associated with stent selection and configuration are poorly defined. In this study, the authors aimed to characterize the risk factors that contribute to complications in SAE of intracranial aneurysms. METHODS Over a 10-year period, a single surgeon treated 486 aneurysms with SAE in which open-cell Neuroform or closed-cell Enterprise stents were used. Single stents were used in 386 cases, overlapping stents were deployed in 80 cases, and Y-configuration stents were used in the remaining 20 cases. All neurological complications, which included transient deficits, were analyzed; disabling strokes and death were considered major complications. The chi-square test and multivariate logistic regression were used to evaluate the influence of aneurysm size and morphology, aneurysm location, stent selection, and stent configuration on complication rates. RESULTS There were 7 deaths (1.4%), 9 major strokes (1.9%), and 18 minor neurological complications (3.7%). For all complications, multivariate analysis revealed that large aneurysm size (10-25 mm; p = 0.01), giant aneurysm size (> 25 mm; p = 0.04), fusiform aneurysm morphology (p = 0.03), and using a Y-configuration stent (p = 0.048) were independent risk factors. For the major complications, independent risk factors included an aneurysm in the posterior circulation (p = 0.02), using an overlapping stent configuration (p = 0.03), and using a Y-configuration stent (p < 0.01). CONCLUSIONS In this series, SAE for cerebral aneurysm treatment carried an acceptable complication rate. With continued innovations in techniques and devices and with increased experience, the complication rates associated with SAE may be even lower in the future.

Initial Experience with Neuroform EZ in the Treatment of Wide-neck Cerebral Aneurysms

Purpose Stent-assisted coiling allows embolization and parent vessel reconstruction of wide-necked intracranial aneurysms. The Neuroform EZ (Boston Scientific, Fremont, CA, U.S.A.) stent delivery system offers deployment of a Neuroform stent with fewer steps and improved operator control. Initial experience, technical considerations, and treatment outcomes using the Neuroform EZ stent delivery system in combination with coil embolization are reported. Materials and Methods Seventeen consecutive patients harboring 21 wide-necked saccular cerebral aneurysms were treated with stent reconstruction. Twenty aneurysms were unruptured; one was treated within 24 hours of diagnosis of rupture. Twenty aneurysms were located in the anterior circulation; one was in the posterior circulation. Immediate and six-month post-treatment angiography and clinical assessment were performed. Results In all cases, the stents were delivered and positioned without difficulty in deployment. Technical complications occurred in 4 patients, but none were directly related to the stent delivery system. On immediate post-treatment angiography, 5 of 21 aneurysms showed complete occlusion, 5 of 21 showed residual neck, and 11 of 21 showed residual contrast filling of the aneurysm sac. At six month follow-up, all 17 patients were clinically stable. Angiography of 18 of the aneurysms showed total occlusion in 12, residual neck in 3, and residual aneurysm filling in 3. Retreatment was performed in the three with residual aneurysm. Conclusion The Neuroform EZ stent system offers improved anchoring and support in stent delivery, which is particularly useful when multiple stents are overlapped to further protect the parent vessel and increase flow diversion away from the aneurysm sac. The only significant problem encountered was coil prolapse, which could be treated with a second stent when necessary. The ease of deployment improves upon the already clinically successful Neuroform design.

Treatment of wide-necked aneurysms with the Low-profile Visualized Intraluminal Support (LVIS Jr) device: a multicenter experience.

Background The Low-profile Visualized Intraluminal Support (LVIS) Junior stent is newly approved for the treatment of wide-necked intracranial aneurysms. Objective To report our multicenter experience with use of the LVIS Jr device. Methods The neurointerventional databases of the participating institutions were retrospectively reviewed for aneurysms treated with LVIS Jr from the time of Food and Drug Administration approval until February 2016. All patients in the study period were included. Clinical presentation, aneurysm location, aneurysm size, vessel size, procedural complications, clinical and imaging follow-up were included in the analysis. Results Eighty-five patients (54 female and 31 male) met the inclusion criteria for the study. Sixty-eight (80%) of the aneurysms were unruptured and the remainder were ruptured. The most common location of the treated aneurysms was anterior communicating artery (36%), middle cerebral artery bifurcation (22%), and basilar terminus (15%). The mean aneurysm size was 6.1 mm. The mean minimum parent vessel size was 2.3 mm. The LVIS Jr was successfully deployed in all but one case (99%). Initial angiographic results demonstrated Roy–Raymond class 1–2 occlusions in 61/84 patients (73%). At 6 months, 85% of the patients seen at follow-up had Roy–Raymond class 1–2 aneurysm occlusion. No procedure-related deaths occurred. Two cases of procedure-related complications (intraprocedural rupture and delayed rupture at day 2) were seen, leading to permanent neurologic morbidity. Both these cases were in patients with ruptured aneurysms. Conclusions The LVIS Jr is a technically feasible, safe, and effective treatment for wide-necked intracranial aneurysms. Early results are promising but will need to be corroborated with longer-term follow-up.

