Endovascular Repair of Diffuse Pulmonary Arteriovenous Malformations with Systemic Arterial Shunts.

Diffuse pulmonary arteriovenous malformations (PAVMs) are defined as arteriovenous malformations (AVMs) involving subsegmental, segmental, or both types of arteries in at least 1 lung lobe and are more extensive than multiple PAVMs. Diffuse PAVMs involving systemic arterial shunts are very rare. We describe a rare case, in which diffuse PAVMs involving systemic arterial shunts were successfully treated with coil embolization.

Capillary-venule malformation is a microfistulous variant of arteriovenous malformation.

OBJECTIVE: To describe typical clinical presentation of patients with microfistular, capillary-venule (CV) malformation as a variant form of arteriovenous malformations (AVM). METHODS: A retrospective clinical analysis of 15 patients with CV-AVM confirmed by a computational flow model enrolled in a prospective database of patients with congenital vascular malformation between January 2008 and May 2018. RESULTS: The mean age of the patients at first time of presentation was 30 years with balanced sex ratio. Presentation was dominated by soft tissue hypertrophy (n = 12 [80.0%]) and atypical varicose veins (n = 11 [73.3%]). The anatomic location of enlarged varicose veins gave no uniform pattern and did not correspond with the typical picture of primary varicose vein disease. Most often, symptomatic CV-AVM was found at the lower extremities in this series of unselected patients. The most frequent compartment affected was the subcutis (n = 14 [93.3%]), involvement of muscle was recorded in one-third and cutis in one-fourth of patients. CONCLUSIONS: A high grade of clinical suspicion is needed to recognize CV-AVM and to prevent inadequate therapy owing to missed diagnosis.

Recurrent Hemoptysis: A Bronchial Dieulafoy's Lesion in a Pediatric Patient.

OBJECTIVE: This paper presents a case of a bronchial Dieulafoy's lesion in a pediatric patient with recurrent hemoptysis. CASE REPORT: A 11-year old female presented multiple times with dry cough and hemoptysis to an outside hospital, each time leading to a diagnosis of epistaxis and subsequent discharge. When she arrived to our tertiary center with heavy hemoptysis and no evidence of epistaxis, the patient was urgently taken to the operating room by both the otolaryngology and pediatric pulmonology services. Active bleeding from a Dieulafoy's lesion on the right lower bronchus was found and selective embolization of two tortuous arteries was subsequently performed. The patient was discharged in stable condition without recurrence of hemoptysis over the last two months. CONCLUSION: While rare, especially in pediatric patients, bronchial Dieulafoy's lesions may cause severe hemoptysis and should be considered in the differential diagnosis when the etiology for hemoptysis is unclear.

A Rare Case of Dysplastic Axillary Artery Aneurysm Associated with Arteriovenous Malformation.

BACKGROUND: Axillary artery aneurysms are rare conditions, and their causes are various. They can determine severe complications, so the treatment is extremely important. METHODS: We report the case of a young man affected by a saccular axillary artery aneurysm associated with intramuscular arteriovenous malformation, without symptoms except for the presence of a pulsatile mass. Duplex scan and computed tomography scan have been essential for a correct diagnosis and planning of the treatment. At first, the patient was submitted to coil embolization of an efferent vessel, and then he was treated surgically through ligation and detachment of the aneurysm and replacement of part of the axillary artery with a Dacron graft (Vascutek, Inchinnan, Renfrewshire, Scotland, UK). RESULTS: Follow-up at 1 and 6 months revealed normal patency of the axillary arterty and the prosthetic graft with complete exclusion and thrombosis of the aneurysm sac.No sensitive nor motor deficit were observed. CONCLUSIONS: Aneurysms of the axillary artery associated with intramuscular arteriovenous malformations are very rare, but have to be suspected. The treatment is challenging and can be surgical, endovascular, or hybrid, based on the patient's conditions and aneurysm's anatomical features.

RhoA activation-mediated vascular permeability in capillary malformation-arteriovenous malformation syndrome: a hypothesis.

Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is a class of capillary anomalies that are associated with arteriovenous malformations and arteriovenous fistulas, which carry a risk of hemorrhages. There are no broadly effective pharmacological therapies currently available. Most CM-AVMs are associated with a loss of RASA1, resulting in constitutive activation of RAS signaling. However, protein interaction analysis revealed that RASA1 forms a complex with Rho GTPase-activating protein (RhoGAP), a negative regulator of RhoA signaling. Herein, we propose that loss of RASA1 function results in constitutive activation of RhoA signaling in endothelial cells, resulting in enhanced vascular permeability. Therefore, strategies aimed at curtailing RhoA activity should be tested as an adjunctive therapeutic approach in cell culture studies and animal models of RASA1 deficiency.

