Predictive Factors for Response of Peripheral Arteriovenous Malformations to Embolization Therapy: Analysis of Clinical Data and Imaging Findings

ACR Appropriateness Criteria® Soft Tissue Vascular Anomalies: Vascular Malformations and Infantile Vascular Tumors (Non-CNS)-Child

Soft tissue vascular anomalies may be composed of arterial, venous, and/or lymphatic elements, and diagnosed prenatally or later in childhood or adulthood. They are divided into categories of vascular malformations and vascular tumors. Vascular malformations are further divided into low-flow and fast-flow lesions. A low-flow lesion is most common, with a prevalence of 70%. Vascular tumors may behave in a benign, locally aggressive, borderline, or malignant manner. Infantile hemangioma is a vascular tumor that presents in the neonatal period and then regresses. The presence or multiple skin lesions in an infant can signal underlying visceral vascular anomalies, and complex anomalies may be associated with overgrowth syndromes. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Targeting the microenvironment in the treatment of arteriovenous malformations

Extracranial arteriovenous malformations (AVMs) are regarded as rare diseases and are prone to complications such as pain, bleeding, relentless growth, and high volume of shunted blood. Due to the high vascular pressure endothelial cells of AVMs are exposed to mechanical stress. To control symptoms and lesion growth pharmacological treatment strategies are urgently needed in addition to surgery and interventional radiology. AVM cells were isolated from three patients and exposed to cyclic mechanical stretching for 24 h. Thalidomide and bevacizumab, both VEGF inhibitors, were tested for their ability to prevent the formation of circular networks and proliferation of CD31+ endothelial AVM cells. Furthermore, the effect of thalidomide and bevacizumab on stretched endothelial AVM cells was evaluated. In response to mechanical stress, VEGF gene and protein expression increased in patient AVM endothelial cells. Thalidomide and bevacizumab reduced endothelial AVM cell proliferation. Bevacizumab inhibited circular network formation of endothelial AVM cells and lowered VEGF gene and protein expression, even though the cells were exposed to mechanical stress. With promising in vitro results, bevacizumab was used to treat three patients with unresectable AVMs or to prevent regrowth after incomplete resection. Bevacizumab controlled bleeding, pulsation, and pain over the follow up of eight months with no patient-reported side effects. Overall, mechanical stress increases VEGF expression in the microenvironment of AVM cells. The monoclonal VEGF antibody bevacizumab alleviates this effect, prevents circular network formation and proliferation of AVM endothelial cells in vitro. The clinical application of bevacizumab in AVM treatment demonstrates effective symptom control with no side effects.

Peripheral Arteriovenous Malformation Embolization Using Squid

Materials and Methods

Between January 2018 and December 2020, twenty patients (7 men and 13 women) with peripheral high-flow arteriovenous malformations who were treated primarily with arterial embolization using squid were retrospectively included. Anatomical sites being treated included the head and neck (16), extremities (2), uterus (1), and pelvis (1). Squid was used as the sole embolic agent in 15 patients, and transarterial embolization was employed in all cases except one where direct puncture embolization was used. Treatments were delivered over one or two sessions, with or without surgery. A total of 27 sessions were carried out with an interval time ranging from 6 to 36 months between sessions.

Results

Technical success was achieved in all cases. In those patients treated with squid alone, 13 exhibited total devascularization following embolization, and a further 4 required surgical excision to achieve complete obliteration of the arteriovenous malformation. There were no major complications, cases of microcatheter entrapment, or dimethyl sulfoxide-related pain recorded. On follow-up, one patient reported persistent pain, and another patient developed a garlicky taste. All other patients reported complete resolution of symptoms following treatment.

Conclusion

This study demonstrates the successful use of squid in managing peripheral arteriovenous malformations with low complication rates and long-term stable results, therefore validating its efficacy when used alone or in combination with other embolic agents. Squid may be the preferred embolic agent in any interventional radiologist's armamentarium as it offers formulations with varying viscosities (squid-18 and squid-12). We conclude that squid should be considered as a first-line embolic agent in the management of peripheral arteriovenous malformations.

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.

