Pancreatic arteriovenous malformation involving the duodenum embolized with ethylene-vinyl alcohol copolymer (Onyx)

Recent advances in nanomaterial-driven strategies for diagnosis and therapy of vascular anomalies

Nanotechnology has demonstrated immense potential in various fields, especially in biomedical field. Among these domains, the development of nanotechnology for diagnosing and treating vascular anomalies has garnered significant attention. Vascular anomalies refer to structural and functional anomalies within the vascular system, which can result in conditions such as vascular malformations and tumors. These anomalies can significantly impact the quality of life of patients and pose significant health concerns. Nanoscale contrast agents have been developed for targeted imaging of blood vessels, enabling more precise identification and characterization of vascular anomalies. These contrast agents can be designed to bind specifically to abnormal blood vessels, providing healthcare professionals with a clearer view of the affected areas. More importantly, nanotechnology also offers promising solutions for targeted therapeutic interventions. Nanoparticles can be engineered to deliver drugs directly to the site of vascular anomalies, maximizing therapeutic effects while minimizing side effects on healthy tissues. Meanwhile, by incorporating functional components into nanoparticles, such as photosensitizers, nanotechnology enables innovative treatment modalities such as photothermal therapy and photodynamic therapy. This review focuses on the applications and potential of nanotechnology in the imaging and therapy of vascular anomalies, as well as discusses the present challenges and future directions.

Pancreatic arteriovenous malformation treated with transcatheter arterial embolization: Two case reports and review of literature

BACKGROUND

Various treatment methods are available for the treatment of pancreatic arteriovenous malformation (P-AVM); however, there are no established treatment options for asymptomatic P-AVM.

CASE SUMMARY

A 47-year-old and a 50-year-old male patients sought treatment for P-AVM in the pancreas, which was incidentally detected during routine abdominal computed tomography and magnetic resonance imaging conducted as part of a health check-up. They underwent transcatheter arterial embolization (TAE), and over the course of a 9-year follow-up period, the AVM did not worsen and was asymptomatic.

CONCLUSION

TAE can be considered as an alternative treatment option for P-AVM in selective cases where patients are asymptomatic or have a high surgical risk.

An Update of Treatment of Pancreatic Arteriovenous Malformations

Pancreatic arteriovenous malformation is a rare entity (0.9%). There are about 200 articles available in PubMed. This review article includes 86 published articles, with 117 cases published after 2000. The median age at diagnosis was 51, and most of the patients were male (87.0%). The symptoms included pain, bleeding, pancreatitis, ulcers in the duodenum or stomach, varix formation, jaundice, and ascites. The diagnostic modalities were angiography, contrast-enhanced CT, MRI, and/or Ultra Sound. The most common treatments were surgery and embolization. The clinical success rate of embolization reported was 57.7%. The tailored embolization based on each agio-architecture had a clinical success rate of 80%. If embolic therapy is ineffective, surgical intervention should be considered.

A Cohesive Shear-Thinning Biomaterial for Catheter-Based Minimally Invasive Therapeutics

Shear-thinning hydrogels are suitable biomaterials for catheter-based minimally invasive therapies; however, the tradeoff between injectability and mechanical integrity has limited their applications, particularly at high external shear stress such as that during endovascular procedures. Extensive molecular crosslinking often results in stiff, hard-to-inject hydrogels that may block catheters, whereas weak crosslinking renders hydrogels mechanically weak and susceptible to shear-induced fragmentation. Thus, controlling molecular interactions is necessary to improve the cohesion of catheter-deployable hydrogels. To address this material design challenge, we have developed an easily injectable, nonhemolytic, and noncytotoxic shear-thinning hydrogel with significantly enhanced cohesion via controlling noncovalent interactions. We show that enhancing the electrostatic interactions between weakly bound biopolymers (gelatin) and nanoparticles (silicate nanoplatelets) using a highly charged polycation at an optimum concentration increases cohesion without compromising injectability, whereas introducing excessive charge to the system leads to phase separation and loss of function. The cohesive biomaterial is successfully injected with a neuroendovascular catheter and retained without fragmentation in patient-derived three-dimensionally printed cerebral aneurysm models under a physiologically relevant pulsatile fluid flow, which would otherwise be impossible using the noncohesive hydrogel counterpart. This work sheds light on how charge-driven molecular and colloidal interactions in shear-thinning physical hydrogels improve cohesion, enabling complex minimally invasive procedures under flow, which may open new opportunities for developing the next generation of injectable biomaterials.