Pulmonary Arteriovenous Malformations in Non-hereditary Hemorrhagic Telangiectasia Patients: An 18-Year Retrospective Study.

PURPOSE: Pulmonary arteriovenous malformations (PAVMs) are most commonly associated with hereditary hemorrhagic telangiectasia (HHT). Patients with PAVMs can present with serious complications including stroke, transient ischemic attack (TIA), and brain abscess. PAVMs are rare in non-HHT patients and little is known about this patient population. The aim of this retrospective study is to better understand clinical presentation and outcomes of PAVMs occurring exclusively in non-HHT patients. METHODS: Non-HHT patients with PAVMs at the Mayo Clinic-Rochester between 01/01/2000 and 12/31/2018 were reviewed. Patients with Curacao score > 1 were excluded. Demographics, imaging characteristics, neurological complications, and follow-up imaging were analyzed. RESULTS: Seventy-seven patients with PAVMs were identified. The mean age at diagnosis was 48.2 ± 18.3 years with female preponderance (59.7%). The majority of PAVMs had lower lobe predominance (66.7%) and were simple and single in 75.3% and 89.6% of cases, respectively. Most patients were asymptomatic (46.8%) with dyspnea being the most common symptom (28.6%). Neurologic complications occurred in 19.5% of patients. The majority of PAVMs were idiopathic (61%). Thirty patients (39%) had one or more possible risk factors including previous thoracic surgery (23.4%), congenital heart disease (19.5%), and chest trauma (10.4%). Embolization was performed in 37 (48.1%) patients and only 4 (5.2%) underwent surgical resection. CONCLUSIONS: Non-HHT PAVMs occur more commonly in females, are most commonly simple and single, and have lower lobe predominance and a high rate of neurologic complications. Potential predisposing risk factors were identified in about 40% of the cases. Clinicians should be aware of the risk of PAVM development in patients with history of chest trauma, congenital heart disease, lung infection/abscess, and thoracic surgery.

A Case of an Aggressive Intraosseous Arteriovenous Malformation in the Lower Extremity: Special Considerations for Diagnosis and Management.

BACKGROUND: Arteriovenous malformations (AVMs) are rare, congenital vascular anomalies. Intraosseous AVMS most frequently arise in the head and neck, with only a small fraction occurring in the extremities. Herein, we report the findings of a combined soft tissue and intraosseous AVM involving the lower extremity of a 13-year-old child. This case highlights the necessity of an interdisciplinary approach for the effective treatment and management of these rare vascular anomalies. CASE DESCRIPTION: A 13-year-old female presented with a 4-year history of intermittent pain and swelling over her right lateral malleolus. The patient was evaluated with radiologic imaging revealing an AVM involving the right distal leg, ankle, and hindfoot with intraosseous involvement of the distal tibia and talus. She was then referred to Vascular and Plastic Surgery and an angiogram was performed demonstrating shunting from the anterior tibial, peroneal, and posterior tibial arteries to the AVM. Venous drainage was to the anterior tibial and greater saphenous veins. Three embolizations were performed over the course of 6 months. Following the third embolization, the patient was taken to the operating room where Plastic and Orthopedic Surgery performed total resection of the nidus and involved bone which was then grafted with injectable synthetic bone graft. RESULTS: Successful resection of the nidus was achieved, and the patient had an uncomplicated recovery. Within 6 months postoperatively, the patient demonstrated full range of lower extremity motion and was able to participate in age appropriate gross motor activities. Radiologic evaluation 7 months postoperatively showed no evidence of nidus recurrence. CONCLUSION: Intraosseous involvement of AVMS is rare and presents a therapeutic challenge due to its invasive potential and high incidence of recurrence. Wide local excision with bone grafting and interdisciplinary management are paramount for complete resection.

Interventional Management of Arteriovenous Malformations.