Endovascular and Percutaneous Embolotherapy for the Body and Extremity Arteriovenous Malformations

Arteriovenous malformations (AVMs) consist of abnormal communications between the arteries and veins. They can involve any part of the body and extremity and grow in proportion to age and in response to hormonal influence or trauma. When symptoms progress from Schöbinger clinical stage II to III, transcatheter and/or direct puncture embolization are less-invasive and repeatable options for symptom palliation. The goal of embolization is to obliterate the AV shunt, and the choice of lesion access and embolic agents is based on the individual anatomy and flow. Embolization can be technically challenging due to complex vascular anatomy and morbidity risks. Therefore, a multidisciplinary management is essential for the diagnosis and therapeutic intervention of AVMs.

Head and neck arteriovenous malformations: University of Tennessee experience, 2012–2022

OBJECTIVE

Head and neck arteriovenous malformations (AVMs) are complex lesions that represent a subset of vascular anomalies (VAs). The authors present an analysis of their institutional experience managing these lesions as a multidisciplinary team.

METHODS

A retrospective chart review was performed of head and neck AVM patients treated at the authors’ institution from 2012 to 2022. Recorded data included patient demographic characteristics, details of clinical presentation, Schöbinger clinical scale and Yakes AVM classification results, and details of all endovascular and surgical treatments. The primary outcome of the study was clinical response to treatment. Angiographic occlusion and complication rates were reported. Chi-square tests were used for comparative statistics.

RESULTS

Sixteen patients (9 female, 56%) with AVMs of the head and neck presented from age 3 to 77 years. The Schöbinger stage was stage II in 56% of patients (n = 9) and stage III in 44% of patients (n = 7). The Yakes AVM classification was nidus type (2a, 2b, or 4) in 7 patients (43%) and fistula type (1, 3a, or 3b) in 9 patients (57%). The majority of patients (n = 11, 69.0%) were managed with embolization as the only treatment modality, with an average of 1.5 embolizations/patient (range 1–3). Surgical resection was employed in 5 patients (4 in combination with embolization). Symptom resolution and symptom control were achieved in 69% and 31% of patients, respectively, in the entire cohort. A radiographic cure was demonstrated in 50% of patients. There were no statistical differences in clinical outcomes or radiographic cure rates between patients treated with different modalities.

CONCLUSIONS

Head and neck AVMs can be treated successfully with a primarily endovascular management strategy by a multidisciplinary team with the goal of symptomatic control.

Case report study of thalidomide therapy in 18 patients with severe arteriovenous malformations

Arteriovenous malformations (AVMs) are fast-flow lesions that may be destructive and are the most difficult-to-treat vascular anomalies. Embolization followed by surgical resection is commonly used; however, complete resection is rarely possible and partial resection often leads to dramatic worsening. Accumulating data implicate abnormal angiogenic activity in the development of AVMs. Thalidomide has been reported as an inhibitor of vascular proliferation. Here, we report a prospective experimental observational study testing the effects of the angiogenesis inhibitor thalidomide on 18 patients with a severely symptomatic AVM that is refractory to conventional therapies. All patients experienced a rapid reduction in pain, cessation of bleeding, and ulcer healing. Cardiac failure resolved in all three affected patients. Reduced vascularity on arteriography was observed in two patients. One AVM appeared to be cured after 19 months of thalidomide and an 8-year follow-up. Eight AVMs were stable after a mean thalidomide cessation of 58 months, and four lesions recurred after 11.5 months. Combined treatment with embolization permitted dose reduction in five patients with clinical improvement. Grade 3 side effects were dose dependent, including asthenia (n = 2) and erythroderma (n = 2). The results suggest that thalidomide is efficacious in the management of chronic pain, bleeding and ulceration of extensive AVMs that are refractory to conventional therapy. Further clinical study is needed to confirm the safety and efficacy of thalidomide treatment in AVM.

Vascular anomalies of the head and neck: diagnosis and treatment

Vascular malformations and vascular tumors comprise the two specific subsets of vascular anomalies that arise as a result of disorganized angiogenesis and neoplasm, respectively. Malformations are separate entities from vascular tumors (e.g., hemangiomas) and are recognized by the International Society for the Study of Vascular Anomalies (ISSVA) as such. Vascular malformations are classified into four main groups: simple, combined, anomalies of major vessels, and those associated with other vascular anomalies. Vascular tumors are neoplastic growths of blood vessels and are morphologically and molecularly distinct from malformations but can arise in the head and neck and have syndromic association. Head and neck vascular anomalies are not uncommon in the pediatric population and require special care in the workup, diagnostic imaging and clinical care. The purpose of this manuscript is to discuss the diagnosis and management of the most common intracranial and extracranial vascular malformations and tumors in the head and neck in children and adolescents.

