Showing papers by "Cameron G. McDougall published in 2016"

Evolution of treatment and a detailed analysis of occlusion, recurrence, and clinical outcomes in an endovascular library of 260 dural arteriovenous fistulas.

Abstract: OBJECTIVE Many small series and technical reports chronicle the evolution of endovascular techniques for cranial dural arteriovenous fistulas (dAVFs) over the past 3 decades, but reports of large patient series are lacking. The authors provide a thorough analysis of clinical and angiographic outcomes across a large patient cohort. METHODS The authors reviewed their endovascular database from January 1996 to September 2015 to identify patients harboring cranial dAVFs who were treated initially with endovascular approaches. They extracted demographic, presentation, angiographic, detailed treatment, and long-term follow-up data, and they evaluated natural history, initial angiographic occlusion, complications, recurrence, and symptomatic resolution rates. RESULTS Across a cohort of 251 patients with 260 distinct dAVFs, the overall initial angiographic occlusion rate was 70%; recurrence or occult residual lesions were seen on subsequent angiography in 3% of cases. The overall complication rate was 8%, with permanent neurological complications occurring in 3% of cases. Among 102 patients with dAVFs without cortical venous reflux, rates of resolution/improvement of pulsatile tinnitus and ocular symptoms were 79% and 78%, respectively. Following the introduction of Onyx during the latter half of the study period, the number of treated dAVFs doubled; the initial angiographic occlusion rate increased significantly from 60% before the use of Onyx to 76% after (p = 0.01). In addition, during the latter period compared with the pre-Onyx period, the rate of dAVFs obliterated via a transarterial-only approach was significantly greater (43% vs 23%, p = 0.002), as was the number of dAVFs obliterated via a single arterial pedicle (29% vs 11%, p = 0.002). CONCLUSIONS Overall, in the Onyx era, the rate of initial angiographic occlusion was approximately 80%, as was the rate of meaningful clinical improvement in tinnitus and/or ocular symptoms after initial endovascular treatment of cranial dAVFs.

Pipeline Embolization Device with or without Adjunctive Coil Embolization: Analysis of Complications from the IntrePED Registry

Abstract: Flow diversion to treat cerebral aneurysms has revolutionized neurointerventional surgery. Because the addition of coils potentially increases the time and complexity of endovascular procedures, we sought to determine whether adjunctive coil use is associated with an increase in complications. Patients in the International Retrospective Study of Pipeline Embolization Device registry were divided into those treated with the Pipeline Embolization Device alone (n = 689 patients; n = 797 aneurysms; mean aneurysm size, 10.3 ± 7.6 mm) versus those treated with the Pipeline Embolization Device and concurrent coil embolization (n = 104 patients; n = 109 aneurysms; mean aneurysm size, 13.6 ± 7.8 mm). Patient demographics and aneurysm characteristics were examined. Rates of neurologic morbidity and mortality were compared between groups. The Pipeline Embolization Device with versus without coiling required a significantly longer procedure time (135.8 ± 63.9 versus 96.7 ± 46.2 min; P < .0001) and resulted in higher neurological morbidity (12.5% versus 7.8%; P = .13). These data suggest that either strategy represents an acceptable risk profile in the treatment of complex cerebral aneurysms and warrants further investigation.

Re-treatment rates after treatment with the Pipeline Embolization Device alone versus Pipeline and coil embolization of cerebral aneurysms: a single-center experience.

