Coiling Using Dual Microcatheter Technique—A Novel Approach

Posterior circulation aneurysms are difficult to treat, and if an incorporated artery is arising from the neck of aneurysm, management becomes much more challenging. Here, we are describing a novel technique used to treat a patient with a large, wide-necked left vertebral artery (VA)-posterior inferior cerebellar artery (PICA) junctional aneurysm. PICA seems to be arising from the aneurysm neck, but the aneurysm neck was not very clearly defined. So, we placed a second microcatheter into PICA, which not only allowed the coils to be placed in the aneurysm, without disrupting the flow through PICA but also helpful in assessing the aneurysmal occlusion. This technique allowed coils to be placed successfully without compromising flow through PICA.

Unruptured Intradural Posterior Circulation Dissecting/Fusiform Aneurysms Natural History and Treatment Outcome

Background The natural history and outcome of unruptured posterior circulation dissecting fusiform aneurysms is not fully understood. These have a high risk of morbidity and mortality, not only due to natural history but also due to the challenging and controversial treatment approaches currently available compared to other types of intracranial aneurysms. Methods We performed a retrospective study of a prospectively collected aneurysm database at a quaternary neurovascular hospital. We included consecutive patients with unruptured intradural vertebrobasilar dissecting aneurysms between January 2000 and July 2016 who were followed to 2020. Description of baseline, procedural, and outcomes data was performed. Comparisons of patient who had aneurysm rupture on follow-up, increase in 2 or more points of mRS in follow-up and progression of the aneurysm was performed. Results Seventy patients with 78 fusiform posterior circulation aneurysms were identified. Thirty-nine (55.7%) patients were male with a mean age of 51.7 years (SD ± 17.6). When multiple, aneurysms were more likely to be fusiform (60%) than saccular (40.0%). Baseline diameter (measured on CTA/MRA/DSA), length as well as symptomatic presentation were significantly higher in aneurysms which grew over time. Coronary disease, diabetes and growth were associated an >2 increase in mRS. Diabetes as well as initial symptomatic presentation were associated with rupture. Conclusions Unruptured dissecting/fusiform aneurysm are associated with a considerable rate of rupture during follow-up. Growth is associated with morbidity even in the absence of rupture. Initial large size, coronary disease, diabetes, and to a lesser extent female gender may merit closer follow-up and/or prophylactic treatment.

Usefulness of Pointwise Encoding Time Reduction with Radial Acquisition-Magnetic Resonance Angiography after Endovascular Treatment for Intracranial Aneurysms

Purpose Imaging follow-up after endovascular treatment is important; however, time-of-flight magnetic resonance angiography (TOF-MRA) has limitations associated with magnetic susceptibility and radiofrequency shielding caused by the stent and coils. We evaluated the diagnostic performance of pointwise encoding time reduction with radial acquisition (PETRA)-MRA after endovascular treatment for intracranial aneurysms. Material and methods A total of 186 patients with 211 aneurysms who underwent both pointwise encoding time reduction with radial acquisition- and time-of-flight magnetic resonance angiography in the same imaging session for follow-up after endovascular treatment. We subjectively graded the overall image quality, visualization of treated sites, and occlusion status. Results Although the overall image quality scores of pointwise encoding time reduction with radial acquisition-magnetic resonance angiography were significantly lower than those of time-of-flight magnetic resonance angiography for both observers (4.04 ± 0.81 vs. 4.85 ± 0.35 [observer 1], 4.60 ± 0.69 vs. 4.94 ± 0.24 [observer 2]) (both P < .001), the visibility of treated sites using pointwise encoding time reduction with radial acquisition-magnetic resonance angiography was significantly better than that of time-of-flight magnetic resonance angiography overall (4.27 ± 0.97 vs. 3.42 ± 1.01; P < .001), in the distal internal carotid artery (4.46 ± 0.79 vs. 3.40 ± 1.00; P < .001), and in the middle cerebral artery (4.19 ± 0.93 vs. 3.08 ± 0.53, P = 0.007). Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed a higher area under the curve than time-of-flight magnetic resonance angiography for the evaluation of treated aneurysm occlusion, except for posterior circulation aneurysms. Conclusions Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed better visualization of treated sites and better diagnostic performance than time-of-flight magnetic resonance angiography for anterior circulation aneurysms. However, Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed limitations in the follow-up evaluation of posterior circulation aneurysms.