Peripheral Arteriovenous Malformations: Imaging and Endovascular Management Strategies

The peripheral high-flow vascular malformation (HFVM) comprises arteriovenous malformation (AVM) and fistula (AVF), shows varied clinical presentation (ranging from subtle skin lesion to life-threatening congestive heart failure), and frequently poses diagnostic and therapeutic challenges. Importance of assigning a specific diagnosis to the vascular malformation cannot be overstated, as the treatment strategy is based on the type of vascular anomaly. Although the International Society for the Study of Vascular Anomalies (ISSVA) classification system is the most commonly accepted system for classifying congenital vascular anomalies in clinical practice, the Cho–Do et al classification is of utmost help in guiding optimal mode of treatment in peripheral AVM. Although transarterial approach remains the most commonly employed route for peripheral AVM embolization, the role of transvenous and direct percutaneous approach is ever increasing and the final decision on the approach depends on angioarchitecture of the AVM. In this article, we review various commonly employed classification systems for congenital vascular anomalies, and describe clinical features, imaging and treatment strategies for peripheral arteriovenous malformation (PAVM).

The use of dual-lumen balloon for embolization of peripheral arteriovenous malformations

PURPOSE

We aimed to evaluate the safety and feasibility of the embolization of peripheral arteriovenous malformation (AVM) with non-adhesive liquid agents (NALA) injected by dual-lumen balloons (DLB).

METHODS

We conducted a multicenter retrospective study between January 2017 and June 2019, including patients with peripheral AVM embolized with NALA by DLB. Fourteen patients were included. The AVM classification, technical and clinical success were evaluated, as were nidus size, liquid agent used, volume and time of injection in DLB, complications, follow-up and need of surgical intervention.

RESULTS

The mean age of the patients was 37±22.5 years (range, 6-82 years). The mean nidus size was 5.2±2.4 cm (range, 3.0-12.0 cm). By Schobinger classification, 11 AVMs were classified in stage 3 and 3 AVMs were classified in stage 2. By Cho's classification, 2 AVMs were in stage II, 4 AVMs were in stage I, 4 AVMs were in stage IIIa and 4 AVMs were in stage IIIb. Onyx was used in 11 patients (78.6%), while Squid, PHIL, and both Onyx and Squid were used in one patient each (7.1%). Seven patients (50%) required one session of embolization, 4 patients (28.6%) required two, 2 patients (14.3%) required three and 1 patient (7.1%) required four sessions. Complete nidus exclusion was achieved in 11 patients (78.6%), optimal clinical response in 12 patients (85.7%). Four patients (28.6%) exhibited minor complications, all controlled. No major complications were seen. Four patients underwent surgical intervention (28.6%).

CONCLUSION

The embolization of peripheral AVM with NALA in DLB appears to be safe and feasible, achieving high rates of technical and clinical success.

How to Treat Peripheral Arteriovenous Malformations

Arteriovenous malformations (AVMs) are direct communications between primitive reticular networks of dysplastic vessels that have failed to mature into capillary vessels. Based on angiographic findings, peripheral AVMs can be classified into six types: type I, type IIa, type IIb, type IIc, type IIIa, and type IIIb. Treatment strategies vary with the types. Type I is treated by embolizing the fistula between the artery and the vein with coils. Type II (IIa, IIb, and IIc) AVM is treated as follows: first, reduce the blood flow velocity in the venous segment of the AVM with coils; second, perform ethanol embolotherapy of the residual shunts. Type IIIa is treated by transarterial catheterization of the feeding arteries and injection of diluted ethanol. Type IIIb is treated by transarterial or direct puncture approaches. A high concentration of ethanol is injected through the transarterial catheter or direct puncture needle. When the fistula is large, coil insertion is required to reduce the amount of ethanol. Type I and type II AVMs showed the best clinical results; type IIIb showed a satisfactory response rate. However, type IIIa showed the poorest response rate, either alone or in combination with other types. Clinical success can be achieved by using different treatment strategies for different angiographic AVM types.

Therapeutic outcomes of embolotherapy of extremity bone intraosseous arteriovenous malformation with ethanol, coils, and n-butyl cyanoacrylate

OBJECTIVE

We evaluated the therapeutic outcomes of embolotherapy for bone arteriovenous malformations (AVMs) affecting the extremities using ethanol, coils, and n-butyl cyanoacrylate (NBCA).

