Arteriovenous fistula, abbreviated as AVF, constitutes a pathological or surgical connection between an artery and vein. It can be present in any region of the body.
Arteriovenous fistulas (AVFs) are pathological or surgical vascular connections between arteries and veins. They can be congenital or acquired defects, for example after a penetrating trauma or an aneurysmal rupture. The symptomatology depends on the location and regional anatomy of AVF. Surgical AVF is used for long-term vascular access in hemodialysis.
Usually, acquired AVFs lead to a mass that can be palpated, transmits pulses, and a bruit can be heard during auscultation. These masses are commonly observed in an extremity previously affected by a significant traumatization. Symptoms of high-output congestive heart failure may also be reported, most frequently if the flow via the AVF is greater than 1/5 of the cardiac output, and include peripheral edema, cough, fatigue, shortness of breath, and ascites .
With regard to congenital AVFs, the region where they are formed dictates the symptomatology. More specifically:
- AVFs in extremities
Symptoms may fail to arise for years after the patient is born. Similarly to acquired AVFs, congenital AVFs located on the extremities induce peripheral edema and hypertrophy of the extremity in young patients. This manifestation is aggravated when the AVF is found in the lower part of the extremity . The clinical picture may be further complicated with the onset of ulcers, thromboembolic events, and cardiac failure  .
- Intracranial AVFs
- Pulmonary AVFs
A considerable number of patients presenting with pulmonary AVFs are also diagnosed with vascular anomalies in the nasopharynx, liver, spleen and gastrointestinal tract, as manifestations of the Rendu-Osler-Weber syndrome. Pulmonary arteriovenous fistulas per se may lead to dyspnea on exertion, symptoms related to high-output congestive heart failure, pulmonary hypertension, and hypoxemia  . Compensatory polycythemia may develop, leading to non-specific symptoms, such as a headache and fatigue.
- Spinal AVFs
They can lead to manifestations related to myelopathy.
- Hepatic AVFs
These AVFs can be related to Rendu-Osler-Weber syndrome, Ehlers-Danlos syndrome, and biliary atresia.
- Femoral AVFs
Patients frequently have varicosities. Symptoms associated with diminished perfusion of the limb can also arise.
Entire Body System
- Congestive Heart Failure
None of the patients developed symptomatic steal syndrome or congestive heart failure. Five of 6 patients had successful usage of the new AVF, and subsequently underwent ligation and excision of the aneurysmal AVF, thus avoiding a temporary HDC. [ncbi.nlm.nih.gov]
Pulmonary arteriovenous fistulas per se may lead to dyspnea on exertion, symptoms related to high-output congestive heart failure, pulmonary hypertension, and hypoxemia. [symptoma.com]
The insertion of the cAV coupler resulted in a sustained anti-hypertensive effect nine months post-procedure, with mean 24-hr ABP of 154/91 mm Hg on only two anti-hypertensives. [ncbi.nlm.nih.gov]
- Heart Failure
Both patients had undergone abdominal surgery several years prior to the heart failure event with the initial finding of moderate pulmonary hypertension and high-output heart failure. [ncbi.nlm.nih.gov]
- Vascular Disease
The controls were randomly selected from uremic patients who were primary AVF operation, excluded obvious vascular stenosis and vascular diseases. Among them, 4 sample in the experimental group and 4 controls were used in LncRNA sequencing. [ncbi.nlm.nih.gov]
Arteriovenous fistula, abnormal direct opening between an artery and a vein ; it sometimes results from accidental penetration wounds or from vascular disease, or it may be congenital in origin. [britannica.com]
disease interventional cardiology A 62-year-old female underwent successful primary percutaneous coronary intervention for an acute anterior wall myocardial infarction via the right radial artery access. [heartasia.bmj.com]
The Dialysis Outcomes and Practice Patterns (DOPPS) III reports that patients were less likely to use an AVF if they were female, of older age, had a greater body mass index or had diabetes, peripheral vascular disease or recurrent cellulitis/gangrene [advancedrenaleducation.com]
- Wide Pulse Pressure
The physical manifestations of this would be a relatively normal systolic blood pressure with a decreased diastolic blood pressure resulting in a wide pulse pressure. [en.wikipedia.org]
Face, Head & Neck
- Bilateral Leg Paralysis
A 14-year-old girl presented with a 3-week history of slowly progressive unilateral leg weakness that quickly progressed to bilateral leg paralysis, sphincter dysfunction, and complete sensory loss the day of her presentation. [ncbi.nlm.nih.gov]
- Generalized Seizure
CASE DESCRIPTIONS: A 73-year-old man presented with generalized seizure and reported severe but intermittent headache in the right temporo-occipital area. Single-photon emission computed tomography (SPECT) showed hyperperfusion in that area. [ncbi.nlm.nih.gov]
- Thalamic Pain
Two days later, his motor power deteriorated and he developed right hemisensory loss and severe thalamic pain. Aphasia was atypical and mimicked the transcortical type. [ncbi.nlm.nih.gov]
Radiological modalities employed in the diagnosis of arteriovenous fistulas are computed tomography (CT) angiography, magnetic resonance (MR) angiography, digital subtraction angiography (DSA), and color Doppler ultrasound.
CT angiography is a successful diagnostic procedure which produces accurate and specific findings. The modality reveals contrast material entering the vein prematurely during the arterial phase and illustrate the precise location of AVF. It has been found that CT angiography yields results that are in agreement with digital subtraction angiography . The latter can provide particularly accurate information concerning the arteries involvement in the fistula formation and can help to create a diagram concerning the optimal therapeutic intervention.
Color Doppler ultrasound demonstrates blood flow patterns and velocity in the vessels. Frequent findings are an arterial-like wave in the adjacent vein and turbulent flow at the site of a connection. MRA is performed, in order to diagnose and clearly delineate the borders of AVFs  .
MR angiography could be performed in order to visualize AVFs more precisely  .
With regard to blood laboratory studies, patients affected by extensive AVFs may exhibit abnormal results such as thrombocytopenia, elevated PT and PTT time, decreased fibrinogen, and prolonged euglobulin clot lysis time.
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