High-flow Fistula Research Articles

Surgical reduction of a high-flow dialysis fistula has long-term positive effects of the heart

Abstract Introduction Part of chronic haemodialysis patients develop a high-flow arteriovenous fistula (AVF). The volume overload caused by the presence of a high-flow AVF leads to increased cardiac output, dilation of cardiac chambers, increased pulmonary artery pressure or even to the development of high-output heart failure. Our previous data showed a positive effect of AVF flow-reducing surgery in 6 weeks follow-up. Purpose The purpose of this study was to analyse the long-term effect of AVF blood flow (Qa) reduction on cardiac structure and function. Methods We included patients with high-flow AVFs (defined as Qa over 1500 mL/min) indicated for blood flow reduction surgery for heart failure symptoms or pre-defined echocardiographic changes (left ventricular hypertrophy, severe secondary valvular regurgitations, or pulmonary hypertension). Echocardiography was performed one day before the surgery, the 6 weeks, 6 months, and 12 months thereafter. Qa was measured by ultrasound during the same visits. Results 27 patients were included, 20 men and 7 women, aged 57 ± 13 years. The procedure led to an immediate decrease in Qa. However, we observed failure of the procedure within 1 year in 8 (= 30%) patients defined by increased Qa back to pre-surgery values. Detailed results are displayed in Table 1. Estimated pulmonary arterial systolic pressure and left atrial volume remained significantly lower after 1 year despite the Qa rise. Effective cardiac output (= difference of cardiac output and Qa) rose immediately and remained increased during the follow-up period despite the increase in AVF blood flow. Conclusions We observed a long-time positive effect of AVF blood flow reduction surgery on the heart despite a significant Qa rise. The effective cardiac output remained increased despite the gradual increase of Qa, probably due to the adaptation of systemic arterioles.

Pulmonary hypertension in patients on chronic hemodialysis

Abstract Introduction Pulmonary hypertension (PH) is a common condition in patients with advanced chronic kidney disease and is associated with higher morbidity and mortality. High arteriovenous fistula (AVF) flow is one of known etiological factors, but the association of AVF flow within the acceptable range and PH has not been tested. Moreover, the prevalence of PH differed among various studies. Purpose The aims of this study were: 1. to describe the prevalence of PH in the Czech hemodialysis population; 2. to analyze the relation between dialysis fistula flow and PH; 3. to reveal other etiology of PH in a cross-sectional non-invasive trial. Methods We analyzed index visits of the cohort CZecking HF-CKD study (ISRCTN 18275480). Thus, this is a cross-sectional analysis based on detailed echocardiography with cardiac output (CO) calculation, evaluation of the central venous pressure (CVP) and AVF flow, bio-impedance and basic laboratory tests. All these measurements were done within an hour. The presence of PH was based on the peak systolic pulmonary arterial pressure (PASP) estimation above 35 mmHg. Results We analyzed data of 162 patients. They were 73,2 ± 12,6 years old, dialysis vintage 30 ± 69 months. Pulmonary hypertension was present in 35 % of analyzed patients. Among these patients, mild PH was present in 35 %, moderate in 53 % and severe in 12 %. There was no significant impact of AVF/AVG flow on the presence of PH or PASP value (Table 1.). However patients with PH had higher prevalence of heart failure (HF), which was present in 86 % of patients with PH and only in 46 % without PH (p<0.00001), see Figure 1. This and other differences presented in Table 1. document significant contribution of postcapillary PH. Patients with PH were also more overhydrated when considered by CVP, by overhydration measurement using bioelectrical impedance analysis and had higher N-terminal pro brain natriuretic peptide (NTproBNP) (Table 1.). There was a positive correlation between systemic vascular resistance (SVR) and PASP (R=0,333, p= .001). Conclusions PH is present in approximately one third of the dialysis patients. The presence of heart failure and changes of left heart chambers show for the postcapillary etiology of PH. Neither the prevalence nor the severity of PH were significantly related to arteriovenous access flow.

