A new liquid material for embolization of arteriovenous malformations

We have developed a liquid material for embolization of arteriovenous malformations that is a mixture of ethylene vinyl alcohol copolymer and metrizamide dissolved in dimethyl sulfoxide. Upon contact with blood, dimethyl sulfoxide rapidly diffuses into the blood and forms an ethylene vinyl alcohol copolymer elastic soft sponge that obstructs both the feeder and the nidus. The material, which is not adhesive, was used for embolization of three left cerebral arteriovenous malformations with satisfactory results.     

Superselective arterial embolisation with a liquid polyvinyl alcohol copolymer in patients with acute gastrointestinal haemorrhage

Objectives

To evaluate the results of emergency embolisation in acute arterial bleeding of the gastrointestinal tract with a liquid polyvinyl alcohol copolymer from two centres.

Methods

We retrospectively analysed 16 cases (15 patients) of acute arterial bleeding of the gastrointestinal tract where emergency embolotherapy was performed by using the copolymer when acute haemorrhage was not treatable with endoscopic techniques alone. Cause of haemorrhage and technical and clinical success were documented.

Results

Arterial embolotherapy was successful in all 16 cases. The technical success rate was 100%. The cause of bleeding was pancreatitis in four, graft-versus-host disease (GVHD) of the colon in three, malignancy in three, angiodysplasia in two, ulcer in two and panarteritis nodosa and trauma in one each. There were no procedure-related complications. No bowel necrosis occurred because of embolisation. In 13 cases, the patients were discharged in good condition (81%); the three patients with GVHD died because of the underlying disease.

Conclusions

The copolymer seems to have great potential in embolotherapy of acute arterial gastrointestinal bleeding. In our series none of the patients had rebleeding at the site of embolisation and no clinically obvious bowel necrosis occurred.     

Preoperative embolization of solid cervicomedullary junction hemangioblastomas: report of two cases

Solid cervicomedullary haemangioblastomas represent a small but technically challenging subset of posterior fossa haemangioblastomas because of their site, high vascularity and tendency to bleed. We present our experience with preoperative embolisation of two solid cervicomedullary haemangioblastomas. In both cases the main feeding artery was the posterior inferior cerebellar artery. Arterial pedicles were catheterised with a microcatheter. The embolic material was small particles (150–250 μm) of polyvinyl alcohol. The result was almost complete preoperative obliteration of the vessels of the tumours. The procedure was well tolerated and facilitated easier bloodless, successful resection in both cases, 24 h after embolisation. Received: 9 January 1996 Accepted: 27 February 1996     

Bronchial artery embolization with an ethylene vinyl alcohol copolymer agent (Squid) and polyvinyl alcohol particles for treatment of hemoptysis

Bronchial artery embolization (BAE) is considered the first choice treatment for hemoptysis. To our knowledge no cases of BAE using a recent ethylene vinyl alcohol copolymer agent (Squid) have been previously mentioned. Two cases of BAE for remitting hemoptysis using Squid and polyvinyl alcohol particles are reported in this technical note. The final angiographic control confirmed full exclusion of the target territory in both cases. Both patients felt some chest pain immediately after the embolization, not requiring any medications. No more episodes of hemoptysis occurred in the following 3 months after the procedure.

Bronchial artery embolization (BAE) is considered the first choice treatment for hemoptysis. Hemoptysis is often caused by active tuberculosis and post tuberculosis sequelae including fibrosis. Other indications for BAE include malignancy, pneumoconiosis, cystic fibrosis, sarcoidosis, and lung infections. (1).Several embolic agents were previously used in BAE, including microparticles, coils, adhesive and nonadhesive liquid embolizing agents. To our knowledge, no cases of BAE using a recent ethylene vinyl alcohol copolymer agent (Squid) have been previously mentioned. Here, we report two cases of BAE using Squid and polyvinyl alcohol (PVA) particles.     

