Open repair, endovascular repair, and conservative management of true splenic artery aneurysms

Embolization and sclerotherapy for head and neck arteriovenous malformations with uncontrollable torrential bleeding

Torrential bleeding is a rare and life-threatening complication of arteriovenous malformations (AVMs). We report a case of head and neck AVMs present with uncontrollable torrential bleeding, which was treated with embolization and sclerotherapy. Then we explored the potential multidisciplinary handling of the procedure for this kind of case. A 25-year-old female patient was born with right face and head AVMs. The AVMs had grown gradually and ruptured spontaneously with uncontrollable torrential bleeding before admission. Emergent direct hemostasis, nasotracheal intubation, and staged embolization and sclerotherapy were carried out on this patient. Finally, the bleeding stopped and the wound healed successfully. Embolization and sclerotherapy are effective for head and neck AVMs with uncontrollable torrential bleeding. Multidisciplinary collaboration is needed to achieve a good outcome.

Ethanol Embolization of Chest Wall Arteriovenous Malformations: Four-Year Findings

OBJECTIVES

To summarize the clinical characteristics and investigate the efficacy of ethanol embolotherapy in the treatment of chest well arteriovenous malformation (AVM). Treatment-associated complications were also explored.

MATERIALS AND METHODS

Between March 2017 and August 2021, 32 consecutive patients (mean age, 23.7 years; age range, 5-54 years) who underwent ethanol embolotherapy for chest well AVMs under general anesthesia were included in this study. Embolization was performed through a direct puncture, transarterial catheterization, or a combination of the 2 procedures. The mean follow-up duration after the last treatment was 18.0 months (range, 3-42 months). The degree of devascularization on follow-up (assessed using angiography or computed tomography), and the clinical signs and symptoms of AVMs were evaluated as the therapeutic outcomes. The major and minor complications associated with the procedures were recorded.

RESULTS

A total of 103 embolization procedures (mean, 3.2; range, 2-7) comprising 101 ethanol embolization and 2 coil embolizations were performed on 32 patients with chest wall AVMs. The AVM nidus was accessed through the transarterial approach alone in 4 patients, by direct puncture in 11, and a combined procedure in 17 patients. Overall, more than 80% of the procedures were performed using the combined approach. Complete AVM devascularization was achieved in 12 (37.5%) patients. Moreover, 76% to 99% AVM was achieved in 18 patients (56.3%), and 50% to 75% in 2 patients (6.3%). Bleeding, pain, heart failure, and cosmetic deformities were the indications for treatment. For 3 patients (3/32, 9.4%) who had bleeding, the treatment stopped the hemorrhage. Complete pain relief was reported in 8 patients (8/32, 25.0%), whereas complete relief from congestive heart failure post-embolization was observed in 5 of the 6 patients with congestive heart failure (5/6, 83.3%). Complete correction of cosmesis deformities after embolization was achieved in 10 patients (10/32, 31.3%). Two patients who underwent surgery to correct persistent deformity after embolization only showed insignificant improvement. In addition, 6 (18.8%) patients developed 13 complications including blister, necrosis, hemothorax, transient hemoglobinuria, and transient pulmonary artery hypertension.

CONCLUSIONS

Ethanol embolotherapy is a safe and effective procedure for chest well AVMs. Surgery is required for some patients with residual cosmesis deformity.

CLINICAL IMPACT

Currently, there is no standard treatment for chest well AVMs due to their rarity and high heterogeneity. The present study shows that thanol embolotherapy is a safe and clinically effective treatment procedure for the chest well AVMs. Transarterial embolization in combination with direct puncture embolization can reach the AVM nidus. Ethanol embolotherapy can achieve complete obliteration of the AVM nidus in the majority of patients. Surgery may still be needed to correct cosmetic deformity after embolization. The present study provides valuable evidence to inform clinical decision-making.

Multidisciplinary approach to hand arteriovenous malformations: treatment strategies and clinical outcomes - insights from a 25-year experience at a single vascular anomalies center

OBJECTIVE

Hand arteriovenous malformations (AVMs) are extremely difficult to manage for their functional importance and cosmetic disfiguration. A single-center retrospective study was conducted to identify long-term outcomes of multidisciplinary team management of hand AVMs.

METHODS

Institutional review board approved this retrospective study. Multidisciplinary vascular anomalies center data was reviewed from 1995 to 2023. Patient demographics, Schobinger's AVM stage, sclerotherapy details, surgical history, and adverse events after sclerotherapy were reviewed.

RESULTS

A total of 150 patients with hand AVMs visited our hospital from 1995 to 2023, with a mean age of 33 years (range, 1-75 years), and 91 were females. Forty-four patients were Schobinger stage II, and 106 were stage III. Sclerotherapy was performed on 101 patients (67%) with 320 sessions. Angiographic devascularization rates after sclerotherapy were: 16 with 100%, 30 with over 90%, 34 with 50% to 90%, 15 with 0% to 50%, and six showed aggravation. Sclerotherapy-related adverse events occurred in 123 of 320 sessions (39%), with 112 minor and 11 major events. Fifteen patients (15%) eventually underwent amputation surgery a mean of 1618 days after sclerotherapy for necrosis (n = 3) and delayed complications (n = 12). Thirteen patients (9%) underwent primary surgical amputation for ulcers or bleeding (all Schobinger stage III). Thirty-six patients (24%) were followed without any procedure.

CONCLUSIONS

Multidisciplinary management of hand AVMs shows varied long-term outcomes. Although sclerotherapy is effective for many patients, it carries a significant risk of adverse events. The necessity for amputation in some cases highlights the severity of advanced AVMs and the need for individualized treatment approaches.

Congestive colopathy in a patient with arteriovenous malformations and multiple mesenteric thromboses

Arteriovenous malformations (AVMs) in mesenteric vessels are exceptionally rare. These congenital vascular anomalies lead to direct vascular flow between the highly pressured arterial system and the low-pressure venous system. We describe the case of a patient with prior left colectomy for splenic flexure colonic adenocarcinoma presenting with persistent abdominal pain after developing multiple mesenteric thromboses. CT and colonoscopy showed left hemicolon congestion, anastomotic stenosis and mucosal oedema. Mesenteric angiogram revealed AVMs in the right colic and left colic arteries. Embolisation of the left colic AVM led to symptom resolution without recurrence at interval follow-up.

