Overview of multimodal MRI of intracranial Dural arteriovenous fistulas

Dural arteriovenous fistulas(DAVFs)include a wide range of pathological conditions that are associated with intracranial vessel abnormalities.While some types of DAVFs present with typical neuroimaging characteristics,others share overlapping pathological and neuroimaging features that can hinder accurate differentiation.Hence,misclassification of the various types of DAVFs is common.Thorough knowledge of DAVF imaging findings is essential to avoid such misinterpretations.Traditional digital subtraction angiography(DSA)is considered the gold standard for diagnosing and evaluating DAVFs.However,angiography cannot detect changes in a patient’s brain structure.Conventional magnetic resonance imaging(MRI)sequences,including MR angiography(MRA),allow the evaluation of DAVFs without ionizing radiation or invasiveness.Advanced MRI techniques,such as susceptibility-weighted imaging(SWI)and dynamic contrast-enhanced MRA,provide added value to real-time physio-pathological data regarding the hemodynamics of DAVFs.Beyond these techniques,new insights using high-resolution vascular wall MRI are incorporated for the noninvasive evaluation of DAVFs.This article reviews the pathophysiology of DAVFs,focusing on the specifics of MRI findings that facilitate their classification.The role of conventional and advanced MRI sequences for DAVFs was assessed using insights derived from the data provided by structured reports of multimodal MRIs to evaluate DAVFs.

Application of intraoperative indocyanine green videoangiography in the surgical treatment of spinal dural arteriovenous fistulas

Objective To evaluate the clinical significance of intraoperative indocyanine green (ICG) videoangiography in surgical management of spinal dural ateriovenots fistulae (dAVFs) . Methods In this retrospective analysis we examined nine cases of dAVFs,diagnosed by complete spinal angiography,in which laminoplasty were performed through posterior approach. An operating microscope-integrated light

Clinical features of bilateral multiple pulmonary arteriovenous fistulas with paroxysmal aphasia as the first symptom:a case report

Objective:to describe the clinical features of bilateral multiple pulmonary arteriovenous fistulas(PAF)with paroxysmal aphasia as the first symptom.Methods:we collected the clinical history and examination data of a patient with paroxysmal aphasia.In order to trace the etiology,we performed chest computed tomography(CT)and pulmonary CT angiography(CIA).Results:the patient had paroxysmal aphasia with dizziness,brain magnetic resonance imaging(MRI)showed cerebral infarction,the transcranial Doppler(TCD)foaming test was positive,transesophageal ultrasound showed no patent foramen ovale,and chest CT and CIA showed bilateral multiple PAF.Conclusion:bilateral multiple PAF are rare in clinic.When patients have paroxysmal neurological symptoms,the possibility of PAF leading to embolism should be considered.

Impact of stage-specific limb function exercises guided by a selfmanagement education model on arteriovenous fistula maturation status

BACKGROUND The exercise of limb function is the most economical and safe method to promote the maturation of arteriovenous fistula(AVF).However,due to the lack of a uni-fied exercise standard in China,many patients have insufficient awareness of the importance of AVF,leading to poor effectiveness of limb function exercise.The self-management education model can effectively promote patients to take pro-active health-related actions.This study focuses on the characteristics of patients during the peri-AVF period and conducts a phased limb function exercise under the guidance of the self-management education model to observe changes in fac-tors such as the maturity of AVF.AIM To assess the impact of stage-specific limb function exercises,directed by a self-management education model,on the maturation status of AVFs.METHODS This study is a randomized controlled trial involving 74 patients with forearm AVFs from the Nephrology Department of a tertiary hospital in Sichuan Province,China.Patients were randomly divided into an observation group and a control group using a random number table method.The observation group underwent tailored stage-specific limb func-tion exercises,informed by a self-management education model which took into account the unique features of AVF at various stages,in conjunction with routine care.Conversely,the control group was given standard limb function exercises along with routine care.The assessment involves the maturity of AVFs post-intervention,post-operative complications,and the self-management level of the fistula in both groups patients.Analyses were conducted using SPSS version 23.0.Count data were represented by frequency and percentage and subjected to chi-square test comparisons.Measurement data adhering to a normal distribution were presented as mean±SD.The independent samples t-test was utilized for inter-group comparisons,while the paired t-test was used for intra-group comparisons.For measurement data not fitting a normal distribution,the median and interquartile range were presented and analyzed using the Wilcoxon rank sum test.RESULTS At the 8-wk postoperative mark,the observation group demonstrated significantly higher scores in AVF symptom recognition,symptom prevention,and self-management compared to the control group(P<0.05).However,the variance in symptom management scores between the observation and control groups lacked statistical signi-ficance(P>0.05).At 4 wk after the operation,the observation group displayed a superior vessel diameter and depth from the skin of the drainage vessels in comparison to the control group(P<0.05).While the observation group did manifest elevated blood flow rates in the drainage vessels relative to the control group,this distinction was not statistically significant(P>0.05).By the 8-wk postoperative interval,the observation group outperformed the control group with notable enhancements in blood flow rates,vessel diameter,and depth from the skin of drainage vessels(P<0.01).Seven days following the procedure,the observation group manifested significantly diminished limb swelling and an overall reduced complication rate in contrast to the control group(P<0.05).The evaluation of infection,thrombosis,embolism,arterial aneurysm stenosis,and incision bleeding showed no notable differences between the two groups(P>0.05).By the 4-wk postoperative juncture,complications between the observation and control groups were statistically indistinguishable(P>0.05).CONCLUSION Stage-specific limb function exercises,under the guidance of a self-management education model,amplify the capacity of AVF patients to discern and prevent symptoms.Additionally,they expedite AVF maturation and miti-gate postoperative limb edema,underscoring their efficacy as a valuable method for the care and upkeep of AVF in hemodialysis patients.

