Cloft, Harry J.

Abstract BACKGROUND: Extradural arteriovenous malformations (AVMs) are uncommon vascular malformations of the spine. They are characterized by an arteriovenous communication (localized in the paraspinal soft tissues and the epidural venous plexus) that may have retrograde intradural venous drainage. Surgical treatment of extradural AVMs can be challenging because of the common location ventral to the dural sac and the presence of arterialized venous lakes. OBJECTIVE: To assess the effectiveness of embolization with a liquid embolic material (Onyx; ev3 Inc, Irvine, California) in 7 consecutive patients with extradural spinal AVMs and intradural venous drainage. METHODS: We retrospectively collected information regarding patient characteristics, clinical presentation, symptom duration, diagnostic imaging, treatment, complications, and clinical and radiological follow-up. RESULTS: Patients were 5 men and 2 women (mean age, 66 years; range, 45-76 years). Symptom duration varied from 2 months to 6 years. Six patients underwent embolization of the AVM as the primary treatment; 1 patient was treated after attempted surgery. Complete obliteration was demonstrated in each patient on completion angiography and was confirmed during follow-up in 6. Three patients had resolution of their preembolization symptoms. Three patients had improvement but not complete resolution of their motor deficits. In 1 patient, the AVM was an incidental finding during an investigation for chronic low-back pain; symptoms were not thought to be related to the AVM, and symptoms were not ameliorated by successful embolization. CONCLUSION: Our early experience with these uncommon lesions suggests that Onyx embolization is a valuable and effective strategy for extradural spinal AVMs and intradural venous drainage.

Background and Purpose Endovascular and surgical options are both available for the treatment of unruptured cerebral aneurysms. Knowledge of the costs for hospitalization of these patients is important to understanding economic impact of these patients on hospitals. Methods Using the National Inpatient Sample, hospitalizations for clipping and coiling of unruptured cerebral aneurysms from 2001 to 2008 were identified by cross-matching ICD-9 codes for diagnosis of unruptured aneurysm with procedure codes for clipping or coiling of cerebral aneurysms, and excluding all patients with diagnosis of subarachnoid hemorrhage and intracerebral hemorrhage. Hospital costs for 2008 were correlated with age, gender, and discharge status, and compared to Medicare payments. Results Costs of both clipping and coiling have increased from 2001 to 2008. The median 2008 hospital costs were US$23 574 (IQR 18233–29941) for clipping and US$25 734 (IQR 17436–35846) for coiling without complication, which were higher than the average Medicare payment of US$12 599. The median hospital costs were US$36 188 (IQR 21831–55308) for clipping and US$40 502 (IQR 24289–50108) for coiling treatments complicated by major morbidity, and US$68 165 (IQR 32972–100211) for clipping and US$56 020 (IQR 00000–00000) for coiling treatments complicated by mortality, which were higher than the average Medicare payments for patients with major complications and comorbidities of US$22 946. In multivariate analysis, female gender was associated with higher costs for coiling (p=0.02), and poor discharge status was associated with higher costs for both clipping (p<0.001) and coiling (p<0.001). Conclusions Hospitalization costs for patients undergoing clipping and coiling of unruptured cerebral aneurysms are substantially higher than Medicare payments.

The introduction of flow diverters for treatment of intracranial aneurysms represents a major paradigm shift in the treatment of these lesions. The theoretical hallmark of flow diverters is the treatment of the diseased segment harboring the aneurysm instead of treating the aneurysm itself. Flow diverters are designed to induce disruption of flow near the aneurysm neck while preserving flow into parent vessel and adjacent branches. After flow diversion, intra-aneurysmal thrombosis occurs, followed by shrinkage of the aneurysmal sac as the thrombus organizes and retracts. Preliminary clinical series document effective treatment of wide-neck and/or large and giant aneurysms with acceptable complication rates. However, several questions remain unanswered related to the incidence and mechanisms of aneurysm rupture after treatment with flow diverters, fate of small perforating vessels, and long-term patency rates.

