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.

Endovascular Treatment of Arteriovenous Malformations of the Head and Neck: Focus on the Yakes Classification and Outcomes.

PURPOSE: To evaluate endovascular treatment of head and neck arteriovenous malformations (AVMs) based on the Yakes AVM classification and correlate treatment approach with clinical and angiographic outcomes. MATERIALS AND METHODS: A retrospective single-center study was performed in patients who underwent endovascular treatment of head and neck AVMs between January 2005 and December 2017. Clinical and operative records, imaging, and postoperative courses of patients were reviewed. Clinical stage was determined according to the Schobinger classification. AVM architecture and treatment approaches were determined according to the Yakes classification. Primary outcomes were clinical and angiographic treatment success rates and complication rates, with analysis according to the Yakes classification. RESULTS: A total of 29 patients (15 females) were identified, with a mean age of 30.6 years. Downgrading of the Schobinger clinical classification was achieved in all patients. Lesions included 8 Yakes type IIa, 5 type IIb, 1 type IIIa and IIIb, and 14 type IV. Lesions were treated using an intra-arterial, nidal, or transvenous approach, using ethanol and liquid embolic agents. Arteriovenous shunt eradication of >90% was achieved in 22 of 28 patients (79%), including 9 of 13 (69%) of Yakes type IV lesions and 13 of 15 (87%) of the other types. There were 5 significant complications in 79 procedures (6%), including 4 of 50 (8%) in Yakes type IV lesions. CONCLUSIONS: Schobinger stage was downgraded in all patients. Arteriovenous shunt eradication of >90% was achieved in most patients. Yakes type IV lesions required more sessions, and shunt eradication was higher in the Yakes II and III groups.

A Proposed Classification of Intraretinal Microvascular Abnormalities in Diabetic Retinopathy Following Panretinal Photocoagulation.

Purpose: To investigate the characteristics of intraretinal microvascular abnormalities (IRMAs) before and after panretinal photocoagulation (PRP) for diabetic retinopathy (DR) by using optical coherence tomography angiography (OCTA). Methods: Forty-six eyes of 29 patients with DR were included (26 eyes with severe nonproliferative diabetic retinopathy [SNPDR] and 20 eyes with proliferative diabetic retinopathy [PDR]). En face OCTA images of IRMAs in a 6 × 6-mm area were acquired by using Cirrus 5000 with AngioPlex. The morphological changes in IRMAs were evaluated before and after PRP. The changes in the IRMAs were divided into five subtypes: unchanged; tuft regression; reperfusion; mixed (combined tuft regression/reperfusion); and worsening (new appearance of tuft). Results: Unchanged IRMAs were identified in 15 SNPDR eyes and 2 PDR eyes; all neovascularization (NV) had regressed after PRP. Tufts were more frequently observed in the PDR eyes (15/20, 75%) than in the SNPDR eyes (8/26, 31%) (P = 0.003), and two tufts tended to exceed the inner limiting membrane, which showed progression to NV before PRP. The reperfusion phenomenon was observed in 7/26 SNPDR eyes and 4/20 PDR eyes, including the mixed type, and showed two vascular patterns: abnormal (dilated, tortuous, and twisted) and normal vessels. The worsening type was observed in 1/26 SNPDR eye and 2/20 PDR eyes. Conclusions: OCTA enabled classification of IRMA into more detailed types. The unchanged and reperfusion types suggested that IRMAs had aspects of remodeling. However, IRMAs with tufts were observed in 75% of the PDR eyes, and the tufts had aspects of NV.

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.

Direct percutaneous puncture digital-subtraction-angiography-based classification and treatment selection for soft-tissue arteriovenous malformations of maxillofacial region: a retrospective study.

Treatment of arteriovenous malformations (AVMs) should be individualized based on the imaging findings. A total of 117 AVM cases were categorized into three types based on the angio-architectural characteristics: Type I (n=14, no draining vein or diameter of the draining vein <2mm); Type II (n=64, draining vein diameter 2-6mm); and Type III (n=39, draining vein diameter >6mm). Subjects were randomly allocated to one of two treatment groups: Group A (n=59) received multipoint percutaneous ethanol injection (MPEI), while Group B (n=58) received super-selective angiograms followed by embolization with gelfoam (EFAG) plus MPEI. Patients were followed up for 2-6 years. A significant between-group difference with respect to treatment outcomes was observed only for Type III cases (P<0.05). Direct percutaneous puncture digital-subtraction-angiography-guided classification of AVMs provides easy-to-follow guidelines for its clinical management. EFAG plus MPEI with reduced procedure time and the amount of ethanol should be used for Type III AVMs.