The Preventive Effect of Comprehensive Nursing Intervention on Arteriovenous Fistula Failure in Patients in the Hemodialysis Room

Objective:To explore the preventive effect of comprehensive nursing intervention on arteriovenous fistula failure in patients in the hemodialysis room.Methods:82 patients with arteriovenous fistula in the hemodialysis chamber treated in our hospital from July 2022 to October 2023 were selected as the research subjects.The random number table method divided them into a control group and an experimental group of 41 cases each.The control group received general nursing intervention measures,while the experimental group underwent comprehensive nursing intervention.The incidence of complications(internal fistula failure,bleeding,thrombosis,infection),psychological emotions(SAS scale,SDS scale),quality of life(physical pain,physiological function,emotional function,social function),and nursing satisfaction(very satisfied,basically satisfied,satisfied,dissatisfied)were compared between the two groups of patients.Results:The incidence of complications in the experimental group(4,9.76%)was significantly lower than that in the control group(29,70.73%);the SAS scores and SDS scores of the patients in the experimental group after intervention were both lower than those in the control group;the quality of life score(physical pain,physiological function,emotional function,and social function)was all higher than those of the control group;the post-intervention nursing satisfaction of the experimental group(40,97.57%)was also significantly higher than that of the control group(29,73.17%);and the listed differences were statistically significant(P<0.01).Conclusion:For patients with hemodialysis ventricular arteriovenous fistula failure,comprehensive nursing intervention can reduce the incidence of complications,relieve anxiety and stress,improve quality of life and nursing satisfaction,and achieve better preventive effects.

Surgical interruption of spinal dural arteriovenous fistulas

Spinal dural arteriovenous fistula (SDAVF) is the most common type of spinal vascular malformation.~1 Surgical excision of SDAVF is the most effective treatment^(1,2) and the most often used procedure has been wide laminectomy,^(2,3) (which causes) instability of the spinal column. Therefore, we report the clinical results of 72 cases with SDAVF treated in our department by hemilaminectomy, which preserved the stability of the spinal column.

Therapeutic embolization of cavernous sinus dural arteriovenous fistulas via transvenous approach

Objective To describe the transvenous catheterization technique for the treatment of cavernous sinus dural arteriovenous fistulas (CSdAVFs), including its indications, complications and efficacy.Methods Eight patients with symptomatic CSdAVFs were treated by endovascular embolization with platinum coils, via the inferior petrosal sinus (IPS) in 6 patients, and via the Sylvian vein after surgical exposure in other 2 patients.Results Complete angiographic resolution of the fistula was obtained in six patients immediately after the procedures, and a complete resolution of symptoms and signs was achieved in all patients. The residual fistulas in two patients disappeared completely in the follow-up angiography.Conclusion Transvenous embolization is a useful and safe approach in the management of CSdAVFs.

