Preoperative Endovascular Embolization of Glomus Jugulare Tumors: A Retrospective Case Series of 22 Embolizations in 20 Patients and Literature Review

Objective Glomus jugulare tumors, or tympanojugular paragangliomas, are rare, highly vascularized skull base tumors originated from paraganglion cells of the neural crest. With nonabsorbable embolic agents, embolization combined with surgery has become the norm. The authors assess the profile and outcomes of patients submitted to preoperative embolization in a Brazilian tertiary care hospital. Methods The present study is a single-center, retrospective analysis; between January 2008 and December 2019, 22 embolizations were performed in 20 patients in a preoperative character, and their medical records were analyzed for the present case series. Results Hearing loss was the most common symptom, present in 50% of the patients, while 40% had tinnitus, 30% had dysphagia, 25% had facial paralysis, 20% had hoarseness, and 10% had diplopia. In 7 out of 22 embolization procedures (31%) more than a single embolic agent was used; Gelfoam (Pfizer, New York, NY, USA) was used in 18 procedures (81%), in 12 of which as the single agent, followed by Embosphere (Merit Medical, South Jordan, UT, USA) (31%), Onyx (Medtronic, Minneapolis, MN, USA) (9%), and polyvynil alcohol (PVA) and Bead Block (Boston Scientific, Marlborough, MA, USA) in 4,5% each. The most common vessel involved was the ascending pharyngeal artery, involved in 90% of the patients, followed by the posterior auricular artery in 15%, the internal maxillary artery or the occipital artery in 10% each, and the superficial temporal or the lingual arteries, with 6% each. Only one patient had involvement of the internal carotid artery. No complications from embolization were recorded. Conclusions Preoperative embolization of glomus tumors is safe and reduces surgical time and complications, due to the decrease in size and bleeding.

Portal Vein Embolization Using N-Butyl Cyanoacrylate-Glue: What Impact Does a Central Vascular Plug Have?

Purpose To examine if the addition of a central vascular plug (CVP) to portal vein embolization (PVE) with N-butyl cyanoacrylate-glue (NBCA) increases future liver remnant (FLR) growth. Material and Methods This is a single-center retrospective study of 115 consecutive patients with colorectal liver metastases undergoing PVE in 2013–2019. All patients were embolized with NBCA as the main embolic agent. In 2017–2019 NBCA was combined with a CVP in the central part of the right portal vein. Growth of the FLR and standardized FLR (sFLR) including degree of hypertrophy (DH) and kinetic growth rate (KGR) were analyzed, as well as procedure data such as use of cone-beam CT (CBCT), dose area product (DAP), fluoroscopy time and contrast dose. Results A total of 40 patients (35%) underwent PVE with a combination of CVP and NBCA. The DH was higher in these patients after 4 weeks, mean 13.6% (SD 7.8) vs. 10.5% (SD 6.4; p = 0.022), verified in multivariate analysis (coefficient 4.1, p = 0.015). A CVP did not significantly increase the resection rate (90% vs 82%, p = 0.4). Cone beam CT was used in 65 patients (57%). Use of CBCT did not affect FLR growth, and fluoroscopy time and contrast doses were not different in patients having a CBCT or not. Slightly lower DAP (median 3375 vs. 4499 cGy*cm2; p = 0.09) was seen in procedures where CBCT was used. Conclusion A CVP in addition to NBCA embolization was associated with increased growth of the FLR compared to NBCA alone.

Endovascular Embolization of Posttraumatic High-Flow Priapism: Uncommon Arteriovenous Fistula of the Corpus Cavernosum

Background priapism is a persistent penile erection lasting more than four hours without sexual arousal or stimulation. Non-ischemic high-flow priapism is an uncommon finding. Case presentation: we report on a high-flow priapism, an uncommon arteriovenous fistula of the corpus cavernosum after a straddle trauma which was successfully treated by super selective trans-arterial embolization using a temporary embolic agent. At follow up no recurrent episodes of priapism occurred without symptoms of erectile dysfunction or other complications. Conclusion Super selective embolization has a high rate of technical success with preservation of erectile function in this case without complications.

Fatal hemorrhagic complication after coil embolization of a petrosal arteriovenous shunt

Background Cerebello-pontine AVMs (CPAVMs) and petrous apex dural arteriovenous fistulae (DAVFs) are rare and sometimes difficult to distinguish. We report a fatal hemorrhagic complication after coil embolization of the petrosal vein draining a trigeminal AVM misdiagnosed as a DAVF. Case presentation A 73-year-old woman with a petrous apex arteriovenous shunt with dual dural and pial arterial supply presented with posterior fossa hemorrhage. The draining petrosal vein was catheterized and coiled via the superior petrosal sinus. Two episodes of contrast extravasation occurred during coiling, but the lesion was completely occluded at the end of the procedure. The patient developed a fatal posterior fossa hemorrhage in the recovery room. Microscopic pathology revealed numerous dilated vessels within the trigeminal nerve. Conclusion CPAVMs and DAVFs with pial drainage should be distinguished pre-operatively. Occlusion of a pial vein (as opposed to a sinus) in the treatment of an arteriovenous shunt carries hemorrhagic risk if a liquid embolic agent is not used to completely occlude all pathological vessels.