Posterior Circulation Intervention but Mind the Spinal Cord!

Spinal cord infarction (SCI), a rare complication following endovascular treatment of posterior circulation aneurysms, is infrequently recognized in the periprocedural period. We illustrate the same with digital subtraction angiography and diffusion-weighted magnetic resonance imaging in this series of two cases. Categorically, the anterior spinal artery was patent, post-procedure, in both instances. Likely, guiding catheter-induced local flow alterations initiates the pathogenesis. A subsequent insufficiency of radiculomedullary artery (RMA) reinforcements is the probable mechanism leading to hemodynamic compromise. Our observations further reiterate that periprocedural antiplatelet therapy is conceivably ineffective in preventing SCI. Besides, advanced age and uncontrolled hypertension could potentially exacerbate the periprocedural RMA compromise. Due vigilance is required to recognize this rare and potentially life-threatening complication in posterior circulation neurovascular intervention.

Feasibility of robot-assisted neuroendovascular procedures

OBJECTIVE Geographic factors prevent equitable access to urgent advanced neuroendovascular treatments. Robotic technologies may enable remote endovascular procedures in the future. The authors performed a translational, benchtop-to-clinical study to evaluate the in vitro and clinical feasibility of the CorPath GRX Robotic System for robot-assisted endovascular neurointerventional procedures. METHODS A series of bench studies was conducted using patient-specific 3D-printed models to test the system’s compatibility with standard neurointerventional devices, including microcatheters, microwires, coils, intrasaccular devices, and stents. Optimal baseline setups for various procedures were determined. The models were further used to rehearse clinical cases. Subsequent to these investigations, a prospective series of 6 patients was treated using robotic assistance for complex, wide-necked intracranial saccular aneurysms between November 2019 and February 2020. The technical success, incidence of periprocedural complications, and need for conversion to manual procedures were evaluated. RESULTS The ideal robotic setup for treatment of both anterior and posterior circulation aneurysms was determined to consist of an 80-cm guide catheter with a 115-cm-long intermediate catheter, a microcatheter between 150 and 170 cm in length, and a microwire with a minimum length of 300 cm. All coils, intrasaccular devices, and stents tested were compatible with the system and could be advanced or retracted safely and placed accurately. All 6 clinical procedures were technically successful, with all intracranial steps being performed robotically with no conversions to manual intervention or failures of the robotic system. There were no procedure-related complications or adverse clinical outcomes. CONCLUSIONS This study demonstrates the feasibility of robot-assisted neurointerventional procedures. The authors’ results represent an important step toward enabling remote neuroendovascular care and geographic equalization of advanced endovascular treatments through so-called telestroke intervention.

The utility of platelet inhibition testing in patients undergoing Pipeline embolization of intracranial aneurysms