Treatment of postcatheterization femoral arteriovenous fistulas with simple prolonged bandaging

Background The methods for the treatment of postcatheterization femoral arteriovenous fistulas （AVF-s） - simple observation, ultrasound guided compression, covered stents implantation and coil embolization have poor outcome. Surgery is the standard method for treatment of femoral AVFs, but it is a traumatic operation. In this study, we report the results of the treatment of postcatheterization femoral AVFs by simple prolonged compressing bandage. Methods To treat iatrogenic femoral AVFs caused by transfemoral catheterization, prolonged binding with elastic or common bandage was applied in 16 cases. Catheterization was performed in 7 cases for radiofrequency current catheter ablation, in 4 for occlusion of congenital heart disease, in 3 for percutaneous coronary intervention, in 1 for coronary angiography and in 1 for right heart catheterization. Results All iatrogenic femoral AVFs were healed after simple binding with elastic or common bandage for 4-46 days （mean （15±10） days）. During the period of binding, local skins ulceration occurred at puncture site in two cases and femoral vein thrombus was found in one patient. During 6-24 months （mean （11.8±3.6） months） followup with colour Doppler ultrasonography, no recurrent artedovenous shunting or other complications were observed. Conclusion The results suggest that simple prolonged bandaging for postcatheterization femoral AVFs is an effective and economical procedure.

Postoperative Development of Dural Arteriovenous Fistulas after Aneurysmal Clipping: A Case Report and Literature Review

Dural arteriovenous fistulas(DAVFs)are rare vascular abnormalities that comprise 10%-15%of all intracranial arteriovenous malformations.The pathogenesis of DAVFs is still uncertain,although growing angiographic evidence supports the acquired characteristics of this vascular disease.Here,we present the case of a 39-year-old man with incidental bilateral paraophthalmic aneurysms who experienced spontaneous retroocular pressure and mild headache.Magnetic resonance angiography revealed enlargement and a change in the shape of the right paraophthalmic aneurysm.The patient underwent a right pterional craniotomy for the intracranial aneurysms.Five months later,he presented with progressive pulsatile tinnitus.A diagnostic angiogram demonstrated a Cognard type I DAVF of the right sigmoid sinus.Based on this case,angiography monitoring is recommended.Herein we review and summarize postoperative DAVF cases.Common causes of acquired DAVFs and treatment selection are discussed based on relevant literature.

Transient ischemic attack induced by pulmonary arteriovenous fistula in a child:A case report

BACKGROUND Cerebral ischemic stroke is attributed to paradoxical cerebral embolism.Pulmonary arteriovenous fistula(PAVF)is a rare potential cause of cerebral ischemic stroke,and cerebral ischemic stroke induced by PAVF in children is rare.CASE SUMMARY We report a case of right PAVF that presented as a transient ischemic attack(TIA)in a 13-year-old boy.The patient underwent embolization therapy and remained clinically stable for 2 years after treatment.CONCLUSION TIA induced by PAVF in children is rare,lacks typical clinical manifestations,and should not be ignored.

Hybrid Operation Settings for the Treatment of Complex Dural Arteriovenous Fistulas:A Report on Two Cases

The clinical manifestations of complex dural arteriovenous fistula(DAVF)with intracranial venous sinus occlusion are unspecific,and their symptoms are related to venous drainage pattern,number of fistulas,anatomical site and degree of venous sinus occlusion,etc.We present two patients with DAVF that could not be completely embolized while being treated by conventional intervention.Therefore,we perform hybrid operation under general anesthesia and investigate the efficacy of hybrid operating settings for DAVF.

Multimodal MRI diagnosis and transvenous embolization of a basicranial emissary vein dural arteriovenous fistula:A case report

A dural arteriovenous fistula(DAVF) is an abnormal linkage connecting the arterial and venous systems within the intracranial dura mater. A basicranial emissary vein DAVF drains into the cavernous sinus and the ophthalmic vein, similar to a cavernous sinus DAVF. Precise preoperative identification of the DAVF location is a prerequisite for appropriate treatment. Treatment options include microsurgical disconnection, endovascular transarterial embolization(TAE), transvenous embolization(TVE), or a combination thereof. TVE is an increasingly popular approach for the treatment of DAVFs and the preferred approach for skull base locations, due to the risk of cranial neuropathy caused by dangerous anastomosis from arterial approaches. Multimodal magnetic resonance imaging(MRI) can provide anatomical and hemodynamic information for TVE. The therapeutic target must be precisely embolized in the emissary vein, which requires guidance via multimodal MRI. Here, we report a rare case of successful TVE for a basicranial emissary vein DAVF, utilizing multimodal MRI assistance. The fistula had vanished, pterygoid plexus drainage had improved, and the inferior petrosal sinus had recanalized, as observed on 8-month follow-up angiography. Symptoms and signs of double vision, caused by abduction deficiency, disappeared. Detailed anatomic and hemodynamic assessment by multimodal MRI is the key to guiding successful diagnosis and treatment.

