Difference between revisions of "Arteriovenous Fistula"

Revision as of 16:14, 22 December 2010

Description

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:

1. Increased blood return to the right heart raises cardiac output

2. Decreased blood perfusion at the affected site

3. Venous hypertension

Predisposing causes of arteriovenous fistula formations are: trauma, surgery, neoplasia, etc.

Diagnosis

History & Clinical Signs

Signs depend on where the AV fistula has formed.

-Subcutaneous edema

-Warm Swelling

-Inflammation

-Pain +/-

-Palpable vibration (thrill) over fistula

-Increased pulse & heart rate

-Audible continuous murmur over the fistula site

-Branham sign (decreased heart rate with surgical occlusion of blood flow to fistula)

Angiography

-Abnormal direct connection between an artery and a vein

Ultrasonography

-Abnormal flow visualized

Treatment

-Surgical ligation of abnormal vessels to and from the fistula area

-(+/-) Amputation

Prognosis

-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

@@ Line 1: / Line 1: @@
-{{OpenPagesTop}}
+===Description===
-== 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
-Some causes of an arteriovenous fistula include trauma, surgery and neoplasia.
+*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.
-== Clinical Signs ==
+'''The consequences of an arteriovenous fistula are the following:'''
-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).
+. Increased blood return to the right heart raises cardiac output
+. Decreased blood perfusion at the affected site
-== Diagnosis ==
+. Venous hypertension
-Clinical signs and history are quite indicative of the condition.
-'''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.
+*Predisposing causes of arteriovenous fistula formations are: trauma, surgery, neoplasia, etc.
-== Treatment and Control==
+===Diagnosis===
-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.
+====History & Clinical Signs====
+*Signs depend on where the AV fistula has formed.
-== Prognosis ==
+-Subcutaneous edema
-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.
+-Warm Swelling
+-Inflammation
-== References ==
+-Pain +/-
-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
+-Palpable vibration (thrill) over fistula
-Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company
+-Increased pulse & heart rate
-Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier
+-Audible continuous murmur over the fistula site
+-Branham sign (decreased heart rate with surgical occlusion of blood flow to fistula)
-{{review}}
-{{OpenPages}}
+====Angiography====
-[[Category:Vascular_Diseases_-_Dog]] [[Category:Vascular_Diseases_-_Cat]] [[Category:Arterial_Pathology]] [[Category:Expert_Review]]
+-Abnormal direct connection between an artery and a vein
-[[Category:Cardiology Section]]
+====Ultrasonography====
+-Abnormal flow visualized
+===Treatment===
+-Surgical ligation of abnormal vessels to and from the fistula area
+-(+/-) Amputation
+===Prognosis===
+-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
+[[Category:Vascular Diseases - Dog]][[Category:Vascular Diseases - Cat]][[Category:Arterial_Pathology]][[Category:To_Do_-_Cardiovascular]]