This article is about AV fistulas in general. For the surgical procedure, see Cimino fistula.
"Arteriovenous shunt" redirects here. For nonpathologic AV shunts, see metarteriole and glomus body.
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein.[1] It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm.[citation needed]
Contents
1Presentation
1.1Associated conditions
1.2Complications
2Causes
3Mechanism
4See also
5References
6External links
Presentation
Associated conditions
Hereditary hemorrhagic telangiectasia
Complications
Just like berry aneurysm, an intracerebral arteriovenous fistula can rupture causing subarachnoid hemorrhage.[2]
Causes
Congenital (developmental defect)
Rupture of arterial aneurysm into an adjacent vein
Penetrating injuries
Inflammatory necrosis of adjacent vessels
Intentionally created (for example, Cimino fistula as vascular access for hemodialysis). Blood must be aspirated from the body of the patient, and since arteries are not easy to reach compared to the veins, blood may be aspirated from veins. The problem is that the walls of the veins are thin compared to those of the arteries. The AV fistula is the solution for this problem because, after 4-6 weeks, the walls of the veins become thicker due to the high arterial pressure. Thus, this vein can now tolerate needles during hemodialysis sessions.
Mechanism
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 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 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 400–500 mL/min immediately, and 700–1,000 mL/min within 1 month. A brachiocephalic 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".[3]
An arteriovenous fistula can increase preload.[4] AV shunts also decrease the afterload of the heart. This is because the blood bypasses the arterioles which results in a decrease in the total peripheral resistance (TPR). AV shunts increase both the rate and volume of blood returning to the heart.
^Park, Myung K. (2002). Pediatric cardiology for practitioners. With a contribution by R. George Troxler (4th ed.). St. Louis: Mosby. ISBN 978-0-323-01444-1.
^Vascular, Vol. 14, Supl. 1, Nov. 2006, p. S1
^"Pulmonary: Heart Failure". Archived from the original on 1 February 2009. Retrieved 2008-12-21.
… pulmonary arteriovenous malformations (PAVMs), we and others agree that transthoracic contrast echocardiography (TTCE) is the initial test of choice to evaluate for the presence of a right-to-left shunt . Subsequent …
…individuals, arteriovenous malformations occur in the lung and may be associated with massive hemoptysis . Some patients with hepatic involvement develop clinically significant arteriovenous shunts and high-output …
…the lesions can include arteriovenous shunts (eg, arteriovenous malformations [AVMs]/arteriovenous fistulae [AVFs]) and telangiectasia. Arteriovenous shunts – An arteriovenous shunt is a direct communication …
… This topic provides an overview of general issues regarding arteriovenous (AV) fistula maintenance, including measures to prevent AV fistula thrombosis and management of the high-risk fistula. These same …
…complications in IE. Assessment of need for removal of any infected implanted devices or atrioventricular shunts. Identification of patients with an indication for early valve surgery. Follow-up and prevention …
English Journal
Thrombolysis in Ischemic Stroke Patients with Isolate Pulmonary Arteriovenous Malformations.
Lin G, Jiang P, Lou M.
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association. 2019 Jun;28(6)e68-e70.
Pulmonary arteriovenous malformations are rare cause for ischemic stroke. British Thoracic Society Clinical Statement considered insufficient evidence of safety or clinical benefit to recommend thrombolysis for stroke with pulmonary arteriovenous malformations. For pulmonary arteriovenous malformati
Efficacy and Safety of Transvenous Embolization of Type II Renal Arteriovenous Malformations with Coils.
Lee SY, Do YS, Kim CW, Park KB, Kim YH, Cho YJ.
Journal of vascular and interventional radiology : JVIR. 2019 Jun;30(6)807-812.
To evaluate the efficacy and safety of transvenous coil embolization of the venous sac for type II renal arteriovenous malformation (AVM). A retrospective review was conducted of 8 patients (5 women and 3 men; mean age, 57 years; age range, 41-69 years) who underwent transvenous coil embolization fo
Arteriovenous access practices in Australian and New Zealand dialysis units.
Smyth B, Kotwal S, Gallagher M, Gray NA, Polkinghorne KR.
The journal of vascular access. 2019 May;()1129729819851061.
The creation and maintenance of dialysis vascular access is associated with significant morbidity. Structured management pathways can reduce this morbidity, yet practice patterns in Australia and New Zealand are not known. We aimed to describe the arteriovenous access practices in dialysis units in
… In transarterial embolization (TAE) of spinal epidural arteriovenous fistula (SEDAVF), it is essential to control the blood flow at the shunt point. … We report a case of SEDAVF treated with TAE with occluding one of several segmental arteries (SAs) involved in the shunt using a balloon.</p><p><b>Case Presentation:</b> …
… We report a case of cavernous sinus dural arteriovenous fistula (CSdAVF) presenting with medulla oblongata dysfunction in parallel to thrombosis of a varix on a drainage route after transvenous embolization (TVE).</p><p><b>Case Presentation:</b> … TVE was successfully performed and the shunt flow completely disappeared. …
2. a passage or anastomosis between two natural channels, especially between blood vessels. Such structures may be formed physiologically (e.g., to bypass a ... arteriovenous shunt a U-shaped plastic tube inserted between an ...
Arteriovenous shunts are abnormal connections between coronary arteries and a compartment of the venous side of the heart. The abnormal connection may originate in the right or left coronary artery, or, more rarely, multiple shunts ...
An arteriovenous (AV) fistula is an abnormal connection between an artery and a vein. Normally, blood flows from your arteries to your capillaries to your veins. Nutrients and oxygen in your blood travel from your capillaries to tissues ...