Thomas R. Marotta

Canadian Experience with the Pipeline Embolization Device for Repair of Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE: Flow-diverting stents, such as the PED, have emerged as a novel means of treating complex intracranial aneurysms. This retrospective analysis of the initial Canadian experience provides insight into technical challenges, clinical and radiographic outcomes, and complication rates after the use of flow-diverting stents for unruptured aneurysms. MATERIALS AND METHODS: Cases were compiled from 7 Canadian centers between July 2008 and December 2010. Each center prospectively tracked their initial experience; these data were retrospectively updated and pooled for analysis. RESULTS: During the defined study period, 97 cases of unruptured aneurysm were treated with the PED, with successful stent deployment in 94 cases. The overall complete or near-complete occlusion rate was 83%, with a median follow-up at 1.25 years (range 0.25–2.5 years). Progressive occlusion was witnessed over time, with complete or near-complete occlusion in 65% of aneurysms followed through 6 months, and 90% of aneurysms followed through 1 year. Multivariate analysis found previous aneurysm treatment and female sex predictive of persistent aneurysm filling. Most patients were stable or improved (88%), with the most favorable outcomes observed in patients with cavernous carotid aneurysms. The overall mortality rate was 6%. Postprocedural aneurysm hemorrhage occurred in 3 patients (3%), while ipsilateral distal territory hemorrhage was observed in 4 patients (3.4%). CONCLUSIONS: Flow-diverting stents represent an important tool in the treatment of complex intracranial aneurysms. The relative efficacy and morbidity of this treatment must be considered in the context of available alternate interventions.

A Novel Grading Scale for the Angiographic Assessment of Intracranial Aneurysms Treated Using Flow Diverting Stents

Flow diverting stents are emerging as a treatment option for difficult intracranial aneurysms. Current grading scales for assessment of angiographic outcomes following aneurysm treatment do not apply to aneurysms treated by flow diversion. We propose a novel grading scale based on the degree of angiographic filling and contrast stasis. This scale will facilitate communication and standardize reporting of outcomes following flow diversion treatments.

The unruptured intracranial aneurysm treatment score A multidisciplinary consensus

Objective: We endeavored to develop an unruptured intracranial aneurysm (UIA) treatment score (UIATS) model that includes and quantifies key factors involved in clinical decision-making in the management of UIAs and to assess agreement for this model among specialists in UIA management and research. Methods: An international multidisciplinary (neurosurgery, neuroradiology, neurology, clinical epidemiology) group of 69 specialists was convened to develop and validate the UIATS model using a Delphi consensus. For internal (39 panel members involved in identification of relevant features) and external validation (30 independent external reviewers), 30 selected UIA cases were used to analyze agreement with UIATS management recommendations based on a 5-point Likert scale (5 indicating strong agreement). Interrater agreement (IRA) was assessed with standardized coefficients of dispersion (vr*) (vr* = 0 indicating excellent agreement and vr* = 1 indicating poor agreement). Results: The UIATS accounts for 29 key factors in UIA management. Agreement with UIATS (mean Likert scores) was 4.2 (95% confidence interval [CI] 4.1–4.3) per reviewer for both reviewer cohorts; agreement per case was 4.3 (95% CI 4.1–4.4) for panel members and 4.5 (95% CI 4.3–4.6) for external reviewers (p = 0.017). Mean Likert scores were 4.2 (95% CI 4.1–4.3) for interventional reviewers (n = 56) and 4.1 (95% CI 3.9–4.4) for noninterventional reviewers (n = 12) (p = 0.290). Overall IRA (vr*) for both cohorts was 0.026 (95% CI 0.019–0.033). Conclusions: This novel UIA decision guidance study captures an excellent consensus among highly informed individuals on UIA management, irrespective of their underlying specialty. Clinicians can use the UIATS as a comprehensive mechanism for indicating how a large group of specialists might manage an individual patient with a UIA.

Autologous Vein-covered Stent Repair of a Cervical Internal Carotid Artery Pseudoaneurysm: Technical Case Report

OBJECTIVE AND IMPORTANCE Stenting of a cervical internal carotid pseudoaneurysm is presented using a stent covered with saphenous vein. This procedure resulted in immediate exclusion of the aneurysm and maintained patency of the carotid artery. CLINICAL PRESENTATION A gunshot to the neck resulted in airway obstruction and respiratory arrest with neurological injury in a male patient. Angiographic investigation revealed an enlarging cervical internal carotid pseudoaneurysm, possibly the source of a cerebral embolism. Anticoagulation had to be stopped because of bleeding complications. A decision was made to conduct definitive percutaneous treatment of the pseudoaneurysm. TECHNIQUE A Palmaz stent (JJIS, Warren, NJ) was covered with saphenous vein harvested from the patients leg. Using standard technique and a simple innovation for stent construct introduction into the sheath, the vein-covered stent was placed across the opening of the aneurysm and dilated into position with a balloon. CONCLUSION Immediate exclusion of a cervical internal carotid pseudoaneurysm was performed using an autologous vein-covered stent. One-month follow-up confirmed continued exclusion of the pseudoaneurysm and carotid patency without stenosis.

