Siddiqui Ah

Complications after treatment with pipeline embolization for giant distal intracranial aneurysms with or without coil embolization.

BACKGROUND AND IMPORTANCEnThe Pipeline Embolization Device (PED) is a flow diverter designed to treat intracranial aneurysms through endoluminal parent vessel reconstruction. The role of adjunctive coil embolization is unknown.nnnCLINICAL PRESENTATIONnThis report details the authors experience with the PED in 2 patients with symptomatic, giant distal intracranial aneurysms (1 basilar artery and 1 M1 segment middle cerebral artery). Both patients had successful parent vessel reconstruction. In the first patient, the basilar artery aneurysm was treated with PEDs alone, and the patient experienced early fatal brainstem hemorrhage from aneurysm rupture. In the second patient, the M1 aneurysm was treated with 2 PEDs along with dense coil embolization, with a good initial angiographic result. This patient experienced acute thrombosis of the PED post-procedure, likely related to mass effect and thrombogenicity of the dense coil mass.nnnCONCLUSIONnFlow diversion is an evolutionary step in the treatment of giant intracranial aneurysms. However, complete aneurysm occlusion occurs over a delayed period. The authors recommend placement of coils in addition to PED in the treatment of large or giant distal intracranial aneurysms in an attempt to protect the dome. However, robust packing is to be avoided because it can lead to acute PED thrombotic or compressive occlusion.

Comparison of Modern Stroke Thrombectomy Approaches Using an In Vitro Cerebrovascular Occlusion Model

BACKGROUND AND PURPOSE: A new in vitro cerebrovascular occlusion model of the intracranial circulation was developed recently for testing thrombectomy devices. Using this model, we compared recanalization success associated with different modern endovascular thrombectomy approaches. MATERIALS AND METHODS: Model experiments were performed in 4 thrombectomy test groups: 1) primary or direct Stentriever thrombectomy with a conventional guide catheter (control group), 2) primary Stentriever thrombectomy with a balloon-guide catheter, 3) combined Stentriever–continuous aspiration approach, and 4) direct aspiration alone. Successful recanalization was defined as a TICI score of 2b or 3. RESULTS: Seventy-one thrombectomy experiments were conducted. Similar rates of TICI 2b–3 scores were achieved with balloon-guide and conventional guide catheters (P = .34). The combined Stentriever plus aspiration approach and the primary aspiration thrombectomy resulted in significantly higher rates of TICI 2b or 3 than the conventional guide-catheter approach in the control group (P = .008 and P = .0001, respectively). The primary Stentriever thrombectomy with the conventional guide catheter showed the highest rate of embolization to new territories (53%). CONCLUSIONS: Data from our in vitro model experiments show that the Stentriever thrombectomy under continuous aspiration and primary aspiration thrombectomy approaches led to the highest degree of recanalization.

A proposed grading system for endovascular treatment of cerebral arteriovenous malformations: Buffalo score

Background: The Spetzler–Martin arteriovenous malformation (AVM) grading system has proven to be useful in guiding treatment of cerebral AVMs with craniotomy. It is based on anatomical characteristics each of which makes surgical resection of an AVM more difficult, namely, deep venous drainage, eloquence of surrounding tissue, and large nidus size. A higher score correlates with more complications after treatment. Although this grading system has proven reliable over time, it does not reflect the major determinants of risk associated with endovascular treatment. The authors developed a grading system unique to endovascular treatment of cerebral AVMs. Methods: The proposed grading system accounts for the principal AVM anatomical and physiological features that make endovascular embolization more difficult and, thus, the likelihood of complications greater. These include number of arterial pedicles, diameter of arterial pedicles, and eloquent location of AVM nidus. The proposed grading system was retrospectively applied to 50 patients undergoing endovascular AVM embolization, and its ability to predict complications was compared to the Spetzler–Martin grading system. Results: Perioperative complications among the 50 patients included 4 major and 9 minor complications. The proposed grading system was predictive of complication risk, with an increasing rate of perioperative complications associated with an increasing AVM grade. An improved correlation of perioperative complication incidence was noted with the proposed system (P = 0.002), when compared with the Spetzler–Martin grading system (P = 0.33). Conclusion: This grading system for the endovascular treatment of AVMs is simple, easily reproduced, and clinically valuable.

