ARTERIOVENOUS MALFORMATIONS OF THE BRAIN: ACHIEVEMENTS, ANALYSIS OF DIAGNOSIS AND TACTICS OF SURGICAL TREATMENT IN THE CONDITIONS OF THE REPUBLICAN RESEARCH CENTER OF EMERGENCY MEDICAL CARE (20-YEAR OF THE CLINIC EXPERIENCE)

Aim. To assess the results of the activities of the neurosurgical service of the Republican Research Center of Emergency Medicine (RRCEM) over a twenty-year period of operation with an analysis of the results of neurosurgical care for patients with arteriovenous malformations of the brain (AVM). Material and Methods. The analysis was carried out of 54 patients examined and operated on for AVM, in the period from 2001 to 2020, who were treated at the Department of Adult Neurosurgery of the RRCEM. Results. The basis of our principle of a differentiated surgical approach in the treatment of AVM is the determination of the AVM grading according to the Spetzler-Martin and Lawton-Young scales. Limiting only microsurgical AVM resection is advisable for AVMs – I and II grades according to the Spetzler-Martin and Lawton-Young scales. For patients with high grades of AVMs – grade III and more, it is more expedient to use a combined technique, and with deeply located AVMs, endovascular embolization.

First Experience in the Control of the Venous Side of the Brain AVM

Background and purpose: Brain arteriovenous malformations (AVM) are increasingly curable with endovascular embolization. This study examines the preliminary experience with a novel double-sided hybrid approach in the treatment of cerebral arteriovenous malformations (AVM) versus a purely single-sided intra-arterial approach. Materials and methods: The single-center study cohort included 18 patients with brain AVMs (Spetzler–Martin Grade 2 or 3) having stand-alone endovascular treatment with either the arterial-side-only pressure cooker technique (aPCT) (group 1; n = 9) or a double-sided hybrid intra-arterial and transvenous approach (HIPRENE) (group 2; n = 9). Results: Patients belonging to group 2 had lower rates of intra-procedural hemorrhaging (66.7% vs. 33.3%, p = 0.169) and needed fewer treatment sessions to achieve nidus occlusion (1.7 vs. 1.2, p = 0.136). The HIPRENE treatment regime led to higher nidus occlusion rates after the initial treatment compared to aPCT (77.7% vs. 44.4%, p = 0.167). Group 2 patients had a lower rate of neuromonitoring events (22.2% vs. 44.4%, p = 0.310) and fewer accounts of blood flow obstruction in post-operative MRIs (33.3% vs. 55.6%, p = 0.319). Conclusion: A double-sided hybrid intra-arterial and transvenous approach might have benefits for curative endovascular brain AVM treatment in patients with Spetzler–Martin Grade 2 or 3. In our small study cohort, the HIPRENE treatment regime had higher nidus occlusion rates after the first treatment, which reduces the number of treatment sessions and lowers intra- and post-operative complication rates. Further randomized controlled studies are awaited to corroborate our preliminary outcomes.

Changing Paradigm for Brain AVM Treatment

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Cyclo-oxygenase 2, a putative mediator of vessel remodeling, is expressed in the brain AVM vessels and associates with inflammation

Background Brain arteriovenous malformations (bAVM) may rupture causing disability or death. BAVM vessels are characterized by abnormally high flow that in general triggers expansive vessel remodeling mediated by cyclo-oxygenase-2 (COX2), the target of non-steroidal anti-inflammatory drugs. We investigated whether COX2 is expressed in bAVMs and whether it associates with inflammation and haemorrhage in these lesions. Methods Tissue was obtained from surgery of 139 bAVMs and 21 normal Circle of Willis samples. The samples were studied with immunohistochemistry and real-time quantitative polymerase chain reaction (RT-PCR). Clinical data was collected from patient records. Results COX2 expression was found in 78% (109/139) of the bAVMs and localized to the vessels’ lumen or medial layer in 70% (95/135) of the bAVMs. Receptors for prostaglandin E2, a COX2-derived mediator of vascular remodeling, were found in the endothelial and smooth muscle cells and perivascular inflammatory cells of bAVMs. COX2 was expressed by infiltrating inflammatory cells and correlated with the extent of inflammation (r = .231, p = .007, Spearman rank correlation). COX2 expression did not associate with haemorrhage. Conclusion COX2 is induced in bAVMs, and possibly participates in the regulation of vessel wall remodelling and ongoing inflammation. Role of COX2 signalling in the pathobiology and clinical course of bAVMs merits further studies.

