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Leonardo Rangel-Castilla, Hakeem J. Shakir and Adnan H. Siddiqui

The ability to traverse an anatomically challenging and complex arch is paramount to the success of any neuroendovascular procedure. With age, the aortic arch becomes elongated, calcified, and less compliant. The authors present the initial experience with a multiple parallel guidewire system (ZigiWire Mode 3) for catheterization through a complex tortuous aortic arch to access extracranial vessels. The ZigiWire is an organized guidewire system that uses consecutive delivery of 3 small-diameter (0.014-inch) guidewires that are progressively advanced in parallel to secure support-wire access. The authors have found it useful in situations in which traditional methods for great-vessel access have failed. Moreover, the progressive construction of a large wire from smaller wires prevents “kickback” force from a single larger guidewire, allowing stable distal access. The authors have been able to advance different diagnostic and guide catheters over the ZigiWire. This guidewire has allowed them to successfully complete neuroendovascular procedures in patients who were previously considered unsuitable for the procedure because of tortuous vascular access.

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Leonardo Rangel-Castilla, Hussain Shallwani and Adnan H. Siddiqui

Transvenous embolization (TE) has been increasingly applied for arteriovenous malformation (AVM) treatment. Transient cardiac standstill (TCS) has been described in cerebrovascular surgery but is uncommon for endovascular embolization. The authors present a patient with a ruptured thalamic AVM in whom both techniques were applied simultaneously. Surgery was considered, but the patient refused. Transarterial embolization was performed with an incomplete result. The deep-seated draining vein provided sole access to the AVM. A microcatheter was advanced into the draining vein. Under TCS, achieved with rapid ventricular pacing, complete AVM embolization was obtained. One-year magnetic resonance imaging and cerebral angiography demonstrated no residual AVM.

The video can be found here: https://youtu.be/CAzb9md_xBU.

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Sharon Webb, Parham Yashar, Peter Kan, Adnan H. Siddiqui, L. Nelson Hopkins and Elad I. Levy

Object

The treatment of acute intracranial vertebrobasilar artery occlusion (VBO) has been described but often with poor results. The authors of this study set out to evaluate their institution's outcomes following multimodal treatment of VBO.

Methods

They retrospectively reviewed their endovascular database for all patients treated for acute intracranial VBO between December 2004 and June 2010. Twenty-four patients were identified. Two patients were excluded from evaluation—one because of incomplete medical records and one because the etiology was basilar stenosis and not stroke. Occlusion location, hypercoagulable causes, time to endovascular treatment, time to revascularization, comorbidities, devices used, procedural anticoagulation, and outcomes were analyzed.

Results

Among the 22 eligible study patients, the mean National Institutes of Health Stroke Scale (NIHSS) score at presentation was 15.3. The mean time from presentation to initiation of the endovascular procedure was 4.77 hours. The mean time for recanalization from the start of angiography was 1.63 hours. In 16 patients (73%), revascularization was successful (Thrombolysis in Myocardial Infarction [TIMI] score of 2 or 3). Thirteen (59%) of the 22 patients were discharged to home or a rehabilitation facility. One patient was transferred to a chronic care facility. The overall survival rate was 64%. The average NIHSS score for the 14 surviving patients at discharge was 3.9. At the follow-up (average 14.5 months, range 1–58 months), 10 patients (71%) had achieved good outcomes (modified Rankin Scale [mRS] score ≤ 2) and 4 (29%) had poor outcomes (mRS Score 3–6).

Conclusions

Published case series have historically shown poor outcomes and high mortality rates in association with the treatment of acute VBO, prompting surgeons to be less aggressive in the treatment of this disease than they might be otherwise. Data in this series show that the revascularization of posterior circulation occlusions is feasible and that good outcomes and lower mortality rates with newer endovascular technologies are possible, and thus more prompt and aggressive treatment of this disease may be warranted.

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Mandy J. Binning, Alexander A. Khalessi, Adnan H. Siddiqui, L. Nelson Hopkins and Elad I. Levy

Intracranial arterial dissection is an important cause of stroke in young patients. Treatment options include observation, antiplatelet or anticoagulation regimens, and endovascular stent placement. The authors describe the case of a 14-year-old boy who presented with a symptomatic, posttraumatic dissection extending from the intracranial internal carotid artery to the middle cerebral artery. Images obtained approximately 48 hours after this incident revealed a subacute right frontal lobe infarct, and a CT stroke study (CT angiography and CT perfusion) confirmed the vascular injury and associated decreased perfusion, prompting revascularization with a self-expanding stent. The patient did well clinically after stent placement and showed no evidence of restenosis on follow-up angiography 3 and 6 months later. This report is, to the authors' knowledge, the first description of the use of a stent for a symptomatic intracranial dissection in an adolescent.