Superselective angiography,embolisation and surgery in treatment of arteriovenous malformations of the brain

We prospectively evaluated a diagnostic and therapeutic procedure combining superselective, angiography, endovascular embolisation and surgery in arteriovenous malformations (AVM) of the brain. Our aim was to achieve the best possible result exposing the patients to the lowest possible risk. During a 3 year period 48 patients were studied, of whom 22 (46%) were treated by incomplete preoperative embolisation and subsequent complete surgical removal of the AVM. All angiography and embolisations were performed with the Tracker catheter system using polyvinyl alcohol particles and/or platinum fibre coils. The other 26 patients were treated as follows: incomplete embolisation in 11 (23%), complete embolisation in 2 (4%), angiography and surgery in 3 (6%) and combined embolisation and radiation in 7 (15%), 3 patients were excluded from any therapy after superselective angiography. The total number of acute complications and permanent sequelae were 8 (17%) and 3 (6%) respectively. We concluded that superselective cerebral angiography, a relatively safe procedure, should play an impotant role in deciding treatment strategies for AVMs of the brain. The risks of combined embolisation and surgery are probably lower than those of either alone. In a few cases surgery or embolisation alone carries an unequivocally lower risk, and combined therapy is not justifiable.     

Hydrophilic polymer-coated guide wire combined with progressive suppleness pursil catheter for safer,more definitive embolisation of arteriovenous malformations

For safe, more definitive embolisation of arteriovenous malformations, improved selectivity of the catheter is desirable. This report describes the advantage of the combined use of a progressive suppleness pursil catheter and a hydrophilic polymer-coated guide wire, together with precaution against complications. In 14 patients, 27 vessels were catheterised with this. Chemical embolisation using oestrogen alcohol and polyvinyl acetate was carried out only if sufficiencytly superselective catheterization was achieved with negative results on a provocation test. Chemical embolisation was successful in 25 vessels, but in three vessels catheterised very distally, it required much more time to withdraw the catheter because of the friction between it and the wall of the vessel.     

Preoperative selective internal carotid artery dural branch embolisation for petroclival meningiomas

We assessed the clinical value of preoperative embolisation of the dural branches of the internal carotid artery (ICA) in cases of petroclival meningioma was evaluated. We carried out preoperative selective embolisation on seven consecutive patients with large petroclival meningiomas, using nonbraided 2 F steam-shaped microcatheters and shapeable hydrophilic microguide-wires to enter the dural branches of the ICA. The embolisations were performed using digital subtraction fluoroscopy with 150–250m polyvinyl alcohol particles. The tumours were resected a few days after embolisation. We reviewed angiographic findings before and after endovascular devascularisation, blood loss during tumour resection and clinical outcome. All endovascular procedures were technically successful, and postembolisation angiography showed disappearance of or marked decrease in tumour stain in all cases. Intraoperative bleeding was easily controlled, and intraoperative blood loss was low.     

Use of ethylene vinyl alcohol copolymer for tubal sterilization by selective catheterization in rabbits

PURPOSE: To assess the efficacy of ethylene vinyl alcohol copolymer (Uryx) in nonsurgically occluding the fallopian tube and achieving tubal sterilization in the rabbit model. MATERIALS AND METHODS: Ten mature virgin female New England rabbits underwent transvaginal selective bilateral fallopian tube cannulation with use of a coaxial catheter system under general anesthesia. Selective salpingography was performed bilaterally to assess patency of the fallopian tubes. Ethylene vinyl alcohol copolymer was injected unilaterally through a microcatheter to completely fill the middle portion of the tube. Three to seven days after injection, each animal was bred. Conception was determined by ultrasonography (US) 7-19 days after effective breeding. If pregnant, the rabbit was killed. Otherwise, it was permitted to rebreed until pregnancy was achieved. Histologic specimens of the fallopian tubes were prepared and analyzed. RESULTS: Patency of the fallopian tubes was demonstrated bilaterally in all animals by the free spillage of contrast material into the peritoneum. The delivery of ethylene vinyl alcohol copolymer into the fallopian tubes was successful in all animals but one, in which most of the plug almost immediately extruded into the uterus. Pregnancy was detected by US in the untreated fallopian tube in the nine rabbits that were receptive to breeding. No pregnancies were detected in the injected side. Histologic analysis demonstrated variable degrees of occlusion, fibrosis, and inflammation, with the majority of specimens demonstrating mild to moderate inflammation and moderate to marked fibrosis. CONCLUSION: Ethylene vinyl alcohol copolymer can reliably be placed nonsurgically via the transvaginal approach into the fallopian tubes with use of a coaxial catheter system. Ethylene vinyl alcohol copolymer appears to result in less fibrosis than previously investigated agents and demonstrates a 100% early sterilization rate in the rabbit model.     