Frameless neuronavigation based only on 3D digital subtraction angiography using surface-based facial registration

OBJECT Cerebrovascular lesions can have complicated abnormal anatomy that is not completely characterized by CT or MR angiography. Although 3D rotational angiography provides superior spatial and temporal resolution, catheter angiograms are not easily registered to the patient, limiting the use of these images as a source for neuronavigation. However, 3D digital subtraction angiography (DSA) contains not only vascular anatomy but also facial surface anatomy data. The authors report a novel technique to register 3D DSA images by using only the surface anatomy contained within the data set without having to fuse the DSA image set to other imaging modalities or use fiducial markers. METHODS A cadaver model was first created to assess the accuracy of neuronavigation based on 3D DSA images registered by facial surface anatomy. A 3D DSA scan was obtained of a formalin-fixed cadaver head, with acquisitions of mask and contrast runs. The right common carotid artery was injected prior to the contrast run with a 45% contrast solution diluted with water-soluble red liquid latex. One week later, the head was registered to a neuronavigation system loaded with the 3D DSA images acquired earlier using facial surface anatomy. A right pterional craniotomy was performed and 10 different vascular landmarks were identified and measured for accuracy using the neuronavigation system. Neuronavigation based only on 3D DSA was then used to guide an open clipping procedure for a patient who presented with a ruptured distal lenticulostriate aneurysm. RESULTS The accuracy of the measurements for the cadaver model was 0.71 ± 0.25 mm (mean ± SE), which is superior to the 1.8-5 mm reported for neuronavigation. The 3D DSA-based navigation-assisted surgery for the distal lenticulostriate aneurysm aided in localization, resulting in a small craniotomy and minimal brain dissection. CONCLUSIONS This is the first example of frameless neuronavigation based on 3D catheter angiography registered by only the surface anatomy data contained within the 3D DSA image set. This is an easily applied technique that is beneficial for accurately locating vascular pathological entities and reducing the dissection burden of vascular lesions.

Use of flow-diverting stents as salvage treatment following failed stent-assisted embolization of intracranial aneurysms

Flow-diverting stents, including the Pipeline embolization device (PED) and Silk, have been beneficial in the treatment of aneurysms previously unable to be approached via endovascular techniques. Recurrent aneurysms for which stent-assisted embolization has failed are a therapeutic challenge, given the existing intraluminal construct with continued blood flow into the aneurysm. We report our experience using flow-diverting stents in the repair of 25 aneurysms for which stent-assisted embolization had failed. Nineteen (76%) of these aneurysms at the 12-month follow-up showed improved Raymond class occlusion, with 38% being completely occluded, and all aneurysms demonstrated decreased filling. One patient developed a moderate permanent neurologic deficit. Appropriate stent sizing, proximal and distal construct coverage, and preventing flow diverter deployment between the previously deployed stent struts are important considerations to ensure wall apposition and prevention of endoleak. Flow diverters are shown to be a reasonable option for treating previously stented recurrent cerebral aneurysms.

Y-stent-assisted coil embolization of cerebral aneurysms

Y-stent-assisted coiling is a technique used by neuroendovascular surgeons to treat complex, wide-necked, bifurcation aneurysms in locations such as basilar tip and middle cerebral artery bifurcation. Several recent studies have demonstrated low complication rate and favorable clinical and angiographic outcomes. The Y-stent technique is illustrated here in detail and the intraoperative nuances are also discussed to minimize potential complications associated with technique. The video can be found here: http://youtu.be/77pEmqx_fyQ .