Abstract: OBJECT The optimal strategy for use of the Pipeline Embolization Device (PED, ev3 Neurovascular) has not been clearly defined. The authors examined re-treatment rates after treatment with PED alone versus PED and adjunctive coil embolization (PED/coil). METHODS The authors retrospectively examined cerebral aneurysms treated with the PED from May 2011 to March 2014. Overall, 133 patients (25 men, 108 women; mean age 60.4 years, range 23-85 years) were treated for 140 aneurysms (mean size 11.8 ± 8.3 mm) requiring 224 PEDs (mean 1.7 PEDs per patient). Sixty-eight patients (13 men, 55 women) were treated with PED alone for 73 aneurysms (mean size 10.6 ± 9.2 mm) and 65 patients (12 men, 53 women) were treated with PED/coil for 67 aneurysms (mean size 12.8 ± 7.4 mm). RESULTS Eight aneurysms in 8 patients were re-treated in the PED-alone cohort versus only 1 aneurysm in 1 patient in the PED/coil cohort for re-treatment rates of 11.8% (8/68) and 1.5% (1/65), respectively (p = 0.03). Two patients in the PED-alone cohort were re-treated due to PED contraction, while the other 6 were re-treated for persistent filling of the aneurysms. The PED/coil patient experienced continued filling of a vertebrobasilar artery aneurysm. No aneurysms in either group ruptured after treatment. CONCLUSIONS Adjunctive coil embolization during flow diversion with the PED resulted in a significantly lower re-treatment rate compared with PED alone, suggesting an added benefit with adjunctive coil embolization. This result may provide the basis for future evaluation with randomized, controlled trials.

Posterior Inferior Cerebellar Artery Patency after Flow-Diverting Stent Treatment.

Abstract: BACKGROUND AND PURPOSE: The rate of PICA occlusion after flow-diverting stent placement for vertebral and vertebrobasilar artery aneurysms is not known. The purpose of this study is to determine the medium-term rate of PICA patency and risk factors for occlusion after such aneurysm treatment. MATERIALS AND METHODS: Patients were identified who had vertebral or vertebrobasilar artery aneurysms and who were treated by placing a flow-diverting stent across the PICA ostium. Demographic and procedural factors associated with stent placement were recorded. Patency of the PICA was evaluated immediately after stent placement and on follow-up angiography. RESULTS: Thirteen patients with vertebral or vertebrobasilar artery aneurysms were treated in the study period, of whom 4 presented with subarachnoid hemorrhage. The average number of devices that spanned the PICA ostium was 1.77 (range, 1–3), with no immediate PICA occlusions. There were no postoperative strokes in the treated PICA territory, although there was 1 contralateral PICA-territory stroke of unclear etiology without clinical sequelae. In 11 patients with follow-up angiography at a mean of 10.6 months (range, 0.67–27.9 months), the PICA patency rate remained 100%. CONCLUSIONS: Flow-diverting stent placement across the PICA ostium in the treatment of vertebral and vertebrobasilar artery aneurysms may not result in immediate or midterm PICA occlusion.

The myth of restenosis after carotid angioplasty and stenting

Abstract: Background and purpose Reported rates of in-stent restenosis after carotid artery stenting (CAS) vary, and restenosis risk factors are poorly understood. We evaluated restenosis rates and risk factors, and compared patients with ‘hostile-neck’ carotids (a history of ipsilateral neck surgery or irradiation) and atherosclerotic lesions. Methods Demographic, clinical, and radiological characteristics of patients undergoing cervical CAS between 1995 and 2010 with at least 1 month of follow-up were reviewed. Patients with substantial (≥50%) radiographic restenosis were compared with those without significant restenosis to identify restenosis risk factors. Results The analysis included 121 patients with 133 stented vessels; 91 (68.4%) lesions were symptomatic. Indications for stent placement included hostile-neck lesions, substantial surgical comorbidities, inclusion in a randomized carotid stenting trial, acute carotid occlusion, tandem stenosis, large pseudoaneurysm, high carotid bifurcation, and contralateral laryngeal nerve palsy. Procedures were technically successful in all but one lesion (99.2%). Perioperative stroke occurred in four cases (3.0%). Mean follow-up was 38 months (range 1–204 months), during which 23 vessels (17.3%) developed restenosis. Hostile-neck carotids (n=57) comprised 42.9% of all vessels treated and were responsible for 15 of 23 restenosis cases, resulting in a significantly higher restenosis rate than that of primary atherosclerotic lesions (26.3% vs 10.5%, p=0.017). By univariate analysis, the presence of calcified plaque was significantly associated with the incidence of in-stent restenosis (p=0.02). Conclusions Restenosis rates after carotid angioplasty and stenting are low. Patients with a history of ipsilateral neck surgery or irradiation are at higher risk for substantial radiographic and symptomatic restenosis.