METHODS

We reviewed the data from 36 patients (18 males, 18 females; mean age 25 years; age range, 1-64 years) with bone AVMs affecting their extremities who had undergone embolotherapy using ethanol, coils, and NBCA from December 1996 to July 2019. Of the 36 patients, 19 had had pure bone AVMs and 17 mixed bone and soft tissue (MBS) AVMs. Embolotherapy was performed using direct puncture or a transvenous or an intra-arterial approach (range, 1-18 procedures; mean, 5 procedures). During the 178 embolotherapy procedures, ethanol was used in all 36 patients, except for 1. Coils were used in 14 patients, and NBCA and a lipiodol mixture in 9 patients. The therapeutic outcomes were evaluated by the clinical symptom response and the degree of devascularization on follow-up angiography or computed tomography. The major and minor complications were also evaluated.

RESULTS

The clinical success (cure or markedly improvement) rate of embolotherapy for pure bone AVMs was significantly better than that for the MBS AVMs (88% vs 18%; P < .001). The complete devascularization rate of the bone AVM component of the MBS AVMs was 71%; however, the cure rate of the MBS AVMs was 0% owing to the remaining soft tissue AVMs. Of the 36 patients, 12 experienced complications, including 11 minor (2 skin bullae formation and 10 transient peripheral nerve injury) and 1 major (longstanding nerve palsy).

CONCLUSIONS

Embolotherapy for bone AVMs affecting the extremities using ethanol, coils, and an NBCA mixture is effective and safe for the resolution or improvement of symptoms, especially in those with pure bone AVMs.

Japanese clinical practice guidelines for vascular anomalies 2017

The objective was to prepare guidelines to perform the current optimum treatment by organizing effective and efficient treatments of hemangiomas and vascular malformations, confirming the safety, and systematizing treatment, employing evidence-based medicine (EBM) techniques and aimed at improvement of the outcomes. Clinical questions (CQs) were decided based on the important clinical issues. For document retrieval, key words for literature searches were set for each CQ and literature published from 1980 to the end of September 2014 was searched in Pubmed, Cochrane Library, and Japana Centra Revuo Medicina (JCRM). The strengths of evidence and recommendations acquired by systematic reviews were determined following the Medical Information Network Distribution System (MINDS) technique. A total of 33 CQs were used to compile recommendations and the subjects included efficacy of resection, sclerotherapy/embolization, drug therapy, laser therapy, radiotherapy, and other conservative treatment, differences in appropriate treatment due to the location of lesions and among symptoms, appropriate timing of treatment and tests, and pathological diagnosis deciding the diagnosis. Thus, the Japanese Clinical Practice Guidelines for Vascular Anomalies 2017 have been prepared as the evidence-based guidelines for the management of vascular anomalies.

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.

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.

Uterine Arteriovenous Malformations

Uterine arteriovenous malformations are rare but may represent a life-threatening cause of vaginal bleeding. The typical patient affected is a multiparous woman during her thirties. The origin can be congenital or acquired, with the latter being more common after uterine surgery and presenting mainly as arteriovenous fistulous connections into the myometrium supplied by uterine arteries. The correct diagnosis of uterine arteriovenous malformations requires imaging findings of tubular and tortuous structures with mixed signal from arterial and venous flows; transvaginal color-Doppler ultrasound is the initial technique applied, then integrated with contrast-enhanced magnetic resonance or computed tomography. Multiple treatment approaches are available, including conservative-medical, endovascular embolization and surgery. Transarterial embolization represents the most applied, preserving childbearing capacity with negligible procedural complications; clinical and technical success rates are elevated, up to 90%. The goal of embolization is to occlude the point of fistula or the nidus and the application of multiple embolizing agents has been reported: despite there is no clear superiority of one over the others, liquids, especially those related to the dymethil-sulfoxide family, present relevant technical advantages. Surgery is nowadays to be considered when the endovascular approach fails and in these cases hysterectomy remains the common recommendation.

Peripheral Arteriovenous Malformations-A Case Series

Context:

Arteriovenous malformations (AVMs) are aggressive vascular malformations that often result in significant morbidity. Patients may present to a dermatologist due to associated skin changes. Early diagnosis is important as treatment is available to halt their progression toward irreversible destruction of adjacent tissues.

