Faculty Bibliography

The limitations of intravenous thrombolysis therapy have paved the way for the development of novel endovascular technologies for use in the setting of acute stroke. These technologies range from direct intraarterial thrombolysis to various thrombus disruption or retrieval devices to angioplasty and stenting. The tools in the armamentarium of the neuroendovascular interventionalist enable fast, effective revascularization to be offered to a wider population of patients that may otherwise have few therapeutic options available to them. In this paper, we review the current state-of-the-art in neuroendovascular intervention for acute ischemic stroke. Particular emphasis is placed on delineating the indications and outcomes for use of these various technologies.

Pre-operative embolization is a routinely utilized therapeutic adjunct to the resection of hypervascular lesions of the head and neck. In particular, pre-operative cerebral angiography and tumor embolization has become standard practice at many centers in the management of select intracranial meningiomas. However, controversy remains regarding its specific indications and clinical utility. In this article, we examine the principles of meningioma embolization, emphasizing the indications, risks and benefits associated with its use in the pre-operative setting.

BACKGROUND:Scatter radiation during interventional radiology procedures can produce cataracts in participating medical personnel. Standard safety equipment for the radiologist includes eye protection. The typical configuration of fluoroscopy equipment directs radiation scatter away from the radiologist and toward the anesthesiologist. This study analyzed facial radiation exposure of the anesthesiologist during interventional neuroradiology procedures. METHODS:Radiation exposure to the forehead of the anesthesiologist and radiologist was measured during 31 adult neuroradiologic procedures involving the head or neck. Variables hypothesized to affect anesthesiologist exposure were recorded for each procedure. These included total radiation emitted by fluoroscopic equipment, radiologist exposure, number of pharmacologic interventions performed by the anesthesiologist, and other variables. RESULTS:Radiation exposure to the anesthesiologist's face averaged 6.5 ± 5.4 μSv per interventional procedure. This exposure was more than 6-fold greater (P < 0.0005) than for noninterventional angiographic procedures (1.0 ± 1.0) and averaged more than 3-fold the exposure of the radiologist (ratio, 3.2; 95% CI, 1.8-4.5). Multiple linear regression analysis showed that the exposure of the anesthesiologist was correlated with the number of pharmacologic interventions performed by the anesthesiologist and the total exposure of the radiologist. CONCLUSIONS:Current guidelines for occupational radiation exposure to the eye are undergoing review and are likely to be lowered below the current 100-150 mSv/yr limit. Anesthesiologists who spend significant time in neurointerventional radiology suites may have ocular radiation exposure approaching that of a radiologist. To ensure parity with safety standards adopted by radiologists, these anesthesiologists should wear protective eyewear.

Subclavian steal phenomenon occurs when cerebral blood flow is diverted to supply the arm. We report 3 patients with asymptomatic subclavian steal phenomenon with retrograde blood flow in the vertebral artery who presented with subarachnoid hemorrhage due to dissecting aneurysms of the involved vertebral artery. The association of subclavian steal phenomenon complicated by subarachnoid hemorrhage due to dissecting vertebral aneurysms has not been previously described.

BACKGROUND:Isolated intraventricular hemorrhage (IVH) secondary to lenticulostriate artery aneurysm rupture is extremely rare. Thus, the diagnostic imaging modalities and therapeutic interventions utilized in the management of such cases are not clearly defined. CASE DESCRIPTION/METHODS:Here we describe a case of isolated or primary IVH (PIVH) in a 71-year-old woman presenting with severe headache. Emergent catheter cerebral angiography, performed after nondiagnostic computed tomography angiography (CTA), revealed the bleeding source to be a 4 × 2.6 mm distal medial lenticulostriate artery aneurysm that ruptured directly into the lateral ventricle. The poorly accessible location of the aneurysm for both endovascular and direct surgical treatment argued for conservative management. A good clinical outcome was obtained with rapid angiographic resolution of the ruptured aneurysm. CONCLUSION/CONCLUSIONS:Thus, lenticulostriate artery aneurysm rupture must be given diagnostic consideration in cases of isolated IVH. Emergent catheter cerebral angiography should be performed in cases such as this when noninvasive imaging is unrevealing. Conservative management may be a reasonable therapeutic option in patients with this kind of aneurysm, and spontaneous resolution can be observed.

BACKGROUND:Delayed ischemic neurological deficits (DIND) due to cerebral vasospasm remains a major cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage (aSAH). Methods to prevent DIND remain limited both in safety and efficacy. A novel intra-aortic dual balloon catheter (NeuroFloâ„¢: CoAxia, Maple Grove, MN) is under investigation for treatment of ischemic stroke, including DIND. Because this technique does not require cerebral artery navigation, it may be useful as a bedside procedure, outside of the conventional angiography suite. We report the first case of ultrasound-guided application of the NeuroFloâ„¢ system at bedside in the Neurological Intensive Care Unit. METHODS:A 52-year-old woman presented with Hunt Hess IV aSAH complicated by medically refractory cerebral vasospasm. Despite surgical clipping of her aneurysm, the patient remained critically ill, failing maximal conventional medical therapy. For that reason, the NeuroFloâ„¢ system was deployed using two-dimensional, spectral and color-flow Doppler ultrasound guidance at the patient's bedside while maintaining all forms of cerebral blood flow monitoring. RESULTS:The procedure was well tolerated and there was no complication. CONCLUSION/CONCLUSIONS:Bedside application of the NeuroFloâ„¢ system may be safely performed in critically ill patients. The NeuroFloâ„¢ system is under investigation for treatment of refractory cerebral vasospasm to prevent delayed ischemic neurological disease.