Background and Purpose— To evaluate the periprocedural outcome after carotid artery stenting with embolic brain protection (EBP+) versus without embolic brain protection (EBP−). Methods— We retrospectively reviewed data from a prospective nonrandomized database of 357 patients who underwent carotid artery stenting in the neuroradiology division of our institution from 1999 to 2009. One hundred five patients underwent angioplasty and stenting without distal protection, whereas 252 were treated with distal protection. Patients were analyzed according to their EBP status (+ or −) for the primary end points of perioperative stroke, death, or myocardial infarction. Results— Unprotected stenting was mostly performed in the early years of this study and this is reflected in significant baseline differences between the two groups. In our earlier experience, carotid artery stenting was used in patients with more significant comorbidities. Diabetes mellitus ( P =0.04), previous coronary artery disease ( P =0.02) and myocardial infarction ( P =0.04), and symptomatic lesion ( P =0.01) were significantly more common in the EBP− cohort. Despite these baseline differences, there were no significant differences in the primary end points (2% in the EBP+ group and 4.8% in the EBP−, P =0.15). The incidence of ipsilateral stroke in the EBP− and in the EBP+ group was 3.8% versus 0.8%, respectively ( P =0.6). There were 2 perioperative deaths (1 in each group) and 4 myocardial infarctions (3 in the EBP+ arm and 1 in the EBP− arm, all non-Q infarcts; P =nonsignificant). Conclusions— In accordance with recent literature, this series cast doubts as to the real effectiveness of distal embolic protection devices in reducing periprocedural complications.

Background and Purpose— Maturing techniques have spurred widespread implementation of endovascular embolectomy therapy for ischemic stroke. We evaluated a large administrative database to determine outcomes in patients treated with endovascular embolectomy in the general population. Methods— Using the National Inpatient Sample, we evaluated outcomes of patients treated for acute ischemic stroke in the United States from 2006 to 2008. Patients who had an ischemic stroke and underwent endovascular clot retrieval were identified. Morbidity, defined as “discharge to long-term facility,” and mortality were evaluated as a function of patient age and of concomitant thrombolytic agent administration. Results— For 2006 to 2008, a total of 3864 patients received endovascular clot retrieval with 266 (6.9%) patients in 2006, 800 (20.7) patients in 2007, and 2798 (72.4%) patients in 2008. The discharge to a long-term facility rate was 51.3% (1983 of 3864). The in-hospital mortality rate was 24.3% (940 of 3864). For patients <65 years old, the rate of in-hospital death was 17.1% (283 of 1658) as compared with a rate of 29.7% (656 of 2206) for patients ≥65 years old ( P <0.0001). The rate of discharge to a long-term facility was 47.6% (789 of 1658) for patients <65 years old and 54.1% (1193 of 2206) for patients ≥65 years old ( P <0.0001). The rate of intracranial hemorrhage was 15.5% without concomitant thrombolysis and 20.0% with concomitant thrombolysis ( P =0.0009). Conclusions— Rates of morbidity and mortality remain high for patients with acute stroke, even in the setting of endovascular embolectomy. Advanced age portends a worse outcome and patients treated with concomitant use of thrombolytic agent had higher rates of intracranial hemorrhage than those without such therapy.

Background and Purpose— Age might differentially affect outcomes in patients treated for unruptured cerebral aneurysms with surgical clipping versus endovascular coil therapy. We evaluated a large administrative database to determine the effect of age on outcomes in patients treated for unruptured cerebral aneurysm. Methods— Using the National Inpatient Sample, we evaluated morbidity (discharge to long-term facility) and mortality of patients undergoing clipping or coiling of unruptured cerebral aneurysms in the United States between 2001 and 2008. Outcomes were evaluated in relation to four age strata: younger than 50 years; 50 to 64 years; 65 to 79 years; and patients 80 years or older. Results— Patients younger than 50 years old undergoing coiling had significantly lower morbidity rates when compared to patients who underwent clipping (3.5% versus 8.1%; P <0.0001), but no difference in mortality (0.6% versus 0.6%; P =0.72). Patients between 50 and 64 years old undergoing coiling had significantly decreased morbidity (4.0% versus 13.7%; P <0.0001) and mortality (0.5% versus 1.1%; P <0.0001) when compared to patients who underwent clipping. Coiled patients 65 to 79 years old had lower morbidity (6.9% versus 26.8%; P <0.0001) and mortality (0.8% versus 2.0%; P <0.0001) compared to patients who underwent clipping. Patients aged 80 years or older undergoing coiling also had lower morbidity (9.8% versus 33.5%; P <0.0001) and mortality (2.4% versus 21.4%; P <0.0001) when compared to patients who have undergone clipping. Conclusions— Patients treated with endovascular coiling have significantly less morbidity and mortality than those treated with surgical clipping, and these differences become more pronounced with age.