Aims:

To study the clinical profile of peripheral AVMs presenting to the dermatologist and to provide a diagnostic algorithm.

Settings and Design:

A retrospective study of patients of all age groups with peripheral AVMs who presented to the Department of Dermatology at a tertiary care hospital in India was performed. Syndromic forms were also included.

Subjects and Methods:

We conducted a search of patients with peripheral AVMs, which were seen over a period of 51 months, i.e., from July 2014 to September 2018, from electronic medical records and reviewed their clinical details.

Statistical Analysis Used:

Descriptive statistics such as frequency, mean, and median were computed.

Results:

We report a series of 13 patients with peripheral AVMs, which constituted 6.7% (13/193) of all vascular malformations during this period. Of these, 8.3% (1/12) belonged to Schobinger's stage 1, 41.7% (5/12) to stage 2, 50% (6/12) to stage 3, and one with subcutaneous involvement devoid of cutaneous changes. The most common location was the extremities, which was seen in 53.8% (7/13). Syndromic association was present in 46.2% (6/13). Management included embolization, surgery, and medical treatment.

Conclusions:

The proportion of peripheral AVMs out of all vascular malformations was similar to reported studies. The extremities were more frequently involved as compared to the head and neck. The diagnostic algorithm provided will help us to optimize investigations and direct early management.

Japanese Clinical Practice Guidelines for Vascular Anomalies 2017

The objective was to prepare guidelines to perform the current optimum treatment by organizing effective and efficient treatments of hemangiomas and vascular malformations, confirming the safety and systematizing treatment, employing evidence‐based medicine techniques and aimed at improvement of the outcomes. Clinical questions (CQ) were decided based on the important clinical issues. For document retrieval, key words for published work searches were set for each CQ, and work published from 1980 to the end of September 2014 was searched in PubMed, Cochrane Library and Japana Centra Revuo Medicina databases. The strengths of evidence and recommendations acquired by systematic reviews were determined following the Medical Information Network Distribution System technique. A total of 33 CQ were used to compile recommendations and the subjects included efficacy of resection, sclerotherapy/embolization, drug therapy, laser therapy, radiotherapy and other conservative treatment, differences in appropriate treatment due to the location of lesions and among symptoms, appropriate timing of treatment and tests, and pathological diagnosis deciding the diagnosis. Thus, the Japanese Clinical Practice Guidelines for Vascular Anomalies 2017 have been prepared as the evidence‐based guidelines for the management of vascular anomalies.

Japanese clinical practice guidelines for vascular anomalies 2017

The objective was to prepare guidelines to perform the current optimum treatment by organizing effective and efficient treatments of hemangiomas and vascular malformations, confirming the safety, and systematizing treatment, employing evidence-based medicine (EBM) techniques and aimed at improvement of the outcomes. Clinical questions (CQs) were decided based on the important clinical issues. For document retrieval, key words for literature searches were set for each CQ and literature published from 1980 to the end of September 2014 was searched in Pubmed, Cochrane Library, and Japana Centra Revuo Medicina (JCRM). The strengths of evidence and recommendations acquired by systematic reviews were determined following the Medical Information Network Distribution System (MINDS) technique. A total of 33 CQs were used to compile recommendations and the subjects included efficacy of resection, sclerotherapy/embolization, drug therapy, laser therapy, radiotherapy, and other conservative treatment, differences in appropriate treatment due to the location of lesions and among symptoms, appropriate timing of treatment and tests, and pathological diagnosis deciding the diagnosis. Thus, the Japanese Clinical Practice Guidelines for Vascular Anomalies 2017 have been prepared as the evidence-based guidelines for the management of vascular anomalies.