Vascular lesions in the brain are common with advancing age; however, the independent and cumulative contributions of postmortem vascular lesions to antemortem cognitive status are not well established. We examined association of six vascular lesions (large infarcts, lacunar infarcts, leukoencephalopathy, microinfarcts, cribriform changes, and cerebral amyloid angiopathy) with antemortem diagnoses of dementia, Alzheimer's disease (AD), and vascular dementia (VaD) in 190 older adults from an autopsy series. We also developed a summary score based on three macroscopic vascular lesions: large infarcts (0, 1, and >or=2), lacunar infarcts (0, 1, and >or=2), and leukoencephalopathy (none, mild, and moderate-to-severe). Sixty-eight percent of cases had vascular lesions. Only leukoencephalopathy was associated with dementia (odds ratio (OR) 3.5, 95% CI 1.0-12.4), and only large infarcts were associated with VaD (OR 4.3, 95% CI 1.2-15.4). The vascular score was associated with dementia (OR 1.6, 95% CI 1.2-2.3), AD (OR 1.5, 95% CI 1.0-2.1) and VaD (OR 2.0, 95% CI 1.4-3.0). Leukoencephalopathy, large infarcts, and higher vascular burden is associated with the clinical expression of dementia and subtypes.

Ischemic stroke remains one of the leading cause of adult death and disability in the United States. Reperfusion of the occluded vessel is the standard of care in the setting of acute ischemic stroke according to established guidelines. Since the introduction of intravenous (IV) recombinant tissue plasminogen activator (rt-PA) in the late 1990s, significant advances have been made in methods to deliver thrombolytic agents and in devices for mechanical recanalization of occluded vessels. Furthermore, improvements in patient selection contribute to achievement of good clinical outcomes after endovascular therapy. This article summarizes findings from recent clinical trials and presents evidence-based guidelines for endovascular interventions in the treatment of ischemic stroke.

BACKGROUND:During the past few years, the field of endovascular surgical neuroradiology has been expanding. Neurosurgeons, radiologists, and neurologists are currently being trained. We analyzed data from a national survey of endovascular training programs to assess the current training status and future projections. METHODS:Survey participation requests were sent out to program directors and members of the Society of Endovascular Neurosurgery, the Society of Neurointerventional Surgery, and the Society of Vascular and Interventional Neurology. The format was an on-line survey designed by the authors, and completed through the SurveyMonkey.com website. Forty-three programs were identified and invited to participate. RESULTS:We achieved a response rate of 81% (n = 35). Twenty-seven (79%) of the 35 respondents listed their training program as academic, and 7 (20%) listed it as a mixture of academic with private practice. The training program faculty consisted of 57 radiologists, 39 neurosurgeons, and 10 neurologists. Length of fellowship offered was the same for all specialties in 43%, and differed based on clinical experience/background in 51%. Of the programs, 86% offered a 2-year fellowship, 49% had a mandatory resident rotation, 17% offered an infolded complete fellowship for residents, and 34% offered an infolded partial fellowship. Only 9% reported no resident exposure at all. There were 12% of respondents who reported to have knowledge of vascular surgeons or cardiologists performing intracranial procedures. At the time of the survey, there were 68 fellows in training, and most entered training immediately after residency (38%), whereas 26% entered after a fellowship and another 26% trained while in residency. There will be a 14% increase of graduates within the next 5 years. Comparing the past 5 years (2003-2007) with future 5-year projections (2008-2012), the number of radiologists is declining by 37% (73 vs. 46), whereas the number of neurosurgeons (74 vs. 106) and neurologists (20 vs. 37) is increasing by 42.5% and 112%, respectively. CONCLUSIONS:This survey suggests that there is a strong interest in endovascular surgical neuroradiology. The overall number of graduates is increasing, particularly in neurosurgery and neurology. Although the majority of current faculty is still comprised of neuroradiologists, the number of graduates in radiology will be decreasing during the next 5 years, reflecting a trend toward greater subspecialization within the fields of neurosurgery and neurology. Peer-Review Article.

Intracranial atherosclerotic disease (ICAD) contributes to a significant number of ischemic strokes. There is debate in the recent literature concerning the impact of the location of stenosis in ICAD on outcome. Some reports have suggested that disease processes and outcomes vary by vessel location, potentially altering the natural history and indications for intervention. Here we have performed a comprehensive, critical review of the natural history of ICAD by vessel in an attempt to assess the differences in disease specific to each of the vascular territories. Our assessment concludes that only minor differences exist between patients with different vessels affected in vessel-specific ICAD. We have found that middle cerebral artery disease confers a lower mortality than vessel-specific ICAD in other intracranial vessels, asymptomatic disease follows a more benign course than symptomatic disease, and that plaque progression or the detection of microemboli on transcranial Doppler may predict poor outcome. Given the expanding indications for treatment of ICAD and rapidly developing endovascular techniques to confront this disease, a thorough understanding of the natural history of ICAD aids the interventional neuroradiologist in determining when to treat and how to predict outcome in this patient population.