Difference between revisions of "Arteriovenous Fistula"

Latest revision as of 14:24, 15 October 2013

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.

Clinical Signs

Signs depend on where the AV fistula has formed. Some signs include subcutaneous 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).

Diagnosis

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.

Treatment and Control

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.

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.

References

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

Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company

Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier

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@@ Line 1: / Line 1: @@
-===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
-*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.
-'''The consequences of an arteriovenous fistula are the following:'''
+== Clinical Signs ==
-. 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).
-. Decreased blood perfusion at the affected site
-. Venous hypertension
+== Diagnosis ==
+Clinical signs and history are quite indicative of the condition.
-*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.
-===Diagnosis===
+== Treatment and Control==
-====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.
-*Signs depend on where the AV fistula has formed.
--Subcutaneous edema
+== Prognosis ==
--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.
--Inflammation
--Pain +/-
+== References ==
--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
--Increased pulse & heart rate
+Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company
--Audible continuous murmur over the fistula site
+Fossum, T. W. et. al. (2007) Small Animal Surgery (Third Edition) Mosby Elsevier
--Branham sign (decreased heart rate with surgical occlusion of blood flow to fistula)
+{{review}}
-====Angiography====
+{{OpenPages}}
--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]]
-====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:Arterial_Pathology]][[Category:To_Do_-_Cardiovascular]]