Canine and feline abdominal arterioportal communications can be classified based on branching patterns in computed tomographic angiography.

Arterioportal vascular anomalies are communications between the splanchnic arteries and the portal system that represent a rare cause of presinusoidal portal hypertension in small animals. There is little information concerning the imaging findings of arterioportal communications in small animals and no classification could be found for radiologists and surgeons. The aims of this retrospective descriptive multicentric study were to describe the computed tomographic characteristics of arterioportal communications in a group of cats and dogs, and to propose a classification based on computed tomography (CT) angiographic anatomy. Computed tomography databases from multiple veterinary hospitals were searched for cats and dogs with a diagnosis of arterioportal communication. A total of 36 animals (33 dogs, three cats) met the inclusion criteria. There were 32 intrahepatic arterioportal malformations and four extrahepatic fistulae. The intrahepatic arterioportal malformations were classified as right divisional (11/32) and left divisional (21/32), and the left divisional were subclassified as left medial (16/21) and left lateral (4/21). One patient showed multiple intrahepatic arterioportal communications with concomitant left medial and left lateral conformations. Two patients with intrahepatic arteriovenous malformation showed concomitant congenital intrahepatic shunts. The proposed anatomical classification based on CT angiography could allow veterinary radiologists to have a more systematic approach and help improve the radiologist-surgeon communication.

Angioarchitecture and hemodynamics of microvascular arterio-venous malformations.

INTRODUCTION: Arteriovenous malformations (AVMs) are characterized by pathological high flow, low resistance connections between arteries and veins. Treatment is critically dependent on correct interpretation of angioarchitectural features. However, some microfistular AVMs do not match the characteristics described in current AVM classification systems. Therefore, we propose a new subgroup of microfistular AVMs, composed of enlarged, fistulous paths on the venous half of capillaries and/or dilated draining venules (hyperdynamic, capillary-venulous malformation [CV-AVM]). CV-AVMs still ensure arterial flow to the periphery and fistulous venous drainage is less pronounced than in classical AVMs such that these lesions are often misinterpreted as venous malformations. MATERIALS AND METHODS: We developed a computational model to study the effects of microvascular anomalies on local hemodynamics, as well as their impact on angiographic contrast propagation. Flow rates and pressures were computed with a lumped parameter description, while contrast propagation was determined by solving the 1D advection-diffusion equation. RESULTS AND CONCLUSIONS: For the newly proposed CV-AVM angioarchitecture, the computational model predicts increased arterio-venous contrast agent transit times and highly dispersive transport characteristics, compared to microfistular, interstitial type IV AVMs and high flow type II and III AVMs. We related these findings to time-contrast intensity curves sampled from clinical angiographies and found that there is strong evidence for the existence of CV-AVM.

Vascular Anomalies (Part I): Classification and Diagnostics of Vascular Anomalies.

