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Objective: Recently, the occlusion rate of transarterial embolization (TAE) for intracranial non-sinus-type dural arteriovenous fistulas (NSDAVFs) has improved after ONYX was introduced. Additionally, when TAE for NSDAVF is unsuccessful, transvenous embolization (TVE) has become available as an alternative treatment. We investigated the factor for the favorable occlusion rate of endovascular treatment for NSDAVF at our institutions. Methods: Two hundred and twenty-seven patients with intracranial dural arteriovenous fistulas (DAVFs) were treated at our institutions between September 2014 and October 2022. The patients diagnosed with NSDAVF in all DAVFs who underwent endovascular treatment were included. The clinical characteristics, angiographical outcomes, and clinical outcomes of patients who underwent endovascular treatment were evaluated. Results: Thirty-eight patients had intracranial NSDAVF (tentorial: 23 cases, parasagittal-convexity: 7, anterior cranial fossa: 6, middle cranial fossa: 2). Our participants' mean age was 64.8 ± 11.3 years, and 31 (81.6%) of them were males. Patients' symptoms were as follows: asymptomatic (24), hemorrhage (10), tinnitus (3), and trigeminal neuralgia (1). TAE and TVE were performed on 35 and 3 patients, respectively. The rate of immediate angiographical occlusion was 84.2% (32/38). The follow-up angiographical occlusion rate in 6 months was 88.5% (31/35). Complications occurred in three cases. There was no morbidity or mortality after 30 days. Conclusion: TAE using the combination of the new microcatheter and microguidewire and TVE in the case of difficult or failed TAE for NSDAVF could achieve high success rates and safety. [ABSTRACT FROM AUTHOR]

Background Anterior cranial fossa dural arteriovenous fistulas (ACF-dAVFs) are aggressive vascular lesions. The pattern of venous drainage is the most important determinant of symptoms. Due to the absence of a venous sinus in the anterior cranial fossa, most ACF-dAVFs have some degree of drainage through small cortical veins. We describe the natural history, angiographic presentation and outcomes of the largest cohort of ACF-dAVFs. Methods The CONDOR consortium includes data from 12 international centers. Patients included in the study were diagnosed with an arteriovenous fistula between 1990-2017. ACF-dAVFs were selected from a cohort of 1077 arteriovenous fistulas. The presentation, angioarchitecture and treatment outcomes of ACF-dAVF were extracted and analyzed. Results 60 ACF-dAVFs were included in the analysis. Most ACF-dAVFs were symptomatic (38/60, 63%). The most common symptomatic presentation was intracranial hemorrhage (22/38, 57%). Most ACF-dAVFs drained through cortical veins (85%, 51/60), which in most instances drained into the superior sagittal sinus (63%, 32/51). The presence of cortical venous drainage predicted symptomatic presentation (OR 9.4, CI 1.98 to 69.1, p=0.01). Microsurgery was the most effective modality of treatment. 56% (19/34) of symptomatic patients who were treated had complete resolution of symptoms. Improvement of symptoms was not observed in untreated symptomatic ACF-dAVFs. Conclusion Most ACF-dAVFs have a symptomatic presentation. Drainage through cortical veins is a key angiographic feature of ACF-dAVFs that accounts for their malignant course. Microsurgery is the most effective treatment. Due to the high risk of bleeding, closure of ACF-dAVFs is indicated regardless of presentation. [ABSTRACT FROM AUTHOR]

Uterine vascular anomalies (UVAs), while rare, can result in severe, life-threatening hemorrhage. An understanding of the presentation and management options for UVAs is important for interventional radiologists to appropriately evaluate and care for these patients. The authors propose a standardized terminology for UVAs to avoid confusion and conflating congenital from acquired vascular lesions, which have a different pathophysiology. Limited high-level evidence and no definitive guidelines for UVA management exist, although endovascular treatment with uterine artery embolization has generally become the first-line approach for symptomatic or persistent UVAs with high technical and clinical success rates. There is also no consensus on the optimal embolization technique; the authors propose an initial approach to first embolize the dominant uterine artery supplying the UVA with gelatin sponge, with the option to embolize the contralateral side at the time of initial embolization if there is persistent supply (avoiding bilateral empiric embolization). Repeat embolization is feasible and recommended in the setting of recurrence, and both clinical and imaging follow-up is important. Ultimately, a multidisciplinary approach with individualized patient management is needed, particularly in the face of a lack of consensus guidelines for the management of symptomatic UVAs. [ABSTRACT FROM AUTHOR]

Objective: Pulsatile tinnitus can be a symptom of vascular pathology. However, many of these pathologies present as incidental findings on scanning for unrelated symptoms. This study investigated whether the pathologies attributed to pulsatile tinnitus could instead be considered incidental findings. Methods: This retrospective study evaluated imaging results of 272 pulsatile tinnitus cases for clinically relevant pathologies, and examined correlations between the site of symptoms and the imaging findings. Results: Of 272 patients, 238 (88 per cent) had normal scans, 17 (6 per cent) had clinically insignificant incidental findings, and 18 (7 per cent) had findings requiring further investigation or intervention; regarding these latter 18 patients, findings for 8 patients (42 per cent) did not correlate with the symptomatic side. The rates of intracranial aneurysm and arteriovenous malformation in the pulsatile tinnitus group were comparable to those in normal populations. Conclusion: The comparable rates of vascular abnormalities within the symptomatic pulsatile tinnitus group, plus clinically relevant findings contralateral to symptoms, suggest that vascular pathologies could be incidental findings rather than causes of pulsatile tinnitus. Evaluation is recommended of the effectiveness of the new National Institute for Health and Care Excellence guidelines for pulsatile tinnitus investigation. [ABSTRACT FROM AUTHOR]

Herein, we describe the use of a novel multiplug flow control technique for the curative transarterial embolisation of cerebrovascular malformations using liquid embolic agents (LEAs). The idea behind the use of this technique is to substantially control or arrest flow during LEA injection, with multiple plugs simultaneously formed from microcatheters that are placed within all or multiple feeders, so that the penetration of LEAs is facilitated, with flow control decreasing the washout of a malformation. This technique enables the complete occlusion of a vascular malformation in a shorter injection time than that in other methods because penetration is achieved faster. Details of this technique have been described in the treatment of two cases: one case of unruptured temporal arteriovenous malformation and in the other with a falcotentorial dural arteriovenous fistula, in which the vascular malformations were successfully occluded with transarterial embolisation. [ABSTRACT FROM AUTHOR]

High-flow vascular malformations include arteriovenous malformations and congenital arteriovenous fistulas. Arteriovenous fistulas are characterized by a direct connection between an artery and a vein. Congenital arteriovenous fistulas are rare lesions and occur in the central venous system and the extremities resulting to ischemic complications distal to the arteriovenous shunt and ulceration. The diagnosis is primarily based on history and physical examination, but duplex-ultrasound scanning and magnetic resonance imaging are the preferred imaging modalities for the assessment of this entity. Schöbinger and Yakes staging systems have been used widely to classify the malformations according to the clinical effects and the angioarchitecture, respectively. We present a rare case of a young patient, who presented with critical limb ischemia due to high-flow congenital vascular malformation and was treated via endovascular embolization. [ABSTRACT FROM AUTHOR]