Extracranial-intracranial bypass using a cephalic vein graft for iatrogenic internal carotid artery injury during functional endoscopic sinus surgery: illustrative case.

Injury to the internal carotid artery (ICA) during functional endoscopic sinus surgery is a rare but potentially fatal complication. Although treatment algorithms have been developed, guidelines for effectively managing iatrogenic ICA injury have not been established. A case of ICA perforation during functional endoscopic sinus surgery treated with cerebral bypass utilizing a cephalic vein graft is presented. A woman in her late 50s presented with a left cavernous ICA injury that had occurred during endoscopic nasal polypectomy at an outside hospital. Hemostasis was achieved with intranasal Foley catheter placement. Left common carotid artery angiography revealed a high-flow carotid-cavernous fistula. Cerebral revascularization was chosen as the optimal procedure. The initial intent was to use a radial artery graft, but the radial artery was found to be occluded intraoperatively. Postoperatively, the patient experienced decreased vision and left eye movement but was otherwise neurologically intact. Postoperative angiography showed complete resolution of the fistula. In cases involving ICA injury and carotid-cavernous fistula formation, microsurgical trapping with high-flow bypass is a favorable treatment option. The cephalic vein is a viable graft option when unexpected challenges arise with a radial artery graft. https://thejns.org/doi/10.3171/CASE24222.

A Case of the Uncommon Cause of Chronic Coronary Syndrome: Coronary Fistula and Coronary Stenosis, Which One to Intervene?

AbstractWe report a case of chronic coronary syndrome (CCS) that had two completely distinct mechanisms in one patient. We applied comprehensive diagnostic tools using noninvasive and invasive physiology and imaging tests before, during, and after the intervention procedure to evaluate the outcome. The patient had previously visited many physicians and was diagnosed with noncardiac chest pain. He was referred to our department due to the increased frequency and intensity of angina pectoris. After a careful diagnosis, we found a nonsignificant stenosis (50%) in the mid-left anterior descending (mid-LAD) artery and an unexpectedly high-flow coronary artery fistula from the LAD to the main pulmonary artery (MPA). We tried a combination therapy with escalation of the anti-ischemic therapy but failed. He was rehospitalized with unstable angina pectoris. After a comprehensive physiology and imaging test, our team decided to perform fistula embolization with detachable coils and defer stenting in the mid-LAD artery. After the intervention procedure, his angina subsided, and his exercise capacity was remarkably improved. Cardiac computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) evaluation in 3 months revealed all coils in situ and improved cardiac function. We postulate that comprehensive diagnostic tools are required to select appropriate management and prevent unnecessary procedures.

Unilateral Direct High-Flow Traumatic Carotid-Cavernous Fistula Presenting as Isolated Bilateral Abducent Nerves Palsy: A False Localizing Sign

Unilateral Direct High-Flow Traumatic Carotid-Cavernous Fistula Presenting as Isolated Bilateral Abducent Nerves Palsy: A False Localizing Sign

Endovascular and percutaneous embolization of a giant post traumatic arteriovenous fistula of inferior epigastric vessels

BackgroundArteriovenous fistulas involving the anterior abdominal wall can result from trauma. Such fistulas may remain asymptomatic and undetected for a prolonged duration of time. They tend to recruit multiple arterial feeders with remodelling in the feeding arteries, making them challenging to treat.Case presentationWe discuss a rare case of a 60-year-old male who presented with complaints of a progressive painless swelling in right lower abdomen. There was a history of blunt injury to abdomen at the same site during alleged road traffic accident 3 years ago. On CT angiography, an arteriovenous fistula was localised to the anterior abdominal wall arising predominantly from the right inferior epigastric artery with a giant venous sac and terminating as a tortuous single venous channel into the right external iliac vein. Few other small feeders were also seen arising from branches of right superior epigastric artery along Winslow’s pathway. The main challenge in endovascular management of this patient was embolization of a high flow shunt with a large venous sac and multiple arterial feeders. The dominant arterial feeder was embolized using vascular plug. The superficial location of the lesion offered an additional percutaneous window besides endovascular approach. The venous sac was percutaneously accessed and embolized using n-butyl cyanoacrylate after balloon occlusion of outflow vein. On follow up ultrasonographic evaluation at 3 months, near complete thrombosis of the venous sac was achieved.ConclusionsTraumatic arteriovenous fistulas involving the inferior epigastric vessels are rare clinical entities. CT angiogram and digital subtraction angiography help in the optimal diagnosis and treatment planning. The use of mechanical embolization devices to cause flow arrest offers an opportunity to use liquid embolic agents which offer better percolation within the lesion. Interventional radiology offers an ideal management of these complex high flow fistulas with a good technical success and acceptable safety profile.

