Abdulrahman Y. Alturki

Use of Platelet Function Testing Before Pipeline Embolization Device Placement: A Multicenter Cohort Study

Background and Purpose— Thromboembolic complications constitute a significant source of morbidity after neurointerventional procedures. Flow diversion using the pipeline embolization device for the treatment of intracranial aneurysms necessitates the use of dual antiplatelet therapy to reduce this risk. The use of platelet function testing before pipeline embolization device placement remains controversial. Methods— A retrospective review of prospectively maintained databases at 3 academic institutions was performed from the years 2009 to 2016 to identify patients with intracranial aneurysms treated with pipeline embolization device placement. Clinical and radiographic data were analyzed with emphasis on thromboembolic complications and clopidogrel responsiveness. Results— A total of 402 patients underwent 414 pipeline embolization device procedures for the treatment of 465 intracranial aneurysms. Thromboembolic complications were encountered in 9.2% of procedures and were symptomatic in 5.6%. Clopidogrel nonresponders experienced a significantly higher rate of thromboembolic complications compared with clopidogrel responders (17.4% versus 5.6%). This risk was significantly lower in nonresponders who were switched to ticagrelor when compared with patients who remained on clopidogrel (2.7% versus 24.4%). In patients who remained on clopidogrel, the rate of thromboembolic complications was significantly lower in those who received a clopidogrel boost within 24 hours pre-procedure when compared with those who did not (9.8% versus 51.9%). There was no significant difference in the rate of hemorrhagic complications between groups. Conclusions— Clopidogrel nonresponders experienced a significantly higher rate of thromboembolic complications when compared with clopidogrel responders. However, this risk seems to be mitigated in nonresponders who were switched to ticagrelor or received a clopidogrel boost within 24 hours pre-procedure.

Ischemic Stroke After Treatment of Intraprocedural Thrombosis During Stent-Assisted Coiling and Flow Diversion

Background and Purpose— Intraprocedural thrombosis poses a formidable challenge during neuroendovascular procedures because the risks of aggressive thromboembolic treatment must be balanced against the risk of postprocedural hemorrhage. The aim of this study was to identify predictors of ischemic stroke after intraprocedural thrombosis after stent-assisted coiling and pipeline embolization device placement. Methods— A retrospective analysis of intracranial aneurysms treated with stent-assisted coiling or pipeline embolization device placement between 2007 and 2016 at 4 major academic institutions was performed to identify procedures that were complicated by intraprocedural thrombosis. Results— Intraprocedural thrombosis occurred in 34 (4.6%) procedures. Postprocedural ischemic stroke and hemorrhage occurred in 20.6% (7/34) and 11.8% (4/34) of procedures complicated by intraprocedural thrombosis, respectively. Current smoking was an independent predictor of ischemic stroke. There was no statistically significant difference in the rate of ischemic stroke or postprocedural hemorrhage with the use of abciximab compared with the use of eptifibatide in treatment of intraprocedural thrombosis. Conclusions— Current protocols for treatment of intraprocedural thrombosis associated with placement of intra-arterial devices were effective in preventing ischemic stroke in ≈80% of cases. Current smoking was the only independent predictor of ischemic stroke.

Predictors of Incomplete Occlusion following Pipeline Embolization of Intracranial Aneurysms: Is It Less Effective in Older Patients?