Purpose: Pial arteriovenous fistulae (PAVF) are rare intracranial vascular malformations, predominantly seen in children and distinct from arteriovenous malformations and dural arteriovenous fistulae. PAVF often leads to high morbidity and mortality. The aim of our study was to describe the clinical features and endovascular management of PAVF at various intracranial locations; to analyze the use of liquid embolic agents and coils alone or in combination in the treatment of PAVF and to analyze the outcome of embolization. Materials and Methods: Retrospective review of diagnostic angiography and neurointerventional database of our institution identified a cohort of 15 patients with non-galenic PAVF from 2008 to 2014 out of 6750 patients. Fourteen patients were treated endovascularly with coils and liquid embolic materials in combination or alone. Patients were followed up for evaluation of prognosis. Results: Age of the patients ranged from 3 to 37 years. Most patients were male and most common presentation was headache followed by seizure. Most common location of fistula was frontal lobe. The most common type was single artery single hole fistula with venous varix. Satisfactory obliteration was seen in all cases. One patient developed intraparenchymal hematoma on the first post procedural day and outcome was poor. Conclusions: PAVF are rare intracranial vascular malformations which can effectively be managed endovascularly with liquid embolic, coils alone, or in combination. Complete occlusion of the fistula can be achieved in most cases in a single sitting with a reasonable morbidity related to the procedure, compared with the natural history of this disease. [ABSTRACT FROM AUTHOR]

There are not many error proof clinical scores to assess the native dialysis access. CAVeA2T2 score is a recent tool in use. Objective of the study is to assess the clinical utility of CAVeA2T2 scoring system in predicting the survival rate of brachiocephalic arteriovenous fistula (BC-AVF). Methods: All consecutive patients fulfilling the inclusion criteria for BC-AVF from January 2016 to January 2018 were included. According to their CAVeA2T2 score they were divided into two groups (Group A: < 2 and Group B: ≥2). Cumulative primary and secondary patency survival of BC-AVF for both groups were measured. Results: A total of 112 BC-AVFs were analysed. Mean age was 42±SD 14 years (M: F =5:1). Mean CAVeA2T2 score was 1.45±1.8. In terms of primary patency, there was no statistically significant difference between two groups (p=0.074, p = 0.229 and p=0.357 at 6 weeks, 6 months and 12 months respectively). However, the difference was significant in terms of secondary patency (p=0.002, p=0.036 and p=0.032 at 6 weeks, 6 months and 12 months respectively). On comparing the cumulative survival between two groups; a significantly low primary patency rate survival (Log Rank x2 = 12.9, p-value = 0.001) and secondary patency rate survival (Log Rank x2 = 7.6, p-value = 0.001) of BC-AVF was found in Group B. Conclusion: We found CAVeA2T2 score an easily applicable and useful tool to assess the patency and survival of BC-AVF. Patients have a poor patency and significantly low survival rate when their CAVeA2T2 score was ≥2. [ABSTRACT FROM AUTHOR]

Background High signal intensity of cerebral venous sinuses on magnetic resonance angiography (MRA) indicates high flow of shunt from arterial blood, suggesting dural arteriovenous fistula (dAVF). Herein, we describe the cases of 2 patients with intracranial venous reflux caused by brachiocephalic vein occlusion (BVO) mimicking dAVF on MRA. Case Description Case 1 was a 71-year-old woman who had received arteriovenous graft (AVG) surgery for hemodialysis and presented with headache. MRA depicted high signal intensities in the left jugular vein, inferior petrosal sinus, and ophthalmic vein suggesting intracranial dAVF. However, cerebral angiography revealed intracranial venous reflux through the jugular vein caused by BVO. After balloon angioplasty with stenting for BVO, normal venous drainage was restored and her symptoms resolved. Case 2 was a 62-year-old woman who had received AVG for hemodialysis and was hospitalized due to seizure. MRA revealed high signal intensities of the left transverse-sigmoid sinus and jugular vein, and it was suspected that they were associated with BVO. She did not receive immediate intervention because of her septic condition. The patient ultimately died of fatal intracranial hemorrhage and subarachnoid hemorrhage. Conclusions Central venous occlusion may occur in patients with end-stage renal disease who are receiving AVG for hemodialysis. Intracranial venous reflux resulting from BVO can induce various neurologic disorders including intracranial venous hypertension or hemorrhage. Prompt recognition and implementation of endovascular treatment can be beneficial in cases of symptomatic central venous occlusion. Highlights • Brachiocephalic vein occlusion (BVO) mimics dural arteriovenous fistula on MRI. • Cerebral angiography can distinguish BVO from dural arteriovenous fistula. • Early interventions for BVO are beneficial for mitigating intracranial complications. [ABSTRACT FROM AUTHOR]

Objective Dural arteriovenous fistulas (dAVFs) are abnormal direct shunts between the occipital or meningeal artery and a meningeal vein or dural venous sinus. Treatment strategies include endovascular, microsurgical, stereotactic radiosurgical, or combined interventions. With few previous reports focused on dAVF treatment in a hybrid operating room (hOR), the authors reviewed their 6-year experience in this unique setting for these complex fistulas. Methods Patients with complex cerebral dAVFs underwent endovascular and microsurgical treatment in the hOR. In this retrospective review, 8 consecutive patients with cerebral dAVFs (Borden type 2 or higher) underwent endovascular and microsurgical treatment. Demographic characteristics, symptoms related to the dAVF, preoperative angiographic features, preinterventional therapies, intraoperative digital subtraction angiography (iDSA), and postoperative clinical and radiologic findings were reviewed. Results Of these 8 patients, 5 patients underwent multiple embolizations (up to 3) and hybrid procedures, with no procedure-related complications. After microsurgical resection, iDSA revealed remnants of the fistula, which was then immediately re-resected, in 2 patients. At closing of the hybrid procedure, iDSA revealed no fistula remnants in 7 patients (88%). At mean follow-up examination (58 months), 5 patients (62%) had cure of the dAVF, confirmed by noninvasive angiography. Two patients (25%) experienced a recurrence of the dAVF within 5 months. Conclusions Our hybrid techniques achieved high rates of dAVF obliteration, with all 8 patients achieving good or excellent outcomes and symptom relief. Angiographic follow-up within 6 months after the hybrid procedure is recommended for all patients even when intraoperative findings do not show remnants. Highlights • Combined techniques in the hOR for dAVFs are presented. • Our hOR created flexibility for cycling between techniques in one multistage procedure. • Review noted all 8 patients had good/excellent outcomes in clinical examination. • Angiographic follow-up by 6 months after the hybrid procedure is recommended for all patients. [ABSTRACT FROM AUTHOR]

Spinal dural arteriovenous fistula (SDAVF) is the most common vascular malformation of the spine in adults. However, the coincidence of tethered cord syndrome, lipoma, and SDAVF on the sacral level is exceptionally rare. We describe two patients, probably the fifth and sixth ever reported. The first was a 33 year-old female who underwent surgical cord de-tethering. Surprisingly, a sacral SDAVF was discovered intraoperatively, despite negative digital subtraction angiography (DSA). The second patient was a 30 year-old male with similar pathologies. After three failed embolizations, the fistula was surgically disconnected. Both patients recovered well. A review of patients with sacral SDAVF coexisting with spinal dysraphism, with an emphasis on the basis of symptoms was done. As a rule, in these coincident disorders, the SDAVF was the direct cause of increasing symptoms. Previous reports and our findings reveal that surgery might be superior to endovascular embolization for treating sacral SDAVFs with coexisting entities, because surgery offers a one-step treatment. [ABSTRACT FROM AUTHOR]

Introduction: Intracranial pial fistulas are an extremely uncommon type of vascular pathology consisting of one or multiple arterial connections to a single venous drainage channel without the presence of an intervening nidus. Due to its typical location and high-flow dynamics, its management is diffi cult and options include endovascular treatment and open surgical treatment. The arterial supply of these lesions is usually derived from pial or cortical vessels, and commonly such lesions are not localized in the dura mater. Materials and Methods: Authors report the experience of consecutive ten cases managed at the Instituto Nacional de Neurología y Neurocirugía “Manuel Velasco Suárez” of México extending from 2007 to 2012 with endovascular technique, constituting one of the largest series in the Western literature. Discussion: Pial fistulas are associated with a poor natural history, and the selection of individualized therapeutic strategies can provide good outcomes. Conclusion: The neuroendovascular intervention is currently considered as safe, low cost, and effective management modality for such lesions. [ABSTRACT FROM AUTHOR]