Microstent-assisted coiling for wide-necked intracranial aneurysms.

OBJECTIVE To describe the results, technical feasibility, efficacy and challenges encountered in our preliminary experience using a self-expandable microstent, optimized for intracranial use, as an adjunct in the endovascular treatment of wide-necked aneurysms. METHODS Only broad-necked aneurysms (dome-to-neck ratio < or = 2, or an isolated neck size > 4.5 mm) were treated with Neuroform microstent from July 2003 to May 2004. The techniques used for stent deployment were either parallel or sequential. Angiographic results were recorded immediately for all patients and classified as Class 1 (complete occlusion), Class 2 (neck remnant) or Class 3 (sac remnant) by three interventional neuroradiologists not involved in the procedure. Follow-up angiography at six months was obtained for one case. Modified Rankin Score scale was assessed for all patients. RESULTS Seventeen intracranial aneurysms in a total of 18 patients were treated (mean age, 52.2 yr). Eight patients (44.4%) presented with acute subarachnoid hemorrhage. Eleven aneurysms (61.1%) were in the posterior circulation. Average dome size was 10.2 mm (range, 3.7-19.8 mm) and average neck size was 5.36 mm (range, 3.0-10.0 mm). Six out of seven aneurysms of the anterior circulation were approached with parallel technique. Eight aneurysms of the posterior circulation were approached with sequential technique. Average number of coils deployed was 9.64 (range, 4-23 coils). Eleven aneurysms (64.8%) resulted in Class 1 and/or Class 2. One technical failure was observed. Technical complications were recognized in four patients (23.5%), all of them with unruptured aneurysms in the anterior circulation. Two patients (11.7%) presented transient immediate clinical complications. One patient (5.8%) had minor permanent neurological complication. Neither major clinical complications nor death were encountered. Favorable clinical outcome (Modified Rankin Scale score 0-2) was observed in 88.2% of the patients (average follow-up time, 4.72 months). CONCLUSIONS Absence of major permanent complications and satisfactory immediate obliteration degree in our preliminary experience indicates that microstent-assisted coiling technique is useful for the minimally invasive treatment of broad-necked complex aneurysms that are not ideal for conventional endovascular treatment and are at a high risk for conventional surgical treatment.

The pipeline flow-diverting stent for exclusion of ruptured intracranial aneurysms with difficult morphologies.

BACKGROUND: The Pipeline Embolization Device (PED) is a flow-diverting stent that may represent a new therapeutic tool for difficult-to-treat intracranial aneurysms, including those that present with subarachnoid hemorrhage (SAH). OBJECTIVE: To demonstrate the feasibility of utilizing the PED as a primary treatment for ruptured aneurysms with challenging morphologies. METHODS: Three patients with ruptured intracranial aneurysms presented with SAH. Three distinct and difficult-to-treat aneurysm morphologies were encountered: (1) a small basilar trunk pseudoaneurysm, (2) a carotid artery blister aneurysm, and (3) an A1/A2 junction-dissecting-type aneurysm. All were treated with deployment of one or more PEDs across the aneurysm. RESULTS: PEDs were successfully deployed in all 3 cases. Two patients were treated with 2 overlapping PEDs, and the third patient was treated with a single device. Aneurysm obliteration was achieved in all 3 cases with no early rehemorrhage or other clinically adverse event. CONCLUSION: Endovascular treatment with the pipeline flow-diverting stent may be a viable treatment option for otherwise difficult-to-treat aneurysm morphologies in the context of acute SAH.

Pipeline Embolization Device in Aneurysmal Subarachnoid Hemorrhage

The authors used the Pipeline device to treat 20 patients with acutely ruptured intracranial aneurysms. The most common types of aneurysms treated were blister and dysplastic/dissecting. Procedure-related morbidity/mortality overall was 15%, and 1 death directly related to the procedure occurred. Occlusion rates were 75% and 94% at 6 months and 12 months, respectively. The authors concluded that the Pipeline device offers a feasible treatment option in acute or subacute ruptured aneurysms, especially the blister type. Ruptured giant aneurysms remain challenging for both surgical and endovascular techniques; at this stage, the Pipeline device should be used with caution in this aneurysm subtype. BACKGROUND AND PURPOSE: The PED is an FDS designed for the treatment of intracranial aneurysms. Data regarding the use of this device in acute or subacute aSAH is limited to a few case reports or small series. We aimed to demonstrate the feasibility of using an FDS, the PED, for the treatment of ruptured intracranial aneurysms with challenging morphologies. MATERIALS AND METHODS: We conducted a retrospective review of all known patients treated with the PED for aSAH at 4 institutions between June 2008 and January 2012. Pertinent clinical and radiologic information was submitted by individual centers for central collation. The decision to treat with the PED was made on a case-by-case basis by a multidisciplinary team under compassionate use. RESULTS: Twenty patients (15 women; median age, 54.5 years; IQR, 8.0 years) were found. There were 8 blister, 8 dissecting or dysplastic, 2 saccular, and 2 giant aneurysms. Median time to treatment was 4 days (range, 1–90 days; IQR, 12.75 days) from rupture. Three patients had previous failed treatment. Procedure-related symptomatic morbidity and mortality were 15%, with 1 (5%) procedure-related death. Two patients died relative to medical complications, and 1 patient was lost to follow-up. Sixteen patients were available for follow-up, 81% had a GOS of 5, and 13% had a GOS of 4 attributed to a poorer initial clinical presentation. One patient died of urosepsis at 4 months. Occlusion rates were 75% and 94% at 6 months and 12 months, respectively. There were 3 delayed complications (1 silent perforator infarct, 2 moderate asymptomatic in-stent stenoses). No symptomatic delayed complications or rehemorrhages occurred. CONCLUSIONS: The FDS may be a feasible treatment option in the acute or subacute setting of selected ruptured aneurysms, especially blister aneurysms. Ruptured giant aneurysms remain challenging for both surgical and endovascular techniques; at this stage, FDSs should be used with caution in this aneurysm subtype.