Feasibility, safety, and periprocedural complications associated with endovascular treatment of selected ruptured aneurysms under conscious sedation and local anesthesia.

BACKGROUNDnEndovascular coil embolization of ruptured aneurysms is performed under general anesthesia at most centers for perceived improved image quality and patient safety.nnnOBJECTIVEnTo report the feasibility of and outcomes associated with endovascular treatment of subarachnoid hemorrhage (SAH) patients with ruptured cerebral aneurysms performed under conscious sedation with local anesthetics.nnnMETHODSnBetween January 2005 and December 2009, 187 patients with aneurysmal SAH were treated with coil embolization at the authors hospital. For each patient, procedural details, mode of anesthesia, and clinical and radiographic outcomes were reviewed retrospectively (retrospective case series).nnnRESULTSnA total of 197 coil embolizations were performed: 112 under general anesthesia, 78 under conscious sedation with local anesthetics, and 7 converted from conscious sedation to general anesthesia. None of the patients who presented with Hunt & Hess grade IV or V were treated under conscious sedation. For patients who presented with Hunt & Hess grades I, II, and III, 79.2%, 66.7%, and 32.6% of patients, respectively, underwent successful completion of treatment under conscious sedation. The symptomatic procedural complication rate was 2.5% overall and 2.4% for the conscious sedation group alone. Among the 14 interventions with intraprocedural perforation, 11 were performed under general anesthesia and 3 were performed under conscious sedation.nnnCONCLUSIONnIn the authors experience, conscious sedation with local anesthetics for endovascular treatment of ruptured intracranial aneurysms is feasible and safe in most patients with low-grade SAH. It may allow direct evaluation of the patients neurological status, potentially leading to earlier detection and response to intraprocedural complications.

Evaluation of a Second-Generation Self-Expanding Variable-Porosity Flow Diverter in a Rabbit Elastase Aneurysm Model

BACKGROUND AND PURPOSE: The self-expanding V-POD is a second-generation flow-diverting device with a low-porosity PTFE patch on a self-expanding microstent. The authors evaluated this device for the treatment of elastase-induced aneurysms in rabbits. MATERIALS AND METHODS: Three V-POD types (A, circumferential patch closed-cell stent [n = 9]; B, asymmetric patch closed-cell stent [n = 7]; and C, asymmetric patch open-cell stent [n = 4]) were evaluated by using angiography, conebeam micro-CT, histology, and SEM. Aneurysm flow modifications were expressed in terms of immediate poststent/prestent ratios of maximum CA volume entering the aneurysm dome tracked on procedural angiograms. Flow modifications were correlated with 4 weeks follow-up angiographic, micro-CT, histologic, and SEM results. RESULTS: Mechanical stent-deployment difficulties in 4 aneurysms (1 type A; 3 type B) led to suboptimal results and exclusion from analysis. Of the remaining 16 aneurysms, 4-week post-treatment angiograms showed no aneurysm filling in 10 (63%), 3 (∼19%) had no filling with a small remnant neck, and 3 (∼19%) had <0.25 filling. Successfully treated aneurysms (n = 16) demonstrated an immediate poststent/prestent CA maximum volume ratio of 0.13 ± 0.18% (0.0%–0.5%). Favorable contrast-flow modification on immediate angiography after deployment correlated significantly with aneurysm occlusion on follow-up angiography, micro-CT, and histology. The occlusion percentage derived from micro-CT was 96 ± 6.8%. Histology indicated advanced healing (grade ≥3) in the aneurysm dome in 13 of 16 cases. SEM revealed 15 of 16 stents in an advanced state of endothelialization. CONCLUSIONS: This study showed the feasibility and effectiveness of V-POD for aneurysm healing in a rabbit elastase model.

Feasibility, Safety, and Periprocedural Complications of Pipeline Embolization for Intracranial Aneurysm Treatment Under Conscious Sedation: University at Buffalo Neurosurgery Experience.