BACKGROUND: Vascular anomalies are a diagnostic and therapeutic challenge. They require dedicated interdisciplinary management. Optimal patient care relies on integral medical evaluation and a classification system established by experts in the field, to provide a better understanding of these complex vascular entities. METHOD: A dedicated classification system according to the International Society for the Study of Vascular Anomalies (ISSVA) and the German Interdisciplinary Society of Vascular Anomalies (DiGGefA) is presented. The vast spectrum of diagnostic modalities, ranging from ultrasound with color Doppler, conventional X-ray, CT with 4 D imaging and MRI as well as catheter angiography for appropriate assessment is discussed. RESULTS: Congenital vascular anomalies are comprised of vascular tumors, based on endothelial cell proliferation and vascular malformations with underlying mesenchymal and angiogenetic disorder. Vascular tumors tend to regress with patient's age, vascular malformations increase in size and are subdivided into capillary, venous, lymphatic, arterio-venous and combined malformations, depending on their dominant vasculature. According to their appearance, venous malformations are the most common representative of vascular anomalies (70 %), followed by lymphatic malformations (12 %), arterio-venous malformations (8 %), combined malformation syndromes (6 %) and capillary malformations (4 %). CONCLUSION: The aim is to provide an overview of the current classification system and diagnostic characterization of vascular anomalies in order to facilitate interdisciplinary management of vascular anomalies. KEY POINTS: · Vascular anomalies are comprised of vascular tumors and vascular malformations, both considered to be rare diseases.. · Appropriate treatment depends on correct classification and diagnosis of vascular anomalies, which is based on established national and international classification systems, recommendations and guidelines.. · In the classification, diagnosis and treatment of congenital vascular anomalies, radiology plays an integral part in patient management.. CITATION FORMAT: · Sadick M, Müller-Wille R, Wildgruber M et al. Vascular Anomalies (Part I): Classification and Diagnostics of Vascular Anomalies. Fortschr Röntgenstr 2018; 190: 825 - 835.

[Benign aggressive vascular anomalies in children]. / Anomalies vasculaires bénignes agressives de l'enfant et de l'adolescent.

Superficial vascular anomalies constitute a large group of malformative and tumoral conditions developed from all types of vessels. Vascular tumors are the result of cellular hyperplasia, whereas vascular malformations (VMs) are constituted of dysplastic vessels. The classification from International Society for the Study of Vascular Anomalies (ISSVA) is based on this pathogenic difference. The most common vascular tumor is infantile hemangioma, which treatment, when necessary, is propranolol. Congenital hemangiomas and tumors that might be complicated with Kasabach-Merritt phenomenon, i.e. deep thrombocytopenia, are much rarer. Management of Kasabach-Merritt phenomenon is now largely based on sirolimus. Low-flow VMs include capillary, venous and lymphatic malformations; arteriovenous malformations are high-flow malformations. These different types of VMs might be combined. Currently, there is an increasing work in delineating the different entities based on molecular findings. Treatment of VMs depends on the impairment linked to them, and is decided case by case, in pluridisciplinary consultations. Interventional treatments, especially surgery and sclerotherapy, are usually partially efficient, and management of patients with VMs increasingly involves medical drugs. First-line treatment of coagulation disorders associated with venous malformations is based on low molecular weight heparin; sirolimus seems efficient in hemorrhagic complications refractory to usual treatment. Sirolimus is about to become the standard treatment in painful inflammatory manifestations of mixed and/or complicated lymphatic malformations.

Classification and Pathology of Congenital and Perinatal Vascular Anomalies of the Head and Neck.

Accurate histopathologic description in correlation with clinical and radiological evaluation is required for treatment of vascular anomalies, both neoplastic and malformative. It is important to examine current clinical, histologic, and immunophenotypical features that distinguish the major types of congenital and perinatal vascular anomalies affecting the head and neck. General discussions of pathogenesis and molecular diagnosis must also be taken into account. This article provides an overview of the features that distinguish the major types of congenital and perinatal vascular anomalies affecting the head and neck, and summarizes the diagnostic histopathologic criteria and nomenclature currently applied to these lesions.

Spinal Arteriovenous Shunts: Angioarchitecture and Historical Changes in Classification.

The purposes of this study were to review historical changes in the classification of spinal arteriovenous (AV) shunts and to propose a practical classification system. The associated literature regarding the classification of spinal AV shunts was reviewed in the angiography era between 1967 and 2015. The classification systems of spinal AV shunts and a proposed classification system were presented with neuroradiological imaging and medical illustrations. There have been seven major classification systems based on the evolution of diagnostic methods as well as treatments for spinal AV shunts: the first description of spinal AV shunts diagnosed and classified using spinal angiography in 1971; the second classification based on a case report of intradural direct perimedullary arteriovenous fistulas (AVFs) treated by microsurgery in 1987; the third classification based on a case series of intradural perimedullary AVFs treated by endovascular interventions in 1993; the fourth and fifth classification systems based on a case series of spinal AVFs and arteriovenous malformations (AVMs) treated by microsurgery or endovascular interventions in 2002; the sixth classification based on a case series of cranio-spinal dural AV shunts in 2009; and the seventh classification based on a case series of extradural AVFs treated by microsurgery and endovascular interventions in 2011. Based on historical reports, the author proposed a classification system according to the sites (dural, intradural, and extradural) and types (AVF and AVM) of AV shunts. By learning the historical background, we may obtain a clearer understanding of the complex and confusing classification system of spinal AV shunts.