Staged endovascular and open surgical approach for treatment of a giant left upper back arteriovenous malformation

We present a case of a symptomatic, giant, left upper back arteriovenous malformation that was treated through a staged endovascular and open approach. Through a series of embolizations, followed by resection, we were able to preserve the limb and upper back neurovascular supply, demonstrating an approach to preserve sensation and function and improving quality of life.

Soft Tissue Vascular Anomalies of the Extremities: A Proposed Diagnostic Approach

This narrative review aims to summarise the classification of vascular anomalies, their clinical presentation, and their radiological features to propose a diagnostic algorithm to approach patients with suspected soft tissue vascular anomalies of the extremities. The management of vascular anomalies necessitates a multidisciplinary approach. Clinical presentation and physical examination are sufficient in most cases to achieve a correct diagnosis. This is especially true for small congenital lesions of the skin and subcutaneous tissue. Imaging is used for accurate characterization of these lesions, especially in cases of atypical or vague clinical presentation, and to assess extension in cases of lesions that are larger and localized in deeper tissues.

Congenital Vascular Malformations in Children: From Historical Perspective to a Multidisciplinary Approach in the Modern Era-A Comprehensive Review

Congenital vascular malformations (CVMs) are the result of an aberrant development during embryogenesis. Although these lesions are present at birth, they are not always visible yet. Once symptomatic, patients suffer from pain, bleeding, ulcers, infections or lymphatic leakage, depending on the subtype of vessels involved. Treatment includes conservative management, surgery, sclerotherapy, embolization and pharmacological therapy. The clinical presentation varies widely and treatment can be challenging due to the rarity of the disease and potential difficulties of treatment. This review gives an overview of the historical developments in diagnosis and classification and exposes the key elements of innovations in the past decades on the identification of genetic mutations and personalized treatment. These advances in the field and a multidisciplinary approach are highly valuable in the optimization of clinical care aimed at both curing or stabilizing the CVM and pursuing physical and psychosocial wellbeing.

Hemodynamic Study of Cerebral Arteriovenous Malformation: Newtonian and Non-Newtonian Blood Flow

OBJECTIVE

Arteriovenous malformation is a disease of the vascular system that occurs mainly in the cerebral arteries and spine. Numerical simulation as a powerful method is used to investigate the Cerebral Arteriovenous Malformation hemodynamic after occlusion of the abnormality step by step by embolization.

METHODS

The computed tomography (CT) Angiographic imaging data of 2 patients are used and a geometric model is extracted by the Mimics software. Numerical simulation of blood flow is performed in both Newtonian and non-Newtonian models. The Navier-Stokes and continuity governing equations are solved by a finite element method using the COMSOL Multiphysics software (the commercial computational fluid dynamics (CFD) simulation software). To validate the numerical results, the real data on blood flow rate in the feeding artery and draining veins are used, as well as angiographic images at different times.

RESULTS

Regarding the comparison of pressure contours for different occlusions of 0, 30, 50, and 90%, by increasing the amount of occlusion in the nidus, there is an increase in the blood pressure. Regarding the comparison of the blood flow velocity in the feeding artery, draining veins, and inside the AVM nidus for Newtonian and non-Newtonian models, there is a significant difference between these 2 simulations in vessels with smaller dimensions (such as vessels inside the nidus).

CONCLUSIONS

By increasing the amount of nidus occlusion, the blood pressure is increased, so the blood supply process is better. According to a significant difference between the Newtonian and non-Newtonian simulations in vessels with smaller dimensions (such as vessels inside the nidus), therefore, non-Newtonian simulation should be done for different occlusions of 30, 50, and 90%.

Intraoperative Neuromonitoring during Peripheral Arteriovenous Malformation Embolization

PURPOSE

To evaluate whether intraoperative neuromonitoring (IONM), including pre-embolization lidocaine injection challenge ("provocative testing") is associated with reduced risk of irreversible nerve injury during embolization of peripheral arteriovenous malformations (AVMs).

MATERIALS AND METHODS

Medical records of patients with peripheral AVMs who underwent embolotherapy with IONM with provocative testing between 2012 and 2021 were reviewed retrospectively. Data collected included patient demographic characteristics, AVM location and size, embolic agent used, IONM signal changes after lidocaine and embolic agent injections, postprocedural adverse events, and clinical outcomes. Decisions regarding whether embolization would proceed at specific locations were based on IONM findings after the lidocaine challenge and as embolization proceeded.

RESULTS

A cohort of 17 patients (mean age, 27 years ± 19; 5 women) who underwent 59 image-guided embolization procedures with adequate IONM data was identified. No permanent neurologic deficits occurred. Transient neurologic deficits were observed in 3 patients (4 sessions), comprising skin numbness (2 patients), extremity weakness (1 patient), and extremity weakness and numbness (1 patient). All neurologic deficits resolved by postoperative day 4 without additional treatment.

CONCLUSIONS

IONM, including provocative testing, during AVM embolization may minimize potential nerve injury.

Hybrid surgery of arteriovenous malformation and aneurysm of the sole

The study describes the successful treatment of a rare type of arteriovenous malformation (AVM) in the sole using hybrid surgery, which consists of open resection and embolization. Moreover, the possibility of utilizing ultrasound during examination in addition to angiography for the diagnosing of AVM of the sole is proposed.

Lower-Extremity Arteriovenous Malformation Masquerading as Peripheral Artery Disease

An arteriovenous malformation (AVM) refers to an anomalous, direct connection between an artery and a vein. Typically, these two vessels are interposed by high-resistance capillary beds, the absence of which results in a high-flow system from an artery into a vein. Venous vessel walls are not designed to handle such high-pressure blood flow, and their vessel wall structure becomes permanently altered and weakened. For this reason, AVMs are at an increased risk for hemorrhages and ruptures. AVMs present with a spectrum of symptoms, ranging from skin discoloration, ischemia in distal tissues, and heart failure from arteriovenous shunting. Here, we present a case of a patient who underwent amputation of his second left toe, initially thought to be a result of peripheral arterial disease (PAD) due to his extensive smoking history. Further imaging findings revealed a rare lower-extremity AVM as the source of his ischemia, not PAD. Ultimately, the treatment of the vascular anomaly and resolution of the patient's symptoms were achieved via transarterial embolization. This case emphasizes the importance of looking beyond PAD as the cause of distal lower-extremity ischemia and provides insights into an uncommon and often missed diagnosis of extracranial AVMs.

Embolo/sclerotherapy for the treatment of hand arteriovenous malformations: a single-center retrospective cohort experience

Purpose

To retrospectively report our preliminary experience of treating hand arteriovenous malformations (AVMs) with embolo/sclerotherapy.

