Andrew K. Johnson

Stent-assisted embolization of 100 middle cerebral artery aneurysms

OBJECT The introduction of intracranial stents to aneurysm treatment allows endovascular repair of nearly all aneurysms, but the safety and durability of stent-assisted embolization of middle cerebral artery (MCA) aneurysms is unclear. METHODS Ninety-one patients with 100 complex MCA aneurysms not amenable to simple coiling were treated with stent-assisted embolization as a first option. Technical and clinical results, initial follow-up imaging, and long-term annual MR angiography (MRA) were reviewed. RESULTS Intracranial stents were successfully deployed in all 100 aneurysms. There was 1 case of significant neurological morbidity (1%) and 1 case of death (1%) related to treatment. Initial posttreatment angiography revealed complete occlusion of 48 aneurysms (48%), a residual neck in 21 (21%), and residual aneurysm filling in 31 (31%). Follow-up imaging performed in 85 (90.4%) of a possible 94 aneurysms showed complete occlusion of 77 aneurysms (90.6%), residual neck in 3 (3.5%), and residual filling in 5 (5.9%). Four aneurysms (4.7%) required retreatment. Long-term MRA follow-up revealed stability or progressive thrombosis in 47 (97.9%) of 48 aneurysms. In 11 patients Y-configuration stenting caused only 1 minor complication and provided durable occlusion in all cases. CONCLUSIONS Stent-assisted techniques increase the number of aneurysms that may be treated endovascularly and represent an acceptable alternative to craniotomy. Stents provided adequate vessel reconstruction, low complication rates, and good long-term occlusion.

Stent assisted embolization of 64 anterior communicating artery aneurysms

Introduction Anterior communicating artery (ACoA) aneurysms comprised over half of the ruptured aneurysms in the International Subarachnoid Trial. Endovascular treatment of ACoA aneurysms has provided good results, but until the introduction of intracranial stents, many ACoA aneurysms could not be treated without craniotomy. The current study analyzes the results of ACoA aneurysm treatment using stent assisted embolization. Methods 64 patients with ACoA aneurysms underwent stent assisted aneurysm repair. Four were treated in the acute rupture phase and a fifth ruptured aneurysm was stented in a second procedure after initial coiling. Five aneurysms were 10 mm or more in greatest diameter. Follow-up angiography was performed 6 months after treatment; then, patients were followed with annual MR angiography. Technical, clinical, and long term radiographic results were analyzed. Results Stents were successfully deployed in each case. One patient was eventually treated with a three stent construct and died of perioperative hemorrhage. One major stroke occurred during a separate procedure when a patient was taken off antiplatelet medications. These cases were the only aneurysm related morbidity (1.6%) and mortality (1.6%) events during the entire follow-up period. After stent assisted embolization, 32 (50.0%) ACoA aneurysms were completely occluded, 15 (23.4%) had residual neck, and 17 (26.6%) had residual filling. At first radiographic follow-up, 39 of 55 (70.9%) showed complete occlusion. Three (5.5%) total aneurysms required retreatment. Conclusions Stent assisted aneurysm treatment was a safe and effective option in this series of ACoA aneurysms with maximum diameter less than 15 mm. ACoA aneurysms may be more likely to recur regardless of treatment option, but stent assisted embolization may be durable after stable initial radiographic follow-up.

Evaluation of cerebral artery perforators and the pipeline embolization device using optical coherence tomography

Introduction Optical coherence tomography (OCT) provides high resolution imaging of tissue; this technology has been validated using intra-arterial catheters in the evaluation of arterial anatomy, pathology and treatments. The perforating cerebral arteries and intracranial stents have not been previously visualized with an OCT catheter. Methods Using a standard transfemoral endovascular technique, a LightLab C7 Dragonfly catheter was inserted in the middle and posterior cerebral arteries of a fresh frozen cadaver. OCT images of the cerebral vessels and a deployed Pipeline Embolization Device were acquired using the LightLab C7-XR OCT Intravascular Imaging System. Results Distal cerebral artery access with the imaging catheter was feasible via the femoral artery using a distal access catheter instead of the standard monorail system used in coronary investigations. Imaging of perforators and stent struts had exceptional resolution. Conclusion The first use of a commercial OCT catheter in the evaluation of intracranial vessels using transfemoral endovascular techniques is described. Challenges of intracranial OCT include blood clearance and vessel tortuosity. This technology may aid in the diagnosis and treatment of cerebrovascular disease in the future.

Long-term radiographic results of stent-assisted embolization of cerebral aneurysms.