Classification and pathophysiology of spinal vascular malformations.

Spinal arteriovenous malformations and fistulas comprise spinal vascular malformations (sVMs), a rare but challenging neurosurgic entity. A number of mechanisms have been proposed as explanations of neurologic decline in the setting of arteriovenous shunting, including venous hypertension, venous congestion, hemorrhage, vascular steal, or mass effect, which can be worsened with venous varices or aneurysmal dilations. Anatomic location and features dictate the categorization of sVMs. Two major systems are in place for classification of sVMs - (1) the American/French/English connection and (2) the Spetzler system - as well as a number of systems that have been described over the past century.

Spinal arteriovenous malformations: surgical management.

Spinal arteriovenous malformations (AVMs) are a diverse population of vascular lesions associated with significant long-term morbidity and neurologic impairment. Spinal AVMs can be classified into three categories: intramedullary, extradural-intradural, and conus, depending on their angioarchitecture and anatomy. Extradural-intradural lesions are typically incurable due to their diffuse nature, but patients may benefit from targeted therapy of symptomatic components. Intramedullary and conus AVMs are amenable to safe surgical resection when combined with endovascular embolization and use of a pial dissection technique that spares entry into the neural parenchyma.

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.

Finding the Nidus: Detection and Workup of Non-Central Nervous System Arteriovenous Malformations.

Vascular anomalies are a diverse group of pathologic conditions. They have different manifestations, natural histories, and treatments. Compared with other vascular malformations, arteriovenous malformations (AVMs) are considered the most symptomatic and difficult to manage. AVMs inherently progress and have a high rate of recurrence after treatment. Imaging helps provide an accurate and early diagnosis, which can then be used to direct appropriate management, with embolization evolving as the primary therapy. Thus, radiology plays a crucial role in the detection, workup, and management of AVMs. Ultrasonography (US) is a useful initial imaging modality, particularly when AVMs involve the extremities or a superficial or accessible location. Limitations include poor identification of soft-tissue and bone components, as well as suboptimal evaluation of deep or complex AVMs. Magnetic resonance (MR) angiography is the preferred imaging modality for AVMs and should be considered in any symptomatic patient or in the initial evaluation of vascular anomalies that are equivocal at US. Computed tomographic angiography should be reserved for those patients who are unable to undergo MR angiography or for evaluation of acute symptoms, such as bleeding or airway compromise. Conventional catheter-based angiography is useful for real-time depiction and evaluation of AVMs, particularly in the planning and execution of endovascular treatment and in the diagnosis of an AVM when findings from noninvasive imaging are equivocal for a high-flow component. As with the diagnostic workup, MR angiography is the preferred posttreatment modality. (©)RSNA, 2016.

[Vascular anomaly in the midcheek region of an infant--review of the diagnostic procedure]. / Gefäßanomalie in der Wangenregion eines Säuglings - Diagnostischer Prozess anhand einer Kasuistik.

Clinical history, physical examination, evolution and imaging findings (Colour Doppler sonography, MRI if available) are of pivotal importance in the diagnostic pathway of an infantile vascular anomaly. Histopathology with specific stains and markers is contributive in difficult cases. Differentiation between vascular tumors (hemangioma) and vascular malformations is now well known and integrated into the ISSVA classification. We report here a 6-months-old boy, who presented with a localized cutaneous and expansive vascular birthmark in the left cheek and developed bleedings at the age of 18 months. Diagnostic features of a hemangioma were not evident, and the final diagnosis of a venous malformation was confirmed by histopathology.

[Arteriovenous malformation of the left upper limb in stage II of Schöbinger: A case report in Madagascar]. / Malformation artérioveineuse du membre supérieur gauche au stade II de Schöbinger : à propos d'une observation à Madagascar.