Arteriovenous malformations (AVMs) are fast flow malformations characterized by the presence of arteriovenous shunting. These congenital lesions can be evolutive, leading to serious complications such as bleeding, skin ulceration, and cardiac failure. The interventional radiologist plays an important role in the management of these patients. He should be involved in the clinical evaluation to make the proper diagnosis, evaluate the symptoms and potential indication for endovascular treatment. This evaluation should be done in a multidisciplinary clinic with access to plastic surgeons, internal medicine and dermatologist, as well as specific specialists that might need to be implicated (ENT surgeon in the face and neck area, for example). The Schobinger clinical classification is important to assess patient evolution and indicate intervention. We recommend to treat symptomatic or evolutive AVMs. Doppler ultrasound is the first imaging examination that should be performed. Then, MR angiography or computed tomography angiography (CTA) can be proposed depending on the anatomic area involved. Embolization is currently the first line of treatment for these patients. There is currently promising research in the identification of genetic markers and molecular target(s) but there is no recognized pharmacologic treatment for AVM available yet. Digital substraction angiography (DSA) is usually performed for guidance during the embolization session but is also essential to properly classify a specific lesion, according to its anatomy. The anatomic classifications proposed by Cho and Yakes are both useful to choose the best therapeutic approach: Endovascular, direct puncture, retrograde venous approach or a combination of these techniques. Ethanol is the most efficient agent but is at higher risk of skin necrosis and nerve injury and should therefore be used with caution in dangerous territories. Glue and Onyx are liquid agents that are also well suited to occlude the nidus; they can be used in association with ethanol. On the venous side, mechanical occlusion with coils or Amplatzer plugs is mostly used. Again, they can be used in association with a liquid agent (Ethanol, glue or Onyx) to reflux in the nidus. Surgery can be indicated to resect residual AVM following embolization if residual symptoms are present and the planned surgery is feasible, with relative safety.

Endovascular Management of Massive Hemoptysis Secondary to Systemic Collaterals in Previously Treated Pulmonary Arteriovenous Malformation.

Pulmonary arteriovenous malformations (PAVMs) are abnormal connections between pulmonary artery and vein through a thin-walled aneurysmal sac, leading to a right-to-left shunt. These are commonly associated with hereditary hemorrhagic telangiectasia, and treatment guidelines have been set on how to approach their management. Incorrect proximal placement of an embolization device can lead to delayed recruitment of systemic collaterals leading to presentation with hemoptysis. We are presenting a case of a 17-year-old male with treated PAVMs and with fresh hemoptysis. In this case report, we attempt to explain the management of such a complication and follow the principles of arteriovenous malformation embolization on the left side.

Pulmonary gas exchange in hereditary hemorrhagic telangiectasia patients with liver arteriovenous malformations.

BACKGROUND: The severity of Hereditary Hemorrhagic Telangiectasia (HHT) disease is generally related to vascular visceral involvement represented by arteriovenous malformations (AVMs). Pulmonary function tests (PFTs) remain normal in HHT patients without Pulmonary AVMs (PAVMs) and respiratory comorbidity. The aim of our study was to compare the diffusing capacity of the lung for carbon monoxide (DLCO) and nitric oxide (DLNO) and its 2 components: the pulmonary capillary blood volume (Vc) and the alveolar-capillary membrane conductance (Dm), in HHT patients with PAVMs, PAVMs and liver AVMs (LAVMs), LAVMs without PAVM, no PAVM and LAVM, and controls. METHODS: Sixty one consecutive adult patients (HHT without PAVM and LAVM: n = 7; HHT with PAVMs: n = 8; HHT with PAVMs and LAVMs: n = 25; HHT with LAVMs: n = 21) and controls matched for age and sex ratio without respiratory, heart and liver pathology (n = 15) were non-invasively evaluated using PFTs, combined DLCO/DLNO, arterial blood gas at rest, contrast echocardiography and enhanced computed tomography scan of the liver and chest the day of pulmonary function testing. RESULTS: We found that patients with LAVMs but without PAVMs exhibited increased Vc/Dm ratio. Interestingly, HHT patients with hepatic artery enlargement showed higher Vc/Dm ratio than HHT patients with normal hepatic artery diameter. CONCLUSION: Vc/Dm ratio may have practical impact in HHT patients' management to detect precociously the occurrence of LVAMs. However, further studies are needed to assess the accuracy and potential prognostic value of pulmonary gas exchange measurements in HHT patients with LVAMs.

Differences in the Electrophysiological Monitoring Results of Spinal Cord Arteriovenous and Intramedullary Spinal Cord Cavernous Malformations.

