John P. Weaver

Stent-Assisted Reconstructive Endovascular Repair of Cranial Fusiform Atherosclerotic and Dissecting Aneurysms Long-Term Clinical and Angiographic Follow-Up

Background and Purpose— The purpose of this study was to investigate the periprocedural morbidity, mortality, and long-term clinical and angiographic follow-up using stent-assisted coiling and stenting alone for treatment of cranial fusiform dissecting and atherosclerotic aneurysms. Methods— The Institutional Review Board approved the study. A retrospective analysis was performed of 30 fusiform dissecting and atherosclerotic aneurysms treated in 28 patients (20 females; mean age, 52.6 years). Eleven aneurysms (37%) were located in the posterior circulation. Twenty-one (70%) originated from arterial dissection and 4 aneurysms (13%) presented with subarachnoid bleeding. Twenty-four (80%) aneurysms were treated with stents and coils, whereas 6 (20%) were treated with stents alone. Results— Immediate postprocedural angiograms in 24 aneurysms treated with stent-assisted coiling showed complete occlusion in 12 and subtotal occlusion in 11 aneurysms, whereas no occlusion was seen in one aneurysm and in all 6 aneurysms treated with stents alone. A clinical improvement or stable outcome was achieved in 25 patients (89%). The 2 cases of permanent morbidity included a patient with a finger dysesthesia associated with a perforator stroke and another patient with hemiparesis and aphasia due to a delayed in-stent thrombosis. One patient died after treatment of a giant vertebrobasilar junction aneurysm. Angiographic follow-up was available in 23 of the 27 surviving patients (85%) at a mean of 16.2 months (range, 1 to 108 months). Recanalization in 4 patients (17%) at 3, 5, 24, and 36 months required retreatment in 3. In-stent stenosis of ≤50% was found in 3 patients. Conclusion— Stent-assisted coil embolization is an attractive option for ruptured and nonruptured fusiform aneurysms with stable long-term outcome. However, recanalization observed up to 3 years after the initial obliteration emphasizes the need for long-term follow-up angiography.

Mechanical Characterization of Thromboemboli in Acute Ischemic Stroke and Laboratory Embolus Analogs

BACKGROUND AND PURPOSE: Mechanical behavior of the thromboembolus is one of the key factors that determine the efficacy of thrombectomy devices for revascularization in AIS. We characterized the mechanical properties and composition of thromboemboli from clinical cases and compared them with commonly used EAs. MATERIALS AND METHODS: Thromboemboli were obtained from patients with AIS by using aspiration devices and from carotid atherosclerotic plaques harvested during endarterectomy. In the laboratory, common EAs were created by varying blood donor species (human, porcine, and bovine), thrombin concentration, and presence of barium sulfate. Stiffness and elasticity of the specimens were measured with DMA. Scanning electron microscopy and histology were used to investigate the ultrastructure and composition of all specimens. RESULTS: Red thromboemboli from patients composed mainly of fibrin and erythrocytes were much softer than the calcified and cholesterol-rich material. Of the EAs created in the laboratory, those made from bovine blood presented the highest stiffness that was independent of thrombin concentration. Addition of thrombin increased the stiffness and elasticity of human and porcine EAs (P < .05). The presence of barium sulfate significantly reduced the elasticity of all EAs (P < .05). CONCLUSIONS: Endovascular device testing and development requires realistic EAs. The stiffness and elasticity of the cerebral thromboemboli analyzed in this study were closely matched by recalcified porcine EAs and thrombin-induced human EAs. Stiffness of the thrombus extracted from carotid endarterectomy specimens was similar with that of the thrombin-induced bovine and porcine EAs.

Subarachnoid hemorrhage: an update of pathogenesis, diagnosis and management

Subarachnoid hemorrhage (SAH) remains a devastating neurological disorder, which most commonly develops after rupture of an intracranial aneurysm. Advances have occurred in the areas of epidemiology, diagnostic imaging, medical management and surgical intervention, related to aneurysmal SAH. Interested physicians must become aware of these and other advances to diagnose and manage this potentially lethal disorder more effectively. This review provides information about the pathogenesis and complications of aneurysmal SAH and an update of new and evolving treatment modalities to provide an in-depth overview for the clinician and researcher involved in this rapidly evolving field.