Materials and methods

Retrospectively review the demographics, treatment detail, outcome data, and complications of 13 consecutive patients with hand AVMs from January 2018 to December 2021. We embolize the dominant outflow vein with elastic coils and then use absolute ethanol or polidocanol for intravascular sclerotherapy and bleomycin for interstitial sclerotherapy.

Results

Yakes type II presents in four lesions, type IIIa in six, and type IIIb in three. A total of 29 treatment episodes were conducted for the 13 patients (1 episode for 3 patients, 2 for 4 patients, and 3 for 6 patients; the repeated treatment rate was 76.9%). The mean stretched length of coils for 1 treatment episode was 95 cm. The mean absolute ethanol dosage was 6.8 ml (range 4-30 ml). In addition, 10 ml of 3% polidocanol foam was injected and interstitial sclerotherapy with 150,000 IU bleomycin was performed on every patient. The post-operative arterial-dominant outflow vein pressure index (AVI) increased in the 29 procedures (6.55 ± 1.68 vs. 9.38 ± 2.80, P < 0.05). The Mann-Whitney U test showed that the post-operative AVI was higher in patients without re-intervention (P < 0.05). Local swelling occurred after all the procedures. Blistering occurred in 6 of the patients in 13 (44.8%) of the 29 procedures. Superficial skin necrosis occurred in 3 of the patients in 5 (17.2%) of the 29 procedures. The swelling, blistering, and superficial skin necrosis recovered within 4 weeks. No finger amputation occurred. The follow-up time was 6 months. The 6-month assessment of clinical improvement after the last treatment episode showed that 2 patients were cured, 10 were improved, and 1 remained unchanged. With regard to angiographic evaluation, 9 showed partial response and 4 complete response.

Conclusion

Embolo/sclerotherapy can be effective and safe for hand AVM. The AVI increased significantly after embolo/sclerotherapy, and the index may be valuable in predicting recurrence in further study.

A successful bilateral iliac arteries ligation as an emergency management to a life-threatening AVM bleeding: A case report and literature review

INTRODUCTION AND IMPORTANCE

Uterine arteriovenous malformation (AVM) is a defect due to direct connection between uterine arteries and veins, it has wide range of symptoms and severity, usually causes vaginal bleeding which may be mild or severe and may cause death in some rare cases. Diagnostic methods may include ultrasound, MRI, CT and/or angiography which reveal a high blood flow hypoechoic mass. Many options have been applied as management procedures, including invasive and noninvasive procedures, aiming to save patient life and stop bleeding or preserve fertility in the less severe cases.

CASE PRESENTATION

21 years old primigravida patient developed episodes of severe vaginal bleeding due to AVM after complete molar pregnancy evacuation and chemotherapy, managed successfully by bilateral internal iliac artery ligation and applying compression sutures on the uterus and continuing with compound medical treatment, trying to preserve fertility and ability to get pregnant in the future.

CLINICAL DISCUSSION

We point out AVM types, its sings, symptoms and the diagnostic procedures. We discuss the bilateral iliac artery ligation and applying modified compression sutures on uterus as possible emergency managements to AVM when there is a threatening on life due to huge bleeding. We also mentioned the other surgical and medical treatments.

CONCLUSION

We confirm the importance of keeping AVM in mind as a possible diagnose when there is unknown cause vaginal bleeding. Consider doing bilateral iliac artery ligation and applying the modified compression sutures as emergency procedures to stop or reduce AVM bleeding.

Trametinib as a promising therapeutic option in alleviating vascular defects in an endothelial KRAS-induced mouse model

Somatic activating Kirsten rat sarcoma viral oncogene homologue (KRAS) mutations have been reported in patients with arteriovenous malformations. By producing LSL-Kras (G12D); Cdh5 (PAC)-CreERT2 [iEC-Kras (G12D*)] mice, we hoped to activate KRAS within vascular endothelial cells (ECs) to generate an arteriovenous malformation mouse model. Neonatal mice were treated daily with tamoxifen from postnatal (PN) days 1-3. Mortality and phenotypes varied amongst iEC-Kras (G12D*) pups, with only 31.5% surviving at PN14. Phenotypes (focal lesions, vessel dilations) developed in a consistent manner, although with unpredictable severity within multiple soft tissues (such as the brain, liver, heart and brain). Overall, iEC-Kras (G12D*) pups developed significantly larger vascular lumen areas compared with control littermates, beginning at PN8. We subsequently tested whether the MEK inhibitor trametinib could effectively alleviate lesion progression. At PN16, iEC-Kras (G12D*) pup survival improved to 76.9%, and average vessel sizes were closer to controls than in untreated and vehicle-treated mutants. In addition, trametinib treatment helped normalize iEC-Kras (G12D*) vessel morphology in PN14 brains. Thus, trametinib could act as an effective therapy for KRAS-induced vascular malformations in patients.

Shoulder Pain Associated With Multiple Arteriovenous Malformations Successfully Treated With Embolization

A 44-year-old male presented with left upper extremity and shoulder pain with worsening functional impairment after years of repetitive use, overtraining, and multiple injuries from weightlifting and mixed martial arts. Imaging showed no obvious injury or ligamentous deformity other than mild osteoarthritis (OA) of the left glenohumeral joint. Duplex ultrasonography (US) revealed four arteriovenous malformations (AVMs) surrounding the shoulder joint and left upper extremity. The vasculature was mapped via angiography through a transradial approach. Initial treatment included transarterial embolization of two AVMs off the axillary artery and branching anterior circumflex humeral artery. Secondary treatment included embolization of two lesions months later via direct puncture, one through a transvenous approach and the second through direct transmalformation cannulation, via the nidus, near the clavicle and posterior scapular lateral border. Treatment resulted in significant improvement in pain and range of motion. Follow-up assessments revealed improvement in overall symptoms, recovered function, and return to exercise and competitive mixed martial arts. This case highlights the value of duplex ultrasonography, embolization, and transarterial and transvenous approaches for the treatment of AVM-associated extremity or joint pain.

The trend of percutaneous and open surgical procedures for peripheral arteriovenous malformations in the National Health Service England

INTRODUCTION

This study aimed to assess the trend of percutaneous and open surgical procedures for peripheral arteriovenous malformations (AVMs) performed in NHS hospitals in England between 2012 and 2018.