Although more prevalent in males in the 6th and 7th decade of life, spinal dural arteriovenous fistulas (SDAVFs) are an uncommon cause of progressive myelopathy. Magnetic resonance imaging and more recently Gd bolus MR angiography have been used to diagnose, radiographically define, and preprocedurally localize the contributing lumbar artery. Three-dimensional myelographic MR imaging sequences have recently been developed for anatomical evaluation of the spinal canal. The authors describe 3 recent cases in which volumetric myelographic MR imaging with a 3D phase-cycled fast imaging employing steady state acquisition (PC-FIESTA) and a 3D constructive interference steady state (CISS) technique were particularly useful not only for documenting an SDAVF, but also for providing localization when CT angiography, MR imaging, MR angiography, and spinal angiography failed to localize the fistula. In a patient harboring an SDAVF at T-4, surgical exploration was performed based on the constellation of findings on the PC-FIESTA images as well as the fact that the spinal segments leading to T-4 were the only ones that the authors were unable to catheterize. In a second patient, who harbored an SDAVF at T-6, after 2 separate angiograms failed to demonstrate the fistula, careful assessment of the CISS images led the authors to focus a third angiogram on the left T-6 intercostal artery and to perform superselective microcatheterization. In a third patient with an SDAVF originating from the lateral sacral branch, the PC-FIESTA sequence demonstrated the arterialized vein extending into the S-1 foramen, leading to a second angiogram and superselective internal iliac injections. The authors concluded that myelographic MR imaging sequences can be useful not only as an aid to diagnosis but also for localization of an SDAVF in complex cases.

Collateral circulation in intracranial atherosclerosis has never been systematically characterized. We investigated collaterals in a multicenter trial of symptomatic intracranial atherosclerotic disease. Baseline angiography was reviewed for information on collaterals in stenoses of the internal carotid, middle cerebral, vertebral, and basilar arteries. A battery of angiographic scales was utilized to evaluate lesion site, arterial patency, antegrade flow, downstream territorial perfusion, and collateral circulation, blinded to all other data. Collateral circulation was adequately available for analysis in 287/569 (50%) subjects with proximal arterial stenoses ranging from 50% to 99%. Extent of collaterals was absent or none in 69%, slow or minimal in 10%, more rapid, yet incomplete perfusion of territory in 7%, complete but delayed perfusion in 11%, and rapid, complete collateral perfusion in 4%. Extent of collateral flow correlated with percentage of stenosis ( P < 0.0001), with more severe stenoses exhibiting greater compensation via collaterals. Overall, collateral grade increased with diminished antegrade flow across the lesion (thrombolysis in myocardial ischemia) and resultant downstream perfusion (thrombolysis in cerebral infarction) (both P<0.001). Our findings provide the initial detailed description of collaterals across a variety of stenoses, suggesting that collateral perfusion is a pivotal component in pathophysiology of intracranial atherosclerosis and implicating the need for further evaluation in ongoing studies.

Background and Purpose— We sought to determine the vascular risk factors and demographic features associated with the severity and location of intracranial stenosis. Methods— Data on patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial were used for the analyses. Demographic features and vascular risk factors were compared in patients with moderate stenosis (n=336) versus severe stenosis (n=225) and according to the location of intracranial stenosis (middle cerebral, internal carotid, basilar, or vertebral artery). Results— History of a lipid disorder (77% in severe vs 67% in moderate, P =0.01), metabolic syndrome (63% in severe vs 53% in moderate, P =0.05), and diabetes (43% in severe vs 35% in moderate, P =0.04) were more common in patients with severe intracranial stenosis by univariate analyses. A history of a lipid disorder was independently associated with severe stenosis (odds ratio=1.62; 95% CI, 1.09 to 2.42; P =0.02). The distribution of stenosis location differed among age groups ( P =0.0015), sexes ( P =0.0001), races ( P =0.0243), qualifying events ( P =0.0156), diabetes ( P =0.0030), coronary artery disease ( P =0.0030), and hyperlipidemia ( P =0.054). Patients with basilar artery stenoses were older and more likely to have hyperlipidemia. Patients with middle cerebral artery stenoses were more likely to be women and black. Patients with internal carotid artery stenoses were more likely to have diabetes. Patients with vertebral artery stenoses were more likely to have coronary artery disease. Conclusions— History of a lipid disorder had the strongest association with severity of intracranial stenosis and should be the target of prevention therapies. Different locations of intracranial stenoses are associated with different vascular risk factors and demographic features, suggesting that there may be a difference in the underlying pathophysiology of stenoses among the intracranial arteries.

Intracranial aneurysms in the pediatric population are relatively rare entities. Immunocompromised patients (often from HIV/AIDS or pharmacological immunosuppression) represent a significant fraction of children with cerebral aneurysms. One proposed mechanism of aneurysm formation in these patients is from direct infection of the affected arteries. In this study, the authors report on a case of a 14-year-old girl with common variable immunodeficiency with T-cell dysfunction and a CSF polymerase chain reaction test positive for varicella-zoster virus who underwent evaluation for carotid and basilar artery fusiform aneurysms.