BackgroundThe utility of using the VerifyNow P2Y12 platelet inhibition assay in patients undergoing Pipeline embolization of intracranial aneurysms remains controversial. As we have routinely employed the assay for patients undergoing flow diversion, we elected to explore the relationship between P2Y12 hyporesponse as indicated by a P2Y12 Reaction Units (PRU) value >200 and treatment outcomes, including intraprocedural platelet aggregation and ischemic complications.MethodsAll successful intracranial aneurysm Pipeline treatments performed at our institution from November 2011 to May 2019 were included. The rate of P2Y12 hyporesponse and treatment outcomes were evaluated. Multivariable logistic regression was utilized to determine independent predictors of treatment outcomes.Results333 qualifying treatments were performed in 297 patients. Clopidogrel hyporesponse was initially noted in 24%, falling to 17% by day-of-procedure by dose titration. A glycoprotein (GP) IIb/IIIa inhibitor was administered prophylactically in 3% of cases for persistent, profound hyporesponse. 27 (8.1%) patients developed acute platelet aggregation; only 6 demonstrated day-of-procedure P2Y12 hyporesponse. Day-of-procedure hyporesponse was not associated with intraprocedural platelet aggregation or ischemic complications. Greater Pipeline embolization device (PED) diameter was associated with a reduced odds of platelet aggregation (OR 0.38, 95% CI 0.17 to 0.85; p=0.019). Antiplatelet non-compliance (OR 25.20, 95% CI 3.86 to 164.61; p=0.001) and treatment of posterior circulation aneurysms (OR 5.23, 95% CI 1.22 to 22.33; p=0.026) were the only independent predictors of ischemic complications.ConclusionsP2Y12 hyporesponse was not associated with acute platelet aggregation or ischemic complications in our patients undergoing Pipeline embolization of intracranial aneurysms, possibly due to aggressive management of the hyporesponse using clopidogrel dose titration and/or GP IIb/IIIa inhibitor administration.

Efficacy and safety of flow diverters in posterior circulation aneurysms and comparison with their efficacy in anterior circulation aneurysms: A systematic review and meta-analysis

Purpose We aimed to assess the efficacy and safety of flow-diverter stents (FDs) in the management of posterior circulation cerebral aneurysms and compare FD efficacy between anterior and posterior circulation aneurysms. Methods We searched the PubMed, Scopus, Cochrane, and Web of Science databases for relevant studies through March 2020. Studies assessing FDs for posterior circulation aneurysms that included ≥20 treated aneurysms were included. Moreover, the studies compared FD efficacy between anterior and posterior circulation aneurysms were included. Data regarding angiographic aneurysmal occlusion, procedural complications, mortality, and morbidity were extracted and pooled in a random-effects meta-analysis model. Results Fourteen studies with a total of 659 patients and 676 posterior circulation aneurysms were included. The pooled rate of aneurysmal occlusion at long-term angiographic follow-up was 78% [95% confidence interval (CI), 71–85]. The pooled rates of intraparenchymal hemorrhage, ischemia, and procedure-related mortality and neurological morbidity were 2%, 8%, 7%, and 6%, respectively. Complete occlusion occurred in 82.4% of the posterior circulation aneurysm subgroup and 77.5% of the anterior circulation aneurysm subgroup. The difference was not significant (relative risk 1.01; 95% CI, 0.86–1.19; p = 0.91). Regression analysis showed that elderly patients and females had higher morbidity. Conclusion Posterior circulation aneurysms can be effectively treated with FDs with comparable occlusion rates to those in anterior circulation aneurysms. However, periprocedural complications are not negligible.

Flow-related posterior cerebral artery aneurysms with internal carotid artery occlusions: An institutional series

Background Aneurysm formation after internal carotid artery (ICA) occlusion has been described in animal models and human case series with alteration of cerebral blood flow dynamics considered an aetiological risk factor. Such de novo aneurysms have seldom been described in the posterior cerebral artery (PCA) with the majority observed in the anterior circulation collateral pathways. Methods We retrospectively reviewed our institutional database of posterior circulation aneurysms in patients with iatrogenic, atherosclerotic or congenital ICA occlusions. A comprehensive review of the online literature using the PubMed and Medline databases was performed to identify previous cases of PCA aneurysms that were considered ‘flow-related’. Results We present five patients with symptomatic or ruptured PCA aneurysms with ICA occlusions. Age at presentation ranged from 21-58 and aneurysm size from 3–12 mm. All cases had angiographic evidence of posterior-anterior flow via the ipsilateral posterior communicating artery (PComA). The clinical presentation, diagnostic imaging and management strategies are further discussed. A literature review identified only two previous reported cases. Conclusion To our knowledge this is the first single centre series of posterior circulation aneurysms in patients with ICA occlusions that are considered to be ‘flow-related.’ The natural history of these rare lesions is unclear and the best management and surveillance strategy requires a patient-tailored approach by an experienced neurovascular team.