OBJECTIVE: Spinal arteriovenous malformations (SAVMs) and intramedullary spinal cord cavernous malformations (ISCCMs) have a very low incidence of disease. The purpose of this study was to compare the differences in electrophysiologic monitoring in these 2 surgeries. METHODS: The study included 109 patients (SAVMs, n = 55; ISCCMs, n = 54) recruited from November 2012 to January 2016. All patients underwent electrophysiologic monitoring during the entire operation, including somatosensory-evoked potentials, motor-evoked potentials, and electromyography. We used an amplitude reduction of >80% as warning criterion for motor-evoked potentials and an amplitude reduction of more than 50% and latency prolongation of more than 10% as warning criteria for somatosensory-evoked potentials. RESULTS: In our study, the sensitivity and specificity of intraoperative monitoring during SAVM surgery were 77.3% and 87.1%, respectively. The sensitivity and specificity of intraoperative monitoring during ISCCM surgery were 68.8% and 83.3%, respectively. We found that 21 patients with SAVM showed permanent changes, 17 had immediate postoperative impairment, 8 recovered before discharge, and 5 showed neurologic deficits at long-term follow-up. Of the 17 patients with ISCCMs showing permanent changes, 11 had immediate postoperative impairment, 5 recovered before discharge, and 2 had long-term residual neurologic deficits. CONCLUSIONS: Electrophysiological monitoring provides effective guidance during operation on spinal vascular malformations. Electrophysiologic monitoring revealed that surgical resection of SAVMs resulted in more permanent changes and postoperative dysfunction when compared with ISCCMs. The incidence of both false-positive and -negative results suggests that electrophysiologic monitoring cannot fully predict the complete function of the patients.

Expanding the clinical and molecular findings in RASA1 capillary malformation-arteriovenous malformation.

RASA1-related disorders are vascular malformation syndromes characterized by hereditary capillary malformations (CM) with or without arteriovenous malformations (AVM), arteriovenous fistulas (AVF), or Parkes Weber syndrome. The number of cases reported is relatively small; and while the main clinical features are CMs and AVMs/AVFs, the broader phenotypic spectrum caused by variants in the RASA1 gene is still being defined. Here, we report the clinical and molecular findings in 69 unrelated cases with a RASA1 variant identified at ARUP Laboratories. Sanger sequencing and multiplex ligation-dependent probe amplification were primarily used to evaluate RASA1. Several atypical cases were evaluated using next-generation sequencing (NGS) and array-comparative genomic hybridization (aCGH). Sixty individuals had a deleterious RASA1 variant of which 29 were novel. Nine individuals had a variant of uncertain significance. Five large RASA1 deletions were detected, giving an overall deletion/duplication rate of 8.3% (5/60) among positive cases. Most (75.4%) individuals with a RASA1 variant had CMs, and 44.9% had an AVM/AVF. Clinical findings in several cases expand the RASA1 phenotype. Our data suggest that screening for large RASA1 deletions and duplications in this disorder is important and suggest that NGS multi-gene panel testing is beneficial for the molecular diagnosis of cases with complex vascular phenotypes.

Clinical importance of the anterior choroidal artery: a review of the literature.

The anterior choroidal artery (AChA) is a critical artery in brain physiology and function. The AChA is involved in many diseases, including aneurysm, brain infarct, Moyamoya disease (MMD), brain tumor, arteriovenous malformation (AVM), etc. The AChA is vulnerable to damage during the treatment of these diseases and is thus a very important vessel. However, a comprehensive systematic review of the importance of the AChA is currently lacking. In this study, we used the PUBMED database to perform a literature review of the AChA to increase our understanding of its role in neurophysiology. Although the AChA is a small thin artery, it supplies an extremely important region of the brain. The AChA consists of cisternal and plexal segments, and the point of entry into the choroidal plexus is known as the plexal point. During treatment for aneurysms, tumors, AVM or AVF, the AChA cisternal segments should be preserved as a pathway to prevent the infarction of the AChA target region in the brain. In MMD, a dilated AChA provides collateral flow for posterior circulation. In brain infarcts, rapid treatment is necessary to prevent brain damage. In Parkinson disease (PD), the role of the AChA is unclear. In trauma, the AChA can tear and result in intracranial hematoma. In addition, both chronic and non-chronic branch vessel occlusions in the AChA are clinically silent and should not deter aneurysm treatment with flow diversion. Based on the data available, the AChA is a highly essential vessel.

Spontaneous Regression of Parapharyngeal Arteriovenous Malformation.

Arteriovenous malformations (AVMs) are fast-flow vascular malformations that mostly occur in the head and neck region. They are typically progressive and their spontaneous regression is almost never seen. We present a case with pulsatile tinnitus and a parapharyngeal AVM. It resolved completely after diagnostic catheter-based angiography alone.

Varicocele due to renal arteriovenous malformation mimicking a renal tumor: a case report.