Management of extracranial arteriovenous malformations of the head and neck

The purpose of this study was to review the outcomes of the different therapies for extracranial head and neck arteriovenous malformations (AVMs). AVMs are high-flow congenital vascular anomalies. They are composed of a complex system of vessels directly connecting feeding arteries to draining veins forming a nidus. They may be potentially life-threatening due to progressive symptoms and infiltrative disease. Extracranial AVMs most commonly affect the head and neck area (47.4%) followed by the extremities (28.5%). AVMs are best characterized as being either focal or diffuse. Focal AVMs have good outcomes following adequate treatment. Diffuse lesions have multiple feeding vessel, which results in high rates of recurrence despite treatment. The management of AVMs includes conventional surgery and endovascular techniques. A combination of embolization and surgical resection has become the treatment of choice over the last years. The main goal of both forms of treatment being the complete blockage or resection of the nidus. Transcatheter embolization of vessels has evolved over the years and new embolic agents have emerged. The types of materials available for embolization are classified into mechanical devices, liquid agents and particulates. Efficacy, rate of recurrence and most common complications were evaluated. AVMs recurrence after embolization or resection is reported in up to 80% of cases. Incomplete resection and embolization can induce aggressive growth of the remaining nidus and the risk of progression is up to 50% within the first 5 years and recurrences can occur up to 10 years later. Although ethanol seems to be associated with the highest degree of cure and permanent occlusion, the overall complication rate reported was 48%. Other materials, such as cyanoacrylate, have obtained modest rates of complete remission, while the reported rates of complete regression of AVMs with Fibrin glue and Polyvinyl alcohol are above 50%. At present, there are no unified agreement on the ideal embolic agent. Therefore, a multidisciplinary approach is recommended to support decision making about the best therapeutic approach and to achieve optimal outcome. A long-term post-treatment follow-up is recommended to recognize early recurrence.

Subclassification and Treatment Results of Ethanol Embolotherapy of Type II Arteriovenous Malformations of the Extremity and Body

PURPOSE

To evaluate the safety and efficacy of ethanol and coil embolization of type II arteriovenous malformation (AVM) according to a new subtype classification.

MATERIALS AND METHODS

Eighty-four type II AVMs in the body or extremity of 79 patients who underwent AVM treatment from 1996 to 2017 were retrospectively subclassified according to the angiographic morphology of the draining vein as type IIa (arterioles shunt to focal segment of single draining vein), type IIb (arterioles shunt to venous sac with multiple draining veins), and type IIc (arterioles shunt along long segment of draining vein). Coil and ethanol embolization of the focal or long segment of the draining vein or the venous sac was performed with direct puncture or transvenous approach according to subtype. Treatment outcomes, number of treatment sessions, and complications were analyzed.

RESULTS

AVM cure (ie, complete embolization) rates were 95%, 76%, and 65% in types IIa, IIb, and IIc AVMs, respectively. The cure rate of type IIa AVMs was significantly better than that of type IIc AVMs (P = .015). Median numbers of treatment sessions were 1 in types IIa and IIb AVMs and 2.5 in type IIc AVMs, with a significant difference between type IIc and the other 2 types (P < .05). Minor complications occurred in 20% of patents and major complications occurred in 7%.

CONCLUSIONS

The cure rate of type IIa AVMs was significantly better than that of type IIc AVMs, which also required significantly more treatment sessions than the other 2 types.

Efficacy and Safety of Transvenous Embolization of Type II Renal Arteriovenous Malformations with Coils

PURPOSE

To evaluate the efficacy and safety of transvenous coil embolization of the venous sac for type II renal arteriovenous malformation (AVM).

MATERIALS AND METHODS

A retrospective review was conducted of 8 patients (5 women and 3 men; mean age, 57 years; age range, 41-69 years) who underwent transvenous coil embolization for type II congenital renal AVM at 5 different hospitals between 2012 and 2018. Additional intra-arterial ethanol injection was performed if shunt flow persisted after venous sac coiling. Technical success was defined as complete occlusion of shunt flow with coil embolization. Clinical success was defined as no symptom recurrence during the follow-up period. The renal parenchymal infarction rate was measured on computed tomography (CT), and procedure-related complications were reviewed.

RESULTS

Nine sessions of embolization were performed for 8 patients. The mean venous sac size was 24 mm (range, 10-39 mm), and a mean of 14 micro and/or micro-detachable coils (range, 3-50) were used. The technical success rate was 88% (7 of 8) using coil embolization. One patient (12%) required additional ethanol injection to complete occlusion of the shunt flow and had a less than 10% parenchymal infarction on follow-up CT. No procedure-related complications or recurrences occurred during a mean clinical follow-up period of 20.8 months (range, 4.7-76.6 months).

CONCLUSIONS

Transvenous coil embolization of type II renal AVM showed an 88% technical success rate. One patient (12%) showed less than 10% renal parenchymal infarction after additional ethanol injection. No additional complications or recurrences occurred during the follow-up period.

