Rudy J. Rahme

Endovascular stenting of extracranial carotid and vertebral artery dissections: A systematic review of the literature

BACKGROUND:Carotid and vertebral artery dissections are a leading cause of stroke in young individuals. OBJECTIVE:To examine the published safety and efficacy of endovascular stenting for extracranial artery dissection. METHODS:We conducted a systematic review of the literature to identify all cases of endovascular management of extracranial carotid and vertebral artery dissections. RESULTS:For carotid dissections, our review yielded 31 published reports including 140 patients (153 vessels). Reported etiologies were traumatic (48%, n = 64), spontaneous (37%, n = 49), and iatrogenic (16%, n = 21). The technical success rate of stenting was 99%, and the procedural complication rate was 1.3%. Mean angiographic follow-up was 12.8 months (range, 2-72 months) and revealed in-stent stenosis or occlusion in 2% of patients. Mean clinical follow-up was 17.7 months (range, 1-72 months), and neurological events were seen in 1.4% of patients. For vertebral artery dissections, our review revealed 8 reports including 10 patients (12 vessels). Etiologies were traumatic (60%, n = 6), spontaneous (20%, n = 2), and iatrogenic (20%, n = 2). There was a 100% technical success rate. The mean angiographic follow-up period was 7.5 months (range, 2-12 months). No new neurological events were reported during a mean clinical follow-up period of 26.4 months (range, 3-55 months). CONCLUSION:Endovascular management of extracranial arterial dissection continues to evolve. Current experience shows that this treatment option is safe and technically feasible. Prospective randomized trials compared with medical management are needed to further elucidate the role of stenting.

Moyamoya disease: a review of histopathology, biochemistry, and genetics

OBJECT Moyamoya disease (MMD) is a rare cerebrovascular disorder involving stenosis of the major vessels of the circle of Willis and proximal portions of its principal branches. Despite concerted investigation, the pathophysiology of the disorder has not been fully elucidated. Currently, the major proteins believed to play an active role in the pathogenesis include vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), transforming growth factor-β₁ (TGFβ₁), and granulocyte colony-stimulating factor (G-CSF). In terms of the genetics, recent literature suggests a low penetrance autosomal dominant or polygenic mode of transmission involving chromosomes 3, 6, 8, 12, and 17 for familial MMD. This review summarizes the current knowledge on the histopathology, pathophysiology and genetics of MMD. METHODS A PubMed/Medline systematic study of the literature was performed, from which 45 articles regarding MMD pathophysiology were identified and analyzed. CONCLUSIONS Moyamoya disease is characterized by the intimal thickening and media attenuation of the proximal vessels of the circle of Willis as well as the development of an aberrant distal vascular network. The primary proteins that are currently implicated in the pathophysiology of MMD include VEGF, bFGF, HGF, TGFβ₁, and G-CSF. Furthermore, the current literature on familial MMD has pointed to a low penetrance autosomal dominant or polygenic mode of transmittance at loci on chromosomes 3, 6, 8, 12, and 17.

Adenosine for temporary flow arrest during intracranial aneurysm surgery: a single-center retrospective review.

BACKGROUND:Clip application for temporary occlusion is not always practical or feasible. Adenosine is an alternative that provides brief periods of flow arrest that can be used to advantage in aneurysm surgery, but little has been published on its utility for this indication. OBJECTIVE:To report our 2-year consecutive experience with 40 aneurysms in 40 patients for whom we used adenosine to achieve temporary arterial occlusion during aneurysm surgery. METHODS:We retrospectively reviewed our clinical database between May 2007 and December 2009. All patients who underwent microsurgical clipping of intracranial aneurysms under adenosine-induced asystole were included. Aneurysm characteristics, reasons for adenosine use, postoperative angiographic and clinical outcome, cardiac complications, and long-term neurological follow-up with the modified Rankin Scale were noted. RESULTS:Adenosine was used for 40 aneurysms (10 ruptured, 30 unruptured). The most common indications for adenosine were aneurysm softening in 17 cases and paraclinoid location in 14 cases, followed by broad neck in 12 cases and intraoperative rupture in 6 cases. Troponins were elevated postoperatively in 2 patients. Echocardiography did not show acute changes in either. Clinically insignificant cardiac arrhythmias were noted in 5 patients. Thirty-six patients were available for follow-up. Mean follow-up was 12.8 months. The modified Rankin Scale score was 0 for 29 patients at the time of the last follow-up. Four patients had an modified Rankin Scale score of 1, and scores of 2 and 3 were found in 2 and 1 patients, respectively. CONCLUSION:Adenosine appears to allow safe flow arrest during intracranial aneurysm surgery. This can enhance the feasibility and safety of clipping in select circumstances.