Dural arteriovenous shunt involving the superior petrosal sinus: presentation and treatment by transvenous embolisation via the occipital and transverse sinuses

We report a dural arteriovenous shunt on the superior petrosal sinus at the origin of the petrosal vein, and its treatment. This is the first report of transvenous embolisation of such a shunt through the contralateral occipital and transverse sinuses. It was possible to achieve complete obliteration of the superior petrosal sinus shunt by coils and polyvinyl acetate liquid embolisation, in a combined venous and arterial approach. Received: 29 September 1995 Accepted: 27 February 1996     

Severe pulmonary oedema following therapeutic embolization with Onyx for cerebral arteriovenous malformation

Acute respiratory distress syndrome (ARDS) is characterized by sudden onset of respiratory distress, infiltrates on radiographs consistent with pulmonary oedema, hypoxaemia and increased work in breathing. Infiltrates on radiographs are bilateral, but may be patchy or diffuse and fluffy or dense. It is associated with absence of left heart failure and a PaO₂/FiO₂ ratio of ≤200. Ethylene vinyl alcohol copolymer dissolved in dimethyl sulfoxide (DMSO), which was approved by the US FDA in July 2005, is used as an embolic agent for cerebral arteriovenous malformation (AVM). It is a biocompatible liquid polymer that precipitates and solidifies on contact with blood, thus forming a soft and spongy embolus. We report a case of ARDS following therapeutic embolization with ethylene vinyl alcohol copolymer for cerebral AVM under general anaesthesia. Experienced perioperative physicians adopted standard anaesthetic technique and monitoring for this procedure. Acute respiratory distress and hypoxaemia developed in the patient following extubation of the trachea. Infiltrates seen on postprocedural chest radiographs were consistent with pulmonary oedema. DMSO, the solvent for the ethylene vinyl alcohol copolymer, is excreted via the lungs after administration and we postulate that DMSO was the possible cause of ARDS in this patient. Monitoring of haemodynamic parameters (invasive blood pressure, electrocardiography) and ventilatory parameters (ETCO₂, SpO₂, airway pressure monitoring) are important in the recognition of this possible event. One should be vigilant and anticipate this complication following therapeutic embolization with ethylene vinyl alcohol polymer for the treatment of cerebral AVM.     

Transcatheter Embolization of a Renal Artery Aneurysm Using Ethylene Vinyl Alcohol Copolymer

Our aim was to treat a clinically silent renal artery aneurysm. The patient was a 76-year-old man with elevated prostate-specific antigen and prostata biopsies with a gradus II–III adenocarcinoma who was incidentally found to have an aneurysm in his right renal artery. We performed a successful transcatheter embolization of the aneurysm using ethylene vinyl alcohol copolymer (Onyx). To avoid migration of the liquid material into the parent artery, a balloon was inflated in the orifice of the neck of the aneurysm while the liquid was injected. Five-month follow-up computed tomography (CT) imaging confirmed total occlusion of the aneurysm.     

Therapeutic embolization of the venous bed using Vilan 500 in animal experiments

The experiment in four dogs verified a suitability of the Czechoslovak preparation Vilan 500, a copolymer of polyvinyl acetate - polyvinyl alcohol in 93% ethanol, for the embolism of venous vascular bed in the percutaneous, transfemoral catheterization way. In all four cases there was a complete occlusion of embolized spermatic or pararenal veins, verified by a control angiography after one hour and after three months. The prepared venous samples were also examined by histology and changes indicating intraluminar thrombotization and subsequent fibrous reconstruction were observed. In view of the results reached it may be concluded that the catheterization technique and the use of Vilan 500 is suitable as an alternative of non-surgical solution of varicocele.     