BACKGROUND: Endovascular Pipeline Embolization Device (PED) placement for intracranial aneurysms is performed under general anesthesia at most centers because of perceived improved image quality and patient safety. OBJECTIVE: To report the feasibility, safety, and outcomes associated with the use of the PED for intracranial aneurysms performed in awake patients after the administration of conscious sedation (CS) and a local anesthetic. METHODS: Between March 2012 and September 2014, 130 patients with 139 intracranial aneurysms (8 ruptured) were treated with the PED under CS at our institution. Procedure details and time (including duration, radiation exposure, and fluoroscopy) and procedure-related complications were retrospectively reviewed. RESULTS: A total of 155 PED deployment procedures were performed under CS. Treatment was successfully completed in all cases. Anesthesia was converted from CS to general anesthesia during 5 procedures. Mean interval from patient entry at the endovascular suite to procedure initiation was 18 minutes (range, 5 minutes-1 hour 10 minutes). Mean procedure length was 1 hour 25 minutes (range, 30 minutes-3 hours 51 minutes). Mean ± SD values for fluoroscopy time and radiation exposure were 36.17 ± 18.4 minutes and 1367 ± 897 mGy, respectively. The mean amount of contrast material administered was 211.37 ± 83.5 mL. Permanent neurological complications were seen in 4 patients (3%). CONCLUSION: In our experience, CS for PED placement for intracranial aneurysm treatment is feasible and safe. Procedure and fluoroscopy times and amount of radiation exposure are similar to or less than described in reports of PED placement under general anesthesia. CS allows direct neurological evaluation and earlier detection of and response to intraprocedural complications. ABBREVIATIONS: CS, conscious sedation GA, general anesthesia ICA, internal carotid artery PED, Pipeline Embolization Device

To Treat or Not to Treat M2 Occlusions? The Question (and Answer) From a Single Institution.

BACKGROUNDnOcclusions of the M2 segment of the middle cerebral artery may cause significant clinical effects, especially when occurring in the dominant cerebral hemisphere, yet endovascular treatment of these lesions remains controversial.nnnOBJECTIVEnTo examine the safety and efficacy of endovascular treatment of M2 occlusions at our institution.nnnMETHODSnWe retrospectively examined radiographic and clinical data of 53 patients presenting with M2 occlusions to our institution.nnnRESULTSnSuccessful recanalization (Thrombolysis in Cerebral Infarction grade 2b or 3) was achieved in 40 patients (76.9%). No symptomatic intracranial hemorrhage occurred. The mean National Institutes of Health Stroke Scale score at discharge was 6.4 (median, 5.5). In the 38 patients who had follow-up after discharge, the mean follow-up duration was 11.1 months (range, 0.5-36.5 months) and mean National Institutes of Health Stroke Scale score was 3.5 (median, 1).nnnCONCLUSIONnThe results of our single-institution experience suggest that endovascular therapy for M2 occlusions is safe and effective. Additional evaluation with randomized, controlled studies is warranted.nnnABBREVIATIONSnADAPT, direct aspiration first-pass techniqueECASS, European-Australasian Cooperative Acute Stroke StudyICH, intracranial hemorrhageIMS, Interventional Management of StrokeMERCI, Mechanical Embolus Removal in Cerebral IschemiamRS, modified Rankin ScaleNIHSS, National Institutes of Health Stroke ScalePROACT, Prolyse in Acute Cerebral ThromboembolismTICI, Thrombolysis in Cerebral Infarctiont-PA, tissue-type plasminogen activator.

A Patient Dose-Reduction Technique for Neuroendovascular Image-Guided Interventions: Image-Quality Comparison Study

BACKGROUND AND PURPOSE: The ROI–dose-reduced intervention technique represents an extension of ROI fluoroscopy combining x-ray entrance skin dose reduction with spatially different recursive temporal filtering to reduce excessive image noise in the dose-reduced periphery in real-time. The aim of our study was to compare the image quality of simulated neurointerventions with regular and reduced radiation doses using a standard flat panel detector system. MATERIALS AND METHODS: Ten 3D-printed intracranial aneurysm models were generated on the basis of a single patient vasculature derived from intracranial DSA and CTA. The incident dose to each model was reduced using a 0.7-mm-thick copper attenuator with a circular ROI hole (10-mm diameter) in the middle mounted inside the Infinix C-arm. Each model was treated twice with a primary coiling intervention using ROI-dose-reduced intervention and regular-dose intervention protocols. Eighty images acquired at various intervention stages were shown twice to 2 neurointerventionalists who independently scored imaging qualities (visibility of aneurysm-parent vessel morphology, associated vessels, and/or devices used). Dose-reduction measurements were performed using an ionization chamber. RESULTS: A total integral dose reduction of 62% per frame was achieved. The mean scores for regular-dose intervention and ROI dose-reduced intervention images did not differ significantly, suggesting similar image quality. Overall intrarater agreement for all scored criteria was substantial (Kendall τ = 0.62887; P < .001). Overall interrater agreement for all criteria was fair (κ = 0.2816; 95% CI, 0.2060–0.3571). CONCLUSIONS: Substantial dose reduction (62%) with a live peripheral image was achieved without compromising feature visibility during neuroendovascular interventions.

