Guidelines for Peripheral and Visceral Vascular Embolization Training

CIRSE Standards of Practice for the Endovascular Treatment of Visceral and Renal Artery Aneurysms and Pseudoaneurysms

BACKGROUND

Endovascular treatment of visceral and renal artery aneurysms and pseudoaneurysms is an effective, minimally invasive treatment that has been successfully used since the early 1990s, with refined and expanded techniques and tools currently offering excellent outcomes. Due to increased detection of such lesions in recent years, many of which are asymptomatic, revision of the indications for intervention and the correct endovascular treatment approaches has become essential.

PURPOSE

This document will presume that the indication for treatment is clear and approved by the multidisciplinary team and will define the standards required for the performance of each intervention, as well as their relative advantages and limitations. CIRSE Standards of Practice documents are not intended to impose a standard of clinical patient care, but recommend a reasonable approach to, and best practices for, the performance of the endovascular treatment of visceral and renal artery aneurysms and pseudoaneurysms.

METHODS

The writing group was established by the CIRSE Standards of Practice Committee and consisted of five clinicians with internationally recognised expertise in endovascular treatments. The writing group reviewed the existing literature on visceral and renal artery aneurysms and pseudoaneurysms, performing an evidence search using PubMed to identify publications in English and relating to human subjects from 1990 to 2022. The final recommendations were formulated through consensus.

RESULTS

Endovascular treatment has an established role in the successful management of visceral and renal artery aneurysms and pseudoaneurysms, and this Standards of Practice document provides up-to-date recommendations for its safe performance.

Results from the First-in-Human Study of the Caterpillar™ Arterial Embolization System

PURPOSE

To assess occlusion success and adverse events associated with the use of a self-expanding device for peripheral artery embolization.

METHODS

This prospective, single-arm, feasibility study was conducted using the Caterpillar™ Arterial Embolization Device composed of opposing nitinol fibers and a flow-occluding membrane. Twenty patients (24 embolization sites) were treated at four investigational centers in New Zealand and Australia and followed for 30 days. Embolization sites included mesenteric, accessory renal, and iliac arteries and their branches. Primary outcome measures were peri-procedural occlusion confirmed by angiography and freedom from device-related serious adverse events (SAEs) at 30 days. Secondary observations included time to occlusion and assessment of adverse events.

RESULTS

Peri-procedural occlusion was 100%, and freedom from a device-related SAE was 94.7% at 30 days. One patient had abdominal bloating that required hospitalization deemed possibly related to the device or procedure. Twenty-two of 24 embolization sites were occluded with one device (91.7%). Mean procedure duration was 11.7 ± 8.6 min (device deployment time: 1.8 ± 1.0 min), and mean fluoroscopy time was 241 ± 290.7 s. All embolization sites occluded during the procedure with 62.5% occluded within three minutes and 91.6% occluded within ten minutes. No devices migrated or required re-embolization. Freedom from device- and procedure-related adverse events was 84.2%. One patient died from aortic rupture during a subsequent adjunctive abdominal aortic endovascular procedure deemed unrelated to the embolization device or procedure.

CONCLUSIONS

This first-in-human study of the Caterpillar embolization device achieved peri-procedural occlusion in all patients with a 94.7% freedom from device-related SAE at 30 days.

LEVEL OF EVIDENCE

Level 2b-prospective, multicenter, single-arm, first-in-human clinical study. Pre-specified endpoints were analyzed using descriptive statistics.

In Vitro Study of Particle Transport in Successively Bifurcating Vessels

To reach a predictive understanding of how particles travel through bifurcating vessels is of paramount importance in many biomedical settings, including embolization, thromboembolism, and drug delivery. Here we utilize an in vitro model in which solid particles are injected through a rigid vessel that symmetrically bifurcates in successive branching generations. The geometric proportion and fluid dynamics parameters are relevant to the liver embolization. The volumetric flow field is reconstructed via phase-contrast magnetic resonance imaging, from which the particle trajectories are calculated for a range of size and density using the particle equation of motion. The method is validated by directly tracking the injected particles via optical imaging. The results indicate that, opposite to the common assumption, the particles distribution is fundamentally different from the volumetric flow partition. In fact, the amount of delivered particles vary substantially between adjacent branches even when the flow is uniformly distributed. This is not due to the inertia of the particles, nor to gravity. The particle distribution is rather rooted in their different pathways, which in turn are linked to their release origin along the main vessel cross-section. Therefore, the tree geometry and the associated flow streamlines are the prime determinant of the particle fate, while local changes of volumetric flow rate to selected branches do not generally produce proportional changes of particle delivery.