Polidocanol Sclerotherapy Combined with Transarterial Embolization Using n-Butyl Cyanoacrylate for Extracranial Arteriovenous Malformations

Purpose

To assess the safety and effectiveness of polidocanol sclerotherapy combined with transarterial embolization using a liquid adhesive agent (n-butyl cyanoacrylate, NBCA) for treatment of extracranial arteriovenous malformations (AVMs).

Materials and Methods

Twenty-three patients with symptomatic AVMs in the head and neck (6), upper (7) and lower extremity (10) with a mean age of 42 years (range 4–74) treated with polidocanol sclerotherapy were retrospectively assessed. AVMs were classified according to the angiographic morphology of the nidus. There were 2 type I, 6 type II, 6 type IIIa and 9 type IIIb. Arterial embolization using NBCA was performed to reduce arterial flow before sclerotherapy. Polidocanol mixed with contrast material or carbon dioxide was delivered by percutaneous direct puncture.

Results

Treatment was successfully performed in all patients. In the mean follow-up period of 38 months, symptoms resolved or improved in 20/23 patients (87.0%). AVMs were devascularized 100% in 2 patients, 76–99% in 13, 50–75% in 7 and < 50% in 1. More than 50% devascularization was seen in 22 patients (95.6%). Two (8%) patients had complete remission, 17 (74%) had partial remission and 3 (13%) had no remission. There was no aggravation. Treatment was considered effective (complete and partial remission) in 20 patients (87.0%). Minor complications including localized arterial thrombosis (2) and spontaneously healing skin ulcer (1) were seen in 2 patients (8.7%). There were no major procedure-related complications.

Conclusion

Polidocanol sclerotherapy combined with transarterial embolization using NBCA is safe and effective for treating extracranial AVMs with an acceptable risk of minor complications.

Angioarchitecture of Hereditary Arteriovenous Malformations

This article describes three hereditary conditions known to be associated with arteriovenous malformation (AVM), along with their clinical and imaging features and angiographic angioarchitecture. Hereditary hemorrhagic telangiectasia, capillary malformation-AVM (CM-AVM), and PTEN tumor hamartoma syndrome are conditions with autosomal dominant inheritance, caused by mutations in different molecular pathways, which frequently present with symptomatic AVMs. Imaging biomarkers, including sites of predilection, angioarchitecture, and tissue overgrowth patterns, are helpful in identifying these patients and selecting appropriate treatment.

Special Consideration for Intraosseous Arteriovenous Malformations

Intraosseous arteriovenous malformations (AVMs) have been associated with distortion, hypertrophy, osteolytic skeletal changes, bleeding, leg length discrepancy, and pathologic fracture. Computed tomography or magnetic resonance imaging is helpful in the evaluation of the extent and depth of intraosseous AVMs and associated soft-tissue AVMs. Treatment approaches can differ, depending on the angiographic classification. Embolotherapy with ethanol, coils, or n-butyl cyanoacrylate is the primary treatment for symptomatic intraosseous AVMs, and the goal of treatment is symptom improvement with few complications.

Numerical modeling of vessel geometry to measure hemodynamics parameters non-invasively in cerebral arteriovenous malformation

Cerebral arteriovenous malformations (CAVM) are congenital lesions that contain a cluster of multiple arteriovenous shunts (NIDUS). Cardiac arrhythmia in CAVM patients causes irregular changes in blood flow and pressure in the NIDUS area. This paper proposes the framework for creating the lumped model of tortuous vessel structure near NIDUS based on radiological images. This lumped model is to analyze flow variations, with various combinations of the transient electrical signals, which simulate similar conditions of cardiac arrhythmia in CAVM patients. This results in flow variation at different nodes of the lumped model. Here we present two AVM patients with evaluation of 150 vessels locations as node points, with an accuracy of 93%, the sensitivity of 95%, and specificity of 94%. The calculated p-value is smaller than the significance level of 0.05.

Embolization of Congenital Renal Arteriovenous Malformations Using Ethanol and Coil Depending on Angiographic Types

PURPOSE

To evaluate effectiveness and safety of embolization of congenital renal arteriovenous malformations (AVMs) using ethanol and/or coil according to angiographic type.

MATERIALS AND METHODS

Between August 2010 and October 2015, 11 patients (13 sessions; 10 women and 1 man; mean age, 50.8 y) with congenital renal AVMs were treated using ethanol and/or coils via 2 approaches (transarterial access or direct puncture). Demographics, clinical findings, diagnostic modalities, angiographic types, technical and clinical success rates, and complications were reviewed. Renal AVMs were classified into 3 angiographic types, and treatment was based on this classification.