乙烯-乙燃基醇共聚物在脑动静脉畸形治疗中的研究进展

自1960年首次报道栓塞治疗脑动静脉畸形(AVM)来,现不仅成为外科手术前的重要辅助方法,而且在许多脑AVM的治疗中为首选[1]。理想的栓塞材料至少应具备以下条件:①良好的生物相容性;②能有效地栓塞血管病变;③无毒,不致癌,不致畸;④易制备;⑤易通过不同规格的导管;⑥能产生非损害     

Histologic long-term follow-up after embolization with polyvinyl alcohol particles.

A large facial vascular malformation was embolized with polyvinyl alcohol particles twice in 8 years. Resected tissue enabled long-term examination of this material, confirming its chemical inertness and revealing minimal tissue reaction to it apart from calcification. No particle migration, fragmentation, or absorption occurred. There was some recanalization of occluded vessels. Most vessels containing polyvinyl alcohol particles, and all of the larger vessels, were incompletely occluded, with particles becoming embedded in their walls.     

Endovascular Treatment of Acute Arterial Hemorrhage in Trauma Patients Using Ethylene Vinyl Alcohol Copolymer (Onyx)

Purpose  

This study was designed to determine the feasibility and efficacy of endovascular embolization with liquid embolic agent ethylene vinyl alcohol copolymer (Onyx) in patients with acute traumatic arterial bleeding.     

Treatment of a large type II endoleak via extraperitoneal dissection and embolization of a collateral vessel using ethylene vinyl alcohol copolymer (Onyx)

Type II endoleak is defined as persistent blood flow and pressure within an aneurysmal sac after endovascular deployment of a stent graft from patent aortic branches. This paper describes the simultaneous deployment of an endoluminal graft, with limited extraperitoneal dissection of a collateral vessel and use of an ethylene vinyl alcohol copolymer, Onyx, to obliterate a large type II endoleak.     

Percutaneous onyx embolization of cervical paragangliomas

Cervical paragangliomas are a group of vascular neoplasms arising from the extraadrenal neuroendocrine system. The present report describes a series of six cases of cervical paragangliomas successfully and safely embolized preoperatively by means of ethylene vinyl alcohol copolymer delivered by percutaneous needle punctures without the need for balloon protection. Although the results are promising, further studies are needed to confirm the superiority of this method versus other embolization techniques and embolic agents.     

Left Gastric Artery Aneurysm: Successful Embolization with Ethylene Vinyl Alcohol Copolymer (Onyx)

Patients with left gastric artery aneurysms present with hemorrhagic shock due to rupture or occasionally it is an incidental finding on abdominal CT examinations. Due to the increased morbidity and mortality from this condition, adequate diagnosis and treatment are essential. In this article we present a patient with a left gastric artery aneurysm treated with a new embolization agent, ethylene vinyl alcohol copolymer (Onyx).     

Endovascular treatment of a superior mesenteric artery aneurysm secondary to Behcet's disease with Onyx (ethylene vinyl alcohol copolymer)

Behcet’s disease is a complex multisystemic chronic inflammatory disease that is characterized by oral and genital aphtous ulcers and vasculitis. Aneurysms of major arteries are the most important cause of mortality in Behcet’s disease. Four patients with superior mesenteric artery (SMA) aneurysms related to Behcet’s disease have been reported in the literature. We report here the first successful endovascular treatment of a giant, wide-necked SMA aneurysm secondary to Behcet’s disease. We performed a balloon-assisted embolization technique using ethylene vinyl alcohol copolymer (Onyx, ev3, Irvine, CA, USA). There were no signs of recurrence during 2-year follow-up.     

Onyx Embolization of Sporadic Angiomyolipoma

Percutaneous embolization is the currently preferred treatment of symptomatic or ruptured renal angiomyolipomas (AMLs). Alcohol, microparticles, and coils are usually used. We present what is to our knowledge the first case of successful embolization of a solitary sporadic AML with the use of a new nonadhesive liquid embolic agent (ethylene vinyl alcohol copolymer; Onyx). Onyx injection was slow and controllable and achieved complete tumor devascularization, producing a characteristic appearance like a vascular cast. Short-term follow-up magnetic resonance imaging showed complete tumor necrosis without any recurrent pathologic vessels. The specific features, potential advantages in AML treatment, and technical limitations of this new liquid embolic agent are discussed.