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.

Abdominal surgical emergencies in patients with advanced cancer

Abdominal emergency in an advanced oncologic setting is defined as an acute life-threatening abdominal pathology in a patient with incurable cancer. These include bowel obstruction, infections and, more rarely, hemorrhage. To benefit the patient, surgery should both increase the survival and improve the quality of life. These two goals are of equal importance and must be achieved together. This is difficult because these patients are frail, often malnourished and have a poor performance status. They also have a high risk of post-operative morbidity and mortality, a major risk of symptom recurrence and a limited life expectancy. For patients near the end-of-life, a therapeutic decision for surgical intervention must respect ethical and legal standards. This review reports the surgical outcomes and median survival of these patients, specifies rules that must be known and respected, and presents non-operative interventional alternatives.

Angiographic embolization for major trauma in a low-middle income healthcare setting--A retrospective review

INTRODUCTION

Interventional radiology (IR) provides a range of adjunctive techniques to assist with hemorrhage control after trauma that can be employed pre- or post-operatively. The role of IR in lower-middle income countries (LMICs) remains unexplored. This study describes the use of adjunctive angioembolization (AE) in severely injured patients following its recent implementation at an urban trauma center in a LMIC.

METHODS

Adult patients (≥ 16 years) requiring AE from 2011 to 2013 at a single trauma-care facility were included. Data was collected on demographic parameters, transfer status, injury severity score (ISS), emergency resuscitation characteristics, AE and operative characteristics, complications, and in-hospital mortality. Descriptive analyses were performed.

RESULTS

Thirty six patients underwent AE for trauma-related hemorrhagic complications and were included in the study. Average age was 31.5 (± 11.3) years with a male preponderance (91.7%). Penetrating trauma (61.1%) was the most common type of injury. The primary mechanism of injury was gunshot (58.3%). The median ISS was 24 (IQR: 20-29). Pre-operative AE was performed in 23 (63.9%) patients and these patients had a lower median ISS (22) than those who underwent post-operative AE (p = 0.015). Hepatic (55.6%) and pelvic (33.3%) trauma more commonly required radiological intervention. Bleeding from the right hepatic (n = 14), and the right internal iliac (n = 6) arteries and/or their branches, were more often embolized. Microcoils were the preferred AE agents (61.1%). Median length of hospital stay was 7.5 (IQR: 3-14) days. Eight (22.2%) patients did not survive.

CONCLUSION

With the availability of multi-detector computed tomography and a dedicated interventional radiology suite, implementation of AE for the care of trauma patients in LMIC settings is possible.

Transcatheter embolisation of iatrogenic renal vascular injuries

PURPOSE

The aim of our study was to review our experience and long-term follow-up in the treatment of iatrogenic renal vascular injuries using transcatheter embolisation.

MATERIALS AND METHODS

Our retrospective analysis of cases collected in two interventional centres consists of a total of 21 patients who underwent renal arterial embolisation (RAE) for iatrogenic arterial kidney bleeding. Biopsy (n = 4), percutaneous nephrolithotomy (n = 4), nephron-sparing surgery (n = 4), guidewire-induced arterial perforation during coronary angiography or renal stenting (n = 3), percutaneous nephrostomy (n = 3), renal endopyelotomy/pyeloplasty (n = 2) and surgical nephrectomy were the iatrogenic causes. Seven patients presented with haemodynamic instability requiring blood transfusion (33.3%), the remaining were haemodynamically stable (66.7%). Diagnostic renal angiography revealed 9 actively bleeding vessels, 6 pseudoaneurysms, 4 arteriovenous fistulas and 1 arterio-calyceal fistula. In one patient selective renal arteriography was negative probably because the bleeding observed at CT angiography was self-limited. Twenty-one embolisation procedures were performed in 20 patients; one patient required a second embolisation 3 h after the first one. Embolisation was performed with microcoils, polyvinyl alcohol particles, embospheres, spongostan emulsion and vascular plug.

RESULTS

The technical success rate was 100%. The overall clinical success rate was 95%. Apart from a patient who died due to disseminated intravascular coagulation, no major complications requiring intensive care treatment were encountered during or after the procedures. No patient required emergency surgery or subsequent surgical treatment. No statistically significant differences in eGFR or renal function stage appeared after RAE.

CONCLUSIONS

Percutaneous treatment can be proposed as a first-line treatment in iatrogenic renal arterial injuries, resulting in a safe and effective procedure.