Arteriovenous fistula

Arteriovenous fistula

Infobox_Disease
Name = Arteriovenous fistula


Caption =
DiseasesDB = 32435
ICD10 = ICD10|I|28|0|i|26, ICD10|I|77|0|i|70
ICD9 = ICD9|414.19, ICD9|417.0, ICD9|447.0, ICD9|747.3
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj = med
eMedicineTopic = 169
MeshID = D001164
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm.

Vascular access for hemodialysis

Patients with end stage renal failure are treated with hemodialysis. In dialysis, blood is withdrawn from an artery or vein, purified, and returned to a vein. The volume of blood is too great for veins to handle, so a vein must be enlarged. An artery and vein, usually in the arm above or below the elbow, are sewn together, to create a fistula, and arterial pressure eventually enlarges the vein. The enlarged vein can accommodate a cannula or large needle.

Pathophysiology

When an arteriovenous fistula is formed involving a major artery like the abdominal aorta, it can lead to a large decrease in peripheral resistance. This lowered peripheral resistance causes the heart to increase cardiac output in order to maintain proper blood flow to all tissues. The physical manifestations of this would be a relatively normal systolic blood pressure with a decreased diastolic blood pressure resulting in a wide (large) pulse pressure.

Normal blood flow in the brachial artery is 85 to 110 milliliters per minute (mL/min). After the creation of a fistula, the blood flow increases to 400 to 500 mL/min immediately, and 700 to 1,000 mL/min within 1 month. A bracheocephalic fistula above the elbow has a greater flow rate than a radiocephalic fistula at the wrist. Both the artery and the vein dilate and elongate in response to the greater blood flow and shear stress, but the vein dilates more and becomes "arterialized". In one study, the cephalic vein increased from 2.3 mm to 6.3 mm diameter after 2 months. When the vein is large enough to allow cannulation, the fistula is defined as "mature." [Vascular, Vol. 14, Supl. 1, Nov. 2006, p. S1 ]

Treatment

Congenital fistulas, if small, usually do not need treatment.Fact|date=February 2007 Acquired fistulas can be treated by surgery.

ee also

*Branham sign
*Fistula
*Cimino fistula
*HUVG
*Carotid-cavernous fistula

References

External links

* [http://www.merck.com/mmhe/sec03/ch036/ch036e.html Overview] at Merck Manual
* [http://www.mayoclinic.com/health/av-fistula/HQ00263 Overview] at Mayo Clinic


Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • arteriovenous fistula — ▪ pathology       abnormal direct opening between an artery and a vein; it sometimes results from accidental penetration wounds or from vascular disease, or it may be congenital in origin. As a result of the defect, the arterial blood is passed… …   Universalium

  • arteriovenous fistula — 1. a communication, sometimes congenital but often traumatic, between an artery and a nearby vein, so that blood flows directly into the vein (aneurysmal varix) or else is carried into the vein by a connecting sac (varicose aneurysm). 2. a… …   Medical dictionary

  • arteriovenous fistula — noun an abnormal connection between an artery and a vein …   Wiktionary

  • Dural arteriovenous fistula — Classification and external resources This dural arteriovenous fistula of the superior sagittal sinus drains into subarachnoid veins and is classified as Borden type IIIb. DiseasesDB …   Wikipedia

  • Fistula — Classification and external resources MeSH D005402 In medicine, a fistula (pl. fistulas or fistulae) is an abnormal[1] connection or passageway between two epithelium lined organs or vessels that …   Wikipedia

  • arteriovenous — adj. 1. connecting an artery to a vein. an arteriovenous fistula [WordNet 1.5] || …   The Collaborative International Dictionary of English

  • coronary arteriovenous fistula — coronary artery fistula a congenital fistula between a coronary artery and a cardiac chamber, pulmonary trunk or vein, coronary sinus, or vena cava, particularly between the right artery and the right heart …   Medical dictionary

  • pulmonary arteriovenous fistula — a congenital fistula between the pulmonary arterial and venous systems, allowing unoxygenated blood to enter the systemic circulation …   Medical dictionary

  • fistula — An abnormal passage from one epithelial surface to another epithelial surface. [L. a pipe, a tube] abdominal f. a fistulous passage connecting one of the abdominal viscera …   Medical dictionary

  • Arteriovenous malformation — Infobox Disease Name = Arteriovenous malformation Caption = DiseasesDB = 15235 ICD10 = ICD10|Q|27|3|q|20, ICD10|Q|28|0|q|20, ICD10|Q|28|2|q|20 ICD9 = ICD9|747.6, ICD9|747.81 ICDO = OMIM = MedlinePlus = 000779 eMedicineSubj = search eMedicineTopic …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”