Management of Pancreatico-duodenal arterio-venous malformation

Purpose

To describe the interventional management and clinical outcome of pancreatico-duodenal arterio-venous malformations (PDAVMs).

Material and Methods

Seven patients presenting a PDAVM (6 women, 1 male; mean age: 61) were retrospectively reviewed. Technical, clinical success and complications of embolization and surgical management of symptomatic PDAVMs were assessed. Technical success was defined as a complete occlusion of the PDAVM and clinical success as no clinical symptom or recurrence during follow-up. Patients with asymptomatic PDAVMs were followed clinically, by Doppler ultrasound and CT-angiography.

Results

Mean follow-up time was 69 months (15-180). Five symptomatic patients presented with upper gastrointestinal bleeding (n=3), ascites (n=1), and abdominal pain (n=1). Two patients were asymptomatic. The PDAVMs were classified as follow: Yakes I (1), IIIa (2), IIIb (3) and IV (1). Five symptomatic patients were treated with 9 embolization sessions with arterial approach (onyx®, glue, coils) in 7 and venous approach in 2 (plugs, coils, covered stents, STS foam and onyx®). Technical success of embolization was 60% (3/5). Devascularization was incomplete for 2 Yakes IIIB patients. Clinical success of embolization was estimated at 80% (4/5) as one patient required additional surgery (Whipple) because of persistent bleeding. One splenic vein thrombosis was treated successfully by mechanical thrombectomy and heparin. No recurrence occurred during follow-up. No progression was documented in asymptomatic patients.

Conclusion

Embolization of symptomatic PDAVMs is effective and surgery should be performed in second intention. Complete devascularization is more difficult to obtain in Yakes III PDAVM.

Management of pancreatic arteriovenous malformation: Case report and literature review

INTRODUCTION

Pancreatic arteriovenous malformation (P-AVM) is a rare vascular malformation. Fewer than 200 cases have been reported. The clinical manifestations lack specificity. Common symptoms include abdominal pain, gastrointestinal hemorrhage, and jaundice, which is easily confused with other disorders.

PATIENT CONCERNS

A 42-year-old man received TAE due to abdominal pain caused by P-AVM in a local hospital, melena and abdominal pain occurred in a short time after TAE.

DIAGNOSIS

The patient was diagnosed as P-AVM which was confirmed by computed tomography and digital subtraction angiography.

INTERVENTIONS

A pylorus-preserving pancreatoduodenectomy was successfully performed after diagnosis was made.

OUTCOMES

The patient recovered with no complications two weeks after surgery, and no sign of recurrence was found during the 4-mo follow-up period.

CONCLUSION

In our experience, TAE may have limitations in the treatment of P-AVM and surgical resection should be considered as the treatment of choice.

Non-Adhesive Liquid Embolic Agents in Extra-Cranial District: State of the Art and Review of the Literature

This review focuses on the use of “new” generation of non-adhesive liquid embolic agents (NALEA). In literature, non-adhesive liquid embolic agents have mainly been used in the cerebral district; however, multiple papers describing the use of NALEA in the extracranial district have been published recently and the aim of this review is to explore and analyze this field of application. There are a few NALEA liquids such as Onyx, Squid, and Phil currently available in the market, and they are used in the following applications: mainly arteriovenous malformations, endoleaks, visceral aneurysm or pseudoaneurysm, presurgical and hypervascular lesions embolization, and a niche of percutaneous approaches. These types of embolizing fluids can be used alone or in combination with other embolizing agents (such as coils or particles) so as to enhance its embolizing effect or improve its possible defects. The primary purpose of this paper is to evaluate the use of NALEAs, predominantly used alone, in elective embolization procedures. We did not attempt a meta-analysis due to the data heterogeneity, high number of case reports, and the lack of a consistent follow-up time period.

Transportal embolization for pancreatic arteriovenous malformation via a recanalized paraumbilical vein: A case report

A 62-year-old man with liver cirrhosis presented with deterioration of liver function. Imaging studies revealed an arteriovenous malformation (AVM), with a dilated venous space, at the pancreatic head. Transarterial embolization of the AVM, using microcoils, was performed, although many feeding arteries remained. As the transarterial embolization was incomplete, further liver function deterioration was a possibility. In fact, 1 year after the procedure, the patient was referred back to our hospital for treatment of massive ascites and liver function deterioration. Transportal embolization of the dilated venous space was performed, using microcoils via the recanalized paraumbilical vein, with no enhancement of the AVM. No complications occurred. Based on our experience, we propose transportal embolization as an effective treatment option for pancreatic AVM.