METHODS

Hospital Episode Statistics (HES) is a freely available data warehouse that represents the whole population of England served by the NHS. Data from the HES database was obtained and analysed for all hospital episodes between 2012 and 2018 for the total number and trend of 'primary diagnosis', and 'primary procedures and interventions' identified for peripheral AVMs.

RESULTS

Over the period studied, there was an increase in the total number of admissions for peripheral AVMs; total primary diagnosis increased from 2242 to 2857 per year. Open surgery remained more commonly performed than percutaneous procedures throughout the studied period. However, the overall percentage of primary procedures and interventions being percutaneous in this period increased from 29.8% to 41.0% per year. The increase in the number of percutaneous procedures per year seemed to occur in both children (from 43 to 124) and adults (from 408 to 492) over the course of the study period.

CONCLUSIONS

This study concluded that open surgery remained the most commonly performed primary procedure for peripheral AVMs, although there was an increasing trend for percutaneous procedures in NHS hospitals in England. The increase in the number and percentage of percutaneous procedures for peripheral AVMs was likely to have significant resource implications for the provision of care for patients with peripheral AVMs in NHS hospitals.

Management of high-output cardiac failure caused by head and neck AVMs: Percutaneous suture-assisted ethanol and coil embolotherapy

Purpose

The aim of this study was to describe the treatment technique, outcomes, and complications of Schobinger stage IV head and neck arteriovenous malformations (HNAVMs) with associated high-output cardiac failure (HOCF) using ethanol and coils with the percutaneous suture technique.

Methods

From January 2015 to December 2019, 19 patients who had HNAVMs with associated HOCF were treated first with a percutaneous suture of the remarkably dilated dominant drainage vein (RDDOV) and subsequent embolization with coils and ethanol. The percutaneous suture of RDDOV was preferred to be performed, followed by the deployment of coils and the injection of absolute ethanol via transarterial approach, direct puncture approach, or both of them. Treatment outcomes and complication rates were evaluated at follow-up.

Results

A total of 19 patients who experienced HNAVMs with HOCF received 19 percutaneous suture procedures and 84 embolization procedures with ethanol and coils. Complete or >90% shunt reduction of the AVM was achieved in 16 patients. Notably, 19 patients with New York Heart Association (NYHA) stage II improved to stage I, and the symptom of dyspnea disappeared after embolization. The symptoms of five patients with bleeding disappeared. All patients presented with cosmetic concerns; Four were cured, and eight had a clearly recognizable improvement. Of note, 19 (100%) patients presented with impairment of daily life, which was resolved. The minor complications were encountered and recovered by the self. No major complications occurred.

Conclusion

This study provides evidence that ethanol and coil embolotherapy is effective and safe in treating HOCF caused by HNAVMs with acceptable complications in these cases. The percutaneous suture technique for RDDOV management can act as an adjunct for embolotherapy.

Extracranial arteriovenous malformations demonstrate dysregulated TGF-β/BMP signaling and increased circulating TGF-β1

Extracranial arteriovenous malformations (AVMs) are characterized by anomalous arterial-to-venous connections, aberrant angiogenesis, local inflammation and hypoxia, and disorganized histological architecture; however, the precise molecular perturbations leading to this phenotype remain elusive. We hypothesized that extracranial AVM tissue would demonstrate deregulation of the TGF-β/BMP signaling pathway, which may serve as a potential target in the development of molecular-based therapies for AVMs. AVM tissue was harvested during resection from 10 patients with AVMs and compared to control tissue. Blood was collected from 14 AVM patients and 10 patients without AVMs as controls. Expression of TGF-β/BMP pathway components was analyzed using RT-PCR, western blotting, and immunohistochemistry. Circulating levels of TGF-β1 were analyzed by ELISA. Paired t tests were utilized to perform statistical analysis. The mRNA levels of TGF-β1, ALK1, Endoglin (ENG), Smad6, Smad7, and Smad8 were significantly elevated in AVM tissue when compared to controls. Protein levels of TGF-β1 and Smad3 were elevated in AVM tissue while protein levels of BMP-9, ALK1, Smad1, Smad6, and Smad8 were significantly decreased in AVMs. Immunohistochemistry demonstrated increased TGF-β1 in the perivascular cells of AVMs compared to normal controls, and circulating levels of TGF-β1 were significantly higher in AVM patients. Patients with AVMs demonstrate aberrant TGF-β/BMP expression in AVM tissue and blood compared to controls. Targeting aberrantly expressed components of the TGF-β/BMP pathway in extracranial AVMs may be a viable approach in the development of novel molecular therapies, and monitoring circulating TGF-β1 levels may be a useful indicator of treatment success.

Liquid Embolization of Peripheral Arteriovenous Malformations with Ethylene-Vinyl Alcohol Copolymer in Neonates and Infants

In the postnatal period, extensive peripheral arteriovenous malformations (AVM) are associated with high morbidity, especially when localized in the liver. Their urgent treatment is always a challenging problem in neonates and infants. We analyzed four consecutive children aged three days to three years who underwent eight liquid embolization procedures with ethylene-vinyl alcohol copolymer. The AVM were situated on the thoracic wall, in the liver, and on the lower leg. In three cases, the malformations showed total regression. The tibial AVM degenerated widely. If impaired beforehand, cardiac or hepatic function normalized after the interventions. There were no embolization-associated complications such as nontarget embolization or tissue ischemia. We conclude that application of ethylene-vinyl alcohol copolymer seems to be a safe therapeutic option and can be used in neonates and infants with peripheral AVM in consideration of the agent's characteristics. Nevertheless, there are still hardly any data concerning young children.

Shape-Anisotropic Microembolics Generated by Microfluidic Synthesis for Transarterial Embolization Treatment

Particulate embolic agents with calibrated sizes, which employ interventional procedures to achieve endovascular embolization, have recently attracted tremendous interest in therapeutic embolotherapies for a wide plethora of diseases. However, the particulate shape effect, which may play a critical role in embolization performances, has been rarely investigated. Here, polyvinyl alcohol (PVA)-based shape-anisotropic microembolics are developed using a facile droplet-based microfluidic fabrication method via heat-accelerated PVA-glutaraldehyde crosslinking reaction at a mild temperature of 38 ^° C. Precise geometrical controls of the microembolics are achieved with a nearly capsule shape through regulating surfactant concentration and flow rate ratio between dispersed phase and continuous phase in the microfluidics. Two specific models are employed, i.e., in vitro decellularized rabbit liver embolization model and in vivo rabbit ear embolization model, to systematically evaluate the embolization behaviors of the nonspherical microembolics. Compared to microspheres of the same volume, the elongated microembolics demonstrated advantageous endovascular navigation capability, penetration depth and embolization stability due to their comparatively smaller radial diameter and their central cylindrical part providing larger contact area with distal vessels. Such nonspherical microembolics present a promising platform to apply shape anisotropy to achieve distinctive therapeutic effects for endovascular treatments.