Spontaneous thrombosis of high flow pediatric arteriovenous fistulae: Case series of two patients and a comprehensive literature review.

Pediatric pial arteriovenous shunts in the brain and spine are challenging to understand because of low incidence, variable presentation, and associations with genetic syndromes. What is known about their natural history comes from reviews of small series. To better understand the natural history and role for intervention, two cases are presented followed by a review of the literature. In the first case, an infant with a prior history of intracranial hemorrhage from a ruptured pial fistula returns for elective embolization for a second pial fistula which was found to be spontaneously thrombosed 2weeks later. In the second case, a 5-year-old with a vertebro-vertebral fistula, identified on work up for a heart murmur and documented with diagnostic angiography, is brought for elective embolization 6weeks later where spontaneous thrombosis is identified. In reviewing the literature on pediatric single-hole fistulae of the brain and spine, the authors offer some morphologic considerations for identifying which high-flow fistulae may undergo spontaneous thrombosis to decrease the potentially unnecessary risk associated with interventions in small children.

Hemodialysis Patients with High-Flow Arteriovenous Fistulas: An Evaluation of the Impact on Cardiac Function.

: Patients undergoing hemodialysis often experience changes in cardiac function when they have a high-flow arteriovenous fistula (AVF). This study aimed to assess the effect of high-flow AVFs on cardiac function in patients undergoing hemodialysis. : A longitudinal study was conducted on hemodialysis patients with high-flow AVFs. Echocardiographic parameters, such as left ventricular ejection fraction (LVEF), left atrial diameter (LAD), left ventricular end-diastolic dimension (LVEDD), right ventricular end-diastolic dimension (RVEDD), inferior vena cava diameter (IVCD), systolic blood pressure, and diastolic blood pressure, were measured and compared before and after AVF creation. : One hundred hemodialysis patients with high-flow AVFs (mean age: 55.95±13.39 years, mean body mass index: 24.71±3.43 kg/m²) were studied. LVEF significantly decreased (51.10%±5.39% to 47.50%±5.79%), while LAD, LVEDD, and IVCD significantly increased after AVF creation (P<0.05). Systolic (132.49±16.42 mmHg to 146.60±17.43 mmHg) and diastolic (79.98±8.40 mmHg to 83.33±9.68 mmHg) blood pressure substantially rose post-fistularization (P<0.001). Notably, LVEF reduction was more significant in brachio-cephalic AVFs (46.29%±4.24%) compared to distal radio-cephalic or snuffbox AVFs (49.17%±7.15%) (P=0.014). : High-flow AVFs can significantly affect echocardiographic parameters in hemodialysis patients, thereby increasing the risk of cardiac failure. Close cardiac monitoring may be necessary for early intervention. Distal AVFs may be preferable in patients with decreased cardiac function.

