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

Arteriovenous fistulas and digital hypoperfusion ischemic syndrome in patients on hemodialysis

AIM： To determine survival parameters as well as char-acteristics of patients with this syndrome. METHODS： The investigation was conducted over a period of eight years, as a prospective, non-random-ized, clinical study which included 204 patients, treated by chronic hemodialysis. Most patients received hemo-dialysis 12 h per week. As vascular access for hemodi-alysis all subjects had an arteriovenous fstulae. Based on surveys the respondents were divided into groups of patients with and without digital hypoperfusion isch-emic syndrome. Gender, demographic and anthropo-metric characteristics, together with comorbidity and certain habits, were recorded. During this period 34.8% patients died.RESULTS： Patients with digital hypoperfusion ischemic syndrome were older than those without ischemia （P = 0.01）. Hemodialysis treatment lasted signifcantly lon-ger in the patients with digital hypoperfusion ischemic syndrome （P = 0.02）. The incidence of cardiovascular disease （P 〈 0.001） and diabetes mellitus （P = 0.01）, as well as blood fow through the arteriovenous fstula （ P = 0.036）, were higher in patients with digital hypoper-fusion ischemic syndrome. Statistically significant dif-ferences also existed in relation to oxygen saturation （P = 0.04）. Predictive parameters of survival for patients with digital hypoperfusion ischemic syndrome were： adequacy of hemodialysis （B = -3.604, P 〈 0.001）, hypertension （B = -0.920, P = 0.018）, smoking （B = -0.901, P = 0.049）, diabetes mellitus （B = 1.227, P = 0.005）, erythropoietin therapy （B = 1.274, P = 0.002） and hemodiafltration （B = -1.242, P = 0.033）. Kaplan-Meier survival analysis indicated that subjects with and without digital hypoperfusion ischemic syndrome dif-fered regarding the length of survival （P 〈 0.001）, i.e. , patients with confrmed digital hypoperfusion ischemic syndrome died earlier.CONCLUSION： Survival was signifcantly longer in the patients without digital hypoperfusion ischemic syn-drome.

EVALUATION OF THE DIAGNOSTIC CRITERIA FOR THE LOCALIZATION OF ACQUIRED ARTERIOVENOUS FISTULAS BY COLOR DOPPLER FLOW IMAGING

Objective. To evaluate the diagnostic criteria for the localization of acquired arteriovenous fistulas (AVFs) by color Doppler flow imaging (CDFI) based on the features of their hemodynamic changes. Methods. The shape and hemodynamic changes of involved vessels which could be helpful to localize the sites of fistulas were studied according to the observation of 10 cases of acquired AVFs. Results. The sites of the fistulas could be shown by two dimensional ultrasonography and color flow imaging in 40%and 80%cases, respectively. In all cases, turbulent high velocity flow was present at the sites of the fistulas, low resistant flow was present in the arteries proximal to the fistulas, and artery like flow was detected in the veins. Conclusion. CDFI was accurate for the localization of acquired AVFs, which were mainly localized by their hemodynamic changes shown by pulse Doppler ultrasound.

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.

Ruptured venous aneurysm associated with a dural arteriovenous fistula:Two case reports

BACKGROUND In general,venous aneurysm associated with dural arteriovenous fistula(dAVF)is considered to be developed under long standing venous hypertension and manifested as venous ectasia of draining vein itself.However,discrete saccular shaped venous aneurysm without angiographic evidence of venous hypertension arising from the draining vein,like cerebral arterial aneurysm,is quite rare and its pathomechanism remains unclear in patients with dAVF.CASE SUMMARY In this report,we present two cases of ruptured saccular venous aneurysms associated with dAVF without venous hypertension or venous ectasia.In both cases,significant curve or stenosis is observed in draining vein,which is located in just distal portion of the venous aneurysms.These aneurysms were successfully treated with a transarterial embolization.Underlying mechanism of venous aneurysms in these cases is discussed.CONCLUSION Although there is little doubt that hemodynamic stress has a critical role in the development of venous aneurysms in patients with dAVF,preceding venous hypertension or venous ectasia is not necessary for development and enlargement of venous aneurysms.Considering the significant risk of rupture,a careful review of draining vein features including tortuosity or stenosis is needed,especially in venous aneurysms without evidence of venous hypertension.

Surgical treatment of a rare brachial artery aneurysm postarteriovenous fistula closure after kidney transplant:A case report

BACKGROUND Brachial artery aneurysms are defined as dilations greater than 50%of the normal diameter,which are rare among all peripheral arterial aneurysms.While they are often present as pseudoaneurysms,true brachial artery aneurysms are also detected rarely.In this case report,the surgical repair method of true brachial artery aneurysms,which is a rare condition,is explained.CASE SUMMARY Herein,we present a 61-year-old male patient with complaints of swelling and pain in the right arm antecubital region that had been progressing over 6 mo.Upon the diagnosis of a true brachial artery aneurysm associated with arteriovenous fistula,the aneurysm was surgically repaired with an autologous saphenous vein graft.The patient was discharged without any neurovascular complications postoperatively.CONCLUSION True brachial artery aneurysms are rare and there are not any recommendations for their management in the current literature.Even though the treatment of true aneurysms in this artery is primarily based on a surgical treatment,endovascular repair also might be an option.

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.

Application of Clinical Care Pathway in Perioperative Patients with Autologous Arteriovenous Fistula Balloon Expansion

[Objective] To explore the effect of clinical care pathways in perioperative patients with autologous arteriovenous fistula balloon expansion. [Method] 202 patients undergoing autologous arteriovenous fistula from July 2021 to June 2022 were randomly divided into a control group (101 cases) and an observation group (101 cases) to compare the incidence rates of postoperative complications, hospitalization days, hospitalization expenses, knowledge of self-management of arteriovenous fistula and nursing satisfaction. [Results] In the observation group, the incidence of arteriovenous fistula was higher than that of the control group, and the hospitalization days and hospitalization costs were lower than that of the control group. The difference between the two groups was statistically significant (P < 0.05). [Conclusion] The application of the clinical nursing path to intervene in patients with autologous arteriovenous fistula balloon dilation can reduce the incidence of postoperative complications, shorten the hospital length of time, reduce hospitalization costs and improve patient satisfaction, which is clinical promotion significance.

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.

Surgical treatment of post-traumatic pseudoaneurysms and arteriovenous fistulas

Objective: To report the experience in the diagnosis and treatment of post traumatic pseudoaneurysms and arteriovenous fistulas. Methods: A series of 30 patients (11 women and 19 men) with posttraumatic pseudoaneurysms were reviewed retrospectively. Among them 7 patients (5 women and 2 men) were associated with arteriovenous fistula. Results: The causes included sharp penetrating trauma (18 cases), blunt trauma (6 cases) and iatrogenic arterial injury (6 cases). The main clinical manifestations consisted of local pulsatile mass (26 cases), vascular bruits (19 cases), thrill (13 cases), ischemia of distal limb (9 cases), neuropathy (5 cases) and pseudoaneurysm rupture (2 cases). All patients underwent surgery. The operations included: ligation of the vessels (12 cases), surgical resection and primary suture repair of the vascular defect or anastomosis (11 cases), vascular reconstruction with autogenous saphenous vein (3 cases) and synthetic vascular graft (4 cases). Conclusions: Because of the imminent clinical course, early operation is usually indicated. The operative treatment is effective and safe for most of the patients with post traumatic pseudoaneurysms and arteriovenous fistulas.

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.