In vivo feasibility of endovascular Doppler optical coherence tomography

Feasibility of detecting intravascular flow using a catheter based endovascular optical coherence tomography (OCT) system is demonstrated in a porcine carotid model in vivo. The effects of A-line density, radial distance, signal-to-noise ratio, non-uniform rotational distortion (NURD), phase stability of the swept wavelength laser and interferometer system on Doppler shift detection limit were investigated in stationary and flow phantoms. Techniques for NURD induced phase shift artifact removal were developed by tracking the catheter sheath. Detection of high flow velocity (~51 cm/s) present in the porcine carotid artery was obtained by phase unwrapping techniques and compared to numerical simulation, taking into consideration flow profile distortion by the eccentrically positioned imaging catheter. Using diluted blood in saline mixture as clearing agent, simultaneous Doppler OCT imaging of intravascular flow and structural OCT imaging of the carotid artery wall was feasible. To our knowledge, this is the first in vivo demonstration of Doppler imaging and absolute measurement of intravascular flow using a rotating fiber catheter in carotid artery.

Endovascular optical coherence tomography intensity kurtosis: visualization of vasa vasorum in porcine carotid artery

Application of speckle variance optical coherence tomography (OCT) to endovascular imaging faces difficulty of extensive motion artifacts inherently associated with arterial pulsations in addition to other physiological movements. In this study, we employed a technique involving a fourth order statistical method, kurtosis, operating on the endovascular OCT intensity images to visualize the vasa vasorum of carotid artery in vivo and identify its flow dynamic in a porcine model. The intensity kurtosis technique can distinguish vasa vasorum from the surrounding tissues in the presence of extensive time varying noises and dynamic motions of the arterial wall. Imaging of vasa vasorum and its proliferation, may compliment the growing knowledge of structural endovascular OCT in assessment and treatment of atherosclerosis in coronary and carotid arteries.

A novel endovascular clip system for the treatment of intracranial aneurysms: technology, concept, and initial experimental results. Laboratory investigation.

OBJECT The authors describe a novel device for the endovascular treatment of intracranial aneurysms, the endovascular clip system (eCLIPs). Descriptions of the device and its delivery system as well as the results of flow model tests and the treatment of experimental aneurysms are provided. METHODS The eCLIPs comprises a flexible hybrid implantable device (an anchor and a covered leaf) and a balloon catheter delivery system, designed to be positioned and activated in the parent vessel in such a way that the covered portion will abut the aneurysm neck. The eCLIPs was subjected to testing in glass, elastomeric, and cadaveric flow models to determine its navigability, orientation, and activation compared with commercially available stents. In a second experiment, 8 carotid artery sidewall aneurysms in swine were treated using eCLIPs. The degree of occlusion was observed on angiography immediately following and 30 days after device activation, and a histological analysis was performed at 30 days. RESULTS The device could navigate tortuous glass models and human cadaveric vessels. Compared with commercially available stents, the eCLIPs performed well. It could be navigated, oriented, and activated easily and reliably. With regard to the 8 porcine experimental aneurysms, immediate postactivation angiograms confirmed complete occlusion of 4 lesions and near occlusion of the other 4. Angiographic follow-up at 30 days postactivation showed occlusion of all 8 aneurysms and patency of all parent vessels. Histopathological analysis revealed aneurysm healing, with smooth-muscle cells growing across the lesion neck to allow reendothelialization. CONCLUSIONS Aneurysm occlusion with a single extrasaccular endovascular device has potential advantages. The authors believe that eCLIPs may prove to be a useful tool in the endovascular treatment of cerebral aneurysms. The system should reduce risks associated with coiling, procedure time, costs, and radiation exposure. The device satisfactorily occluded 8 experimental sidewall aneurysms. The observed healing pattern is similar to that seen after microsurgical clipping.