Background Torcular dural sinus malformations (tDSMs) are described as slow flow dural arteriovenous fistulae with frequently poor outcomes in the neuroangiographic literature, but other etiologies have been proposed in the obstetric literature, where outcomes have been more favorable. Objective To review tDSMs reported in the literature of multiple specialties for features that support a common etiology, and to identify key prognostic factors, with an emphasis on tDSM trajectory highlighted in part I. Methods Analysis of imaging features and clinical outcome for 77 prenatal and 22 postnatal tDSMs reported in 37 papers from the literature. Results In addition to large venous lakes, 36% of prenatal and 96% of postnatal tDSMs had evidence of arterialization, where specifically assessed. For fetal cases, where there was an observable natural history, 97% underwent a spontaneous decrease--13% after an initial increase and only 1 case with subsequent enlargement after a decrease. Prenatal cases had 83% survival (62% with a favorable outcome) whereas postnatal cases had 59% survival (29% favorable). In addition to a postnatal diagnosis, unfavorable features included ventriculomegaly, parenchymal injury, arterialization, and need for intervention. Favorable features included decreasing tDSM size, presence of clot, and increasing clot percentage. Conclusions Neonatal and fetal tDSMs have overlapping imaging appearances, suggesting a common etiology, where neonatal tDSMs represent those rare fetal tDSMs that do not undergo spontaneous regression and have a propensity for worse outcomes. Decrease in tDSM size is a critical observation when managing a tDSM because it is generally irreversible and associated with a favorable outcome. A morphologically identical lesion to the tDSM has been reported in the fetal imaging literature, but the inability to directly demonstrate the angioarchitecture of these lesions has led to alternative etiologies being advanced for this population (eg, primary dural sinus dysplasia or thrombosis followed by dural sinus dilation).2-13 Some autopsy papers have also reported extraluminal localization of these fetal tDSMs.14 15 In distinction to the neuroangiographic literature, the outcome for these fetal tDSMs has been favorable in as many as 75-90% of cases.8 10 16 These differences in formulation and outcome cast doubt as to whether tDSMs seen in utero and postnatally represent the same entity. They also raise questions about how best to counsel late gestation pregnancies affected with a tDSM and how best to follow such pregnancies. In part I of this article,17we examined a local cohort of tDSM cases and found imaging commonalities across the fetal-neonatal age spectrum. For example, we described a fetal tDSM with directly visualized arteriovenous communications in utero, as well as postnatal tDSMs where AVFs were undetectable even with catheter angiography. We also showed that tDSM involution in our cohort was an irreversible process and one that may occur despite initial enlargement. In part II, we have conducted an analysis of the fragmented multidisciplinary literature on tDSMs to highlight prognostic factors identifiable from other cohorts and assess these in light of the prognosticators in our cohort. We have synthesized these data to offer a plausible model for tDSM evolution across fetal-neonatal life and provided a rational approach to following tDSM pregnancies and performing interventions when necessary. [ABSTRACT FROM AUTHOR]

Background Even for the most common dural sinus malformation (DSM), the torcular DSM (tDSM), generalizable statements about etiology and prognosis are difficult because neurosurgeons/neuroradiologists and obstetrical imagers have focused on different patient age groups, have reported different outcomes, and have offered differing pathophysiologic explanations. Objective To examine the imaging features and outcomes of a local cohort of tDSMs across fetal-neonatal life for commonalities. Methods Review of imaging and clinical outcome for a local cohort of 12 tDSM patients (9 fetal, 3 postnatal). results All 12 tDSMs had similar imaging characteristics, including enlargement of the torcular and intraluminal thrombus early on, later evolving to peripheral scar tissue after treatment or spontaneous regression. Spontaneous decrease in size of the tDSM was observed in 6 prenatal and 1 postnatal case, and this decrease appeared to be irreversible once it occurred. One of 9 prenatal tDSMs was demonstrated to have arteriovenous fistulae in utero, while 2 of 3 postnatal diagnoses had arteriovenous fisutlae. All 6 prenatal tDSM diagnoses followed to term and all 3 postnatal diagnoses had a grossly normal neurologic outcome after a median of 12 months of age. Conclusions Prenatal and postnatal tDSMs have overlapping imaging features suggesting a common etiology, and involution of a tDSM is a key imaging biomarker for a favorable outcome. While there is reason for concern with postnatally diagnosed tDSMs, good outcomes may still be achieved across the fetal-neonatal age spectrum of presentations. These findings are generalized in part II of this article. [ABSTRACT FROM AUTHOR]

Intracranial dural arteriovenous fistulas (DAVFs) are complex intracranial vascular malformations that may lead to hemorrhage. Although the precise mechanisms by which DAVFs occur remain unknown, dural angiogenesis may be a vital factor in its pathogenesis. Nuclear factor erythroid 2-related factor 2 (Nrf2) significantly influences angiogenesis; however, the association between DAVF and Nrf2 remains unclear. Therefore, the present study investigated whether DAVF alters the expression of Nrf2 in an experimental animal model of DAVF. The DAVF group underwent surgery of the left common carotid artery-external jugular vein anastomosis, cauterization of the vein draining transverse sinus and thrombosis of the sagittal sinus to induce venous hypertension (VH). At 1, 4 and 7 days post surgery, rats were sacrificed to collect brain samples. Western blot analysis, immunofluorescence staining and reverse transcription-quantitative polymerase chain reaction were used to determine whether DAVF activated the Nrf2 signaling pathway. The results demonstrated that the expression of Nrf2 mRNA and protein, and the expression of its downstream genes heme oxygenase-1 and NAD(P)H: quinine oxidoreductase-1 significantly increased 1 day after surgery. The expression of these genes decreased but remained high 4 days following surgery and only returned to baseline 7 days after surgery. Compared with the sham-surgery and control groups, DAVF-induced brain edema reached a peak 1 day following DAVF surgery and only returned to normal levels 7 days post-surgery. Taken together, these data indicate the potential contribution of Nrf2 to the formation of DAVFs and suggest that VH may induce the upregulation of Nrf2. [ABSTRACT FROM AUTHOR]

Objective: Transvenous retrograde arteriovenous malformation (AVM) embolization (TRAE) has been proposed. The present study was to review the techniques, their conjunctions and effectiveness. Methods: Eligible related articles were identified by searching the PubMed and Web of Science databases using ''transvenous'' and ''arteriovenous malformation.'' Results: A total of 16 eligible studies, with 60 cases of AVM treated with TRAE, were analyzed. Prior to TRAE procedure, transarterial Onyx 18 was performed in 23 (38.3%), cyanoacrylate in three (5%) and coiling in two (3.3%), neurosurgery in one (1.7%) and radiosurgery in three (5%). These prior treatments were used to reduce the size of the nidus to <3 cm and TRAE was performed. One anterior choroidal artery aneurysm was coiled before TRAE. Systemic hypotension (blood pressure<100 mmHg) occurred in six (10%) patients and local hypotension (proximal arterial temporary balloon protection) in five (8.3%) patients. Complete obliteration was achieved in 56 (93.3%) AVMs, four (6.7%) with residual, of which one was supplemented with radiosurgery. During mean one-year follow-up (1 month to 3.2 years), there were five cases (8.3%) of permanent disability and one (1.7%) mortality resulting from initial hemorrhage. Fifty-four (90%) patients were independent (mRS ≤ 2) at follow-up. Ruptured AVMs and Spetzler-Martin I-III were associated with a high cure rate. Conclusion: According to previous reports, selected AVMs could undergo TRAE. TRAE is safe and curative with Onyx after the nidus size is reduced sufficiently by transarterial embolization, neurosurgery or radiosurgery, with or without the aid of proximal arterial temporary balloon protection. [ABSTRACT FROM AUTHOR]