Moyamoya disease: functional and neurocognitive outcomes in the pediatric and adult populations

OBJECT Moyamoya disease is an occlusive cerebrovascular disorder commonly resulting in neurocognitive impairment. The cognitive outcome parameters commonly affected are intelligence, memory, executive function, and quality of life. In this paper, the authors review the existing literature on cognitive and clinical outcomes in adult and pediatric moyamoya populations separately. METHODS A systematic review of the cognitive and clinical outcome literature was performed using the PubMed/MEDLINE database. Outcomes data were contrasted between adult and pediatric populations. RESULTS Intelligence is the main cognitive outcome parameter affected in pediatric patients with moyamoya disease, whereas adults most commonly suffer from executive function impairment. Memory has not been studied sufficiently in pediatric patients, and its dysfunction in the adult population remains controversial. Quality of life has not been studied appropriately in either population. Surgical revascularization is the only beneficial treatment option, and a combination of direct and indirect bypass techniques has shown benefit, but the impact on the above-mentioned parameters has not been sufficiently elucidated. CONCLUSIONS Moyamoya disease affects the cognition and daily function in pediatric patients to a greater extent than in adult patients. Due to the rarity of the disease, there is a distinct lack of high-level evidence regarding cognitive and clinical outcomes.

De novo large fusiform posterior circulation intracranial aneurysm presenting with subarachnoid hemorrhage 7 years after therapeutic internal carotid artery occlusion: case report and review of the literature.

BACKGROUND AND IMPORTANCE Although the use of proximal artery occlusion, or hunterian ligation, for the treatment of intracranial aneurysms has decreased greatly over the past decades, this approach still finds use for certain giant and complex aneurysms. The main risks of artery sacrifice are ischemic complications but also, although rare, de novo aneurysm formation. We present here a case of de novo formation of a large fusiform basilar artery aneurysm 7 years after internal carotid artery occlusion. CLINICAL PRESENTATION A 17-year-old male patient with a history of a giant right cavernous aneurysm treated 7 years earlier with right-sided endovascular internal carotid artery occlusion presented to our institution with a thunderclap headache. At the time of initial evaluation, the patient was neurologically intact and imaging revealed a 22 × 10-mm fusiform aneurysm of the distal basilar artery with mass effect on the adjacent pons as well as a small amount of subarachnoid and intraventricular blood. Complete occlusion of the right internal carotid artery was demonstrated with retrograde filling of the right middle cerebral artery from the enlarged right posterior communicating artery. The patient was subsequently treated with hunterian occlusion of the basilar artery below anterior inferior cerebellar arteries. A superficial temporal artery to middle cerebral artery bypass was performed on the right side before this occlusion. CONCLUSION Further studies on the epidemiology of de novo aneurysms after carotid artery occlusion are warranted. Patients at higher risk of the development of intracranial aneurysms should be followed aggressively after hunterian ligation, and the possibility of an extracranial-intracranial bypass should be discussed.