Myeloperoxidase in Human Intracranial Aneurysms Preliminary Evidence

Background and Purpose— Noninvasive imaging identifying a predictive biomarker of the bleeding risk of unruptured intracranial aneurysms (UIAs) is needed. We investigated a potential biomarker of UIA instability, myeloperoxidase, in human aneurysm tissue. Methods— Human brain aneurysms were harvested after clipping and were histologically and biochemically evaluated for the presence of myeloperoxidase. Of the tissue collected, 3 were from ruptured aneurysms and 20 were from UIAs. For each UIA, its 5-year aneurysm rupture risk was determined using the Population, Hypertension, Age, Size of Aneurysm, Earlier Subarachnoid Hemorrhage From Another Aneurysm and Site of Aneurysm (PHASES) model. Results— All ruptured aneurysms were myeloperoxidase positive. Of the UIAs, half were myeloperoxidase positive. The median 5-year aneurysm rupture risk was higher for myeloperoxidase-positive UIA (2.28%) than myeloperoxidase-negative UIA (0.69%), and the distributions were statistically different (P<0.005, Wilcoxon–Mann–Whitney test). The likelihood for myeloperoxidase-positive UIA was significantly associated (P=0.031) with aneurysm rupture risk (odds ratio, 4.79; 95% confidence limits, 1.15–19.96). Conclusions— Myeloperoxidase is associated with PHASES estimated risk of aneurysm rupture and may potentially be used as an imaging biomarker of aneurysm instability.

Grading of Regional Apposition after Flow-Diverter Treatment (GRAFT): a comparative evaluation of VasoCT and intravascular OCT

Background Poor vessel wall apposition of flow diverter (FD) stents poses risks for stroke-related complications when treating intracranial aneurysms, necessitating long-term surveillance imaging. To facilitate quantitative evaluation of deployed devices, a novel algorithm is presented that generates intuitive two-dimensional representations of wall apposition from either high-resolution contrast-enhanced cone-beam CT (VasoCT) or intravascular optical coherence tomography (OCT) images. Methods VasoCT and OCT images were obtained after FD implant (n=8 aneurysms) in an experimental sidewall aneurysm model in canines. Surface models of the vessel wall and FD device were extracted, and the distance between them was presented on a two-dimensional flattened map. Maps and cross-sections at potential locations of malapposition detected on VasoCT-based maps were compared. The performance of OCT-based apposition detection was evaluated on manually labeled cross-sections using logistic regression against a thresholded (≥0.25 mm) apposition measure. Results VasoCT and OCT acquisitions yielded similar Grading of Regional Apposition after Flow-Diverter Treatment (GRAFT) apposition maps. GRAFT maps from VasoCT highlighted 16 potential locations of malapposition, of which two were found to represent malapposed device struts. Logistic regression showed that OCT could detect malapposition with a sensitivity of 98% and a specificity of 81%. Conclusions GRAFT delivered quantitative and visually convenient representations of potential FD malapposition and occasional acute thrombus formation. A powerful combination for future neuroendovascular applications is foreseen with the superior resolution delivered by intravascular OCT.

Dantrolene for cerebral vasospasm after subarachnoid haemorrhage: a randomised double blind placebo-controlled safety trial