A Computational Framework for Pre-Interventional Planning of Peripheral Arteriovenous Malformations

PURPOSE

Peripheral arteriovenous malformations (pAVMs) are congenital lesions characterised by abnormal high-flow, low-resistance vascular connections-the so-called nidus-between arteries and veins. The mainstay treatment typically involves the embolisation of the nidus, however the complexity of pAVMs often leads to uncertain outcomes. This study aims at developing a simple, yet effective computational framework to aid the clinical decision making around the treatment of pAVMs using routinely acquired clinical data.

METHODS

A computational model was developed to simulate the pre-, intra-, and post-intervention haemodynamics of a patient-specific pAVM. A porous medium of varying permeability was employed to simulate the sclerosant effect on the nidus haemodynamics. Results were compared against clinical data (digital subtraction angiography, DSA, images) and experimental flow-visualization results in a 3D-printed phantom of the same pAVM.

RESULTS

The computational model allowed the simulation of the pAVM haemodynamics and the sclerotherapy-induced changes at different interventional stages. The predicted inlet flow rates closely matched the DSA-derived data, although the post-intervention one was overestimated, probably due to vascular system adaptations not accounted for numerically. The nidus embolization was successfully captured by varying the nidus permeability and increasing its hydraulic resistance from 0.330 to 3970 mmHg s ml-1. The nidus flow rate decreased from 71% of the inlet flow rate pre-intervention to 1%: the flow completely bypassed the nidus post-intervention confirming the success of the procedure.

CONCLUSION

The study demonstrates that the haemodynamic effects of the embolisation procedure can be simulated from routinely acquired clinical data via a porous medium with varying permeability as evidenced by the good qualitative agreement between numerical predictions and both in vivo and in vitro data. It provides a fundamental building block towards a computational treatment-planning framework for AVM embolisation.

Clinical presentation of simple and combined or syndromic arteriovenous malformations

OBJECTIVE

Arteriovenous malformations of the lower extremities (AVM^LE) can present as simple or complex combined or syndromic forms (eg, Parkes Weber Syndrome). We aimed to characterize the differences in clinical presentation and natural history of these potentially life- and limb-threatening congenital vascular malformations.

METHODS

We conducted a retrospective analysis of a consecutive series of patients with AVM^LE who presented to a tertiary referral center in Switzerland between 2008 and 2018. Clinical baseline characteristics, D-dimer level, and course were summarized and differences between simple, non-syndromic and combined or syndromic AVM^LE determined. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Overall, 506 patients were prospectively enrolled in the Bernese Congenital Vascular Malformation Registry, 31 (6%) with AVM^LE. There were 16 women and 15 men, with a mean age of 18 years at first diagnosis (range, 1 month to 72 years). Simple AVM^LE was present in 22 (71%) and combined or syndromic AVM^LE with limb overgrowth in 9 patients (29%), respectively. Common symptoms and signs were pain (n = 25; 81%), swelling (n = 21; 68%), and soft tissue hypertrophy (n = 13; 42%). Among combined or syndromic patients, three patients died from wound infection with sepsis or disseminated intravascular coagulation with bleeding complications (intracranial hemorrhage and bleeding from extensive leg ulcers). Combined or syndromic patients presented more often with bleeding (67% vs 5%; P < .001), malformation-related infection (44% vs 5%; P = .017) and leg length difference (56% vs 14%; P = .049). D-dimer levels were elevated (mean, 17,256 μg/L; range, 1557-80,000 μg/L) and angiographic appearance showed complex, mixed type of AVMs, including interstitial type IV, in all patients with combined or syndromic AVM^LE.

CONCLUSIONS

Patients with congenital simple AVM^LE most often present with benign clinical features and rarely with complications related to hemodynamic changes. Patients with combined or syndromic AVM^LE often face serious outcomes dominated by complications other than direct high-flow-related heart failure.

Absolute Ethanol Embolization of Lip Arteriovenous Malformations: Observational Results from 10 Years of Experience

PURPOSE

To evaluate the safety and efficacy of ethanol embolization of lip arteriovenous malformations (AVMs).

MATERIALS AND METHODS

Seventy-six patients with lip AVMs were treated with 173 ethanol embolization procedures. Lip AVMs were treated with direct puncture alone in 21 patients (35 procedures, 20.2%), transarterial embolization alone in 13 patients (18 procedures, 10.4 %), and a combination of both in 60 patients (120 procedures, 69.3%). Adjunctive surgical resection was performed after embolization for cosmetic purposes based on the patient's request, including patient preference, functional impairment, and skin necrosis. The mean duration of follow-up was 30.9 months ± 27.6. The follow-up included clinic visits and telephonic questionnaires to evaluate the clinical signs and symptoms of AVMs as well as quality of life measures.

RESULTS

Of 76 patients, 51 showed 100% devascularization of AVMs, as determined using arteriography, followed by 23 with 76%-99% devascularization and 2 with 50%-75% devascularization. Of the 76 patients, 40 achieved complete symptom relief and 25 achieved major improvements in cosmetic deformity after embolization. Additionally, 54 patients achieved satisfactory function and aesthetic improvement with ethanol embolotherapy alone, whereas 22 achieved similar outcomes with a combination of ethanol embolotherapy and surgical intervention. Thirty-three adverse events (including 1 major) were documented.

CONCLUSIONS

Ethanol embolization of lip AVMs, as a mainstay, is efficacious in managing these lesions, with acceptable complications. Surgical resection after embolization may improve function and cosmesis in a subset of patients.

Imaging of benign cervicofacial vascular anomalies and associated syndromes

Cervicofacial vascular anomalies can result in morbidity, pain, and cosmetic concerns in affected individuals. Each anomaly has its own unique natural history, treatment, and associations with underlying genetic syndromes. For optimal patient care, it is important for the neuroradiologist to accurately recognize and characterize these entities to ensure appropriate treatment and management. In this review, we discuss the general characteristics, classifications, and imaging features associated with the most common vascular anomalies such as hemangiomas, arteriovenous malformations and fistulas, capillary malformations, venous malformations, and lymphatic malformations in the context of associated syndromes. Additionally, we discuss novel imaging techniques that aid in identifying these vascular anomalies.