Association of intracranial aneurysm and Loeys-Dietz syndrome: Case illustration, management, and literature review

BACKGROUND AND IMPORTANCE:Loeys-Dietz syndrome (LDS) is a newly described connective tissue disease associated with aortic aneurysms. A strong association between LDS and intracranial aneurysms has not yet been documented in the literature. We present the first detailed report of an intracranial aneurysm finding in an LDS patient. CLINICAL PRESENTATION:The patient is a 20-year-old female recently diagnosed with LDS and found to harbor 2 incidental intracranial aneurysms on a screening magnetic resonance angiography: a 3-mm right carotid ophthalmic aneurysm and an 8-mm partially fusiform paraclinoid carotid artery aneurysm. A standard left pterional craniotomy was performed. Intraoperative adenosine was used instead of temporary clipping because her vessels were extremely friable. After reconstruction, an intraoperative indocyanine green angiogram was obtained, confirming complete aneurysmal obliteration and internal carotid artery patency. CONCLUSION:This is the first detailed report of a clear association between intracranial aneurysms and LDS. An association between LDS and intracranial aneurysms, if substantiated in a larger study, has implications for aneurysm screening in this population. Such an association may shed light on mechanisms of aneurysm formation, growth, and rupture.

Spontaneous Cervical and Cerebral Arterial Dissections Diagnosis and Management

Arterial dissections of head and neck arteries were first identified pathologically in the 1950s, but not until the 1970s and the 1980s did they begin to be widely recognized as a clinical entity. Carotid and vertebral artery dissections account for only 2% of all ischemic strokes, but they account for approximately 20% of thromboembolic strokes in patients younger than 45 years. The cause of supra-aortic dissections can be either spontaneous or traumatic. This article addresses spontaneous cervical and cerebral artery dissections.

Cerebral arteriovenous malformation: Complex 3D hemodynamics and 3D blood flow alterations during staged embolization

Complex hemodynamics in cerebral arteriovenous malformations (AVM) are thought to play a key role in their pathophysiology. We applied 4D flow magnetic resonance imaging (MRI) for the detailed evaluation of AVM function at baseline and to investigate the impact of staged embolization on AVM hemodynamics in a patient with a Spetzler‐Martin grade III AVM. The patient underwent three embolization procedures resulting in >50% nidal casting and obliteration of several arteriovenous fistulae. 4D flow MRI demonstrated highly complex 3D hemodynamics at baseline and revealed intricate arterial feeding, a large vascularized nidus with high variability in regional blood flow velocities, and clearly visible venous drainage with high flow velocities above 50 cm/s. 3D blood flow visualization and quantification during follow‐up illustrated the systemic impact of focal embolization on cerebral hemodynamics resulting in compaction of the AVM, redistribution of blood flow velocities, and altered peak flow velocities and blood flow in multiple vascular territories. 4D flow MRI may offer a useful noninvasive tool to help to identify subtleties and nuances of the quantitative hemodynamic alterations in AVM vascular architecture as a supplement to established imaging modalities. J. Magn. Reson. Imaging 2013;38:946–950.

Past, Present, and Future Perspectives on the Endovascular Treatment of Acute Ischemic Stroke

Interventional neuroradiology plays a continuously expanding and exciting role in the treatment of acute stroke, as evidenced by the development of several important advances, including the advent of multiple new devices and therapies. Furthermore, guidelines regarding endovascular interventions in the setting of acute stroke have been developed and used. In addition to technological advances, the field of pharmacology in the setting of acute stroke is constantly evolving. In a rapidly expanding field, we aim to review significant recent advances related to the endovascular treatment of stroke as well as provide perspective for future directions.

Comparison of intraoperative portable CT scanners in skull base and endoscopic sinus surgery: Single center case series

Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are studied: one conventional multidetector CT (MDCT), two digital flat panel cone-beam CT (CBCT) devices. Technical considerations, ease of use, image characteristics, and integration with image guidance are presented for each device. All three scanners provide good quality images. Intraoperative scanning can be used to update the image guidance system in real time. The conventional MDCT is unique in its ability to resolve soft tissue. The flat panel CBCT scanners generally emit lower levels of radiation and have less metal artifact effect. In this series, intraoperative CT scanning was technically feasible and deemed useful in surgical decision-making in 75% of patients. Intraoperative portable CT scanning has significant utility in complex skull base surgery. This technology informs the surgeon of the precise extent of dissection and updates intraoperative stereotactic navigation.