Difference between revisions of "Arteriovenous Fistula"
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[[Category:Cardiovascular - Dog]][[Category:Arterial_Pathology]][[Category:To_Do_-_Cardiovascular]]
Revision as of 15:37, 16 December 2010
- 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.
History & Clinical Signs
- Signs depend on where the AV fistula has formed.
-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)
-Abnormal direct connection between an artery and a vein
-Abnormal flow visualized
-Surgical ligation of abnormal vessels to and from the fistula area
-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