A Computational Analysis of the Influence of Anastomosis Angle on Stenosis-Prone Locations during Radio-Cephalic Arteriovenous Fistula Maturation

In dialysis treatment, the radio-cephalic arteriovenous fistula (RCAVF) is a commonly used fistula, yet its low maturation rate remains a challenge. To enhance surgical outcomes, the relationship between stenosis-prone locations and RCAVF anastomosis angle is studied during maturation by developing two sets of RCAVF models for early (non-mature) and mature RCAVFs at five anastomosis angles. The impact of hemodynamics and wall shear stress (WSS) is examined to determine optimal anastomotic angles. Results indicate that acute angles produce more physiological WSS distributions and fewer disturbed regions, with early stenosis-prone regions located near the anastomosis that shift to the bending venous segment during remodeling. A pilot study comparing clinical and numerical results is conducted for validation.

Impact and Management under Extracorporeal Circulation of a Patient with Renal Insufficiency on Dialysis with a High-Flow Arteriovenous Fistula in the Cardiac Surgery Department of the Angers Teaching Hospital about a Case and Review of the Literature

Arteriovenous fistulas have a substantial impact on systemic hemodynamics, however their effect on extracorporeal circulation is not well understood. We report our clinical observation on the management under extracorporeal circulation of a patient with renal insufficiency with a high-flow arteriovenous fistula. This is a 59-year-old man who was referred to us for surgical treatment of ischemic coronary artery disease in a context of anuric chronic renal failure. Hypothermia at 32°C is started from the start in CEC due to hyperflow at the level of the arteriovenous fistula. We performed two coronary artery bypasses of the marginal and IVA via the two internal thoracic arteries. The patient is hemofiltered in order to avoid hyperkalaemia and possibly avoid fluid overload related to filling per CEC. The clamping time was 71 minutes and the SCC lasted 141 minutes. There was no homologous transfusion in the operating room. It turns out that the input/output balance is zero at the end of the CEC. The postoperative course was simple.

Pitfalls in internal jugular vein cannulation

Central venous catheter insertion in the internal jugular vein(IJV)is frequently performed in acute care settings,facilitated by its easy availability and increased use of ultrasound in healthcare settings.Despite the increased safety profile and insertion convenience,it has complications.Herein,we aim to inform readers about the existing literature on the plethora of complications with potentially disastrous consequences for patients undergoing IJV cannulation.

Effect of cryotherapy on pain management at the puncture site of arteriovenous fistula among children undergoing hemodialysis

Objective: To evaluate the effectiveness of cryotherapy in managing the pain at the puncture site of Arterio-Venous Fistula (AVF) among children undergoing maintenance hemodialysis (HD).Methods: A one-group pre-post quasi-experiment was performed in two HD centers affiliated with Cairo University.The experiment involved 40 children with AVF undergoing HD.Before puncturing,cryotherapy was applied using 2 cm-3 cm pieces of frozen distilled water in a plastic bag.Pain was assessed subjectively and objectively in two dialysis sessions before and after cryotherapy.A part from a physiological assessment of vital signs,pain was assessed using the Wong-Baker Faces Pain and the Observed Pain Behavior rating scales.All research ethics were applied.Results: HD had a median duration of four years,while cryotherapy had a median application time of 8.8 min.The Wong-Baker Faces Pain score and almost all observed pain behaviors significantly decreased after cryotherapy.Significant improvements were observed in respiratory rate before and after needle puncture and in oxygen saturation after needle puncture.A lower skin dryness was observed after cryotherapy (12.5%) than before cryotherapy (52.5%;p < 0.001).Conclusions: Cryotherapy can effectively reduce the venipuncture pain among children with AVF undergoing maintenance HD.However,the confounding effects of distraction and the non-randomized design used must be both considered when interpreting the findings.This study recommends the use of cryotherapy in managing needle puncture pain.Further research must adopt a randomized trial design with a placebo to support further the benefits of this procedure.