Pipeline embolization for definitive endoluminal reconstruction of blister-type carotid aneurysms after clip wrapping.

Abstract: Background Ruptured blister aneurysms of the carotid artery are difficult to safely treat. We present a novel strategy of microsurgical clip wrapping of internal carotid artery blister aneurysms in the setting of acute rupture, followed by delayed placement of a pipeline embolization device for definitive treatment. Clinical presentation We present two cases of ruptured blister aneurysms of the internal carotid artery treated by wrapping of the diseased segment of the vessel, followed by delayed deployment of a flow diverting stent once the patient was out of the vasospasm window but during the same hospitalization. Results Clip wrapping followed by flow diversion in a delayed fashion results in anatomic remodeling of the diseased artery without a high morbidity. Conclusions A combined approach of acute surgical stabilization followed by definitive endovascular reconstruction may reduce hemorrhagic complications while improving long term treatment durability.

The efficacy and risks of preoperative embolization of spinal tumors

Abstract: Background The goal of preoperative embolization of spinal tumors is to improve surgical outcomes by diminishing the vascular supply to the tumor to reduce intraoperative blood loss and operative time. Objective To report our institutional experience with spinal tumor embolization and review the present literature. Methods Clinical records from January 1, 2001 to December 31, 2012 were reviewed and analyzed. Angiograms were used to calculate the percentage reduction in tumor vascularity, and relevant clinical and operative data were collected and analyzed. Results Thirty-seven patients underwent preoperative spinal tumor embolization (24 metastatic and 13 primary lesions) and were included in the study. One complication resulted in transient lower extremity weakness and was attributed to post-embolization swelling, which fully resolved after surgical resection. The transient neurological complication rate was 1/37 (3%) and the permanent rate was 0/37 (0%). The average surgical estimated blood loss (EBL) was 1946 mL (100–7000 mL) and the average operative time was 330 min (range 164–841 min). After embolization, tumor blush was reduced by 83% on average. Average pre- and postoperative modified Rankin Scale scores were 2.10 and 1.36, respectively (p=0.03). Cases in which tumor blush was decreased by ≥90% (classes 1 or 2) after embolization had significantly less operative blood loss than those cases in which Conclusions Spinal tumor embolization is a safe procedure, is associated with few complications, and may improve surgical outcomes by limiting intraoperative blood loss and reducing operative time.

The road less traveled: transarterial embolization of dural arteriovenous fistulas via the ascending pharyngeal artery

Abstract: Background With the introduction of Onyx, transarterial embolization has become the most common endovascular approach to treating dural arteriovenous fistulas (dAVFs), often via the middle meningeal or occipital arteries. The ascending pharyngeal artery (APA) is a less frequently explored transarterial route because of its small caliber, potential anastomoses to the internal carotid and vertebral arteries, and vital supply to lower cranial nerves. Objective To review our institutional experience and highlight the prevalence of APA supply to dAVFs and cases where it is a safe and effective pedicle for embolization. Methods We reviewed our endovascular database (January 1, 1996 to March 1, 2016) for cranial dAVFs, evaluating dAVF characteristics and embolization results for those treated transarterially via the APA. Results Of 267 endovascularly treated dAVFs, 68 had APA supply (25%). Of these 68 dAVFs, embolization was carried out via this pedicle in 8 (12%) and 7 were ultimately occluded. No complications, including post-treatment cranial neuropathies or radiographic evidence of non-target embolization, were found. For 5 dAVFs, the APA was selected as the initial pedicle for embolization (two marginal sinus, one distal sigmoid, one cavernous, one tentorial). In four of these five cases, dAVF occlusion was achieved via the initial APA feeding artery pedicle. In one case, near-complete, stagnant occlusion was achieved after APA embolization; complete occlusion was achieved after adjunctive embolization of a single additional middle meningeal artery pedicle. In three other cases of complex transverse/sigmoid dAVFs, the APA was used after multiple attempts via middle meningeal and occipital artery pedicles. Occlusion was not achieved transarterially; two of these three dAVFs were ultimately occluded transvenously. Conclusions In rare, select cases, the APA is an excellent route for transarterial embolization of cranial dAVFs.