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Giuseppe Lanzino and Pietro Ivo D'Urso

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Yiemeng Hoi, Ling Gao, Markus Tremmel, Rocco A. Paluch, Adnan H. Siddiqui, Hui Meng and J Mocco

Object

Pathological extremes in cerebrovascular remodeling may contribute to basilar artery (BA) dolichoectasia and fusiform aneurysm development. Factors regulating cerebrovascular remodeling are poorly understood. To better understand hemodynamic influences on cerebrovascular remodeling, we examined BA remodeling following common carotid artery (CCA) ligation in an animal model.

Methods

Rabbits were subjected to sham surgery (3 animals), unilateral CCA ligation (3 animals), or bilateral CCA ligation (5 animals). Transcranial Doppler ultrasonography and rotational angiography were used to compute BA flow, diameter, wall shear stress (WSS), and a tortuosity index on Days 0, 1, 4, 7, 14, 28, 56, and 84. Basilar artery tissues were stained and analyzed at Day 84. Statistical analysis was performed using orthogonal contrast analysis, repeated measures analysis of variance, or mixed regression analysis of repeated measures. Statistical significance was defined as a probability value < 0.05.

Results

Basilar artery flow and diameter increased significantly after the procedure in both ligation groups, but only the bilateral CCA ligation group demonstrated significant differences between groups. Wall shear stress significantly increased only in animals in the bilateral CCA ligation group and returned to baseline by Day 28, with 52% of WSS correction occurring by Day 7. Only the bilateral CCA ligation group developed significant BA tortuosity, occurring within 7 days postligation. Unlike the animals in the sham and unilateral CCA ligation groups, the animals in the bilateral CCA ligation group had histological staining results showing a substantial internal elastic lamina fragmentation.

Conclusions

Increased BA flow results in adaptive BA remodeling until WSS returns to physiological baseline levels. Morphological changes occur rapidly following flow alteration and do not require chronic insult to affect substantial and significant structural transformation. Additionally, it appears that there exists a flow-increase threshold that, when surpassed, results in significant tortuosity.

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Aneela Darbar, Richard T. Stevens, Adnan H. Siddiqui, James S. McCasland and Charles J. Hodge

Object

The brain shows remarkable capacity for plasticity in response to injury. To maximize the benefits of current neurological treatment and to minimize the impact of injury, the authors examined the ability of commonly administered drugs, dextroamphetamine (D-amphetamine) and phenytoin, to positively or negatively affect the functional recovery of the cerebral cortex following excitotoxic injury.

Methods

Previous work from the same laboratory has demonstrated reorganization of whisker functional responses (WFRs) in the rat barrel cortex after excitotoxic lesions were created with kainic acid (KA). In the present study, WFRs were mapped using intrinsic optical signal imaging before and 9 days after creation of the KA lesions. During the post-lesion survival period, animals were either treated with intraperitoneal D-amphetamine, phenytoin, or saline or received no treatment. Following the survival period, WFRs were again measured and compared with prelesion data.

Results

The findings suggest that KA lesions cause increases in WFR areas when compared with controls. Treatment with D-amphetamine further increased the WFR area (p < 0.05) while phenytoin-treated rats showed decreases in WFR areas. There was also a statistically significant difference (p < 0.05) between the D-amphetamine and phenytoin groups.

Conclusions

These results show that 2 commonly used drugs, D-amphetamine and phenytoin, have opposite effects in the functional recovery/plasticity of injured cerebral cortex. The authors' findings emphasize the complex nature of the cortical response to injury and have implications for understanding the biology of the effects of different medications on eventual functional brain recovery.

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Ashish Sonig, Hussain Shallwani, Bennett R. Levy, Hakeem J. Shakir and Adnan H. Siddiqui

OBJECTIVE

Publication has become a major criterion of success in the competitive academic environment of neurosurgery. This is the first study that has used departmental h index–and e index–based matrices to assess the academic output of neuroendovascular, neurointerventional, and interventional radiology fellowship programs across the continental US.

METHODS

Fellowship program listings were identified from academic and organization websites. Details for 37 programs were available. Bibliometric data for these programs were gathered from the Thomson Reuters Web of Science database. Citations for each publication from the fellowship's parent department were screened, and the h and e indices were calculated from non–open-surgical, central nervous system vascular publications. Variables including “high-productivity” centers, fellowship–comprehensive stroke center affiliation, fellowship accreditation status, neuroendovascular h index, e index (h index supplement), h10 index (publications during the last 10 years), and departmental faculty-based h indices were created and analyzed.