Carotid-cavernous fistulas

Carotid cavernous fistulas (CCFs) are rare but clinically significant vascular anomalies characterized by abnormal connections between the cavernous sinus and arteries. This overview presents acomprehensive analysis of anatomy, classification, clinical presentation, diagnosis, imaging, and therapy of CCFs. The cavernous sinus, acentral venous structure in the brain, is of critical importance for understanding CCFs due to its proximity to key structures such as the internal carotid artery and cranial nerves. CCFs are classified into direct and dural types, with direct fistulas typically being high-flow and dural fistulas being low-flow. The symptomatology varies greatly and can range from noises in the head, diplopia, red eye, tearing, to blurred vision and headaches. The diagnostic assessment requires acombination of detailed medical history, neurological and ophthalmological examination, and the use of imaging techniques. In imaging, computed tomography (CT) and magnetic resonance imaging (MRI) are crucial for depicting the anatomical structures and blood vessels, while digital subtraction angiography (DSA) is considered the gold standard for accurate representation of the fistula. The treatment of CCFs is complex and depends on the type of fistula, location, and clinical condition of the patient. This overview emphasizes the importance of precise diagnosis and individualized therapy to achieve optimal results and avoid complications. Ongoing developments in medical imaging and treatment techniques will continuously improve the treatment outcomes of patients with CCFs.

Effect of flow reduction surgery in a patient with high flow arteriovenous fistula with aortic dissection using 4D flow magnetic resonance imaging: A case report.

This study aimed to investigate cardiovascular function in a patient with high-flow arteriovenous fistula (AVF) who underwent aortic dissection (AD) using four-dimensional (4D) flow magnetic resonance imaging (MRI) as well as analyze the effect of flow reduction surgery on AD. On March 12, 2017, a 60-year-old woman underwent emergency surgery for AD. After that, she experienced acute kidney injury, and hemodialysis was initiated. On April 24, 2017, a left brachiocephalic arteriovenous fistula (AVF) was created to facilitate her dialysis. However, after 5 years, the patient presented with a high-flow AVF, and a flow reduction surgery was performed on March 11, 2022. To evaluate the procedure's effectiveness, we measured the changes in left ventricular (LV) function and blood flow in the aorta and vascular access before and after surgery using 4D flow MRI. Notable changes were observed in LV function, blood flow in the aorta before and after the surgery, and maximum velocity and flow volume after surgery. During the 6-month follow-up after the surgery, the maximum velocity and flow volume in the aorta and vascular access were reduced; also, indicators such as LV volume, cardiac output, cardiac index, and LV mass were improved. In patients with high-flow AVF, flow reduction surgery should be considered as it may improve LV function and reduce the risk of AD recurrence by lowering the flow volume of the aorta.

Systemic vascular resistance predicts high-output cardiac failure in patients with high-flow arteriovenous fistula.

Patients with high-flow arteriovenous (AV) access are at risk of developing high-output cardiac failure (HOCF) and subsequent hospitalization. However, diagnosing HOCF is challenging and often requires invasive procedures. The role of systemic vascular resistance (SVR) in diagnosing HOCF is underestimated, and its predictive value is limited. Our study aims to identify non-invasive risk factors for HOCF to facilitate early diagnosis and timely surgical interventions. We included 109 patients with high-flow AV access who underwent serial echocardiography. The retrospective cohort was divided into two groups based on their hospitalization due to HOCF. The two groups were matched for age and gender. After a mean follow-up of 25.1months, 19 patients (17.4%) were hospitalized due to HOCF. The two groups had similar baseline characteristics. However, the HOCF group had a higher value of vascular access blood flow (Qa) (2168±856 vs. 1828±617mL/min; P=0.045). Echocardiographic analysis revealed that the HOCF group had more pronounced left ventricular diastolic dysfunction (E/e': 21.1±7.3 vs. 16.2±5.9; P=0.002), more severe pulmonary hypertension (right ventricular systolic pressure: 41.4±16.7 vs. 32.2±12.8; P=0.009), a higher Doppler-derived cardiac index (CI) (4.3±0.8 vs. 3.7±1.1; P=0.031), and a lower Doppler-derived estimated SVR (eSVR) value (5.5±0.3 vs. 6.9±0.2; P=0.002) than the non-HOCF group. Using multivariable Cox regression analysis, a low eSVR value (<6) emerged as an independent predictor of HOCF hospitalization with a hazard ratio of 9.084 (95% confidence interval, 2.33-35.39; P=0.001). Receiver operating characteristic curve analysis indicated that CI/eSVR values more accurately predicted HOCF hospitalization [sensitivity: 94.7%, specificity: 51.0%, area under the curve (AUC): 0.75, P<0.001] than the Qa/cardiac output ratio (AUC: 0.50, P=0.955), Qa values≥2000mL/min (AUC: 0.60, P=0.181), and Qa values indexed for height in metres (AUC: 0.65, P=0.040). In patients with high-flow AV access, low eSVR values obtained through non-invasive Doppler echocardiography were associated with a high rate of HOCF hospitalizations. Therefore, routine eSVR screening in these patients might expedite the diagnosis of HOCF.