Computational Modeling of Venous Sinus Stenosis in Idiopathic Intracranial Hypertension

Abstract: BACKGROUND AND PURPOSE: Idiopathic intracranial hypertension has been associated with dural venous sinus stenosis in some patients, but the hemodynamic environment of the dural venous sinuses has not been quantitatively described. Here, we present the first such computational fluid dynamics model by using patient-specific blood pressure measurements. MATERIALS AND METHODS: Six patients with idiopathic intracranial hypertension and at least 1 stenosis or atresia at the transverse/sigmoid sinus junction underwent MR venography followed by cerebral venography and manometry throughout the dural venous sinuses. Patient-specific computational fluid dynamics models were created by using MR venography anatomy, with venous pressure measurements as boundary conditions. Blood flow and wall shear stress were calculated for each patient. RESULTS: Computational models of the dural venous sinuses were successfully reconstructed in all 6 patients with patient-specific boundary conditions. Three patients demonstrated a pathologic pressure gradient (≥8 mm Hg) across 4 dural venous sinus stenoses. Small sample size precludes statistical comparisons, but average overall flow throughout the dural venous sinuses of patients with pathologic pressure gradients was higher than in those without them (1041.00 ± 506.52 mL/min versus 358.00 ± 190.95 mL/min). Wall shear stress was also higher across stenoses in patients with pathologic pressure gradients (37.66 ± 48.39 Pa versus 7.02 ± 13.60 Pa). CONCLUSIONS: The hemodynamic environment of the dural venous sinuses can be computationally modeled by using patient-specific anatomy and physiologic measurements in patients with idiopathic intracranial hypertension. There was substantially higher blood flow and wall shear stress in patients with pathologic pressure gradients.

Intraprocedural abciximab bolus versus pretreatment oral dual antiplatelet medication for endovascular stenting of unruptured intracranial aneurysms.

Abstract: Background Standard pretreatment with dual antiplatelet medication (DAPM) was compared with a standalone intraprocedural abciximab bolus for the prevention of thromboembolic and hemorrhagic events during endovascular stenting of unruptured intracranial aneurysms. Materials and methods We treated 94 patients with 99 aneurysms with intracranial stenting (with or without coiling). Patients were either pretreated with DAPM daily for ≥3 days before stenting (pretreatment group) or received an abciximab bolus during or immediately after stent placement followed by postoperative DAPM (abciximab group), at the treating physician9s discretion. Twenty patients underwent immediate postoperative MRI. Demographic, clinical, and radiological information and periprocedural complications were recorded. Results There were 52 procedures in the pretreatment group and 47 in the abciximab group. More flow-diverting stents were placed in the pretreatment group than in the abciximab group (45 vs 23, p 0.99 and p=0.12, respectively). There were no intracranial hemorrhages. In patients with postoperative MRI, there was no difference in the presence of diffusion-restricted lesions between groups (p=0.20). Multivariate analysis of a composite of any complication did not show significant associations with aneurysm or patient variables in either group. Conclusions Standalone intraprocedural abciximab bolus was not associated with an increased rate of complications compared with pretreatment with DAPM for unruptured intracranial aneurysm stenting.

Geographic differences in endovascular treatment and retreatment of cerebral aneurysms