Spinal vascular malformations are uncommon yet important spinal pathologies commonly classified in congenital and acquired lesions. Spinal lipomas consist of three subtypes: intramedullary lipomas, lipomyelo(meningo)celes and lipomas of the filum. Although the association of spinal arteriovenous malformations (AVM) with other congenital anomalies is well known, the coexistence of dural arteriovenous fistulas (AVF) and tethered spinal cord is exceptionally rare and only eight cases have been reported. We present two cases from our institution and speculate on the possible origin of such a rare but insidious association. We review the current literature with a focus on possible pitfalls in diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Objective: Brain arteriovenous malformations (AVMs) are the most common cause of nontraumatic intracerebral hemorrhage in young adults. The genesis of brain AVM remains enigmatic. We investigated microRNA (miRNA) expression and its contribution to the pathogenesis of brain AVMs.Methods: We used a large-scale miRNA analysis of 16 samples including AVMs, hemangioblastoma, and controls to identify a distinct AVM miRNA signature. AVM smooth muscle cells (AVMSMCs) were isolated and identified by flow cytometry and immunohistochemistry, and candidate miRNAs were then tested in these cells. Migration, tube formation, and CCK-8-induced proliferation assays were used to test the effect of the miRNAs on phenotypic properties of AVMSMCs. A quantitative proteomics approach was used to identify protein expression changes in AVMSMCs treated with miRNA mimics.Results: A distinct AVM miRNA signature comprising a large portion of lowly expressed miRNAs was identified. Among these miRNAs, miR-137 and miR-195* levels were significantly decreased in AVMs and constituent AVMSMCs. Experimentally elevating the level of these microRNAs inhibited AVMSMC migration, tube formation, and survival in vitro and the formation of vascular rings in vivo. Proteomics showed the protein expression signature of AVMSMCs and identified downstream proteins regulated by miR-137 and miR-195* that were key signaling proteins involved in vessel development.Interpretation: Our results indicate that miR-137 and miR-195* act as vasculogenic suppressors in AVMs by altering phenotypic properties of AVMSMCs, and that the absence of miR-137 and miR-195* expression leads to abnormal vasculogenesis. Ann Neurol 2017;82:371-384. [ABSTRACT FROM AUTHOR]

Background Intracranial vascular malformations in children are being addressed through a variety of treatment modalities including open surgery, external beam radiation, and image-guided neuroendovascular procedures. These patients often receive multiple treatments and incur serial exposures to ionizing radiation which has been linked to tumor development in population-based data. Objective This study quantifies the effect of collimation on exposures from single procedures and over patient lifetimes to estimate excess risk of lifetime tumor development. Methods 215 patients aged 0-21 years from a single center took part in the study. Radiation exposure from neuroendovascular procedures was tabulated and converted to brain doses using modeled data and extrapolated to risk ratios using results of population- based estimates found in the literature. Results Lifetime and per procedure risk was highest in patients with brain arteriovenous malformations, brain arteriovenous fistulas, and vein of Galen malformations, areflection of our institutional referral patterns. Across all pathologies the per procedure excess relative risk decreased from 13.4 to 2.3 when full collimation was employed. Lifetime excess relative risk decreased from 49.0 to 7.7 for full collimation. Conclusions This is the first study to quantify the effect of collimation on lifetime and per procedure risk of tumor development in a pediatric population. In addition to collimation, technical and operator-based aspects of the neurointerventional suite are discussed to further reduce patient exposure without sacrificing image quality. [ABSTRACT FROM AUTHOR]

We report a case of tentorial dural arteriovenous fistula (DAVF) with a severe intracranial hemorrhage occurring after Onyx embolization. A 40-year-old man presented with an asymptomatic tentorial DAVF on angiography. Transarterial embolization with Onyx was performed via the middle meningeal artery, and the cast filled the fistula itself and its proximal draining vein. Postoperative angiography confirmed complete occlusion of the DAVF. A computed tomography scan performed immediately after the procedure demonstrated an acute subdural hematoma with the temporal hemorrhage. Emergency craniotomy revealed continuous arterial bleeding from a viable glomus-like vascular structure around the proximal part of the embolized draining vein, fed by a pial artery arising from the posterior cerebral artery. Pathologic findings suggested diagnosis of vascular malformation extending into the subdural space. Tentorial DAVFs can extend to the subdural space along their drainage route, and may be involved in severe hemorrhagic complications of curative endovascular treatment using Onyx, particularly those with pial arterial supply. [ABSTRACT FROM AUTHOR]

Arterial color duplex sonography (CDUS) of the extremities is routinely analyzed in the field of emergency radiology. A retrospective review of 500 consecutive arterial CDUS extremity studies was performed in our emergency department. Abnormal CDUS examinations were classified into two groups according to their primary etiology: 1) traumatic arterial injuries (accidents or post-operative complications) and 2) acute arterial ischemia (thrombosis or embolism outside of the setting of acute trauma). This article reviews common CDUS imaging findings in a busy emergency radiology division including traumatic pseudoaneurysm, secondary pseudoaneurysm, arteriovenous fistula, acute ischemic arterial disease and chronic peripheral arterial disease. This essay highlights the crucial role of CDUS in the diagnosis of vascular abnormalities in the emergency setting. CDUS provides several advantages over other imaging modalities including high accuracy, rapid results, portability, lack of radiation, and low cost. [ABSTRACT FROM AUTHOR]

Background: Multiple AVMs are exceptionally rare lesions and only a few larger series have been published, including other vascular pathologies, such as arterio-venous fistulae (AVF) or patients with hereditary syndromes. Our study presents clinical, angiographic, and therapeutic characteristics of patients harboring sporadic multiple AVMs. Methods: Basic demographic data, vascular architecture, clinical presentation, treatment strategies, and treatment outcome were analyzed retrospectively from patients with cerebral AVMs treated in our department between 1990 and 2015. Results: Six out of 539 patients (1.1 %) harbored 15 multiple and distinct cerebral lesions. Nidus size was predominantly small, consequently determining a Spetzler-Martin grade °I-°II (three-tier grading system). In three patients, AVMs shared a proximal feeding artery supply, whereas each AVM displayed its own venous drainage. Five of six patients (83 %) presented with hemorrhage. Four patients received therapy of the AVMs with complete elimination in 3/4 patients (75 %) and 8/9 treated AVMs (89 %). All patients with treatment of the AVM showed good-to-excellent recovery ( n = 4, mRS ≤ 2). Conclusions: Multiple cerebral AVMs are complex vascular lesions. The multiplicity of hemodynamic and malformation-related variables influence treatment strategy and sequence. Thus, awareness of these parameters (of various malformations before and during treatment) is important. The high number of hemorrhagic events in the present series might justify a more aggressive treatment of multiple AVMs than previously thought. [ABSTRACT FROM AUTHOR]

We describe a patient with spontaneous obliteration of spontaneous vertebral arteriovenous fistula (VAVF) associated with fibromuscular dysplasia (FMD) after partial surgery. A 52-year-old hypertensive female woke up one morning with left shoulder pain and weakness of the left upper extremity. A few days later, she developed left-sided audible bruit. She was treated for left frozen shoulder and supportive treatment for audible bruit for four years. She was referred from her general physician to a neurosurgeon because of left arm weakness. Physical examination showed signs of cervical radiculomyelopathy. Magnetic resonance imaging (MRI) showed an extradural mass on the left side of the cervical spinal canal from level C2 to C6. Provisional diagnosis was epidural vascular tumour. Laminectomy and partial removal of the mass was performed at level C5 to C6. Pathological report revealed suspected vascular malformation. Postoperative MRI showed thrombosed epidural vascular structure. Angiography showed dysplastic changes of both vertebral arteries representing FMD with VAVF of the left vertebral artery at level C1–C2. Two years after surgery, follow-up MRI demonstrated complete spontaneous resolution of the large thrombosed epidural vein. Disappearance of her audible bruit immediately after surgery and gradual improvement of her cervical radiculomyelopathy were observed after two years of clinical follow-up. From the literature, we found another 11 patients with 12 VAVFs who had spontaneous obliteration or cure of their fistulas. In the present case, spontaneous obliteration of the fistula seems to correlate with surgery inducing closure of the epidural venous exit leading to thrombosis of the enlarged epidural draining vein. [ABSTRACT FROM AUTHOR]