Background Dantrolene is neuroprotective in animal models and may attenuate cerebral vasospasm (cVSP) in human aneurysmal subarachnoid haemorrhage (aSAH). We evaluated safety, feasibility and tolerability of intravenous dantrolene (IV-D) in patients with aSAH. Methods In this single-centre, randomised, double blind, placebo-controlled trial, 31 patients with aSAH were randomised to IV-D 1.25 mg every 6 h for 7 days (n=16) or equiosmolar free water/5% mannitol (placebo; n=15). Primary safety end points were incidence of hyponatraemia (sNa≤132 mmol/L) and liver toxicity (proportion of patients alanine transaminase, aspartate aminotransferase and AlkPhos >5× upper-limit-of-normal). Secondary end points included tolerability, systemic hypotension and intracranial hypertension. Efficacy was explored for clinical/radiological cVSP, delayed cerebral ischaemia (DCI), and 3-month functional outcomes. Quantitative analyses of angiograms and daily transcranial Doppler (TCD) were performed. Results Between IV-D versus placebo, no differences were observed in the primary outcomes (hyponatremia 44% vs 67% (p=0.29); liver toxicity 6% vs 0% (p=1.0)). Three patients in the IV-D versus two in the placebo group had severe adverse events possibly attributable to infusion and reached stop criteria: one IV-D patient developed liver toxicity; two patients in each group developed brain oedema requiring osmotherapy. The majority of adverse events were not related to infusion (17 vs 5 (RR 2.2; 95% CI 0.7 to 6.7; p=0.16) in IV-D vs placebo). No differences in any categorical cVSP outcomes, DCI, 3-month outcomes or quantitative angiogram and TCD analyses were seen in this small safety trial not powered to detect efficacy. Conclusions In this small trial, IV-D after aSAH was feasible, tolerable and safe. Trial registration number http://clinicaltrials.gov NCT01024972.

Monotherapy with stenting in subarachnoid hemorrhage (SAH) after middle cerebral artery dissection

Isolated middle cerebral artery dissection is a rare clinical entity, with descriptions limited to a few case reports and case series. Symptomatic dissection in the anterior circulation can present as an ischemic stroke in a young population; however, it is rarely associated with subarachnoid hemorrhage. We describe a young patient who presented with acute headache from a subarachnoid hemorrhage that was ultimately determined to be due to a vascular dissection in the middle cerebral artery. The initial angiogram showed vascular irregularities in this area with stenosis. Repeat imaging 4 days after presentation identified a pseudoaneurysm proximal to the stenosis. The patient was successfully treated with a self-expanding nitinol stent and followed up with serial angiography during postoperative recovery in the hospital; additional angiograms were performed approximately 1 and 6 months after treatment. Serial angiograms demonstrated incremental healing of the dissection. The patient was discharged and remains neurologically intact at the 6-month follow-up.

Health impact and economic analysis of NGO-supported neurosurgery in Bolivia

OBJECT Bolivia, one of the poorest countries in the world, ranks 108th on the 2013 Human Development Index. With approximately 1 neurosurgeon per 200,000 people, access to neurosurgery in Bolivia is a growing health concern. Furthermore, neurosurgery in nonindustrialized countries has been considered both cost-prohibitive and lacking in outcomes evaluation. A non-governmental organization (NGO) supports spinal procedures in Bolivia (Solidarity Bridge), and the authors sought to determine its impact and cost-effectiveness. METHODS In a retrospective review of prospectively collected data, 19 patients were identified prior to spinal instrumentation and followed over 12 months. For inclusion, patients required interviewing prior to surgery and during at least 2 follow-up visits. All causes of spinal pathology were included. Sixteen patients met inclusion criteria and were therefore part of the analysis. Outcomes measured included assessment of activities of daily living, pain, ambulation, return to work/school, and satisfaction. Cost-effectiveness was determined by cost-utility analysis. Utilities were derived using the Health Utilities Index. Complications were incorporated into an expected value decision tree. RESULTS Median (± SD) preoperative satisfaction was 2.0 ± 0.3 (on a scale of 0-10), while 6-month postoperative satisfaction was 7 ± 1.4 (p < 0.0001). Ambulation, pain, and emotional disability data suggested marked improvement (56%, 69%, and 63%, respectively; p = 0.035, 0.003, and 0.006). Total discounted incremental quality-adjusted life year (QALY) gain was 0.771. The total discounted cost equaled

High-resolution Imaging of Myeloperoxidase Activity Sensors in Human Cerebrovascular Disease

9036 (95% CI

Modeling Unstable Brain Aneurysms: MR Molecular Imaging of Myeloperoxidase in Vascular Wall and Correlation With Human Pathology

8561-