RESULTS

A positive correlation was seen between the neuroendovascular fellowship h index and corresponding h10 index (R = 0.885; p < 0.0001). The mean, median, and highest faculty-based h indices exhibited positive correlations with the neuroendovascular fellowship h index (R = 0.662, p < 0.0001; R = 0.617, p < 0.0001; and R = 0.649, p < 0.0001, respectively). There was no significant difference (p = 0.824) in the median values for the fellowship h index based on comprehensive stroke center affiliation (30 of 37 programs had such affiliations) or accreditation (18 of 37 programs had accreditation) (p = 0.223). Based on the quartile analysis of the fellowship h index, 10 of 37 departments had an neuroendovascular h index of ≥ 54 (“high-productivity” centers); these centers had significantly more faculty (p = 0.013) and a significantly higher mean faculty h index (p = 0.0001).

CONCLUSIONS

The departmental h index and analysis of its publication topics can be used to calculate the h index of an associated subspecialty. The analysis was focused on the neuroendovascular specialty, and this methodology can be extended to other neurosurgical subspecialties. Individual faculty research interest is directly reflected in the research productivity of a department. High-productivity centers had significantly more faculty with significantly higher individual h indices. The current systems for neuroendovascular fellowship program accreditation do not have a meaningful impact on academic productivity.

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Elad I. Levy, Adnan H. Siddiqui, L. Nelson Hopkins, David J. Langer and Christopher S. Ogilvy

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Jianping Xiang, Robert J. Damiano, Ning Lin, Kenneth V. Snyder, Adnan H. Siddiqui, Elad I. Levy and Hui Meng

OBJECT

Flow diversion via Pipeline Embolization Device (PED) represents the most recent advancement in endovascular therapy of intracranial aneurysms. This exploratory study aims at a proof of concept for an advanced device-modeling tool in conjunction with computational fluid dynamics (CFD) to evaluate flow modification effects by PED in actual, treated cases.

METHODS

The authors performed computational modeling of 3 PED-treated complex aneurysm cases. The patient in Case 1 had a fusiform vertebral aneurysm treated with a single PED. In Case 2 the patient had a giant internal carotid artery (ICA) aneurysm treated with 2 PEDs. Case 3 consisted of tandem ICA aneurysms (III-a and III-b) treated by a single PED. The authors’ recently developed high-fidelity virtual stenting (HiFiVS) technique was used to recapitulate the clinical deployment process of PEDs in silico for these 3 cases. Pretreatment and posttreatment aneurysmal hemodynamics studies performed using CFD simulation were analyzed. Changes in aneurysmal flow velocity, inflow rate, wall shear stress (WSS), and turnover time were calculated and compared with the clinical outcome.

RESULTS

In Case 1 (occluded within the first 3 months), the aneurysm had the most drastic flow reduction after PED placement; the aneurysmal average velocity, inflow rate, and average WSS were decreased by 76.3%, 82.5%, and 74.0%, respectively, whereas the turnover time was increased to 572.1% of its pretreatment value. In Case 2 (occluded at 6 months), aneurysmal average velocity, inflow rate, and average WSS were decreased by 39.4%, 38.6%, and 59.1%, respectively, and turnover time increased to 163.0%. In Case 3, Aneurysm III-a (occluded at 6 months) had a decrease by 38.0%, 28.4%, and 50.9% in average velocity, inflow rate, and average WSS, respectively, and turnover time increased to 139.6%, which was quite similar to Aneurysm II. Surprisingly, the adjacent Aneurysm III-b had more substantial flow reduction (a decrease by 77.7%, 53.0%, and 84.4% in average velocity, inflow rate, and average WSS, respectively, and an increase to 213.0% in turnover time) than Aneurysm III-a, which qualitatively agreed with angiographic observation at 3-month follow-up. However, Aneurysm III-b remained patent at both 6 months and 9 months. A closer examination of the vascular anatomy in Case 3 revealed blood draining to the ophthalmic artery off Aneurysm III-b, which may have prevented its complete thrombosis.

CONCLUSIONS

This proof-of-concept study demonstrates that HiFiVS modeling of flow diverter deployment enables detailed characterization of hemodynamic alteration by PED placement. Posttreatment aneurysmal flow reduction may be correlated with aneurysm occlusion outcome. However, predicting aneurysm treatment outcome by flow diverters also requires consideration of other factors, including vascular anatomy.