Cimino fistula
A Cimino fistula, also Cimino-Brescia fistula, surgically created arteriovenous fistula and arteriovenous fistula, is a type of vascular access for hemodialysis. It is typically a surgically created connection between an artery and a vein in the arm, although there have been acquired arteriovenous fistulas which do not in fact demonstrate connection to an artery.
Structure
The radiocephalic arteriovenous fistula is a shortcut created between cephalic vein and radial artery at the wrist. It is the recommended first choice for hemodialysis access. However, after a period of usage, failures can occur. Possible causes for failure are stenosis and thrombosis especially in diabetics and those with low blood flow such as due to narrow vessels, arteriosclerosis and advanced age. Reported patency of fistulae after 1 year is about 60%, when primary failures were included.Juxa-anastomotic site is the most common site of stenosis. One of the reasons affecting the rate of stenosis could be the anastomotic angle. In computational fluid dynamics study, the ideal anastomotic angle should be less than 30 degrees to ensure laminar flow of the blood, thus prolong the endothelial cell survival, and prevent smooth muscle proliferation within vessel wall, and clogging the vessel. However, in another study using angiographic images of the juxta-anastomotic sites, the ideal anastomotic angle of less than 46.5 degrees was obtained.
Surgically created AV fistulas work effectively because they:
- Have high volume flow rates AV fistula over traversing.
- Use native blood vessels, which, when compared to synthetic grafts, are less likely to develop stenoses and fail.