BACKGROUND Aneurysmal subarachnoid hemorrhage is a disabling disease. Endovascular coiling provides minimally invasive, effective, and safe treatment of both ruptured and unruptured intracranial aneurysms. Intracranial stents have improved the endovascular treatment of complex aneurysms, but the long-term durability of this treatment modality needs clarification. OBJECTIVE To elucidate the long-term success of intracranial stent use in the treatment of aneurysms. METHODS Four hundred ten patients were treated with stent-assisted endovascular management of 464 aneurysms. Treatment of 363 small aneurysms, 88 large aneurysms, and 13 giant aneurysms was analyzed with respect to both long-term anatomic results with digital subtraction angiography and magnetic resonance angiography over the follow-up period. RESULTS The 6-month angiographic results of 387 aneurysm treatments revealed complete aneurysm occlusion in 282 (72.9%), residual aneurysm neck in 50 (12.9%), and residual aneurysm filling in 55 (14.2%). Long-term radiographic follow-up, performed in 262 patients (mean, 3.63 years), showed significant recurrence of only 3 aneurysms after 6-month follow-up imaging. Forty-eight aneurysms (11.9%) were considered radiographic failures during the follow-up period. CONCLUSION The aneurysm recurrence rate after stent-assisted embolization in this series was similar to published data using only coil embolization for the period between treatment and the initial follow-up imaging. For aneurysms that do not initially recur, the presented data suggest improved durability in the subsequent long-term follow-up period. ABBREVIATIONS DSA, digital subtraction angiographyMRA, magnetic resonance angiography.

Progressive deconstruction: a novel aneurysm treatment using the pipeline embolization device for competitive flow diversion: case report.

BACKGROUND AND IMPORTANCE: A variety of deconstructive and reconstructive therapies have been used to treat intracranial aneurysms. The Pipeline embolization device (PED) has become a quite successful option to treat aneurysms, while reconstructing and remodeling the parent vessel. We report a case of off-label PED use, where a flow diverter was placed across the parent vessel of a giant intracranial aneurysm in a novel deconstructive strategy. CLINICAL PRESENTATION: A 40-year-old man with a giant, slow-flow aneurysm of the distal middle cerebral artery (MCA) was treated with the placement of a PED across the vessel containing the aneurysm after superselective test balloon occlusion of that vessel failed. PED was successfully deployed in a competing MCA branch across the origin of the MCA branch supplying the giant aneurysm. The patient continued dual-antiplatelet therapy for 5 months and aspirin monotherapy thereafter. Follow-up angiography, performed 6 months after treatment, demonstrated complete and asymptomatic thrombosis of the aneurysm and its parent MCA branch. A collateral pial and leptomeningeal network developed, reconstructing the distal branches of the occluded MCA branch. After 18 months, the patient remains neurologically intact. CONCLUSION: This appears to be the first description of progressive deconstruction for aneurysm treatment by using PED. Despite not tolerating acute vessel occlusion with superselective test balloon occlusion, the patient was asymptomatic following long-term occlusion with PED secondary to the growth of pial and leptomeningeal collateral networks. ABBREVIATIONS: MCA, middle cerebral artery PED, Pipeline embolization device

Complication analysis in nitinol stent-assisted embolization of 486 intracranial aneurysms.

OBJECT Stent-assisted embolization (SAE) has broadened the scope of endovascular cerebral aneurysm treatment. The risks associated with stent selection and configuration are poorly defined. In this study, the authors aimed to characterize the risk factors that contribute to complications in SAE of intracranial aneurysms. METHODS Over a 10-year period, a single surgeon treated 486 aneurysms with SAE in which open-cell Neuroform or closed-cell Enterprise stents were used. Single stents were used in 386 cases, overlapping stents were deployed in 80 cases, and Y-configuration stents were used in the remaining 20 cases. All neurological complications, which included transient deficits, were analyzed; disabling strokes and death were considered major complications. The chi-square test and multivariate logistic regression were used to evaluate the influence of aneurysm size and morphology, aneurysm location, stent selection, and stent configuration on complication rates. RESULTS There were 7 deaths (1.4%), 9 major strokes (1.9%), and 18 minor neurological complications (3.7%). For all complications, multivariate analysis revealed that large aneurysm size (10-25 mm; p = 0.01), giant aneurysm size (> 25 mm; p = 0.04), fusiform aneurysm morphology (p = 0.03), and using a Y-configuration stent (p = 0.048) were independent risk factors. For the major complications, independent risk factors included an aneurysm in the posterior circulation (p = 0.02), using an overlapping stent configuration (p = 0.03), and using a Y-configuration stent (p < 0.01). CONCLUSIONS In this series, SAE for cerebral aneurysm treatment carried an acceptable complication rate. With continued innovations in techniques and devices and with increased experience, the complication rates associated with SAE may be even lower in the future.

Initial Experience with Neuroform EZ in the Treatment of Wide-neck Cerebral Aneurysms