Embolization of peripheral arteriovenous malformations and fistulas with precipitating hydrophobic injectable liquid (PHIL®)

PURPOSE

This paper reports on the preliminary experience of a single center in the embolization of peripheral AVMs and fistulas with precipitating hydrophobic injectable liquid (PHIL^®), focusing on technical aspects and short-term clinical outcomes.

MATERIALS AND METHODS

Seven males and five females were included in this study, mean age 42.16 years. For ten of them, it was the first embolization treatment; two had been previously treated with Onyx^® embolization. PHIL^® was injected with a transarterial approach without other embolics during the same procedure. Lesions were localized in small bowel (1), colon (1), head face (5), forefoot (1), uterus (1) and thorax (3); all were symptomatic. After 30-day clinical follow-up, a contrast-enhanced CT or MR was acquired at 3 months from intervention to detect eventual lesion residual.

RESULTS

After a single embolization procedure, complete technical success was obtained in 50%, while clinical improvement without additional therapies was appreciable in all patients. No technical failure occurred; in two cases, a small amount of PHIL^® proximally refluxed in nontarget vessels without clinical effects. No tattooing effects of superficial lesions neither artifacts at CT and cone-beam CT controls were evident.

CONCLUSIONS

PHIL^® seems to be a safe and effective liquid embolic agent for the treatment of peripheral AVMs and fistulas; although a direct comparison between PHIL and Onyx was not performed, PHIL might present the advantages of reduced artifacts at postprocedural CT scan and no need for shaking time preparation, but it is more expensive due to lower volume of product for each package and slightly less radiopaque at fluoroscopy.

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Thrombosis of pancreatic arteriovenous malformation induced by diagnostic angiography: case report

Background

We report on a case of pancreatic arteriovenous malformation (PAVM) that obliterated shortly after diagnostic angiography (DSA). PAVM is a rare anomaly that presents with upper abdominal pain, signs of acute pancreatitis and massive gastrointestinal bleeding. The management of PAVM is rather complex, with complete treatment usually accomplished only by a total extirpation of the affected organ or at least its involved portion. DSA prior to treatment decisions is helpful for characterizing symptomatic PAVM, since it can clearly depict the related vascular networks. In addition, interventional therapy can be performed immediately after diagnosis.

Case presentation

A 39-old male was admitted due to recurring upper abdominal pain that lasted several weeks. Initial examination revealed the absence of fever or jaundice, and the laboratory tests, including that for pancreatic enzymes, were unremarkable. An abdominal ultrasound (US) showed morphological and Doppler anomalies in the pancreas that were consistent with a vascular formation. A subsequent DSA depicted a medium-sized nidus, receiving blood supply from multiple origins but with no dominant artery. Coil embolization was not possible due to the small caliber of the feeding vessels. In addition, sclerotherapy was not performed so as to avoid an unnecessary wash out to the non-targeted duodenum. Consequently, the patient received no specific treatment for his symptomatic PAVM. A large increase in pancreatic enzymes was noticed shortly after the DSA procedure. Imaging follow-up by means of CT and MRI showed small amounts of peripancreatic fluid along with a limited area of intra-parenchymal necrosis, indicating necrotizing pancreatitis. In the post-angiography follow-up the patient was hemodynamically stable the entire time and was treated conservatively. The symptoms of pancreatitis improved over a few days, and the laboratory findings returned to normal ranges. Long-term follow-up by way of a contrast-enhanced CT revealed no recanalization of the thrombosed PAVM.

Conclusion

The factors associated with the obliteration of PAVM during or after DSA are poorly understood. In our case it may be attributed to the low flow dynamics of PAVM, as well as to the local administration of a contrast agent. Asymptomatic PAVM, as diagnosed with non-invasive imaging techniques, should not be evaluated with DSA due to the potential risk of severe complications, such as acute pancreatitis.

Transcatheter embolization of pancreatic arteriovenous malformation associated with recurrent acute pancreatitis

Pancreatic arteriovenous malformation (PAVM) is extremely rare; even rarer is its association with pancreatitis. The authors report a case of PAVM causing recurrent episodes of acute pancreatitis in a 46-year-old male. Patient refused surgery and was treated with transcatheter arterial embolization using liquid embolic agent (mixture of n-butyl-2-cyanoacrylate glue and lipiodol), which resulted in a significant decrease in the size of the PAVM.