This was a retrospective analysis of 465 consecutive aneurysms treated with the Pipeline Embolization Device between 2009 and 2016, at 3 academic institutions in the United States. Cases with angiographic follow-up were selected to evaluate factors predictive of incomplete aneurysm occlusion at last follow-up. Older age (more than 70 years), nonsmoking status, aneurysm location within the posterior communicating artery or posterior circulation, greater aneurysm maximal diameter (>21 mm), and shorter follow-up time (<12 months) were significantly associated with incomplete aneurysm occlusion at last angiographic follow-up. BACKGROUND AND PURPOSE: Flow diversion with the Pipeline Embolization Device (PED) for the treatment of intracranial aneurysms is associated with a high rate of aneurysm occlusion. However, clinical and radiographic predictors of incomplete aneurysm occlusion are poorly defined. In this study, predictors of incomplete occlusion at last angiographic follow-up after PED treatment were assessed. MATERIALS AND METHODS: A retrospective analysis of consecutive aneurysms treated with the PED between 2009 and 2016, at 3 academic institutions in the United States, was performed. Cases with angiographic follow-up were selected to evaluate factors predictive of incomplete aneurysm occlusion at last follow-up. RESULTS: We identified 465 aneurysms treated with the PED; 380 (81.7%) aneurysms (329 procedures; median age, 58 years; female/male ratio, 4.8:1) had angiographic follow-up, and were included. Complete occlusion (100%) was achieved in 78.2% of aneurysms. Near-complete (90%–99%) and partial (<90%) occlusion were collectively achieved in 21.8% of aneurysms and defined as incomplete occlusion. Of aneurysms followed for at least 12 months (211 of 380), complete occlusion was achieved in 83.9%. Older age (older than 70 years), nonsmoking status, aneurysm location within the posterior communicating artery or posterior circulation, greater aneurysm maximal diameter (≥21 mm), and shorter follow-up time (<12 months) were significantly associated with incomplete aneurysm occlusion at last angiographic follow-up on univariable analysis. However, on multivariable logistic regression, only age, smoking status, and duration of follow-up were independently associated with occlusion status. CONCLUSIONS: Complete occlusion following PED treatment of intracranial aneurysms can be influenced by several factors related to the patient, aneurysm, and treatment. Of these factors, older age (older than 70 years) and nonsmoking status were independent predictors of incomplete occlusion. While the physiologic explanation for these findings remains unknown, identification of factors predictive of incomplete aneurysm occlusion following PED placement can assist in patient selection and counseling and might provide insight into the biologic factors affecting endothelialization.

Collar Sign in Incompletely Occluded Aneurysms after Pipeline Embolization: Evaluation with Angiography and Optical Coherence Tomography

BACKGROUND AND PURPOSE: Flow diversion with the Pipeline Embolization Device has emerged as an attractive treatment for cerebral aneurysms. Processes involved in aneurysm occlusion include changes in intra-aneurysmal hemodynamics and endothelialization of the device. Here, we call attention to a radiographic sign not previously reported that is detected in incompletely occluded aneurysms after treatment with the Pipeline Embolization Device at angiographic follow-up and referred to as the “collar sign.” MATERIALS AND METHODS: A retrospective review of all patients who underwent placement of a Pipeline Embolization Device for cerebral aneurysms between January 2014 and May 2016 was performed. All aneurysms found to show the collar sign at follow-up were included. Optical coherence tomography was performed in 1 case. RESULTS: One hundred thirty-five aneurysms were treated in 115 patients. At angiographic follow-up, 17 (10.7%) aneurysms were found to be incompletely occluded. Ten (58.8%) of these aneurysms (average diameter, 7.9 ± 5.0 mm) were found to have the collar sign at angiographic follow-up (average, 5.5 ± 1.0 months). Four (40.0%) of the aneurysms underwent a second angiographic follow-up (average, 11.0 ± 0.9 months) after treatment, and again were incompletely occluded and showing the collar sign. Two patients underwent retreatment with a second Pipeline Embolization Device. Optical coherence tomography showed great variability of endothelialization at the proximal end of the Pipeline Embolization Device. CONCLUSIONS: The collar sign appears to be indicative of endothelialization, but continued blood flow into the aneurysm. This is unusual given the processes involved in aneurysm occlusion after placement of the Pipeline Embolization Device and has not been previously reported.