Interdisciplinary management of peripheral arteriovenous malformations: review of the literature and current proceedings

Arteriovenous malformations (AVMs) are a rare congenital vascular disorder. They represent a fast-flow vascular malformation. Clinically, AVMs present a heterogenous expression and can affect every part of the body. Here, we will solely focus on extracranial AVMs. Generally, AVMs progress with the patient's age. Patients often suffer from pulsation, skin discoloration, pain, ulceration, bleeding, and disfigurement. Diagnostic tools include color-coded duplex sonography, MRI and CT imaging, as well as the clinical examination. 4D dynamic perfusion-computed tomography may help in the interventional planning. Digital subtraction angiography is required during interventional therapy. AVMs pose a great challenge to the treating physician. The therapy of this rare disease should be managed in an interdisciplinary center for vascular malformations. It consists of conservative measures, such as compression garments and pain medication, transcatheter or, more rarely, percutanous embolization, and surgical resection. In smaller, localized lesions, resection with primary wound closure may be feasible, whereas extensive AVMs regularly require the reconstruction of the resulting soft tissue defect and possibly affected functional structures by means of free tissue transfer. In the interdisciplinary setting required for an appropriate treatment of AVMs, extensive knowledge of the various therapies, including those from different specialties, is necessary. Therefore, this article aims to provide an overview over both the interventional and surgical therapeutic options.

Uterine Arteriovenous Malformation: A Pictorial Review of Diagnosis and Management

Uterine arteriovenous malformation (UAVM) is a rare condition and is classified as either congenital or acquired UAVM. Patients with UAVMs usually experience miscarriages or recurrent menorrhagia. Ultrasound is used for the initial estimation of UAVMs. Computed tomography and magnetic resonance imaging are noninvasive and valuable methods that provide good compatibility with digital subtraction angiography to support the diagnosis and treatment of UAVM. Timely diagnosis is crucial to provide appropriate treatment for alleviating complications. This article presents a pictorial and literature review of the current evidence of the diagnosis and management of UAVM.

Imaging of vascular malformations with a high-intensity focused ultrasound probe for treatment planning

OBJECTIVE

We aimed to investigate whether a current commercially available high-intensity focused ultrasound (HIFU) probe can adequately image targeted vascular malformations (VMs) in anticipation of HIFU treatment planning and delivery.

METHODS

We enrolled 10 consecutive patients who were scheduled to undergo treatment of symptomatic peripheral VMs confirmed by routine preoperative contrast-enhanced magnetic resonance imaging and soft tissue duplex ultrasound. The lesions were situated no more than 6 cm from the skin. After induction of general anesthesia and before surgical intervention, we prepared and positioned the Sonablate HIFU probe (SonaCare Medical, LLC, Charlotte, NC) to obtain multiple B-mode images of the targeted VM in the transverse and longitudinal dimensions. We then rated the quality of the images and the feasibility of the imaging process itself using a previously devised questionnaire aimed at evaluating the adequacy of the images for potential HIFU treatment planning and delivery. The patients subsequently underwent surgical intervention and clinical follow-up for their VM per the standard protocol.

RESULTS

The study included 10 participants aged 21 to 67 years (mean ± standard deviation, 36.5 ± 16.5 years). Six patients (60%) identified as female. The VMs imaged consisted of eight venous (80%), one lymphatic (10%), and one combined lymphovenous (10%) malformation. The lesions were in the extremities only (50%), trunk only (20%), trunk and extremities (20%), or neck and extremities (10%). Pain related to the VM was present in all 10 patients (100%). In all 10 patients, the boundary and location of the VM could be visualized via the HIFU probe despite the diminished B-mode imaging resolution. The absence of Doppler functionality in the HIFU probe did not prevent the identification of the VMs in any patient up to a depth of 6 cm. The results from the postimaging survey showed that difficulty in preparing the study device for imaging was 1.1 ± 0.3 and difficulty in use was 1.1 ± 0.1, with a score of 1 equal to easy and 5 to difficult. The stability of the acoustic coupling to the patient was 1.3 ± 0.2, with a score of 1 representing very stable.

CONCLUSIONS

We were able to ultrasonically identify and outline all targeted peripheral VMs using a commercially available HIFU probe in anticipation of treatment planning and delivery. Baseline magnetic resonance imaging and soft tissue duplex ultrasound remain essential tools for guiding probe placement and HIFU imaging.

Arteriovenous malformation on the sole of the foot treated successfully by embolization

Arteriovenous malformations of the sole of the foot are rare and can cause disturbances in normal living activities. We report a case of a plantar arteriovenous malformation in a 24-year-old male with pain and difficulty in walking. The arteriovenous malformation was complex, with a large and poorly marginated nidus, so we considered that with surgical resection, walking disabilities would be inevitable. When surgical removal of vascular mass is difficult, embolization alone can be effective. Therefore, he was treated with 4 therapeutic embolization procedures. Transvenous approaches to the venous sac and direct punctures of the nidus was performed. The nidus was successfully eradicated by embolization using alcohol, resulting in the disappearance of associated symptoms. Appropriate imaging is essential for diagnosis and evaluation of treatment. We were successful in achieving improved quality of life and satisfaction for a rare and difficult case by percutaneous embolization and sclerotherapy.

Update on extracranial arteriovenous malformations: A staged multidisciplinary approach

Arteriovenous malformations (AVMs) are vascular lesions that are thought to arise from congenital errors during development of vessels resulting in abnormal connections between arteries and veins. Though most AVMs develop in the brain or spinal cord, they can occur anywhere in the body. These extracranial or peripheral AVMs have a predilection for the head, neck, and limbs. Since these malformations infiltrate normal soft tissue, management requires selective treatment with preservation of normal surrounding architecture. Therefore, they are best addressed through a staged multimodal and multidisciplinary approach, using a combination of different laser, interstitial, intravascular and surgical techniques to specifically target anomalous vessels. The goal of treatment is overall disease improvement and symptom control with interventions that do not result in outcomes worse than the disease itself. Recently, the discovery of somatic and germline mutations in peripheral AVMs have contributed to a better understanding of the pathophysiology, resulting in promising new pharmacologic treatments. Recent evidence suggests that adjuvant medical therapy can enhance and sustain interventional and/or surgical outcomes. Herein we describe how a new understanding of the etiology and physiology of extracranial AVM provides guidance to current treatment approaches.