Purpose Stent-assisted coiling allows embolization and parent vessel reconstruction of wide-necked intracranial aneurysms. The Neuroform EZ (Boston Scientific, Fremont, CA, U.S.A.) stent delivery system offers deployment of a Neuroform stent with fewer steps and improved operator control. Initial experience, technical considerations, and treatment outcomes using the Neuroform EZ stent delivery system in combination with coil embolization are reported. Materials and Methods Seventeen consecutive patients harboring 21 wide-necked saccular cerebral aneurysms were treated with stent reconstruction. Twenty aneurysms were unruptured; one was treated within 24 hours of diagnosis of rupture. Twenty aneurysms were located in the anterior circulation; one was in the posterior circulation. Immediate and six-month post-treatment angiography and clinical assessment were performed. Results In all cases, the stents were delivered and positioned without difficulty in deployment. Technical complications occurred in 4 patients, but none were directly related to the stent delivery system. On immediate post-treatment angiography, 5 of 21 aneurysms showed complete occlusion, 5 of 21 showed residual neck, and 11 of 21 showed residual contrast filling of the aneurysm sac. At six month follow-up, all 17 patients were clinically stable. Angiography of 18 of the aneurysms showed total occlusion in 12, residual neck in 3, and residual aneurysm filling in 3. Retreatment was performed in the three with residual aneurysm. Conclusion The Neuroform EZ stent system offers improved anchoring and support in stent delivery, which is particularly useful when multiple stents are overlapped to further protect the parent vessel and increase flow diversion away from the aneurysm sac. The only significant problem encountered was coil prolapse, which could be treated with a second stent when necessary. The ease of deployment improves upon the already clinically successful Neuroform design.

Severe hemiparesis as a prehospital tool to triage stroke severity: a pilot study to assess diagnostic accuracy and treatment times.

Introduction With the publication of the recent trials showing the tremendous benefits of mechanical thrombectomy, opportunities exist to refine prehospital processes to identify patients with larger stroke syndromes. Materials and methods We retrospectively reviewed consecutive patients who were brought via scene flight from rural parts of the region to our institution, from December 1, 2014 to June 5, 2015, with severe hemiparesis or hemiplegia. We assessed the accuracy of the diagnosis of stroke and the number of patients requiring endovascular therapy. Moreover, we reviewed the times along the pathway of patients who were treated with endovascular therapy. Results 45 patients were brought via helicopter from the field to our institution. 27 (60%) patients were diagnosed with an ischemic stroke. Of these, 12 (26.7%) were treated with mechanical thrombectomy and 6 (13.3%) with intravenous tissue plasminogen activator alone. An additional three patients required embolization procedures for either a dural arteriovenous fistula or cerebral aneurysm. Thus a total of 15 (33%) patients received an endovascular procedure and 21/45 (46.7%) received an acute treatment. For patients treated with thrombectomy, the median time from first medical contact to groin puncture was 101 min, with 8 of the 12 patients (66.7%) being discharged to home. Conclusions We have presented a pilot study showing that severe hemiparesis or hemiplegia may be a reasonable prehospital tool in recognizing patients requiring endovascular treatment. Patients being identified earlier may be treated faster and potentially improve outcomes. Further prospective controlled studies are required to assess the impact on outcomes and cost effectiveness using this methodology.

Use of flow-diverting stents as salvage treatment following failed stent-assisted embolization of intracranial aneurysms

Flow-diverting stents, including the Pipeline embolization device (PED) and Silk, have been beneficial in the treatment of aneurysms previously unable to be approached via endovascular techniques. Recurrent aneurysms for which stent-assisted embolization has failed are a therapeutic challenge, given the existing intraluminal construct with continued blood flow into the aneurysm. We report our experience using flow-diverting stents in the repair of 25 aneurysms for which stent-assisted embolization had failed. Nineteen (76%) of these aneurysms at the 12-month follow-up showed improved Raymond class occlusion, with 38% being completely occluded, and all aneurysms demonstrated decreased filling. One patient developed a moderate permanent neurologic deficit. Appropriate stent sizing, proximal and distal construct coverage, and preventing flow diverter deployment between the previously deployed stent struts are important considerations to ensure wall apposition and prevention of endoleak. Flow diverters are shown to be a reasonable option for treating previously stented recurrent cerebral aneurysms.

Presence of the hyperintense acute reperfusion marker on MRI after mechanical thrombectomy for large vessel occlusion is associated with worse early neurological recovery

Background Mechanical thrombectomy has become the accepted treatment for large vessel occlusion in acute ischemic stroke. Unfortunately, a large cohort of patients do not achieve functional independence with treatment, even though the results are more robust than with medical management. The hyperintense acute reperfusion marker (HARM) on MRI is an indication of the breakdown of the blood–brain barrier and reperfusion injury. Objective To examine the hypothesis that the presence of HARM on MRI correlates with worse neurological recovery after reperfusion therapy. Methods We retrospectively reviewed 35 consecutive patients who between February 24, 2016 and April 23, 2016 underwent MRI to determine the presence of HARM after thrombectomy for anterior circulation large vessel occlusion. Demographic, radiographic imaging, and outcome data were collected. Univariate and binary logistic regression models were performed to assess predictors for improvement of the National Institutes of Health Stroke Scale (NIHSS) score by ≥8 points at 24 hours. Results The 35 patients studied had an average age of 64±14 years of age with a median NIHSS score of 15 (IQR 9–20). Eighteen patients (51%) were found to have a HARM-positive MRI. In univariate analysis, patients with HARM were older, had lower reperfusion rates and more postprocedural hemorrhages. In binary logistic regression modeling, the absence of HARM was independently associated with a ≥8-point NIHSS score improvement at 24 hours (OR=7.14, 95% CI 1.22 to 41.67). Conclusions This preliminary analysis shows that the presence of HARM may be linked to worse neurological recovery 24 hours after thrombectomy. Reperfusion injury may affect the number of patients achieving functional independence after treatment.