Abstract: BACKGROUND AND PURPOSE: Comparing outcomes between endovascular aneurysm coiling trials can be difficult because of heterogeneity in patients and end points. We sought to understand the impact of geography on aneurysm retreatment in patients enrolled in the Matrix and Platinum Science Trial. MATERIALS AND METHODS: Post hoc analysis was performed on data from the Matrix and Platinum Science trial. Patients were stratified as either North American or international. Baseline patient demographics, comorbidities, aneurysm characteristics, procedural complications, and clinical and angiographic outcomes were compared. RESULTS: We evaluated 407 patients from 28 North American sites and 219 patients from 15 international sites. Patient demographics differed significantly between North American and international sites. Aneurysms were well occluded postprocedure more often at international than North American sites ( P < .001). Stents were used significantly more often at North American sites (32.7% [133 of 407]) compared with international sites (10.0% [22 of 219]; P < .001). At 455 days, there was no difference in the proportion of patients alive and free of disability ( P = .56) or with residual aneurysm filling ( P = .10). Ruptured aneurysms were significantly more likely to have been retreated at North American sites within the first year ( P < .001) and at 2 years ( P < .001). Among all patients for whom the treating physician believed there to be Raymond 3 aneurysm filling at follow-up, absolute rates of retreatment at international and North American sites were similar by 2-year follow-up. CONCLUSIONS: Data from the Matrix and Platinum Science Trial demonstrate that aneurysm retreatment occurs with different frequency and at different times in different regions of the world. This trend has critical value when interpreting trials reporting short-term outcomes, especially when judgment-based metrics such as retreatment are primary end points that may or may not take place within the defined study follow-up period. Though these variations can be controlled for and balanced within a given randomized trial, such differences in practice patterns must be accounted for in any attempt to compare outcomes between different trials. Despite these differences, endovascular-treated intracranial aneurysms around the world have similar clinical outcomes.

Middle meningeal arteriovenous fistulas: A rare and potentially high-risk dural arteriovenous fistula.

Abstract: Background: Middle meningeal arteriovenous fistulas (MMAVFs) are rare lesions with a poorly established natural history. We report our experience with patients with MMAVFs who presented with intracranial hemorrhage.

Development of syndrome of inappropriate antidiuretic hormone secretion (SIADH) after Onyx embolisation of a cavernous carotid fistula.

Abstract: Patients with cavernous carotid fistulas (CCFs) can present with pituitary hypoperfusion and hypopituitarism; however, there are no previous reports of pituitary or hormonal abnormalities developing after CCF embolisation in an asymptomatic patient. We describe a patient with no hormonal abnormalities who developed syndrome of inappropriate antidiuretic hormone (SIADH) secretion after CCF embolisation. The patient had bilateral indirect CCFs, which were completely embolised via a transvenous approach, and was neurologically stable postoperatively and discharged. In the subsequent 2 weeks the patient was readmitted twice for acute hyponatraemia and a tonic-clonic seizure. Laboratory studies revealed severe SIADH. Clinical status and sodium levels improved after treatment. One year later the patient was weaned off all medications and remained neurologically stable. SIADH may be a delayed phenomenon after CCF embolisation. Given the proximity of embolised vessels to the pituitary9s vascular supply, CCF treatment may result in flow disturbance, ischaemia and hormonal abnormalities.

Novel cases of amyotrophic lateral sclerosis after treatment of cerebral arteriovenous malformationss.

Abstract: Previous case studies reported nine patients with cerebral arteriovenous malformations (AVM) who developed amyotrophic lateral sclerosis (ALS) after AVM embolisation. Here, we describe three novel cases of ALS which developed 13-34 years after treatment, including embolisation, of cerebral AVM. This study provides further arguments supporting the thesis that embolisation of cerebral AVM might influence the risk of later ALS development.

355 Endovascular Management of Cervical Carotid and Vertebral Artery Dissection: Indications, Techniques, and Outcomes From a 20-Year Experience.

