Faculty Bibliography

BACKGROUND AND OBJECTIVE: Treatment of non-saccular vertebrobasilar aneurysms remains highly challenging despite significant recent advances in endovascular techniques. Establishing the natural history of this heterogeneous disease, as best as currently available data allows, is crucial to help guide counseling and management. METHODS: A review of the literature was conducted to identify publications describing the presentation and natural history of vertebrobasilar dolichoectasia and non-saccular aneurysms. RESULTS: Nine studies of 440 patients met the analysis inclusion criteria. The majority of patients presented with ischemia, mass effect, or incidentally; hemorrhage was uncommon and overlapped with the population of vertebrobasilar dissection. Overall mortality was approximately 40% after 7 years of follow-up, with 43% of these deaths resulting from non-neurologic causes. Neurologic course was dominated by ischemic stroke rather than hemorrhage. Mass effect prognosis was especially poor, with 40% mortality after approximately 4 years. Incidentally discovered lesions which remain morphologically stable have a favorable long term course. CONCLUSIONS: Initial clinical presentation is a strong predictor of subsequent disease course. Although overall prognosis is poor, nearly half of all deaths resulted from non-neurologic causes, underscoring the importance of comprehensive medical management. Aneurysms characterized by expansion, established mass effect, or hemorrhage have a poor natural history, and may be considered for invasive treatment, which is increasingly endovascular in nature. Lesions presenting with ischemia or incidentally are likely best addressed with aggressive neurologic and overall medical management.

We report a case of temporary Solitaire FR stent (Covidien, Mansfield, MA, USA) scaffolding to reduce coil herniation during embolization of a large neck anterior communicating artery aneurysm. In contrast to classic stent-assisted coiling, the fully retrievable stent is recaptured prior to detachment of the last coil. The presented technical nuance hence does not require institution of prolonged antiplatelet coverage. But the door is left open for coil-repositioning in case of coil basket instability. Permanent stent redeployment remains a fall-back option if critical hardware conflict occurs. In comparison to classic balloon remodeling, the presented method may offer easier distal access, particularly in tortuous arterial anatomy. Temporary occlusion of the parent artery, side branches, and perforators is also avoided. Given its specific potential advantages, temporary stent scaffolding using the fully retrievable Solitaire FR device may find its niche as a bailout option, primarily in a very specific subset of distally located wide neck aneurysms.

SUMMARY:Does the world need another ICA classification scheme? We believe so. The purpose of proposed angiography-driven classification is to optimize description of the carotid artery from the endovascular perspective. A review of existing, predominantly surgically-driven classifications is performed, and a new scheme, based on the study of NYU aneurysm angiographic and cross-sectional databases is proposed. Seven segments - cervical, petrous, cavernous, paraophthlamic, posterior communicating, choroidal, and terminus - are named. This nomenclature recognizes intrinsic uncertainty in precise angiographic and cross-sectional localization of aneurysms adjacent to the dural rings, regarding all lesions distal to the cavernous segment as potentially intradural. Rather than subdividing various transitional, ophthalmic, and hypophyseal aneurysm subtypes, as necessitated by their varied surgical approaches and risks, the proposed classification emphasizes their common endovascular treatment features, while recognizing that many complex, trans-segmental, and fusiform aneurysms not readily classifiable into presently available, saccular aneurysm-driven schemes, are being increasingly addressed by endovascular means. We believe this classification may find utility in standardizing nomenclature for outcome tracking, treatment trials and physician communication.

Arteriovenous malformations of the brain are a considerable source of morbidity and mortality for patients who harbor them. Although our understanding of this disease has improved, it remains in evolution. Advances in our ability to treat these malformations and the modes by which we address them have also improved substantially. However, the variety of patient clinical and disease scenarios often leads us into challenging and complex management algorithms as we balance the risks of treatment against the natural history of the disease. The goal of this article is to provide a focused review of the natural history of cerebral arteriovenous malformations, to examine the role of stereotactic radiosurgery, to discuss the role of endovascular therapy as it relates to stereotactic radiosurgery, and to look toward future advances.