Arteriovenous malformations are the most unpredictable and dangerous congenital malformations. They consist of multiple arteriovenous shunts with high flow and can progress to heart failure. They are rarely localized in the upper limb and pose therapeutic problems. We report a new case in a 27-year old woman, admitted for pulsatile pain in the left elbow. The diagnosis was made by clinical examination and ultrasonography. The surgical treatment without embolization and sclerotherapy, consisted of a large resection of the nidus without postoperative complication.

Vascular malformations of the orbit: classification and the role of imaging in diagnosis and treatment strategies*.

PURPOSE: To describe the authors' experience with orbital vascular malformations using the International Society for the Study of Vascular Anomalies (ISSVA) classification and the preferred radiologic techniques. METHODS: Review of clinical and radiologic experience from 1976 to 2012. This article presents the findings from several studies conducted on vascular malformations of the orbit, all of which received institutional review board approval when needed. RESULTS: The orbital vascular malformations can be evaluated, classified, and managed according to the ISSVA classification to provide a common language of communication between specialties, which takes into account flow dynamics. CONCLUSIONS: The ISSVA can be applied for vascular malformations of the orbit.

Consensus Document of the International Union of Angiology (IUA)-2013. Current concept on the management of arterio-venous management.

Arterio-venous malformations (AVMs) are congenital vascular malformations (CVMs) that result from birth defects involving the vessels of both arterial and venous origins, resulting in direct communications between the different size vessels or a meshwork of primitive reticular networks of dysplastic minute vessels which have failed to mature to become 'capillary' vessels termed "nidus". These lesions are defined by shunting of high velocity, low resistance flow from the arterial vasculature into the venous system in a variety of fistulous conditions. A systematic classification system developed by various groups of experts (Hamburg classification, ISSVA classification, Schobinger classification, angiographic classification of AVMs,) has resulted in a better understanding of the biology and natural history of these lesions and improved management of CVMs and AVMs. The Hamburg classification, based on the embryological differentiation between extratruncular and truncular type of lesions, allows the determination of the potential of progression and recurrence of these lesions. The majority of all AVMs are extra-truncular lesions with persistent proliferative potential, whereas truncular AVM lesions are exceedingly rare. Regardless of the type, AV shunting may ultimately result in significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity (10-20% of all CVMs), AVMs remain the most challenging and potentially limb or life-threatening form of vascular anomalies. The initial diagnosis and assessment may be facilitated by non- to minimally invasive investigations such as duplex ultrasound, magnetic resonance imaging (MRI), MR angiography (MRA), computerized tomography (CT) and CT angiography (CTA). Arteriography remains the diagnostic gold standard, and is required for planning subsequent treatment. A multidisciplinary team approach should be utilized to integrate surgical and non-surgical interventions for optimum care. Currently available treatments are associated with significant risk of complications and morbidity. However, an early aggressive approach to elimiate the nidus (if present) may be undertaken if the benefits exceed the risks. Trans-arterial coil embolization or ligation of feeding arteries where the nidus is left intact, are incorrect approaches and may result in proliferation of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route. Surgically inaccessible, infiltrating, extra-truncular AVMs can be treated with endovascular therapy as an independent modality. Among various embolo-sclerotherapy agents, ethanol sclerotherapy produces the best long term outcomes with minimum recurrence. However, this procedure requires extensive training and sufficient experience to minimize complications and associated morbidity. For the surgically accessible lesions, surgical resection may be the treatment of choice with a chance of optimal control. Preoperative sclerotherapy or embolization may supplement the subsequent surgical excision by reducing the morbidity (e.g. operative bleeding) and defining the lesion borders. Such a combined approach may provide an excellent potential for a curative result. Conclusion. AVMs are high flow congenital vascular malformations that may occur in any part of the body. The clinical presentation depends on the extent and size of the lesion and can range from an asymptomatic birthmark to congestive heart failure. Detailed investigations including duplex ultrasound, MRI/MRA and CT/CTA are required to develop an appropriate treatment plan. Appropriate management is best achieved via a multi-disciplinary approach and interventions should be undertaken by appropriately trained physicians.