RESULTS

Technical success rate was 91% (10/11), and clinical success rate was 100% (11/11). Of patients, 7 had type III AVMs, 3 had type I AVMs, and 1 had type II AVM. Embolic agents were ethanol in 5 patients, coils with ethanol in 3 patients, and coils in 3 patients. Of the 8 patients treated with ethanol, 6 had infarcted renal areas of 3.5%-30% (mean, 14.6%). After a mean follow-up period of 16.3 months, there was no evidence of recurrent AVMs on imaging or laboratory studies.

CONCLUSIONS

Embolization of congenital renal AVMs via transarterial or direct percutaneous approaches using ethanol and/or coils based on a simple angiographic classification was safe and effective and elicited good outcomes. Most of the patients with congenital renal AVMs were women.

Early symptoms and long-term clinical outcomes of distal limb's cutaneous arterio-venous malformations: a retrospective multicentre study of 19 adult patients

INTRODUCTION

Cutaneous arterio-venous malformations (AVM) are high-flow vascular malformations made up of a direct link between arteries and veins without intermediary capillary space. 'Distal limb's AVM', which mean involving hands or feet, are rare and their functional prognosis is often poor. Little is known about their early clinical symptoms. The objectives of this study were to identify early clinical symptoms of distal limb's cutaneous AVMs and to determine their long-term clinical outcome.

METHODS

A retrospective study was carried out including adult patients who had distal limb's AVM, who were followed up between January 2000 and November 2013 in two regional tertiary care centres. The information was collected from patients' clinical records and completed by a structured telephone questionnaire.

RESULTS

Nineteen patients were included in the study: four (21%) with foot AVM and 15 (79%) with hand AVM. The first clinical symptoms were as follows: swelling (47%), pain (47%), one or several venous dilatations (37%) and rarely abnormal skin colour, hyperthermia and pulsating sensation. The median diagnosis delay was 9 years after the onset of first manifestations. Amongst the 17 patients who underwent a treatment, 53% had embolotherapy session(s), 12% surgery and 35% had both. After an average follow-up of 57.6 months, 31% of the 13 patients contacted who were receiving treatment were in complete remission; 31% had partial remission; 15% had relapse after initial improvement and 23% had treatment failure. Overall, 74% of patients had a serious development of the AVM: 37% had digital or hand amputation, and 42% remained symptomatic and/or unstable.

CONCLUSION

This study suggests that initial manifestations of distal limb's AVMs are discreet and non-specific, leading to a diagnosis delay of about 10 years, with poor prognosis. Doctors should evoke the diagnosis earlier, when these symptoms are shown: pain and/or swelling, sometimes with a large vein.

Topological Analysis for Arteriovenous Malformations via Computed Tomography Angiography: Part 2: Practical Application

Background:

In a previous study, the authors outlined a technique for calculating the number of abnormal vascular loop structures described in 3-dimensional computed tomography angiography. To be developed into a quantitative evaluation method for soft-tissue arteriovenous malformations (AVMs), the concept needs assessment of validity.

Methods:

Computed tomography angiography results of 19 soft-tissue AVMs and 18 control abdominal vessels are utilized. Enhanced vascular lumen regions over 120 HU were extracted by a region growing method and skeletonized into wire frame graph models. The number of vascular loop structures in graphs is calculated as 1 − [Number of nodes] + [Number of edges], and results are compared between AVM/control groups, pre-/postprogression, and pre-/posttreatment.

Results:

Average vascular lumen capacity of AVMs was 57.5 ml/lesion, and average number of vascular loops was 548 loops/lesion. Loop density of AVMs (weighted average, 9.5 loops/ml) exhibited statistically significant (P < 0.001) greater value than normal abdominal blood vessels (weighted average, 1.3 loops/ml). In all 4 cases without treatment, number of loops and loop density both increased. Particularly, number of loops increased greatly by 2 times or more in 3 cases. In all 7 cases with treatment, number of loops and vascular lumen capacity significantly (P = 0.0156) decreased. Particularly, number of loops showed clearer decrease in cases with entire lesion treatment than partial treatment.

Conclusions:

Total number of described vascular loop structures and their density or volume well reflected the existence, progression, and remission of soft-tissue AVMs. Topological analysis can be expected to be developed into a quantitative evaluation for AVMs.