TU‐A‐116‐06: Pre and Post‐Treatment Temporal Parametric Analysis of Neurovascular Disease Using Gamma Variate Fitting of Time Density Curves From DSA Sequences

PURPOSEnTo calculate temporal parameters of contrast flow, using digital subtraction angiography (DSA), and provide parametric imaging (PI) of pre-and post-treated neurovascular lesions to aid neuro-interventionalists decision.nnnMETHODSnWe developed a program to evaluate changes in contrast flow before and after treatment of neurovascular lesions. The program records each pixel value in a DSA sequence and fits the data with a gamma-variate function. Using the function we calculate parameters such as mean-transit-time (MTT), bolus-arrival-time (BAT) and time-to-peak (TTP) and generate PIs for each quantity. The program was used for pre and post-treatment parametric calculations for four representative neurovascular lesions: ischemic stroke, intracranial stenosis, arteriovenous malformation (AVM) and intracranial aneurysm treated with a flow diverter. Finally we compared the pre and post-treatment PIs for changes in temporal parameters of the contrast flow.nnnRESULTSnProcessing times for a typical DSA acquisition at 10 frames per second were between 15 and 20 minutes. In the ischemic stroke and intracranial stenosis cases we observed increased flow after clot removal and balloon angioplasty respectively, BAT decreased by 2x while MTT and TTP decreased 1.5x as compared with the pre-treatment PI. For the AVM the venous arrival time increased three times after glue embolization, indicating decreased flow through the AVM. For the aneurysm treatment the MTT in the aneurysm dome was 5x larger compared with the pretreatment run indicating a reduced flow in the aneurysm.nnnCONCLUSIONnPre and post-treatment PIs showed significant differences, indicating reestablished flow for ischemic stroke and intracranial stenosis and decreased flow for the AVM and intracranial aneurysm. Execution time can be decreased significantly if software and hardware is optimized. This kind of information could be a very useful tool for treatment assistance during intracranial minimally invasive procedures in the angiographic suites where CT-perfusion is not immediately available. Support NIH-2R01EB002873; Support from NIH Grant 2R01EB002873.

New head equivalent phantom for task and image performance evaluation representative for neurovascular procedures occurring in the Circle of Willis.

Phantom equivalents of different human anatomical parts are routinely used for imaging system evaluation or dose calculations. The various recommendations on the generic phantom structure given by organizations such as the AAPM, are not always accurate when evaluating a very specific task. When we compared the AAPM head phantom containing 3 mm of aluminum to actual neuro-endovascular image guided interventions (neuro-EIGI) occurring in the Circle of Willis, we found that the system automatic exposure rate control (AERC) significantly underestimated the x-ray parameter selection. To build a more accurate phantom for neuro-EIGI, we reevaluated the amount of aluminum which must be included in the phantom. Human skulls were imaged at different angles, using various angiographic exposures, at kVs relevant to neuro-angiography. An aluminum step wedge was also imaged under identical conditions, and a correlation between the gray values of the imaged skulls and those of the aluminum step thicknesses was established. The average equivalent aluminum thickness for the skull samples for frontal projections in the Circle of Willis region was found to be about 13 mm. The results showed no significant changes in the average equivalent aluminum thickness with kV or mAs variation. When a uniform phantom using 13 mm aluminum and 15 cm acrylic was compared with an anthropomorphic head phantom the x-ray parameters selected by the AERC system were practically identical. These new findings indicate that for this specific task, the amount of aluminum included in the head equivalent must be increased substantially from 3 mm to a value of 13 mm.