A case of double ophthalmic arteries arising from the internal carotid artery with unique features is reported. This case was discovered following in the course of time the progress of a thrombosis of the anterior cavernous sinus associated with a low-flow direct arteriovenous fistula of the superior ophthalmic vein. At different time points, the same patient underwent four angiographic studies and one computerized tomography with contrast medium. Angiographies showed that the double internal carotid artery origin of the ophthalmic artery was detectable only within a short range of time. To the best of our knowledge, this case is unique as it demonstrates that a second ophthalmic artery may lie hidden, showing itself only under particular hemodynamic requirements. [ABSTRACT FROM AUTHOR]

Aim To determine whether apoptosis is more common in previously punctured native veins than in non-punctured native veins among patients who undergo surgical creation of arteriovenous fistula (AVF) for dialysis access. Methods Cephalic vein specimens were obtained from January 1, 2013 to December 31, 2014 from 60 patients, 30 with previously punctured native veins and 30 with non-punctured native veins. Before AVF placement, a 1-cm vein segment was excised from distal part of the vein for histological, histochemical, and immunohistochemical analysis. Vein specimens were divided into two portions along the longitudinal axis and stained with hematoxylin and eosin for routine histological evaluation. Immunohistochemical analysis was used to localize Bax, p53, caspase 3, and Bcl-2 expression. Results The group with previously punctured veins showed significantly increased caspase 3 (P < 0.001, two-sided Fisher's Exact Test) and Bax expression (P = 0.002, two-sided Fisher's Exact Test) and significantly decreased Bcl-2 expression (P < 0.001, two-sided Fisher's Exact Test) compared with the control group. There were no significant differences between the groups in p53 expression (χ2 = 0.071, df = 1, P = 0.791). Fistula failure was significantly more common in the study group (26.7% vs 6.7%, χ2 = 4.32, df = 1, P = 0.038). Conclusion Our study indicates a possible role of veni-puncture in apoptosis development and a possible role of apoptosis in fistula failure, but we do not have sufficient evidence to conclude that it represents its main cause. [ABSTRACT FROM AUTHOR]

Purpose: The classic symptoms and signs of carotid cavernous sinus fistula or cavernous sinus dural arteriovenous fistula (AVF) consist of eye redness, exophthalmos, and gaze abnormality. The angiography findings typically consist of arteriovenous shunt at cavernous sinus with ophthalmic venous drainage with or without cortical venous reflux. In rare circumstances, the shunts are localized outside the cavernous sinus, but mimic symptoms and radiography of the cavernous shunt. We would like to present the other locations of the arteriovenous shunt, which mimic the clinical presentation of carotid cavernous fistulae, and analyze venous drainages.Methods: We retrospectively examined the records of 350 patients who were given provisional diagnoses of carotid cavernous sinus fistulae or cavernous sinus dural AVF in the division of Interventional Neuroradiology, Ramathibodi Hospital, Bangkok between 2008 and 2014. Any patient with cavernous arteriovenous shunt was excluded.Results: Of those 350 patients, 10 patients (2.85%) were identified as having noncavernous sinus AVF. The angiographic diagnoses consisted of three anterior condylar (hypoglossal) dural AVF, two traumatic middle meningeal AVF, one lesser sphenoid wing dural AVF, one vertebro-vertebral fistula (VVF), one intraorbital AVF, one direct dural artery to cortical vein dural AVF, and one transverse-sigmoid dural AVF. Six cases (60%) were found to have venous efferent obstruction.Conclusion: Arteriovenous shunts mimicking the cavernous AVF are rare, with a prevalence of only 2.85% in this series. The clinical presentation mainly depends on venous outflow. The venous outlet of the arteriovenous shunts is influenced by venous afferent-efferent patterns according to the venous anatomy of the central nervous system and the skull base, as well as by architectural disturbance, specifically, obstruction of the venous outflow. [ABSTRACT FROM AUTHOR]

Background Venous stenting has become a promising treatment for venous sinus stenosis. However, it is not without its own set of risks. Case Description We reported de novo formation of dural arteriovenous fistula poststenting for venous sinus stenosis in a patient with pseudotumor cerebri. Multiple factors, including subclinical thrombus formation, sinus wall injury by stent placement, and up-regulated inflammatory factors, may contribute to its pathogenesis. Conclusions This case indicates that physicians may need to be aware of this rare complication, which can be managed without resumption of pseudotumor cerebri symptoms. Highlights • We report a rare case of pseudotumor cerebri complicated with DAVF after venous sinus stenting. • Our case is the first to show the long-term outcome of such a condition postembolization. • This report adds more information with DAVF as one of the complications after the currently popular venous sinus stenting. • This rare complication can be managed without resumption of pseudotumor cerebri symptoms. • We analyze several factors that may contribute to DAVF formation postvenous stenting. [ABSTRACT FROM AUTHOR]

Increasing numbers of patients are being diagnosed with end-stage renal disease (ESRD), and the demand for on haemodialysis (HD) is rising. Arteriovenous fistulae (AVFs) remain the best conduit for adequate HD, with fewer complications associated with long-term use compared to bypass grafts and central venous catheters. However, it is known that many newly formed fistulae do not mature to provide useful HD access. The paper provides a narrative overview of factors influencing the process of AVF maturation failure. [ABSTRACT FROM AUTHOR]

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal vascular malformations. However, SDAVFs are still underdiagnosed entities because their clinical symptoms are usually non-specific, as they include low back pain or radiating pain to the limb. There have been several reports of acute paraplegia after lumbar epidural steroid injections in patients with SDAVFs. We present 4 patients with SDAVFs who received lumbar steroid injection. Among the 4 cases, acute paraplegia developed in 2 cases that received a larger volume of injectate than the other cases. Thus, we are suggesting that the volume of injectate may be a contributing factor for acute paraplegia after lumbar steroid injection in patients with SDAVFs. [ABSTRACT FROM AUTHOR]

Background Arteriovenous fistulas are critical for haemodialysis, but maturation rates remain poor. Experimental and anecdotal evidence has supported the use of transdermal glyceryl trinitrate ( GTN) patches. The aim of this RCT was to determine whether use of a GTN patch aids arteriovenous fistula maturation. Methods Patients referred for arteriovenous fistula formation were eligible. The GTN or placebo patch was applied immediately after surgery and left in situ for 24 h. The primary outcome measure was the change in venous diameter at 6 weeks after fistula formation. The secondary outcome measure was clinical fistula patency at 6 weeks. Results Of 200 patients recruited (533 screened), 101 were randomized to the placebo group and 99 to the GTN group. Of these, 81 and 86 respectively completed surgery, and had follow-up data available at 6 weeks. Improvements in venous diameter were similar in the two groups: mean(s.d.) increase 2·3(1·9) mm in the placebo group compared with 2·2(1·8) mm in the GTN group ( P = 0·704). The fistula failure rate did not differ significantly between the two groups: 23 per cent for placebo and 28 per cent for GTN ( P = 0·596). Conclusion GTN transdermal patches used for 24 h after surgery did not improve arteriovenous fistula maturation. Registration number: NCT01685710 (). [ABSTRACT FROM AUTHOR]