Quantitative Blood Flow Reduction in Selective Embolization of Intranidal Fistula of Cerebral Arteriovenous Malformations: Case Series.

Arteriovenous malformations (AVMs) are often associated with high-flow intranidal fistulas (INFs). Although INF embolization has been suggested to provide higher reduction of total AVM flow compared with regular pedicle embolization, this effect has not previously been quantified. The aim of this study was to characterize the effect of AVM INF embolization on total AVM flow. This study is an Institutional Review Board-approved, retrospective case series of patients from 2010 to 2022 with AVMs, both with and without INFs, who underwent quantitative magnetic resonance angiography and endovascular embolization. Twenty patients accounted for 35 separate embolization sessions: 13 patients with INFs underwent a total 21 embolizations and 12 patients without INFs had 14 embolizations. No significant differences were found between groups on age, sex, laterality, drainage pattern, and Spetzler-Martin grade. However, AVMs with INFs were larger than the control group (12.7 vs 8.37 cm 3 , P = .049). Baseline pre-embolization AVM flow significantly differed between AVM with INF vs control groups (522 vs 320 cc/min, P = .005). Similarly, postembolization AVM flow also differed between AVM with INF and control groups (392 vs 224 cc/min, P = .008), with a larger decrease in flow per vessel per embolization session within the AVM INF group compared with controls (101.5 vs 33.2 cc/min, P < .001). Repeated measure analysis of variance showed significant differences pre-embolization and postembolization AVM flow between those with INFs vs controls ( P < .001). This study represents the first to examine the effect of INF embolization on total AVM flow. AVMs with INFs showed higher baseline flow, and targeted embolization toward INFs significantly lowered AVM flow in comparison with controls without INFs. The results of this study emphasize the importance of recognizing the presence of INFs within AVMs and their embolization to reduce AVM flow as part of a multistep management paradigm.

Anatomical considerations regarding a high-flow arteriovenous fistula below the conus medullaris in a patient with hereditary hemorrhagic telangiectasia: Case report.

Cauda equina radicular arteriovenous fistulas are rare "low flow" shunting lesions characterized by direct communication between the radicular artery and vein of a cauda equina nerve root. None have been associated with hereditary hemorrhagic telangiectasia and a high-flow cauda equina radicular arteriovenous fistula has never been reported. We present a unique case of a high-flow cauda equina radicular arteriovenous fistula in a patient with hereditary hemorrhagic telangiectasia. Marked flow-induced vascular remodeling posed significant diagnostic and therapeutic challenges which will be highlighted in this report. A 39-year-old female with genetically confirmed hereditary hemorrhagic telangiectasia presented with progressive thoracic myelopathy secondary to a high-flow single-hole arteriovenous fistula below the conus. The feeding artery, arising from the anterior spinal artery, and draining vein had a paramedian course, favoring the diagnosis of a cauda equina radicular arteriovenous fistula (supplied by a proximal radicular artery) over a filum terminale arteriovenous fistula. Transarterial embolization was attempted but significant elongation and tortuosity of the anterior spinal artery precluded microcatheter access to the fistulous point. Surgical disconnection was successfully performed. The intraoperative findings supported the diagnosis of cauda equina radicular arteriovenous fistula. Delayed neurologic deterioration secondary to overshooting venous thrombosis was observed. She recovered after the initiation of therapeutic anticoagulation. To the best of our knowledge, we hereby report the first high-flow cauda equina radicular arteriovenous fistula. The accurate differentiation of cauda equina radicular arteriovenous fistula from filum terminale arteriovenous fistulas, while challenging, is important to avoid treatment-related complications. Careful preoperative planning, the use of specialized endovascular and surgical techniques, and meticulous postoperative care can ensure the safe and complete disconnection of high-flow cauda equina radicular arteriovenous fistulas.

