Abstract 1122‐000055: Parenchymal and Subarachnoid Angiogenesis in Patients with Vein of Galen Aneurysmal Malformation

Introduction : Vein of Galen Aneurysmal Malformation (VGAM) is an arteriovenous malformation that accounts for 30% of all pediatric vascular malformations. VGAMs undergo significant remodeling of hemodynamic and structural anatomy due to angiogenesis. These changes not only affect the malformation on a molecular and morphological basis, but may also lead to alterations in planned surgical procedures. It is imperative to better understand the dynamic, angiogenic environment of the cerebrovasculature in order to more effectively treat this disease. Methods : We present 36 cases of secondary angiogenesis in VGAM. We also present three case reports of angiogenesis secondary to VGAM. Results : Pre‐interventional angiogenesis was identified in 16 patients (44.4%) and post‐interventional angiogenesis in 20 patients (55.6%) following a stage of embolization therapy. The cohort of patients with pre‐interventional secondary angiogenesis was significantly older than patients with post‐interventional angiogenesis at initial angiogram (12 months ± 40.1 months vs. 4.0 months ± 5.4 months; p<0.05). Choroidal VGAMs presented with angiogenesis more frequently than Mural VGAMs (4/14 Mural vs 32/42 Choroidal; p<0.01). Angiogenesis was localized to either the left, right, or bilateral thalamus in 2 cases, to the cisternal space surrounding the VOG in 16 cases, and both in 18 cases. Conclusions : Upon identification of secondary angiogenesis, our team’s strategy is to embolize the venous component of the fistula. The ideal strategy in our practice is cannulation of the primary feeder of the malformation, as close to the fistula as possible, and injection of highly concentrated n‐BCA glue (70%‐90%) in a transarterial approach. After multiple rounds of embolization, feeders become less dilated and may be difficult to distinguish from angiogenesis. In this pattern, we use low‐concentrate nBCA (40%‐50%) from an identifiable, proximal feeder and occlude the venous component of the fistula. We identified two patterns of secondary angiogenesis: 1) pre‐interventional angiogenesis identified at the initial diagnostic angiogram, 2) de‐novo, post‐interventional angiogenesis during the staged‐embolization treatment‐course. Occasionally, we noted random bursts of angiogenesis. A combination of the hypoxic environment, inflammation, and hemodynamic alterations to the VGAM caused by liquid embolic/coiling may lead to a burst of angiogenesis that subsides after repeated treatment. We hypothesize that the immature sinuses typically associated with VGAM patients, which experience a decrease in blood flow and subsequently narrow after embolization, may contribute to turbulent blood flow. Development of parenchymal and subarachnoid angiogenesis is common during the multi‐session treatment of VGAM. It represents the response to the angiogenic stimuli released from the draining vein. This angiogenesis can be observed to regress spontaneously or mature as we continue to treat the VGAM. It is unnecessary to embolize secondary angiogenesis outright and it is our recommendation to chiefly target primary feeders of the VGAM as close to the venous component as possible.

P.191 Development and Testing of a Novel Hydrogel Embolization Treatment for Neurovascular Diseases: Preliminary Animal Results

Background: Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, aneurysms, and vessel sacrifice, but can be limited by currently available embolization agents. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to develop and test a novel embolization agent using hydrogels, a class of materials which may be bioengineered to suit a variety of indications. Methods: We devised a method of liquid hydrogel embolization with photo-modulated crosslinking for intravascular solidification, using a custom microcatheter set-up. We tested this in swine blood vessels (n=3), the swine renal arterial trees as a vascular tumor model (n=5), and the swine arterial-arterial networks of the rete mirabile as an AVM model (n=3). Hydrogel embolization was assessed for treatment efficacy and safety. Follow-up angiography was performed at 2-4 week intervals. Results: Hydrogel embolization was technically successful in all animals, with full occlusion of the vascular target immediately following embolization and at follow-up. There were no instances of clinical or angiographic complications. Conclusions: We demonstrated a novel method of dynamic photomodulation and delivery of bioengineered hydrogels to address current limitations of endovascular embolization therapies. This promising technology will be investigated further with longer-term comparative animal trials.

Using Data Mining to Assist in Predicting Reproductive Outcomes Following Varicocele Embolization

We carried out a retrospective analysis of infertile couple data using several methodologies and data analysis techniques, including the application of a novel data mining approach for analyzing varicocele treatment outcomes. The aim of this work was to characterize embolized varicocele patients by ascertaining the improvement of some of their clinical features, predicting the success of treatment via pregnancy outcomes, and identifying data patterns that can contribute to both ongoing varicocele research and the more effective management of patients treated for varicocele. We retrospectively surveyed the data of 293 consenting couples undergoing infertility treatment with male varicocele embolization over a 10-year period, and sperm samples were collected before and at 3, 6, and 12 months after varicocele embolization treatment and analyzed with World Health Organization parameters—varicocele severity grades were assessed with medical assessment and scrotal ultrasound, patient personal information (e.g., age, lifestyle, and embolization complications) was collected with clinical inquiries, and varicocele embolization success was measured through pregnancy outcomes. Varicocele embolization significantly improved sperm concentration, motility, and morphology mean values, as well as sperm chromatin integrity. Following this study, we can predict that a male patient without a high varicocele severity grade (with grade I or II) has a 70.83% chance of conceiving after embolization treatment if his partners’ age is between 24 and 33 with an accuracy of 70.59%. Furthermore, male patients successful in achieving pregnancy following embolization are mostly characterized by having a normal sperm progressive motility before treatment, a normal sperm concentration after treatment, a moderate to low varicocele severity grade, and not working in a putatively hazardous environment.

Transcatheter bilateral superselective arterial embolization, a minimally invasive method for persistent hematuria in elderly and comorbid patients with bladder and prostate cancer

Objective: In this article, we aimed to share our experience with superselective vesical and prostatic artery embolization applied by transarterial microcatheter method as a treatment option for recurrent resistant hematuria due to bladder and prostate cancer in elderly and comorbid patients. Materials and Methods: Bilateral transarterial microcatheter method was used for superselective vesical or prostatic artery embolization in 10 patients whose follow-up treatment was continued in our clinic with macroscopic hematuria due to bladder and prostate cancer diagnoses and could not be treated with other palliative and radical surgical methods due to comorbidity and high surgical operative risk. Before and after embolization treatment; hemoglobin (Hb) and hematocrit (Hct) values of the patients, the amount of transfusion of blood and blood products, postoperative complications, urethral foley catheter removal times and patient satisfaction were evaluated. The patients were followed up with controls intermittently for an average of 15 months. Results: The mean age of the patients included in the study was 77.5 (69-86) years. The average hemoglobin value before and after the embolization procedure was 8,16 mg/dL and 9,48 mg/dL, respectively. The average hematocrit value before and after the embolization procedure was 25,5 and 30,4 , respectively. The average amount of blood products (erythrocyte suspension) transfusion was 2.1 (1-3) units before the procedure, and there was no need for blood transfusion in the follow-up after the procedure. The urethral catheters of all patients were removed on the 5th day (3-7 days) after the urine color became completely clear. There were no major complications, recurrent urethral catheterization or mortality, morbidity related to the treatment after the embolization procedure. Conclusion: Superselective vesical and prostatic artery embolization treatment applied by transarterial microcatheter method is an effective and reliable alternative in the case of resistant hematuria due to bladder or prostate cancer that cannot be controlled with other palliative methods due to the high risk of anesthesia in elderly patients with comorbidities. Keywords: persistent hematuria, bladder cancer, superselective vesical artery embolization