Two Unusual but Treatable Causes of Refractory Ascites After Liver Transplantation

Refractory ascites (RA) is thought to complicate the postoperative course of 5-7% (Nishida et al. in Am J Transplant. 6: 140-149, 2006; Gotthardt et al. in Ann Transplant. 18: 378-383, 2013) of liver transplant recipients. RA after liver transplantation is often a frustrating diagnostic dilemma with few good management options unless an obvious mechanical factor is identified. Supportive therapies often fail until a treatable precipitating cause is identified and removed. We describe two patients who developed RA following liver transplantation for primary sclerosing cholangitis, and hepatitis C and alcoholic liver disease, respectively. The cause for RA was hyperkinetic portal hypertension secondary to splenomegaly in the first case and a pancreatic AVM in the 2nd case. After failure of other interventions, surgical splenectomy resulted in immediate and durable resolution of the previously intractable ascites.

Embolization of traumatic and non-traumatic peripheral vascular lesions with Onyx

PURPOSE

The aim of our study is to verify the feasibility and the efficacy of Onyx as embolization agent in the treatment of traumatic and non-traumatic peripheral vascular lesions.

MATERIALS AND METHODS

In the period between September 2006 and March 2012, we treated with Onyx 26 patients (14 males/12 females; age range, 18-85 years old; mean age, 65 years old), 11 of which with traumatic peripheral vascular lesions and 15 with non-traumatic vascular lesions (9 neoplastic hemorrhagic lesions, 3 arteriovenous malformations (AVMs) and 3 aneurysms). Follow-up controls were performed with clinical examination and by multidetector computed tomography (MDCT) imaging 1, 6, and 12 months after the procedure.

RESULTS

All peripheral vascular lesions were embolized with Onyx; 3 patients with aneurysms were treated with Onyx associated with endovascular coils. Four elective and 22 emergency embolization procedures were performed. In all patients, we obtained cessation of bleeding and the complete and permanent embolization of all vascular lesions.

CONCLUSIONS

Onyx is an effective and safe embolization agent for peripheral vascular lesions.

Ethylene vinyl alcohol copolymer (Onyx®) in peripheral interventional radiology: indications, advantages and limitations

Onyx(®) is a remarkable liquid embolizing agent that may allow a well-trained operator to undertake challenging embolization procedures. In multiple interventional radiology indications, the physico-chemical properties of Onyx(®) allow safe embolization. The purpose of this article is to review the advantages and disadvantages of Onyx(®) and identify its main indications.

A successful case of transcatheter arterial embolization with n-butyl-2-cyanoacrylate for pancreatic arteriovenous malformation

A 57-year-old man was referred and admitted to our hospital for treatment of a symptomatic pancreatic mass. Pancreatic arteriovenous malformation (AVM) was diagnosed based on the findings of contrast-enhanced computed tomography (CT) and angiography, and transcatheter arterial embolization (TAE) with N-butyl-2-cyanoacrylate (NBCA) was performed without complications. The patient's symptoms subsequently improved after TAE, and resolution of the pancreatic AVM was detected on contrast-enhanced CT performed six months after the embolization procedure. This case indicates that TAE with NBCA is a safe and effective treatment for pancreatic AVM.

Pancreatic arteriovenous malformation

BACKGROUND

Pancreatic arteriovenous malformation is very rare, but may cause significant clinical symptoms such as catastrophic bleeding. Herein, we discuss the clinical presentation and management of patients pancreatic arteriovenous malformations.

METHODS

The data pool for the analysis was collected from pancreatic arteriovenous malformation cases encountered by our institution and sporadic case reports in the English literature.

RESULTS

A total of 89 cases of pancreatic arteriovenous malformation were collected for this study, including 59 cases of arteriovenous malformation in the pancreatic head (62.3 %) and 30 in the pancreatic body-tail (33.7 %). The most commonly associated complications for overall cases of pancreatic arteriovenous malformation were bleeding (50.6 %), pancreatitis (16.9 %), portal hypertension (6.7 %), and pseudocyst (3.4 %). The most common presenting symptom of pancreatic arteriovenous malformation was gastrointestinal bleeding (47.2 %), followed by epigastric pain (46.1 %). Surgery (43.8 %) was the most common treatment for pancreatic arteriovenous malformation cases, followed by transarterial embolization (11.2 %), a combination of surgery and transarterial embolization (10.1 %), and radiotherapy (2.2 %). No intervention was done for 29.2 % of the cases of pancreatic arteriovenous malformation.

CONCLUSIONS

Pancreatic arteriovenous malformation occurs most commonly in the pancreatic head; gastrointestinal bleeding is the main symptom. Surgical resection or transarterial embolization appears to be indicated in patients with symptomatic pancreatic arteriovenous malformation.