Aims: Ultrasound (US) examination is an important tool in the diagnosis of arteriovenous (AVF) stenoses; different US measures are available for assessing the severity of stenoses. The aim of our study was to analyse risk factors and consequences of AVF stenosis and its severity and to compare the usefulness of different US measures of stenoses' severity.Material and Methods: Ninety-seven prevalent patients from a single dialysis centre with patent AVF were included. We recorded history of disease, clinical and laboratory data. US was used to diagnosis the stenosis and to measure blood flow in the brachial artery, resistivity index (RI), and the diameter of the vessels (arteries, anastomosis, venous outflow).Results: Stenosis was present in 54.64% of the patients (59.6% juxtaanastomotic). Stenosis patients had higher age, lower diameter of the brachial artery, lower anastomosis diameter, and lower diastolic blood pressure (DBP). Atherosclerosis, delayed maturation of AVF, and statin treatment were more prominent in the stenosis group. Logistic regression disclosed delayed maturation, cholesterol, atherosclerosis, and DBP as significant predictors of stenosis. When severe stenosis was measured by the diameter reduction, stenosis patients had higher age, lower HDL cholesterol, and poorer dialysis efficacy. Flow in the brachial artery and RI were less useful for identifying risk factors or differences in outcome.Conclusions: Prevalence of stenosis was high in our cohort, more than half of the patients having some degree of stenosis. Risk factors for stenosis were related to atherosclerosis, low DBP, and delayed maturation of AVF. Diameter of stenosis is the most useful marker of severity. [ABSTRACT FROM AUTHOR]

Background: Optimizing vascular access outcomes is still a challenge, since 30-60% of arteriovenous fistulas fail or do not mature and catheters are widely used in contemporary patients. Methods: This study reports on strategies and outcomes in a single center in which access planning, surgery and maintenance are managed by a team of nephrologists. We retrospectively analyzed 305 fistulas and 61 grafts created in 270 consecutive patients between 2002 and 2013. Results: The percentage of patients receiving a fistula or graft who initiated hemodialysis with a mature access was 68.6%. Among prevalent patients, 71.7% used a fistula, 15.7% a graft and 12.6% a catheter. Rates of primary failure and revision before cannulation were 14.4 and 1.6% for fistulas vs. 4.9 and 3.3% for grafts. After maturation, complications (1.040 vs. 0.188 per patient-year (py)) and interventions (0.743 vs. 0.066 per py) were greater for grafts than for fistulas (p < 0.001). Secondary patency did not significantly differ between grafts and fistulas (median survival 34.8 vs. 57.3 months, p = 0.36), unless primary failures were excluded from Kaplan-Meier analysis (median survival 34.9 vs. 70.9 months, p = 0.03). Conclusions: High fistula prevalence, low access-related morbidity and catheter dependence were achieved using individualized strategies, including midforearm or perforating vein fistula creation and selective graft placement in high risk patients. Direct involvement of nephrologists throughout all steps of access care can improve access outcomes, by promoting a patient-centered approach. [ABSTRACT FROM AUTHOR]

High output heart failure (HF) and pulmonary hypertension have been demonstrated in patients with prevalent arteriovenous (AV) fistulas. Fistulas with flow >2000 mL/minutes are more likely to induce changes in cardiac geometry and pulmonary artery pressure. The effects of reducing flow in AV access and its implications on HF decompensation and hospitalizations have not been studied. Retrospective analysis of 12 patients who needed hospitalization for acute Congestive Heart Failure (CHF) decompensation with AV access flow of 2 L/minutes (as defined by Kidney Disease Outcomes Quality Initiative (KDOQI)) or more were included in the study. All the patients underwent banding of their inflow at the anastomosis with perioperative access flow measurement. Follow-up period was 6 months. 2D echo was done at 6 months postbanding in addition to access flow and clinical evaluation. Complete data was available for all the 12 patients. Study data was collected on all the 12 patients. Mean age was 64.7 years. The mean access flow pre and postbanding were 3784 mL/minutes and 1178 mL/minutes, respectively (P < 0.001). Eighty percent of the patients had diabetes and 41% had coronary artery disease. There was a statistically significant decrease in cardiac output (pre = 7.06 L/minutes, post = 6.47 L/minutes P = 0.03), pulmonary systolic pressure (pre = 54 mmHg, post = 44 mmHg P = 0.02), left ventricular mass index (LVMI) (pre = 130 g/m2, post = 125 g/m2 P = 0.006) and need for rehospitalization for CHF decompensation. The New York Heart Association (NYHA) staging improved by 1 stage postbanding (P = 0.002). The hospitalization rate was 3.75 ± 1.2 in the 6 months before banding and was decreased to 1.08 ± 1.2 (P = 0.002) postbanding. The hemoglobin level, predialysis systolic blood pressure, calcium phosphorous product and the use of Renin Angiotensin Aldosterone System (RAAS) blockade agents and calcium channel blockers were comparable before and after inflow banding. Flow reduction in high flow fistulas are associated with decreased LVMI and pulmonary artery pressures. There is also a significant reduction in the risk for hospitalization due to acute HF and an improvement in NYHA heart failure stage. [ABSTRACT FROM AUTHOR]

Objective: The aim of the present study is to evaluate the relationship between demographic characteristics, hematological and biochemical parameters, and elements of the coagulation system that may predispose a person to thrombosis or to anatomical and functional parameters in Doppler ultrasonography scanning and the maturation and adequacy of arteriovenous fistulas. Materials and Methods: Overall, 36 patients who underwent a native arteriovenous fistula operation were included. Biochemical parameters, hematological parameters, the coagulation system, and a Doppler ultrasonography evaluation were performed before an arteriovenous fistula operation on day 1 after the fistula operation and at the time point when the arteriovenous fistula became dysfunctional. Results: A thrombus occurred between 1 and 73 days (mean: 28.4±26.1) in 10 patients. It was found that the female gender (p<0.001), presence of thrill (p=0.014), quality of vein (p<0.001), peak systolic velocity and end-diastolic velocity of the radial artery at the snuffbox region on day 1 after the operation (p=0.035 and p=0.049, respectively), and the cephalic vein diameter in the Brescia-Cimino region (p=0.011) were associated with thrombosis formation. No relation was found among blood pressure, fistula region, quality of artery, spasm of artery and vein, hematologic and biochemical parameters, coagulation parameters, active protein C resistance, anti-cardiolipin antibody, D-dimer, C-reactive protein, or erythrocyte sedimentation rate and thrombosis formation (p>0.05). Conclusion: Thrombosis occurs at a relatively early period in approximately a quarter of arteriovenous fistulas. Female gender, quality of vein, and the absence of thrill in the post-operative period are important factors in thrombosis formation. [ABSTRACT FROM AUTHOR]

Objective The authors introduce a new fusion technique using 2 three-dimensional digital subtraction angiography images acquired by a flat-panel detector angiographic system to understand the detailed angioarchitecture of complex cerebral and spinal vascular malformations. Methods Eleven consecutive cases of arteriovenous fistula or arteriovenous malformation with lesions that involved 2 major vessels (i.e., internal carotid arteries, external carotid arteries, vertebral arteries, or spinal arteries) were included. Three-dimensional rotational angiography was performed in each affected vessel after conventional cerebral or spinal angiography. Subsequently, the 2 three-dimensional digital subtraction angiography images were fused. Results The fused images provided the accurate three-dimensional angioarchitecture of complex vascular malformations clearly with high spatial resolution. In particular, the relationship between the nidus/fistulous point, the feeding arteries from each major vessel, and the draining veins could be easily delineated from different directions and multiple angles. Surgical or endovascular treatment was performed in all cases based on the information from these fused three-dimensional images. Conclusions A fusion technique using two three-dimensional digital subtraction angiography is beneficial for preoperative planning and successful treatment in cases of complex cerebral and spinal vascular malformations. [ABSTRACT FROM AUTHOR]

The article discusses research on vascular tumors and malformations has seen remarkable progress including the emergence of new treatment agents like propranolol and sirolimus. Topics include classification and diagnosis of vascular tumors and malformations, and the second edition of the clinical practice guidelines; and the syndromes associated with vascular tumors and malformations in the brain and/or spinal cord.