INTRODUCTION: Angioplasty and intracranial stenting (ICS) are both endovascular revascularization procedures that have emerged as treatment options for intracranial atherosclerotic disease (ICAD). Some believe angioplasty alone is better, while others believe stenting is better. This study examines recent trends in utilization and outcomes of angioplasty alone and ICS in the United States using a population-based cohort. METHODS: The National Inpatient Sample (NIS) database was queried for patients with ICAD who underwent angioplasty or ICS from 2005 to 2010. RESULTS: There were 1115 patients (angioplasty: n=495, ICS: n=620) with ICAD who underwent endovascular revascularization. Over time, the number of endovascular revascularization procedures increased. The percentage of symptomatic patients (p=0.015) as well as in the number of comorbidities of patients treated (p<0.001) also increased. Combined post-procedure stroke and death rates were 16% and 28.9% for angioplasty and ICS, respectively (p<0.001). A larger percentage of angioplasty patients presented symptomatically compared to those who underwent ICS (p<0.001). CONCLUSION: Angioplasty appears to be associated with higher rates of peri-procedural complications; however, that may represent patient selection bias. Further studies are needed to identify patients who would benefit from revascularization and to clarify the roles of angioplasty and ICS.

Aim: Embolization of cerebral and spinal neoplasms is performed for highly vascular tumors including hemangioblastomas, paragangliomas, juvenile nasopharyngeal angiofibromas, hemangiopericytomas, schwannomas, meningiomas, and selected metastases. While diagnostic angiography may contribute to clarify the tumoral arterial supply, superselective infusion of embolics may effectively obliterate the tumoral vascular bed. At present, determinants of safe and effective presurgical embolization remain under debate. Methods: We investigate and illustrate the endovascular technique, ideal timing, and effectiveness of presurgical embolization of cerebral and spinal tumors performed at the NYU Langone Medical Center. Results: Detailed diagnostic angiography is key to identify the arterial supply to the tumor, to consistently recognize dangerous external carotid-to-internal carotid anastomoses, and to detect the highly variable arterial supply to cranial nerves and neuronal structures. Meticulous technique is essential for performing safe and effective tumor embolization that causes tumor necrosis and facilitates subsequent resection by limiting intraoperative blood loss. Although general anesthesia precludes the use of provocative testing, it does improve patient comfort and enhances the accuracy of angiography by limiting motion artifact. Additionally, electrophysiology may provide an additional degree of safely when general anesthesia is used. Embolization may be best performed within a week prior to the scheduled surgery to allow for effective tumor necrosis while avoiding neovascularization. Embolic agents include a range of liquids, particulates, or coils. Selecting the most advantageous agent is performed in light of the desired degree of tumor penetration, the presence or possibility of a dangerous anastomosis, and the ability to navigate the microcatheter in a safe position for superselective infusion of embolics. Although the most effective embolization is obtained with small particles that penetrate the tumoral bed at the capillary level, these agents are also the most dangerous to use by putting cranial nerves and normal structures such as the retina and myelon at risk. Conclusion: In depth knowledge of anatomy, meticulous technique, and the proper choice of the embolic material determine the safety and effectiveness of preoperative tumor embolization that may contribute to surgical success.

BACKGROUND: Extracranial-intracranial (EC-IC) bypass and intracranial stenting (ICS) are both revascularization procedures that have emerged as treatment options for intracranial atherosclerotic disease (ICAD). This study describes and compares recent trends in utilization and outcomes of intracranial revascularization procedures in the United States using a population-based cohort. It also investigates the association of ICS and EC-IC bypass with periprocedural morbidity and mortality, unfavorable discharge status, length of stay (LOS), and total hospital charges. METHODS: The National Inpatient Sample (NIS) was queried for patients with ICAD who underwent EC-IC bypass or ICS during the years 2004-2010. Patient characteristics, demographics, perioperative complications, outcomes, and discharge data were collected. RESULTS: There were 627 patients who underwent ICS and 249 patients who underwent EC-IC bypass. Patients who underwent ICS were significantly older (P < 0.001) with more comorbidities (P = 0.027) than those who underwent EC-IC bypass. Patients who underwent EC-IC bypass experienced higher rates of postprocedure stroke (P = 0.014), but those who underwent ICS experienced higher rates of death (P = 0.006). Among asymptomatic patients, the rates of postprocedure stroke (P = 0.341) and death (P = 0.887) were similar between patients who underwent ICS and those who underwent EC-IC bypass. Among symptomatic patients, however, there was a higher rate of postprocedure stroke in patients who underwent EC-IC bypass (P < 0.001) and a higher rate of death among patients who underwent ICS (P = 0.015). CONCLUSION: The ideal management of patients with ICAD cannot yet be defined. Although much data from randomized and prospective trials on revascularization have been collected, many questions remain unanswered. There still remain cohorts of patients, specifically patients who have failed aggressive medical management, where not enough evidence is available to dictate decision-making. In order to further elucidate the safety and efficacy of these intracranial revascularization procedures, further clinical trials are needed.