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| − | ===Description=== | + | {{OpenPagesTop}} |
| | + | == Introduction == |
| | + | As the name implies, an arteriovenous fistula is an abnormal direct connection between an artery and a vein. This connection causes the capillary circulation to be completely ignored. We will concentrate on peripheral fistulas here. The consequences of an arteriovenous fistula are the following: |
| | + | :Increased blood return to the right heart raises cardiac output |
| | + | :Decreased blood perfusion at the affected site |
| | + | :Venous hypertension will arise |
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| − | *As the name implies, an arteriovenous fistula is an abnormal direct connection between an artery and a vein. This connection causes the capillary circulation to be completely ignored. We will concentrate on peripheral fistulas here.
| + | Some causes of an arteriovenous fistula include trauma, surgery and neoplasia. |
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| − | '''The consequences of an arteriovenous fistula are the following:'''
| + | == Clinical Signs == |
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| − | 1. Increased blood return to the right heart raises cardiac output
| + | Signs depend on where the AV fistula has formed. Some signs include subcutaneous [[Oedema|oedema]], presence of a warm swelling, inflammation, pain, palpable vibration (thrill) over fistula, increased pulse & heart rate, an audible continuous murmur over the fistula site and the Branham sign (decreased heart rate with surgical occlusion of blood flow to fistula). |
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| − | 2. Decreased blood perfusion at the affected site
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| − | 3. Venous hypertension
| + | == Diagnosis == |
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| | + | Clinical signs and history are quite indicative of the condition. |
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| − | *Predisposing causes of arteriovenous fistula formations are: trauma, surgery, neoplasia, etc.
| + | '''Angiography''' can be performed and an abnormal direct connection between an artery and a vein will be found. '''Ultrasonography''' can also be used to demonstrate the presence of abnormal flow. |
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| − | ===Diagnosis=== | + | == Treatment and Control== |
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| − | ====History & Clinical Signs====
| + | Treatment is to surgically ligate the abnormal vessels to and from the fistula area. Another possible procedure would be amputation of the limb in severe cases. |
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| − | *Signs depend on where the AV fistula has formed.
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| − | -Subcutaneous edema
| + | == Prognosis == |
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| − | -Warm Swelling
| + | Good with complete ligation and cessation of blood flow through the fistula. Poor if surgical ligation is unsuccessful at stopping blood flow through the fistula. |
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| − | -Inflammation
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| − | -Pain +/-
| + | == References == |
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| − | -Palpable vibration (thrill) over fistula
| + | Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company |
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| − | -Increased pulse & heart rate
| + | Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company |
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| − | -Audible continuous murmur over the fistula site
| + | Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier |
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| − | -Branham sign (decreased heart rate with surgical occlusion of blood flow to fistula)
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| | + | {{review}} |
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| − | ====Angiography====
| + | {{OpenPages}} |
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| − | -Abnormal direct connection between an artery and a vein | + | [[Category:Vascular_Diseases_-_Dog]] [[Category:Vascular_Diseases_-_Cat]] [[Category:Arterial_Pathology]] [[Category:Expert_Review]] |
| − | | + | [[Category:Cardiology Section]] |
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| − | ====Ultrasonography====
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| − | -Abnormal flow visualized
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| − | ===Treatment===
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| − | -Surgical ligation of abnormal vessels to and from the fistula area
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| − | -(+/-) Amputation
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| − | ===Prognosis===
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| − | -Good with complete ligation and cessation of blood flow through the fistula
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| − | -Poor if surgical ligation is unsuccessful at stopping blood flow through the fistula
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| − | [[Category:Vascular Diseases - Dog]][[Category:Arterial_Pathology]][[Category:To_Do_-_Cardiovascular]] | |