The Use of Single Stent-Assisted Coiling in Treatment of Bifurcation Aneurysms: A Multicenter Cohort Study With Proposal of a Scoring System to Predict Complete Occlusion

BACKGROUND The development of stent-assisted coiling has allowed for the endovascular treatment of wide-necked bifurcation aneurysms. A variety of options exist, and little is known about the optimal stent configuration in this setting. We report a large multicenter experience of stent-assisted coiling of bifurcations aneurysms using a single stent, with attention to factors predisposing to aneurysm recanalization. OBJECTIVE To assess the safety and efficacy of single stent-assisted coiling, in addition to analyzing the factors associated with recanalization, and proposal of a predictive scoring scale. METHODS A multicenter retrospective analysis of bifurcation aneurysms treated with a single stent-assisted coiling technique between 2007 and 2015 was performed. Clinical and radiographic data were collected and used to develop a scoring system to predict aneurysm occlusion. RESULTS A total of 74 bifurcation aneurysms were treated with single stent-assisted coiling. At a median follow-up of 15.2 mo, complete occlusion or remnant neck was achieved in 90.6% of aneurysms. Aneurysm location, maximal diameter, neck size, and alpha angle were predictive of aneurysm occlusion at last follow-up. A scoring system to predict complete occlusion based on these factors was developed. An increasing score correlated with a higher rate of complete occlusion. CONCLUSION The treatment of bifurcation aneurysm using single stent technique for stent-assisted coiling is safe and effective. Complete occlusion or remnant neck occlusion was achieved in 90.6% of cases. Class III aneurysms can be effectively treated using a single stent, while class I may require Y-stent technique.

Ruptured Distal Anterior Choroidal Artery Aneurysm Treated with Superselective Provocative Testing and Coil Embolization

BACKGROUND AND IMPORTANCE Aneurysms of the anterior choroidal artery are uncommon, and distal anterior choroidal artery aneurysms are even rarer, with only 34 cases reported in the medical literature. These lesions have been most commonly reported in association with moyamoya disease or arteriovenous malformations. Most published experience with these aneurysms involves open surgical approaches. Reports of endovascular treatment have been in patients with lesions distal to the plexal point and have employed vessel occlusion with liquid embolic agents in preference to coil embolization. CLINICAL PRESENTATION We present a case of a ruptured distal anterior choroidal artery aneurysm located on the cisternal segment of the artery. This lesion was successfully treated with endovascular coil embolization. Additionally, the patient underwent pre-embolization superselective provocative testing with amobarbital to assess the safety of parent vessel occlusion. CONCLUSION Endovascular coil embolization for distal anterior choroidal artery aneurysms is technically feasible and may be preferable to embolization with liquid embolic agents for lesions proximal to the plexal point. This case illustrates the utility of provocative testing and efficacy of endovascular coil embolization for lesions in this unique location.

Flow Diverters as Useful Adjunct to Traditional Endovascular Techniques in Treatment of Direct Carotid-Cavernous Fistulas

BACKGROUND Direct carotid-cavernous sinus fistulas (CCFs) are high-flow arteriovenous shunts that are typically the result of a severe head injury. The endovascular treatment of these lesions includes the use of detachable balloons, coils, liquid embolic agents, and covered stents. To minimize the chance of treatment failure and subsequent complications, endoluminal reconstruction using a flow-diverting stent may be added to the treatment construct. METHODS We present 3 cases and review the existing literature. RESULTS Three patients with direct traumatic CCFs were treated with either coils, coils and Onyx, or a detachable balloon, followed by placement of a flow-diverting stent for endoluminal reconstruction. All 3 cases had complete angiographic occlusion of the CCFs and recovered clinically. No complications were observed. CONCLUSIONS We believe that endovascular coil or balloon occlusion of the fistula from either a transvenous or transarterial approach followed by flow diversion may be an appropriate treatment for direct CCFs. This addition of a flow diverter may facilitate endothelialization of the injury to the internal carotid artery.