High-Flow Indirect Carotid-Cavernous Fistula with Transarterial and Transvenous Endovascular Treatment

Male, 39 years old, with a progressive headache for seven months, progressive right exophthalmos, right chemosis and conjunctival edema, pulsatile tinnitus and carotid bruit in the right frontotemporal region. Cerebral magnetic nuclear angioresonance showed multiple anomalous vascular structures near the sphenoparietal sinus, pterygoid plexus, superior and inferior orbital fissures, all on the right, with swelling of the basilar plexus. A diagnostic cerebral and cervical arteriography was performed, which showed a high-output indirect Carotid-Cavernous Fistula (CCF), nourished mainly by multiple dysplastic dural branches originating from the mandibular and pterygopalatine segments of the internal maxillary artery and secondarily by the inferolateral trunk. There was hypertensive venous drainage anteriorly through the ecstatic superior and inferior ophthalmic veins, corresponding angular and facial veins, and posteriorly to both cavernous sinuses, basilar plexus, superior petrosal sinuses, and internal jugular veins (Type D, Barrow Classification). The patient underwent arterial embolization with hystoacril and lipiodol in branches of the right internal maxillary artery and venous embolization with platinum micro coils with occlusion of the fistula. He evolved well with the improvement of symptoms, being discharged from the hospital and scheduled for outpatient follow-up.

Optimizing Arteriovenous Fistula Care in Kidney Transplant Recipients: A Complex Task.

Optimizing Arteriovenous Fistula Care in Kidney Transplant Recipients: A Complex Task.

Effect of proximal artery restriction on flow reduction and cardiac function in hemodialysis patients with high-flow arteriovenous fistulas

ObjectiveArteriovenous fistula is the preferred vascular access for hemodialysis patients. High-flow arteriovenous fistula may cause high-output heart failure. Various procedures are used to reduce high-flow arteriovenous fistula. This study aimed to assess the efficacy of proximal artery restriction combined with distal artery ligation on flow reduction for high-flow arteriovenous fistula and on cardiac function and echocardiographic changes in patients undergoing hemodialysis. MethodsA retrospective analysis was performed on data collected from the medical records of patients undergoing hemodialysis with heart failure and high-flow arteriovenous fistula between May 2018 and May 2021. Thirty-one patients were treated with proximal artery restriction (banding juxta-anastomosis of the proximal artery) combined with distal artery ligation (anastomosis distal artery ligation). Changes in the Acute Dialysis Quality Initiative Workgroup cardiac function class, blood pressure, and echocardiography before and 6 months after flow restriction were compared, and post-intervention primary patency was followed-up. ResultsThe technical success rate of the surgery was 100%, and no surgery-related adverse events occurred. Blood flow and blood flow/cardiac output decreased significantly after flow restriction. Blood flow decreased from 2047.21 ± 398.08 mL/min to 1001.36 ± 240.42 mL/min, and blood flow/cardiac output decreased from 40.18% ± 6.76% to 22.34% ± 7.21% (P < .001). Post-intervention primary patency of arteriovenous fistula at 6, 12, and 24 months was 96.8%, 93.5%, and 75.2%, respectively. The Acute Dialysis Quality Initiative Workgroup cardiac function class improved significantly after 6 months of flow restriction (P < .001). The systolic and diastolic left heart function improved, as evidenced by a significant decrease in left atrial volume index, left ventricular end-diastolic/end-systolic diameters, left ventricular end-diastolic volume, left ventricular mass index, cardiac output, and cardiac index and an increase in lateral peak velocity of longitudinal contraction, average septal-lateral s', and lateral early diastolic peak velocity after flow restriction (P < .05). Systolic pulmonary artery pressure decreased from 32.36 ± 8.56 mmHg to 27.57 ± 8.98 mmHg (P < .05), indicating an improvement in right heart function. ConclusionsProximal artery restriction combined with distal artery ligation effectively reduced the blood flow of high-flow arteriovenous fistula and improved cardiac function.