Multifrequency bioelectrical impedance assessments ( MFBIAs) aid clinical assessment of hydration status for hemodialysis ( HD) patients. Many MFBIA devices are restricted to whole body measurements and as many patients dialyze using arteriovenous fistulas ( AVFs), we wished to determine whether AVFs affected body water measurements. We reviewed pre- and post- HD segmental MFBIA measurements in 229 patients attending for midweek HD sessions. Up to 144 were dialyzed with a left arm AVF ( L- AVF), 42 with a right arm AVF ( R- AVF), and 43 by central venous access catheter ( CVC). Water content and lean tissue were greater in the left compared to right arm in those patients with L- AVFs both pre and post dialysis (pre 2.1 ± 0.7 vs. 2.0 ± 0.7 L, and post 1.9 ± 0.6 vs. 1.8 ± 0.6 L and pre 2.65 ± 0.9 vs. 2.56 ± 0.8 kg, and post 2.34 ± 0.8 vs. 2.48 ± 0.8 vs. 2.34 ± 0.8 kg, respectively) and were also greater in the right compared to left arm for those patients dialyzing with R- AVFs (pre- HD 1.92 ± 0.5 vs. 1.86 ± 0.6 L and post- HD 1.79 ± 0.5 vs. 1.7 ± 0.5 L, and pre- HD 2.47 ± 0.6 vs. 2.38 ± 0.7 kg and post- HD 2.3 ± 0.74 vs. 1.28 ± 0.7 kg, respectively), all Ps < 0.05. There were no significant differences in arm volumes or composition pre or post dialysis in those dialyzing with CVCs. Segmental MFBIA detects differences in arm water and lean mass in patients with AVFs. The presence on an AVF increases the water content in the ipsilateral arm both pre and post HD. This increased water content of the fistula arm will not be detected by whole body bioimpedance devices. [ABSTRACT FROM AUTHOR]

The approach to ethmoidal dural arteriovenous fistulas (eDAVFs) is usually via a pterional or a frontal craniotomy. However, the transfrontal sinus is a more direct route to the fistula. The aim of this report is to describe our experience and associated complications occurring as a result of flow diversion in the transfrontal sinus approach for eDAVFs. In this report, we discuss visual field defects occurring after a transfrontal sinus operation. This approach is most direct for surgical treatment of an eDAVF, enabling preservation of neural structures with minimal to no negative effects on the brain. Although the surgery was uneventful, the patient presented with a left side visual field defect. An ophthalmologic exam detected an arterial filling delay in the choroidal membrane and ischemic optic neuropathy was highly suspected. The patient is currently recovering under close observation with no special treatment. The transfrontal sinus approach provides the most direct and shortest route for eDAVFs, while minimizing intraoperative bleeding. However, complications, such as visual field defects may result from a sudden flow diversion or eyeball compression due to scalp traction. [ABSTRACT FROM AUTHOR]

The aim of this study was to establish a stable rat model of autogenous arteriovenous fistula (AVF) with chronic renal function insufficiency. Forty Sprague-Dawley rats were randomly divided into an experimental group (n=20) and sham surgery group (n=20) and a 5/6 nephrectomy model was established in the rats. One week later, in the experimental group, the ipsilateral caroid artery was inserted into the external jugular vein by a cuff technique to establish a carotid arteriovenous fistula; in the sham group, the external jugular vein and carotid artery were dissociated. At 7 and 28 days following the establishment of the AVF, the renal functions of the two groups were measured. Hematoxylin and eosin staining and double collagen and elastin staining were conducted to evaluate the area of intimal hyperplasia in the external jugular vein, and the expression of α-smooth muscle actin in the vein was investigated by immunohistochemistry. The creatinine and urea nitrogen levels in the experimental group at each time-point were significantly higher than those in the sham surgery group (P<0.05). The intimal hyperplasia of the external jugular vein of the experimental group was increased significantly compared with that in the sham group at each time-point (P<0.05). The model, which is easy to establish and simple to master, provides a new and feasible experimental method for the study of intimal hyperplasia associated with autogenous AVF in chronic renal insufficiency, and is worthy of wider use. [ABSTRACT FROM AUTHOR]

Purpose This study aimed to evaluate the usefulness of four-dimensional CTA before and after embolization treatment with ONYX-18 in eleven patients with cranial dural arteriovenous fistulas, and to compare the results with those of the reference standard DSA. Patients and Methods Eleven patients with cranial dural arteriovenous fistulas detected on DSA underwent transarterial embolization with ONYX-18. Four-dimensional CTA was performed an average of 2 days before and 4 days after DSA. Four-dimensional CTA and DSA images were reviewed by two neuroradiologists for identification of feeding arteries and drainage veins and for determining treatment effects. Interobserver and intermodality agreement between four-dimensional CTA and DSA were assessed. Results Forty-two feeding arteries were identified for 14 fistulas in the 11 patients. Of these, 36 (85.71%) were detected on four-dimensional CTA. After transarterial embolization, one patient got partly embolized, and the fistulas in the remaining 10 patients were completely occluded. The interobserver agreement for four-dimensional CTA and intermodality agreement between four-dimensional CTA and DSA were excellent ( κ = 1) for shunt location, identification of drainage veins, and fistula occlusion after treatment. Conclusion Four-dimensional CTA images are highly accurate when compared with DSA images both before and after transarterial embolization treatment. Four-dimensional CTA can be used for diagnosis as well as follow-up of cranial dural arteriovenous fistulas in clinical settings. [ABSTRACT FROM AUTHOR]

Objective: Patients receiving haemodialysis treatment generally tend to avoid using the upper extremity with arteriovenous (AV) fistulae and it results in impairment of hand functions. Limited data are available about impairment associated with hand complications in those patients The aim of this pilot study is to evaluate the handgrip and pinching strengths and functional level of both hands in patients receiving haemodialysis. Methods: Fifteen chronic renal failure patients receiving haemodialysis (30-83 years) and 11 age-matched healthy volunteers participated in the study. All the patients were undergoing treatment through arteriovenous fistulae in the upper extremity. Handgrip strength with a manual dynamometer and pinch strength with a pinchmeter were measured. Functional level of both hands was evaluated with Nine-Hole Peg Test. Results: Handgrip strengths of both hands were lower in patients receiving haemodialysis than healthy control group (p<0.01). Lateral, bipod and tripod pinching strengths were also lower in patients (p<0.05) with excepting right hand lateral pinching (p>0.05). 9-Hole Peg Test results in both placement and removal showed a great significant difference in both hands with a statistical significance of p<0.001. Conclusion: Our first results revealed that chronic renal failure patients receiving haemodialysis treatment through arteriovenous fistulae in the upper extremity have a significant impairment in strength and functional level of hand. The lack of differences between two hands may be concluded that the upper extremity impairment in patients results from the disease course or haemodialysis treatment, not from the vascular access. [ABSTRACT FROM AUTHOR]

It remains challenging to accurately predict whether an individual arteriovenous fistula (AVF) will mature and be useable for haemodialysis vascular access. Current best practice involves the use of routine clinical assessment and ultrasonography complemented by selective venography and magnetic resonance imaging. The purpose of this literature review is to describe current practices in relation to pre-operative assessment prior to AVF formation and highlight potential areas for future research to improve the clinical prediction of AVF outcomes. [ABSTRACT FROM AUTHOR]