Transarterial Onyx Embolization of Bilateral Transverse–Sigmoid Dural Arteriovenous Malformation with Transvenous Balloon Assist—Initial U.S. Experience with Copernic RC Venous Remodeling Balloon

BACKGROUND Currently, the mainstay treatment of dural arteriovenous fistula (DAVF) involves endovascular approaches, especially for high-grade lesions. Transarterial embolization with preservation of venous sinuses has become the preferred approach due to the development of newer liquid embolic agents. For further precision during embolization, the use of temporary balloon occlusion to protect the patency of dural sinuses from the embolic agents migration has been described. METHODS A 64-year-old man presented with bilateral pulsatile tinnitus and visual decline. A diagnostic cerebral angiogram demonstrated a complex bilateral Borden type II and Cognard type IIB DAVF. Treatment was carried out endovascularly under general anesthesia in a staged fashion. In the first stage, the balloon was inflated during embolization to protect the right transverse sigmoid venous sinus system and torcula. In the second stage, the balloon was again inflated to protect the left transverse sigmoid venous sinus system and torcula during embolization. Complete obliteration of the left DAVF was achieved, and patency of the left transverse and sigmoid sinuses was preserved. Patency of the right transverse and sigmoid sinus was also conserved post procedure. RESULTS The patient was treated successfully with transarterial Onyx embolization with transvenous balloon protection of the sinus. CONCLUSIONS This case is the first reported use of the Copernic RC balloon in the United States under the compassionate use guidelines of the U.S. Food and Drug Administration. The use of this balloon is becoming a useful treatment alternative in selected cases of DAVFs as it improves the safety and efficacy of transarterial embolization as evidenced in this case.

Sequential Coiling-Assisted Deployment of Flow Diverter for Treatment of Fusiform Middle Cerebral Artery Aneurysms

BACKGROUND AND IMPORTANCE Fusiform intracranial aneurysms remain challenging lesions to treat. These aneurysms have historically required bypass procedures or clip remodeling constructs for cure. Recently, endovascular specialists have reported experience with flow diversion for complex fusiform aneurysms of the vertebrobasilar system, with mixed results. Vascular anatomy for anterior circulation fusiform aneurysms may make these lesions more amenable to flow diversion and embolization procedures; however, published experience with these techniques is lacking. In this report, we describe a sequential coiling-assisted deployment of flow diverter for the treatment of fusiform middle cerebral artery (MCA-M1) aneurysms in 2 cases, 1 presenting acutely with subarachnoid hemorrhage and another with progressive aneurysm enlargement. CLINICAL PRESENTATION Two patients, a 36-yr-old male presenting with subarachnoid hemorrhage and a 60-yr-old female presenting with aneurysm enlargement were treated for fusiform aneurysms of the M1 segment of the MCA using a sequential, partial deployment of coils and flow diverter through 2 microcatheters to facilitate mutual mechanical support for both coil and flow diverter (Pipeline Embolization Device; Medtronic Inc, Dublin, Ireland). Both patients achieved favorable outcomes and follow-up angiography demonstrated complete vessel reconstruction in both cases. CONCLUSION The treatment of complex, fusiform, large vessel aneurysms remains challenging. As experience with new endovascular technologies and techniques grows, these lesions may be treated safely with interventional methods. The technique of partial flow diverter deployment and stabilization with coils with sequential delivery of both devices using dual microcatheter was both safe and effective.

Bow Hunter's Syndrome from a Tortuous V1 Segment Vertebral Artery Treated with Stent Placement.

BACKGROUND Bow hunters syndrome is a dynamic and reversible occlusion of the vertebral artery occurring after rotation or extension of the neck. The V3 segment is the most common site of compression, especially at the atlantoaxial joint. Surgical decompression with or without cervical fusion has been the mainstay of therapy. Endovascular intervention, such as placement of stents, is rarely performed. METHODS We report a patient with bow hunters syndrome from tortuosity of the V1 segment of the VA treated with a self-expanding biliary stent placement. RESULTS The symptoms where completely resolved by this treatment. CONCLUSIONS Stent placement is a safe and effective option for V1 segment causes of Bow Hunters syndrome, especially in absence of bony compression.