Multi-layered repair of high-flow CSF fistulae following endoscopic skull base surgery without nasal packing or lumbar drains: technical refinements to optimise outcome.

Post-operative CSF leak remains a significant problem following endoscopic skull base surgery, particularly when there is a high-flow intra-operative CSF leak. Most skull base repair techniques are accompanied by the insertion of a lumbar drain and/or the use of nasal packing which have significant shortcomings. Our aim was to review the results of a large series of endoscopic skull base cases where a high-flow intra-operative CSF leak rate was encountered and repaired to assess if modifications in technique could reduce the post-operative CSF leak rate. A retrospective review of a prospectively maintained database of skull base cases performed by a single surgeon over a 10-year period was performed. Data regarding patient demographics, underlying pathology, skull base repair techniques and post-operative complications were analysed. One hundred forty-two cases with high-flow intra-operative CSF leak were included in the study. The most common pathologies were craniopharyngiomas (55/142, 39%), pituitary adenomas (34/142, 24%) and meningiomas (24/142, 17%). The CSF leak rate was 7/36 (19%) when a non-standardised skull base repair technique was used. However, with the adoption of a standardised, multi-layer repair technique, the post-operative CSF leak rate decreased significantly (4/106, 4% vs. 7/36, 19%, p = 0.006). This improvement in the rate of post-operative CSF leak was achieved without nasal packing or lumbar drains. With iterative modifications to a multi-layered closure technique for high-flow intra-operative CSF leaks, it is possible to obtain a very low rate of post-operative CSF leak, without lumbar drains or nasal packing.

Combined Transarterial and Inferior Ophthalmic Vein Approach to a Direct Carotid-Cavernous Fistula: Technical Note

We describe our rescue technique for direct puncture of the inferior ophthalmic vein (IOV) for transvenous access of a direct, high-flow carotid-cavernous fistula (CCF). The CCF was caused by rupture of a large internal carotid artery aneurysm. Aneurysm and fistula embolization solely via the transarterial approach did not appear promising due to partial aneurysm thrombosis. Also, transvenous access via the facial vein failed due to extensive vessel tortuosity. Instead, the engorged and arterialized IOV was accessed by direct puncture with an 18-gauge venous cannula. After a small skin incision of the medial aspect of the lower eyelid and further transseptal puncture, the cannula was advanced stepwise between the maxillary bone and the bulbus oculi and below the medial rectus muscle to the IOV under repeated biplane roadmap guidance in 2 planes. Thereafter, the fistula and the aneurysm dome could be embolized with coils via a low-profile microcatheter. Hereby, a protective flow diverter was implanted via the arterial route into the internal carotid artery to seal the parent artery, prevent coil protrusion, and ensure permanent aneurysm occlusion. At 1-month follow-up, the aneurysm and CCF were completely occluded. Direct puncture of the IOV represents a feasible and minimally invasive approach for venous CCF access. The proposed method needs to be validated by further reports.

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.

High-flow arteriovenous fistula resulting from stingray injury.

Stingray punctures are relatively common in several coastal regions and may result in chronic wounds and disability due to injury and envenomation. Vascular complications are rare but can be severe. We describe a case of high-flow arteriovenous fistula resulting from a stingray injury that required a venous bypass.