The appropriate management of nonmaturing arteriovenous (AV) fistulae continues to be a controversial issue. While coil embolization of accessory side-branch veins can be performed to encourage maturation of nonmaturing AV fistulae, the true efficacy and optimal patient population are not well understood. Fistulagrams performed on nonmaturing AV fistulae were retrospectively reviewed in 145 patients (86 males, median age 63 years) for the presence of accessory veins. Fistula and accessory vein measurements were obtained, as were rates of eventual fistula maturation after accessory vein coil embolization. Of 145 nonmaturing fistulae, 49 (34%) had a stenosis without any accessory veins, 76 (52%) had a stenosis and one or more accessory veins, and 20 (14%) had an accessory vein without concurrent stenosis. Eighteen AV fistulae had one or more accessory veins without coexisting stenosis. Nine fistulae had a caliber decrease immediately downstream from the accessory vein. Coil embolization of dominant accessory veins with a caliber decrease immediately downstream ( n = 6) resulted in a 100% eventual fistula maturation rate versus 67% for fistulae without this configuration ( n = 6, p = 0.15). Accessory vein size was not correlated with maturation rates ( p = 0.51). The majority of nonmaturing fistulae with accessory veins had a coexisting stenosis. Higher maturation rates may result with selected anatomic parameters, although additional studies with more robust sample sizes are needed prior to definitive conclusions. [ABSTRACT FROM AUTHOR]

Objective To evaluate the quantitative assessment of flow dynamics during surgery for arteriovenous malformations (AVMs) with FLOW 800 with indocyanine green videoangiography. Methods Changes in flow dynamics in the superficial AVM components (feeder, nidus, and drainer), the adjacent cortical artery, and the cortical vein surrounding AVM were evaluated. Analysis was performed at predissection, postclipping of the feeders, and postresection of the nidus with the use of quantitative values of the maximum fluorescence intensity, time to half-maximum fluorescence intensity (T 1/2 FI), and the fluorescence intensity rate at T 1/2 FI semiautomatically obtained with the use of FLOW 800 software. Results FLOW 800 assessments were performed in 7 cases. The time difference between the T 1/2 FI, defined as transit time, in the cortical artery and the drainer was prolonged from 0.08 ± 0.65 seconds to 2.63 ± 1.79 seconds ( P < 0.0001) at postfeeder clipping phase. The transit time between the cortical artery and the cortical vein was reduced to 3.76 ± 1.37 seconds at post feeder clipping phase ( P = 0.024) and 2.63 ± 0.80 seconds at final phase ( P = 0.005) compared with 4.56 ± 1.47 seconds at predissection phase. The maximum intensity and the fluorescence intensity rate at T 1/2 FI were not significantly different at these phases, excluding the maximum intensity of the drainer decreasing from 533 ± 271 to 399 ± 217 ( P = 0.006) at post feeder clipping phase. Conclusion FLOW 800 analysis with indocyanine green videoangiography provides the real-time hemodynamic status of the AVMs and adjacent brain at various stages of resection. This technique is feasible to resect AVMs more safely and convincingly. [ABSTRACT FROM AUTHOR]

Purpose: We present a technical development of the endovascular treatment technique for vein of Galen aneurysmal malformation, using Onyx™ (ethylene vinyl alcohol copolymer) delivered under flow control through double-lumen balloon microcatheters. Materials and methods: An 11-month-old patient that initially presented with increasing head circumference was diagnosed with mural type vein of Galen aneurysmal malformation. Complete cure was obtained in a single endovascular treatment session. Onyx was delivered simultaneously through two double-lumen balloon microcatheters (Scepter™, Microvention, Terumo Group). In both arterial feeders, balloon inflation occluded the high-flow arterial-venous shunting and thus facilitated the controlled propagation of the embolic product in the afferent artery and the shunt point while preventing distal migration into the venous system. Results: Two years post-procedure, MR imaging showed persistent occlusion of arterial-venous shunts with complete regression of the venous dilatation. On clinical examination, the patient had no neurological deficits, and no cognitive impairment was detected at neuropsychological testing. Conclusion: The use of double-lumen balloon microcatheters for flow control during delivery of Onyx represents a viable alternative for the endovascular treatment of vein of Galen aneurysmal malformations. [ABSTRACT FROM AUTHOR]

carotid-cavernous fistulas are spontaneous or acquired connections between the carotid artery and the cavernous sinus, being classified as direct or indirect; being usually diagnosed in postmenopausal women, but are also associated with other pathologies such as pregnancy, sinusitis and cavernous sinus thrombosis. They are clinically characterized by ophthalmological symptoms and pulsatile tinnitus. A 51-year-old woman who started her current condition about 4 years ago with pulsatile tinnitus, to which were added progressively: Pain, conjunctival erythema, right eye proptosis and the occasional headache of moderate intensity. Carotid-cavernous fistula was diagnosed, for the technical difficulty inherent in the case was made a contralateral transvenous approach and embolization with 360° GDG coils, with successful evolution of the patient. The endovascular management of these lesions is currently possible with excellent results. [ABSTRACT FROM AUTHOR]

The number of elderly patients in hemodialysis has increased in recent years and nowadays there are significant numbers of nonagenarians. However, there is currently no information in the literature about arteriovenous fistula ( AVF) outcomes in patients aged over 90 years after endovascular treatment for stenosis or thrombosis. This retrospective analysis of prospectively collected data included 38 consecutive patients aged over 90 years who were referred for endovascular evaluation and treatment of AVF nonmaturation ( n = 11), dysfunction ( n = 25), or thrombosis ( n = 2) between 2005 and 2013. Median age was 93.9 years, and 24% were diabetic and 47% hypertensive patients. Immature and dysfunctional AVFs were treated by angioplasty, thrombosed fistulas by thromboaspiration. Fistula patency rates were calculated according to the Life-Table method. The immediate overall clinical success rate was 97.4%. Complications included four transient dilation-induced ruptures. Stents were placed for rupture control ( n = 3) and major elastic recoil ( n = 3), and to rectify a basilic vein pseudoaneurysm developed after dilation. Mean follow-up was 62.6 months. Primary patency rates were 60% and 43% at 1 and 2 years, respectively. Secondary patency rates were 95% and 92% at 1 and 2 years, respectively. Patency rates were not significantly different between immature and dysfunctional AVFs. Endovascular treatment of AVF complications appears to be a valuable approach in nonagenarian patients in view of the low invasiveness, low complication rate, and relatively good long-term patency rates. [ABSTRACT FROM AUTHOR]

Pulsatile tinnitus with normal otoscopic findings often presents a diagnostic challenge to otolaryngologists and can be attributed to serious vascular malformations such as dural arteriovenous fistulas (DAVFs). Spontaneous DAVFs are relatively rare. A 65-year-old woman presented with sudden-onset subjective/objective pulsatile tinnitus on the right side that had persisted for 2 months. Angiography and magnetic resonance angiography revealed DAVF formation. Stereotactic radiosurgery was performed, and total remission of the DAVFs was achieved. [ABSTRACT FROM AUTHOR]

Stenosis of arteriovenous (A-V) fistulae secondary to neointimal hyperplasia (NIH) compromises dialysis delivery, which worsens patients' quality of life and increases medical costs associated with the maintenance of vascular accesses. In the present study, we evaluated the role of the receptor tyrosine kinase c-Kit in A-V fistula neointima formation. Initially, c-Kit was found in the neointima and adventitia of human brachiobasilic fistulae, whereas it was barely detectable in control veins harvested at the time of access creation. Using the rat A-V fistula model to study venous vascular remodeling, we analyzed the spatial and temporal pattern of c-Kit expression in the fistula wall. Interestingly, c-Kit immunoreactivity increased with time after anastomosis, which concurred with the accumulation of cells in the venous intima. In addition, c-Kit expression in A-V fistulae was positively altered by chronic kidney failure conditions. Both blockade of c-Kit with imatinib mesylate (Gleevec) and inhibition of stem cell factor production with a specific short hairpin RNA prevented NIH in the outflow vein of experimental fistulae. In agreement with these data, impaired c-Kit activity compromised the development of NIH in A-V fistulae created in c-KitW/Wv mutant mice. These results suggest that targeting of the c-Kit signaling pathway may be an effective approach to prevent postoperative NIH in A-V fistulae. [ABSTRACT FROM AUTHOR]