Treatment Outcomes of Embolization for Peripheral Arteriovenous Malformations

PURPOSE

To evaluate treatment outcomes of embolization for peripheral arteriovenous malformations (AVMs) in a tertiary referral center where ethanol is the primary agent of choice.

METHODS

A retrospective study was performed of 93 patients (median age, 31 years; range, 2-66 years) with peripheral AVMs treated with embolization (n = 442; median, 2 per patient; range, 1-82) between January 2010 and July 2016. Ethanol was used in most cases (n = 428; 97%). AVMs were classified as type I (n = 3), type II (n = 57), type IIIa (n = 5), type IIIb (n = 15), and type IV (n = 13) according to the Yakes classification system. Effectiveness of embolization was based on AVM devascularization on angiography: 100% (total), 90%-99% (near-total), 70%-90% (substantial), 30%-70% (partial), and 0%-30% (failure). Complications were graded according to the Society of Interventional Radiology classification.

RESULTS

In 69% of patients, 70%-100% devascularization was achieved. Total and near-total occlusion of the nidus were more often achieved in AVMs of types I and IIIa (both 100%) than in AVMs of types II, IIIb, and IV (56%, 67%, and 39%, respectively; P = .019). A total of 109 complications were identified: 101 minor (22.9%) and 8 major (1.8%). Major complications included wounds (n = 5), false aneurysm (n = 1), finger contracture (n = 1), and severe pain (n = 1) requiring therapy. The patient complication risk was significantly affected by the number of procedures (relative risk = 2.0; P < .001). Age, AVM location, and angioarchitecture type did not significantly affect complication risk.

CONCLUSIONS

AVM embolization resulted in 70%-100% devascularization in 69% of patients, with few major complications. This study indicates that the type of AVM angioarchitecture affects the number of procedures needed and the achievability of AVM devascularization.

Clinical and imaging features of intraosseous arteriovenous malformations in jaws: a 15-year experience of single centre

Intraosseous arteriovenous malformations in jaws (j-AVMs) are rare congenital high-flow vascular anomalies with a high tendency of life-threatening haemorrhage and are regarded as one of the most dangerous haemorrhagic diseases in maxillofacial region. Pre-treatment clinical and imaging evaluations serve as the most important diagnostic modalities. A retrospective study involved 211 patients with j-AVMs from November 2003 to November 2017 was performed. The male-to-female ratio of j-AVMs was approximately 4:3. The mean age of the patients with j-AVMs is 21.86. Bleeding was the main complaint associated with j-AVMs. J-AVMs occurred in the mandible more often than in the maxilla (64.93% and 32.23%, respectively). Most j-AVMs (95.26%) occurred in the posterior teeth region. Classical imaging features of j-AVMs included: an unclear maxillary sinus with a mild ground-glass appearance (maxillary j-AVMs) and a clear oval or irregular lucency that is mostly centred on the root of the first molar (mandibular j-AVMs) on OPGs, enhancement in the cancellous bone on contrast-enhanced CTs. Other atypical features of j-AVMs were also concluded. A comprehensive diagnose system based on clinical and imaging features of j-AVMs could provide valuable reference data for clinical management of j-AVMs and help avoid improper iatrogenic trauma or delayed treatment.

Resection and Reconstruction of Giant Abdominoscrotal Arteriovenous Malformation

Supplemental Digital Content is available in the text.

Genital arteriovenous malformations are rare and present unique surgical challenges in preserving urogenital function, abdominal wall integrity, and lower limb perfusion. A 32-year-old man with a giant abdominoscrotal arteriovenous malformation presented with recurrent heavy bleeding. Due to the high risk of rebleeding and fatal hemorrhage, surgery with curative intent was proposed and the patient was counseled on the risks of ischemia to the lower limb, testes, and penis. Preoperative embolization of the feeding vessels was performed. Three days later, surgical excision of the mass with the affected scrotum, left rectus muscle, sheath, and overlying abdominal skin followed. The testes were dissected from the malformation and preserved along with the right internal pudendal artery. The left thigh skin was advanced to the scrotal remnants and a neoscrotum created. The resulting large abdominal wall defect was reconstructed in layers with a pedicled anterolateral thigh flap, including innervated vastus lateralis muscle, to prevent herniation. Recovery was uneventful, and a 4-year follow-up revealed no significant clinical or radiological recurrence with recovery of flap sensation, retained erectile function, and no herniation. We report this case due to rarity of giant abdominoscrotal arteriovenous malformations and present preoperative embolization, surgical resection, and functional anterolateral thigh flap reconstruction as a valuable treatment option of this life-threatening illness.

Ethanol combined with coil embolisation for the treatment of arteriovenous malformations in a patient with Parkes Weber syndrome

Parkes Weber syndrome is a rare congenital condition of the vascular system with severe symptoms and life-threatening complications. The challenge is to manage the arteriovenous malformations, and there is no consensus on optimal treatment. We report the case of an 18-year-old woman with Parkes Weber syndrome who was treated with ethanol combined with coil embolisation at an early stage. After two sessions of embolisation, a significant devascularisation was achieved. No sign of recurrence was observed two years after the initial procedure. The patient's symptoms and signs were greatly relieved during the follow-up period. This case raises awareness of Parkes Weber syndrome and highlights the importance of timely intervention, as well as offering a promising therapeutic option for this condition.

Intraosseous Arteriovenous Malformations in the Extremities Managed with Coils and Absolute Ethanol Treatment

BACKGROUND

The extremity intraosseous arteriovenous malformations (AVMs) are rare high flow vascular lesions for which the treatment remains challenging. The aim of the study wasto assess treatment methods, interim results, and complications of coils and absolute ethanol in managing extremity intraosseous AVMs via direct puncture approach.

METHODS

From 2009 to 2017, 12 patients (mean age, 27.5 years; range, 3-54 years) with extremity intraosseous AVMs underwent staged coils and absolute ethanol treatment via the direct puncture approach. All patients were symptomatic before the procedure as per the Schobinger staging system. The mechanical detachable coils and undetachable coils were used first followed by the injection of absolute ethanol used as a sclerosant agent via a direct puncture approach. Follow-up evaluation (6 to 72 months; mean, 23.5 months), including imaging and symptoms and signs, was performed in all patients.

RESULTS

Twenty-seven absolute alcohol procedures were performed for patients with intravascular sclerosis (range: 1-3, mean: 2) with one procedure required per patient (n = 2), 2 per patient (n = 5), or 3 per patient (n = 5). The average stretched length of the total coils per patient was 843.33 cm. The amount of absolute ethanol used ranged from 10 mL to 45 mL (mean, 25.69 mL) in a single session. Nine of twelve patients (75%) exhibited complete responses, and 3 patients (25%) exhibited partial responses. One patient experienced minor complication of transient motor nerve injury and completely recovered half a month later. No major complications occurred.