Optimization of Maturation of Radio-Cephalic Arteriovenous Fistula Using a Model Relating Energy Loss Rate and Vascular Geometric Parameters

The main reason for the early failure of radio-cephalic arteriovenous fistula (RCAVF) is non-maturity, which means that the blood flow rate in the fistula cannot increase to the expected value for dialysis. From a mechanical perspective, the vascular resistance at the artificially designed anastomosis causes an energy loss that affects blood flow rate growth and leads to early failure. This research studied how to maximize the RCAVF maturity and primary patency by controlling the energy loss rate. We theoretically analyzed and derived a model that evaluates the energy loss rate Eavf in RCAVF as a function of its blood vessel geometric parameters (GPs) for given flow rates. There was an aggregate of five controllable GPs in RCAVF: radial artery diameter (Dra), cephalic vein diameter (Dcv), blood vessel distance between artery and vein (h), anastomotic diameter (Da), and anastomotic angle (θ). Through this analysis, it was found that Eavf was inversely proportional to Dra, Dcv, Da, and θ, whereas proportional to h. Therefore, we recommended surgeons choose the vessels with large diameters, close distance, and increase the diameter and angle of the anastomosis to decrease the early failure of RCAVF. Simultaneously, we could explain the results of many clinical empiricisms with our formula. We found that increasing Dcv and θ was more significant in reducing Eavf than increasing Dra and Da. Based on our model, we could define two critical energy loss rates (CELa, CELb) to help surgeons evaluate the blood vessels and choose the ideal range of θ, and help them design the preoperative RCAVF plan for each patient to increase the maturity and the primary patency of RCAVF.

Ear ischemia induced by endovascular therapy for arteriovenous fistula of the sigmoid sinus: A case report

BACKGROUND Arteriovenous fistula of the sigmoid sinus is an abnormal connection of arteries with the sigmoid sinus.Endovascular treatments of such lesions are considered safe and with low rates of complications.CASE SUMMARY A 62-year-old female patient underwent endovascular treatment of an arteriovenous fistula of the right sigmoid sinus on February 7,2017,but her tinnitus was not cured.She was admitted to the Beijing Tiantan Hospital,Capital Medical University,on March 20,2017,and her pre-operative diagnosis,by digital subtraction cerebral angiography,was arteriovenous fistula of the sigmoid sinus.She underwent endovascular embolization of the distal occipital artery and posterior auricular artery using Onyx-18.The arteriovenous fistula of the sigmoid sinus was cured,and her tinnitus disappeared,but ischemia of the upper 2/3 of the right auricle occurred without hearing loss.The patient received treatment to improve microcirculation,in addition to fluid supplementation,analgesia,and hyperbaric oxygen,and the swelling due to ischemia in the right auricle did not progress further.The patient reported no tinnitus,and the right auricle had returned to normal 3 years later.CONCLUSION Ischemic complications of vital organs should be considered when performing embolization procedures for arteriovenous fistulas of cerebral sinuses.Compensation of the organs should be evaluated before the operation,and the related treatment regimens should be planned.

Case Report of a Chronic Wound Due to Venous Insufficiency Following a Traumatic Arteriovenous Fistula

Chronic lower limb wounds are common. They can be of arterial or venous origin. In this article, we will present a clinical case of a 30-year-old patient with a chronic injury to the right medial malleolus. In his history, we can note a gunshot wound to the right leg. Ultrasonography and CT angiography helped in the diagnosis of traumatic arteriovenous fistula. The patient underwent a fistula embolization which allowed the wound to heal. The clinical presentation, additional examinations and the latest treatment recommendations will be discussed in this article.

Onyx embolization of a spinal epidural hemorrhage caused by thoracic spinal epidural arteriovenous fistula:A case report and literature review

Spinal epidural hemorrhages(SEDH)caused by spinal epidural arteriovenous fistulas(SEAVFs)are rare;thus,their specific pathogenesis has not been explained.Furthermore,the standard treatment for SEAVFs has not yet been defined.Here we report the case of a 36-year-old Chinese man who experienced acute onset chest pain and tightness.His symptoms rapidly aggravated until the lower limbs were unable to support him.Spinal magnetic resonance angiography(MRA)revealed a localized SEAVF and a secondary spinal cord lesion at the T4 level.Digital subtraction angiography(DSA)confirmed the presence of the SEDH/SEAVF at the T3–4 level with the left radicular artery feeding the fistula.Based on DSA and MRA findings,SEDH,local spinal cord infarction,and spinal venous reflux disorder were conditionally diagnosed.Using the arterial route,Onyx-34 was injected into the fistula to embolize the feeding arteries and the venous system.Angiography was performed after the microcatheter was withdrawn,and no residual fistula or anterior spinal artery was observed.The six-week follow-up MRI showed acceptable healing of the SEAVF,and the patient improved neurologically.This case suggests that endovascular treatment with Onyx-34 embolization should be considered a promising treatment strategy for this type of complicated SEAVF.