BACKGROUND: Renal arteriovenous malformation is an aberrant vascular connection between the renal artery and vein. Acquired renal arteriovenous malformation (arteriovenous fistulae) accounts for approximately 70% of renal arteriovenous abnormalities. Congenital renal arteriovenous malformation, relatively rare, can result in significant hematuria which may require arterial embolization or nephrectomy. CASE PRESENTATION: A 64-year-old Asian man presented to the Urology department in our hospital with gradual left scrotal swelling for 2 years. Ultrasound and computed tomography showed an irregular mass in the upper pole of his left kidney. Digital subtraction angiography confirmed cirsoid-type left renal arteriovenous malformation combined with left renal vein ostial stenosis. After digital subtraction angiography and selective segmental renal artery embolization, the varicocele was obviously alleviated. CONCLUSIONS: The etiology diagnosis of varicocele is not always straightforward, and renal arteriovenous malformation should be considered in the differential diagnosis of varicocele and renal mass. Renal arteriovenous malformation is difficult to distinguish from renal tumor according to varicocele and computed tomography presentation, while magnetic resonance imaging and digital subtraction angiography help to make a definite diagnosis and selective renal angiographic embolization is one of the best treatments for renal arteriovenous malformation.

Concomitant conus medullaris arteriovenous shunts and sacral dural arteriovenous fistulas: pathophysiological links related to the venous drainage of the lesions in a series of five cases.

BACKGROUND: Spinal cord arteriovenous shunts (scAVSs) are a group of lesions located in the spinal cord itself or in the surrounding structures. The most common scAVSs are spinal dural arteriovenous fistulas (sDAVFs), which are acquired lesions. The pathogenesis of sDAVFs involves thrombosis and venous hypertension as trigger factors. Intradural scAVSs such as spinal cord arteriovenous nidus type malformations (AVMs) and pial arteriovenous fistulas are less common than sDAVFs and are considered to have a so-called 'congenital' origin. The association between different concomitant scAVSs is very rare and the association of sDAVFs with intradural scAVSs has been described in only a few case reports. METHODS: We describe a case series of five patients presenting with a conus medullaris AVS associated with a lower lumbar or sacral DAVF. RESULTS: Three of our patients were <30 years old at presentation. In four of these five cases the intradural scAVS drained caudally, engorging the epidural plexus in the same location as the sDAVF. In only one case, who presented with thrombosis of the drainage of the main compartment of a conus medullaris pial AVF, was the location of the DAVF opposite to the location of the residual drainage. CONCLUSION: We discuss the pathophysiological link between scAVS and sDAVF on the basis of the rarity of the DAVF, the uncommon association between scAVS and sDAVF, the presence of sDAVF in young patients, and the venous hypertension created by the venous drainage towards the sacral area responsible for angiogenesis creating the dural shunt.

Endovascular Treatment of 12 Cases of Renal Arteriovenous Malformations: The Experience of 1 Center and an Overview of the Literature.

OBJECTIVES: Congenital renal arteriovenous malformations (rAVMs) represent rare vascular diseases. The heterogeneous vascular architecture of each rAVM determines the endovascular treatment techniques employed. We reported our experience with the endovascular treatment of a series of rAVMs. MATERIALS: This retrospective study consisted of 12 patients with 12 rAVMs who underwent renal arterial embolization (RAE) in our hospital. Embolic materials, including particles, liquid embolic agents (n-butyl 2-cyanoacrylate, Onyx, and ethanol), and coils, were selectively used based on the decisions of interventional radiologists. Technical success was defined as the complete occlusion of the feeding arteries and nidus on postprocedure renal arteriography. Clinical success was defined as the resolution of hematuria or the disappearance of rAVM-relevant symptoms. RESULTS: The median follow-up period was 13.5 months (range: 4-72). The technical success based on 12 procedures in 12 patients was 83.3% (10 of 12). In the 2 procedures that technically failed, the existence of multiple fine feeding arteries arising from the proximal portion of different segmental renal arteries explains the incomplete embolization. One of the 2 patients achieved clinical success without additional RAE. The other patient had recurrent hematuria 25 months after initial treatment, which was successfully managed conservatively with hemostatic agents. Thus, the clinical success was 91.7% (11 of 12). CONCLUSIONS: Renal artery embolization with the selective use of various embolic materials is an effective treatment for patients with rAVMs. The existence of multiple fine feeding vessels arising from the proximal portion of different segmental renal arteries is likely to affect the technical success of treatment.