Kombinasi Dexmedetomidine – Sevoflurane 0,5 MAC pada Bedah Mikro Reseksi Malformasi Arteri-Vena

Arterio-venous malformation (AVM) is a rare case, particularly among young patients (<40 years old). Maintaining haemodynamic stability and anticipating massive haemorrhage during micro surgery resection of AVM are fundamental for an anaesthetist. Total Intra Venous Anesthesia using propofol is still popular to control intracranial pressure as it is easily titrated and fast acting agent (both in onset and duration). Moreover, general neuruologic evaluation soon after anesthesia terminated is an integral important component of microsurgery of brain MAV. In this case report: a 20-year-old woman suddenly lost her consciousness and left-sided motors strength. Brain angiographic revealed an AVM in right frontal lobe. Microsurgery of brain AVM resection was performed. After 5-minute-preoxygenation, anaesthetic induction was performed by using propofol, fentanyl, rocuronium, and sevoflurane. The surgery went successfully using a combination of dexmedetomidine-sevoflurane 0.5MAC. Post-anaesthesia hemodynamic of this patient was in stable and without new neurologic deficit afterward.

Brain arteriovenous malformation treatment with transvenous endovascular technique after transarterial technique failure

Arteriovenous malformations (AVMs) are unnatural connections in the vascular system. The treatment strategies are dictated by the angioarchitecture, location and presentation of AVMs. The present study sought to report a case report of a 35-year-old female patient diagnosed with a brain AVM and submitted to a transvenous AVM embolization, located at the corpus callosum's splenium, after a previous transarterial embolization failure. As a therapeutic approach, the patient was submitted to transarterial embolization. However, the procedure was performed too proximally in the arteries, which resulted in the total AVM persistency. The patient was submitted to angiographic control until complete AVM occlusion.

Recent progress understanding pathophysiology and genesis of brain AVM—a narrative review

Considerable progress has been made over the past years to better understand the genetic nature and pathophysiology of brain AVM. For the actual review, a PubMed search was carried out regarding the embryology, inflammation, advanced imaging, and fluid dynamical modeling of brain AVM. Whole-genome sequencing clarified the genetic origin of sporadic and familial AVM to a large degree, although some open questions remain. Advanced MRI and DSA techniques allow for better segmentation of feeding arteries, nidus, and draining veins, as well as the deduction of hemodynamic parameters such as flow and pressure in the individual AVM compartments. Nonetheless, complete modeling of the intranidal flow structure by computed fluid dynamics (CFD) is not possible so far. Substantial progress has been made towards understanding the embryology of brain AVM. In contrast to arterial aneurysms, complete modeling of the intranidal flow and a thorough understanding of the mechanical properties of the AVM nidus are still lacking at the present time.

Abstract P495: Aqua Embolic System: Evaluating the Performance of a New Liquid Embolic System Using a Swine AVM Model

Introduction: Liquid embolic material (LEM) plays an essential role in the treatment of hemorrhagic stroke caused by vascular malformation such as arteriovenous malformations (AVMs). However, currently available non-adhesive LEMs has the problem of catheter entrapment, and also known to have cytotoxicity due to the organic solvents such as Dimethyl Sulfoxide (DMSO). Aqua Embolic System (AES) is a new liquid embolic material, which is mainly composed of multiple polysaccharides. AES, when injected via a microcatheter, immediately forms a solid and elastic hydrogel cast upon exposure to Ca2+ in the bloodstream. The use of organic solvents, e.g., DMSO, is not required. The performance of AES was evaluated using an established AVM model utilizing swine rete-mirabile. Methods: Under general anesthesia, the left ascending pharyngeal artery (APA) of Yorkshire swine (40 kg) was catheterized using a microcatheter (ID:0.013 inches), and AES was slowly injected into the rete-mirabile under fluoroscopy. The following parameters were assessed to evaluate the embolization performance of the AES; 1) the amount of AES required for the complete occlusion of the feeding artery, 2) injection speed, 3) radiopacity during the deployment, and 4) incidence of catheter entrapment after the injection. The same evaluation was performed on the contralateral rete-mirabile and the left renal artery as well. Results: 12 arteries in 4 swine were treated, and all arteries were completely occluded without technical complications. The injected materials immediately formed AES cast in all vessels, followed by the reflux over the tip of the microcatheter. All catheters were withdrawn without any sign of catheter entrapment. The AES mixed with tantalum based contrasts medium showed sufficient radiopacity under fluoroscopy. With the injection speed of 0.02ml/sec, the average volume required was 0.85mL for the APA and 2.9mL for the renal artery. No increased thrombogenicity or vasospasm near the treated lesion was observed during the procedure. Conclusions: AES, which is a DMSO free, non-adhesive polysaccharides-based LEM, may be used as an embolic material for the treatment of hemorrhagic stroke caused by cerebrovascular diseases, such as brain AVM.