CONCLUSIONS

The study provides strong evidence, suggesting that direct puncture and coils with absolute ethanol approach is an effective and safe treatment in patients with extremity intraosseous AVMs, yielding minor complications and good results.

Thrombosis of a Long-Segment Aneurysm from the Iliac to Popliteal Artery Associated with Arteriovenous Malformation and Varicose Veins

A 58-year-old male patient with severe claudication due to thrombosis of the left ilio-femoro-popliteal artery aneurysm. He also had a venous stasis ulcer with a history of multiple embolotherapy of arteriovenous malformation. Duplex sonography revealed reflux and varicose veins of the left great saphenous vein (GSV). A sequential bypass surgery was performed that consisted of excision of the left external iliac and common femoral artery aneurysm, external iliac to deep femoral interposition with an expanded polytetrafluoroethylene graft, and femoro-posterior tibial artery bypass with the reversed left GSV. Symptoms of claudication were alleviated and the chronic ulcer was healed in time. To our knowledge, this is the first report of successful bypass in a patient with arterial aneurysm, arteriovenous malformation, and venous insufficiency that can be diagnosed as an atypical case of Parkes Weber syndrome. Long-term follow-up is needed to define the fate of aneurysms and varicose vein graft.

Vascular Reconstruction of a Brachial Artery Aneurysm Proximally to an Arteriovenous Malformation

Brachial artery aneurysms and arteriovenous malformations (AVM) are limb-threatening vascular anomalies. This patient presented with a bilobed brachial artery aneurysm in the antecubital fossa proximally to an AVM arising from the dorsal interosseous and ulnar arteries that had been treated with endovascular embolization, leaving the hand solely supplied by the radial artery. The aneurysm continued to increase in size and imaging revealed concomitant thrombus. A femoral vein interposition graft was used to repair the aneurysm, and postoperatively, the patient retained full left arm function.

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.

A case of duodenal hemorrhage due to arteriovenous malformation around a serous cystic neoplasm

Background

No reports have so far described arteriovenous malformation (AVM) in the pancreas caused by a tumor. We herein report a case of pancreatoduodenectomy for a patient who developed duodenal hemorrhage due to AVM developed around serous cystic neoplasm (SCN) of the pancreas.

Case presentation

A 79-year-old man was referred to our hospital because of anemia (Hb 7.4 g/dl) and pancreatic head tumor. Computed tomography showed microcystic-type SCN, 87 mm in size, in the pancreatic head. Vascular hyperplasia had developed around the cystic lesion. Upper gastrointestinal endoscopy and colonoscopy did not reveal the cause of anemia, so the patient was followed closely without hemostatic therapy. Iron preparations had improved the anemia. Three months later, the patient developed anemia (Hb 5.8 g/dl) again. Gastrointestinal endoscopy showed oozing from the mucosa in the duodenum via the swollen vascular hyperplasia. He was diagnosed as duodenal hemorrhage from the blood vessels around SCN. Pancreatoduodenectomy was performed to control repeated duodenal bleeding. A histopathological examination revealed that the cystic lesion in the pancreatic head was SCN, and the AVM developed around SCN and duodenum, causing repeated duodenal hemorrhage. The patient was discharged on postoperative day 22. Nine months after surgery, the patient had no recurrence of anemia.

Conclusions

There have been no reports of duodenal hemorrhage due to acquired pancreatic AVM around pancreatic tumor, including SCN. We successfully treated a case of duodenal hemorrhage due to pancreatic AVM around SCN by pancreatoduodenectomy.

Soft-tissue vascular malformations and tumors. Part 1: classification, role of imaging and high-flow lesions

Vascular malformations and tumors, also known as "vascular anomalies", comprise an extensive variety of lesions involving all parts of the body. Knowledge of their classification and imaging characteristics is paramount. Whereas hemangiomas are benign vascular tumors, characterized by cellular proliferation and hyperplasia; vascular malformations are not real tumors and characteristically exhibit normal endothelial turnover. Vascular malformations are classified according to the predominant vascular channel as arterial, capillary, venous, lymphatic, or mixed. Ultrasound and MRI are the main imaging modalities used in the diagnosis and classification of the vascular anomalies. In this series of two articles we review the classification of vascular anomalies, describe the role of imaging, summarize their distinctive histopathogenic, clinical and imaging features, and discuss the treatment options. On the first article we discuss the high-flow lesions, whereas the slow-flow lesions will be reviewed on the second. Complex syndromes with associated vascular tumors and malformations will be also presented.

Treatment of Early-stage Extracranial Arteriovenous Malformations with Intralesional Interstitial Bleomycin Injection: A Pilot Study

Purpose To assess the efficacy and safety of intralesional interstitial bleomycin injection in the treatment of early-stage (Schobinger stage I or II) extracranial arteriovenous malformations (AVMs). Materials and Methods This prospective study involved 34 patients with early-stage AVMs, as defined by the Schobinger staging system. The patients received intralesional interstitial bleomycin injected at a maximum dose of 15 000 IU or 1000 IU per kilogram of body weight for children who weighed less than 15 kg per procedure for a total of 6 months (once every month). Therapeutic outcome was evaluated by the degree of devascularization at angiography and the clinical outcome 3 months after the last treatment. Further follow-up was evaluated based on further clinical outcome. Adverse events were recorded according to the Society of Interventional Radiology classification. Results Of the 34 patients with early-stage AVM, 32 (mean age, 20.5 years; 24 female [75%]) completed the study. The results showed that 27 (84.4%, 95% confidence interval [CI]: 71.1, 97.7) patients were responsive to bleomycin injection, including nine (28.1%) with a complete response. Four (12.5%) patients showed no response, and one (3.1%) patient experienced worsening 3 months after the last treatment. During further follow-up (mean follow-up time, 20.7 months; range, 5-28 months), the outcome remained stable in 31 (96.9%) of the 32 patients. A major complication, anaphylactic shock, was observed in one (3.1%, 95% CI: 0, 9.5) patient. Common minor complications included hyperpigmentation, nausea, pruritus, and bullae. Conclusion Intralesional interstitial bleomycin injection is a feasible approach for early-stage AVMs and yields safe and effective outcomes. ^© RSNA, 2017.