Abstract 1122‐000236: Intravascular Delivery and Crosslinking of Photosensitive Hydrogels for Embolizing Animal Models of AVMs and Tumors

Introduction : Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, and other indications, but can be limited by currently available embolic agents, in terms of safety and efficacy. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to test a novel embolization methodology for the treatment of AVMs and tumors. Methods : We formulated low‐viscosity, shear‐thinning hydrogel formulations which were mixed with a photo‐initator agent and non‐ionic contrast medium. We then developed a method of intravascular hydrogel delivery with photo crosslinking at the tip of the catheter, using an integrated optical fibre. This allowed for rapid transition from a low viscosity liquid to a crosslinked solid‐state hydrogel to block blood flow to the vascular target. In addition, the UV intensity can be dynamically modulated, in real‐time, to modify the degree of crosslinking and thus the viscosity of the embolic agent. We utilized the swine rete mirabile as an animal model for AVMs, and the swine renal arterial tree (inferior segmental artery) as a model for hypervascular tumors. 5 animals were utilized without prior preparation. Embolization was graded based on degree of complete obliteration of the rete nidus or the renal arterial tree. Any non‐target embolization or other complications were recorded. Follow‐up angiography was performed at the 4‐week interval. Results : With a combination of shear‐thinning properties and dynamic modulation of photo crosslinking, we show that we are able to deliver an embolic agent with a viscosity range of up to 10^4 Pa*s through a single low viscosity precursor that is injectable through microcatheters (Figure 1). Using this methodology, hydrogel embolization was technically successful in all animals. Following embolization, 4/5 rete mirabile and 5/5 inferior renal arterial trees were completely obliterated. Representative angiographic images are shown in Figures 2 and 3. There were no instances of clinical or angiographic complications. Conclusions : We demonstrated a novel method of intravascular delivery of low viscosity photosensitive hydrogels, with photo crosslinking at the tip of the catheter, to successfully embolize animal models for AVMs and tumors. This promising technology will be investigated further with longer‐term comparative animal trials.

Abstract 1122‐000124: Dural Arteriovenous Fistula and Implications in Aneurysmal Genesis

Introduction : There is a reported association of cerebral arteriovenous malformations and aneurysms, however, data regarding patients presenting with dural arteriovenous fistulas (dAVF) and aneurysms is limited. Here, we present a patient who was incidentally diagnosed with 2 aneurysms in addition to a dAVF; and her treatment course. Previous to her diagnosis, she denied any and all symptomatology that would prompt further evaluation. Methods : Case description: 60‐year‐old female with history of hypertension, hypothyroidism and gastroesophageal reflux disease who initially presented to an outside hospital after a motor vehicle collision in 2016, at that time she reports being diagnosed with multiple aneurysms; but was lost to follow up. In 2020 she was referred to interventional neuroradiology and underwent diagnostic digital cerebral angiogram. Which reported a 13 × 12 × 13.3 mm left para‐ophthalmic internal carotid artery (ICA) aneurysm with a 7 mm neck. A 5.7 × 7.7 × 6.1 mm basilar tip artery aneurysm with a 5.6 mm neck and a right Cognard type four occipital dAVF, with feeding vessels from the right posterior cerebral artery and right occipital artery and anterograde drainage to the dural sinuses. From the time of diagnosis to the initiation of interventions, patient denied any concerning symptomatology. Treatment was initiated 4 months after diagnostic angiogram. She received 5 days of Dual Antiplatelet therapy (DAPT) with aspirin and Plavix previous to the deployment of a woven endobridge device (WEB™ 8‐3mm) into the basilar tip aneurysm; as this was felt to be the aneurysm with highest probability of rupture. Post‐operative course was unremarkable and DAPT was discontinued. Three months after WEB™ deployment, the patient underwent embolization of the right occipital dAVF with a liquid embolic agent (onyx™). Post operatively, she developed decreased peripheral vision in her left eye, though the rest of her hospitalization was unremarkable. 3 months after embolization, she underwent left para‐ophthalmic artery aneurysm flow diversion with a pipeline™ (4‐18mm) flow diverter, with an uncomplicated admission. She was subsequently evaluated by neuro‐ophthalmology who has reported a stable peripheral left eye left inferior quadrantic defect along with a supertemporal defect in her right eye. Results : Discussion: Interestingly, the patient presented 2 aneurysms, one in the anterior circulation and the most concerning, located in the posterior circulation. One could draw conclusions that the dAVF was associated with the basilar aneurysm. As dAVFs are acquired lesions, it is feasible to assume that there may be an association between both types of lesions, perhaps due to flow or pressure being exerted on weakened vessel walls, thus leading to aneurysmal formation. Conclusions : Conclusion: Because a potential for implication in the flow dynamics of the dAVF in aneurysmal formation. We have opted to use computational fluid dynamics to analyze said flow within the dAVF to better understand the causal relationship between aneurysms and dural fistulae. In the long run research into genesis of aneurysms secondary to coexisting vascular lesions could further elucidate the mechanisms by which aneurysms develop.