Abstract: Endovascular intervention for cervical carotid artery and vertebral artery dissections (CAD and VAD) may be indicated in specific circumstances. We reviewed a prospectively maintained database from January 1996 to January 2016 of extracranial dissections undergoing endovascular intervention. There were 116 patients, including 93 in the CAD cohort and 23 in the VAD cohort, with a mean age of 44.9 years (range 5-76) and mean postprocedure follow-up of 41.6 months (range 1-146). Interventions included stent placement (n = 104), coil occlusion of parent artery (n = 11), or stenting with contralateral vessel coil occlusion (n = 1). The 2 cohorts were well matched in age, sex, dissection etiology, and admission/follow-up modified Rankin Scale (mRS) (P = .362, .371, .175, .355, and .835, respectively). The CAD cohort was significantly more likely to undergo stent placement or have failed medical therapy (P 3) in the CAD cohort (P = .014). Six (9.0%) patients of spontaneous etiology also reported recent chiropractic manipulation. The permanent morbidity/mortality rate was 3.4%, including 2 deaths, with a stroke rate of only 0.9% over 4825 patient-years. At last follow-up, 31 of 93 (33.3%) CAD patients and 10 of 23 (43.5%) VAD patients disabled prior to intervention were nondisabled at last follow-up; no patients in either cohort were worsened. In a long-term experience, endovascular management of CAD and VAD is highly effective in specific indications, with an acceptable complication profile. CAD requiring intervention is more likely than VAD to have failed medical therapy, present with thromboembolic events and pseudoaneurysms, and undergo primary stent placement, whereas VAD is more likely to undergo treatment for traumatic occlusions with recanalization.

Editorial: Discipline and training.

Abstract: accompaNyiNg article DOI: 10.3171/2014.11.JNS141030. iNclude wheN citiNg Published online August 14, 2015; DOI: 10.3171/2015.1.JNS142795. Physicians from several different disciplines currently perform endovascular treatment of cerebral aneurysms, i.e., neurosurgery, radiology, and neurology. Early studies using administrative databases showed that better outcomes could be achieved with endovascular techniques compared with surgical clipping for both ruptured and unruptured aneurysms, and that higher volume centers had better outcomes as compared to lower volume centers.5,8 In 2002, the International Subarachnoid Aneurysm Trial (ISAT) demonstrated the relative benefit of endovascular coil occlusion of ruptured aneurysms compared with surgical clipping.12 Since that time, endovascular treatment has become the preferred approach at most centers throughout the world. Presently, neurosurgeons and radiologists comprise the majority of physicians treating cerebral aneurysms, but neurologists are now training in greater numbers and comprise a growing segment of neurointerventional specialists. Does the training background of the operating physician matter? Fennell et al. suggest that it does.2 Using the University HealthSystem Consortium (UHC) database, the authors examined the rate of complications incurred in the treatment of ruptured and unruptured cerebral aneurysms. These authors suggest that neurosurgeons achieve better clinical outcomes, especially when compared with neurologists, and to a lesser degree, compared with radiologists. These are strong assertions. Like any accusation, it is important to have substantial evidence to support the claim. If the article had meaningful evidence, then it could potentially represent a serious indictment. Unfortunately, the UHC database does not provide conclusive information, and therefore the assertions in this paper are weak. As Fennell et al. dutifully note, specific deficiencies of this study include: 1) the UHC database is self-reporting (i.e., not objective); 2) the UHC database does not readily provide individual patient characteristics or demographics under its current reporting structure; 3) there could be significant differences in patient profiles with potentially disparate impact on outcomes due to patient selection; and 4) differences could also be attributed to the overall cerebrovascular volume of the treating center as well as the treating physician.2 Therefore, it is not possible using the UHC database to know whether a complication occurred before, during, or after treatment. In addition, it is also not possible to compare preoperative morbidity of patients within the 3 physician groups, and this single factor alone could represent an impactful and confounding factor in outcomes and results. Other “potential” conclusions that could just as easily be reached from the data set include the possibility that neurosurgery physicians and hospitals are “underreporting” their true complication rates or that neurology and radiology physicians are treating more difficult and complex patients with aneurysms at centers where open cerebrovascular surgery is not readily available, and that neurosurgeons are simply treating less difficult and less complex cases, and having more complex cases undergo surgical clip placement. Each of these arguments could lead to incorrect assertions, as exemplified by the article by Fennell et al., because the data upon which it is referenced is insufficient to draw a meaningful conclusion. Comorbidities have long confounded studies to assess treatment effect, particularly for ruptured aneurysms. Simply selecting out patients with Hunt and Hess Grade I– III subarachnoid hemorrhage for endovascular treatment, while excluding patients with Hunt and Hess Grades IV and V, will influence good outcomes favoring specialists and hospitals. Nevertheless, all physicians should strive to editorial Discipline and training