Iterative Metal Artifact Reduction (iMAR) of the Non-adhesive Liquid Embolic Agent Onyx in Computed Tomography

Background A drawback of Onyx, one of the most used embolic agents for endovascular embolization of intracranial arteriovenous malformations (AVM), is the generation of imaging artifacts (IA) in computed tomography (CT). Since these artifacts can represent an obstacle for the detection of periprocedural bleeding, this study investigated the effect of artifact reduction by an iterative metal artifact reduction (iMAR) software in CT in a brain phantom. Methods Two different in vitro models with two-dimensional tube and three-dimensional AVM-like configuration were filled with Onyx 18. The models were inserted into a brain imaging phantom and images with (n = 5) and without (n = 10) an experimental hemorrhage adjacent were acquired. Afterwards, the iMAR algorithm was applied for artifact reduction. The IAs of the original and the post-processed images were graded quantitatively and qualitatively. Moreover, qualitative definition of the experimental hemorrhage was investigated. Results Comparing the IAs of the original and the post-processed CT images, quantitative and qualitative analysis showed a lower degree of IAs in the post-processed images, i.e. quantitative analysis: 2D tube model: 23.92 ± 8.02 Hounsfield units (HU; no iMAR; mean ± standard deviation) vs. 5.93 ± 0.43 HU (with iMAR; p < 0.001); qualitative analysis: 3D AVM model: 4.93 ± 0.18 vs. 3.40 ± 0.48 (p < 0.001). Furthermore, definition of the experimental hemorrhage was better in the post-processed images of both in vitro models (2D tube model: p = 0.004; 3D AVM model: p = 0.002). Conclusion The iMAR algorithm can significantly reduce the IAs evoked by Onyx 18 in CT. Applying iMAR could thus improve the accuracy of postprocedural CT imaging after embolization with Onyx in clinical practice.

Microspheres present comparable efficacy and safety profiles compared with polyvinyl alcohol for bronchial artery embolization treatment in hemoptysis patients

Background The present study aimed to compare the efficacy and safety profiles of microspheres versus (vs.) polyvinyl alcohol (PVA) for bronchial artery embolization (BAE) treatment in patients with hemoptysis. Methods Totally, 152 patients with hemoptysis who were about to receive BAE treatment were consecutively enrolled and divided into microspheres group (N = 62) and PVA group (N = 90). Technical success and clinical success were assessed after BAE procedure, and the hemoptysis-recurrence status, survival status and adverse events were recorded during follow-up. Results Technical success rates were both 100% in microspheres group and PVA group; clinical success rate (96.8% vs. 100.0%, P = 0.165), 6-month (9.7% vs. 7.8%, P = 0.681) and 1-year (9.7% vs. 8.9%, P = 0.869) hemoptysis recurrence rate, 6-month (4.8% vs. 2.2%, P = 0.374) and 1-year (4.8% vs. 3.3%, P = 0.639) mortality were similar between microspheres group and PVA group. Furthermore, hemoptysis-free survival (P = 0.488) and overall survival (P = 0.321) were of no difference between two groups. In addition, all adverse events were mild, and there was no difference of adverse events between two groups (all P > 0.05). These data were validated by further multivariate regression analysis. Conclusions Microspheres present comparable efficacy and safety profiles compared with PVA for the BAE treatment in patients with hemoptysis, providing evidence for embolic agent selection.

Relevant Biological Effects of Varicocele Embolization with N-Butyl Cyanoacrylate Glue on Semen Parameters in Infertile Men

Surgical treatment or varicocele embolization (VE) with sclerosing or mechanical embolic agents have been shown to improve the semen parameters of infertile men. The aim of this study was to evaluate the impact of VE using N-butyl cyanoacrylate (NBCA) glue on semen parameters in infertile men. From January 2014 to June 2018, infertile adult patients with stage 3 varicocele and an initial semen analysis showing at least one abnormal semen parameter, and who were successfully embolized with NBCA Glubran®2 glue, were retrospectively recruited. The availability of a second semen analysis after VE was mandatory for patient inclusion. The primary endpoint was the change in total sperm number (TSN) after VE. The other parameters of interest were progressive and total sperm motilities (Smot) at 1 h (H1), sperm vitality (SV) and morphology (SMor). One hundred and two patients were included. Eight patients presented null TSN before and after VE. Among the remaining 94 patients, a significant improvement in the median TSN after VE was shown (31.79 × 106/ejaculate [IQR:11.10–127.40 × 106/ejaculate] versus 62.24 × 106/ejaculate [IQR:17.90–201.60 × 106/ejaculate], p= 0.0295). Significant improvement in TSN was found for the 60 oligo- or azoospermic patients (p = 0.0007), whereas no significant change was found for the 42 patients with normal initial TSN (p = 0.49). Other parameters, such as progressive and total SMot, SV and SMor, also significantly improved after VE (p = 0.0003, 0.0013, 0.0356 and 0.007, respectively). The use of NBCA glue as an embolic agent for VE in infertile men with stage 3 varicocele significantly improves the semen parameters.