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Definition
 
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Arteriovenous Fistula Definition: An abnormal direct communication between an artery and a vein without passing through the CAPILLARIES. An A-V fistula usually leads to the formation of a dilated sac-like connection, arteriovenous aneurysm. The locations and size of the shunts determine the degree of effects on the cardiovascular functions such as BLOOD PRESSURE and HEART RATE.
Arteriovenous Malformations Definition: Abnormal formation of blood vessels that shunt arterial blood directly into veins without passing through the CAPILLARIES. They usually are crooked, dilated, and with thick vessel walls. A common type is the congenital arteriovenous fistula. The lack of blood flow and oxygen in the capillaries can lead to tissue damage in the affected areas.
Intracranial Arteriovenous Malformations Definition: Congenital vascular anomalies in the brain characterized by direct communication between an artery and a vein without passing through the CAPILLARIES. The locations and size of the shunts determine the symptoms including HEADACHES; SEIZURES; STROKE; INTRACRANIAL HEMORRHAGES; mass effect; and vascular steal effect.
Coronary Aneurysm Definition: Abnormal balloon- or sac-like dilatation in the wall of CORONARY VESSELS. Most coronary aneurysms are due to CORONARY ATHEROSCLEROSIS, and the rest are due to inflammatory diseases, such as KAWASAKI DISEASE.
Arteriovenous Anastomosis Definition: A vessel that directly interconnects an artery and a vein, and that acts as a shunt to bypass the capillary bed. Not to be confused with surgical anastomosis, nor with arteriovenous fistula.
physiologic anastomosis Definition: vessel that directly interconnects an artery and a vein, and that acts as a shunt to bypass the capillary bed; do not confuse with PATHOLOGIC ARTERIOVENOUS SHUNT; for surgical anastomosis, see CARDIOVASCULAR SHUNT SURGERY.
congenital arteriovenous shunt Definition: structural anomaly present at birth which allows direct passage of blood from an artery to a vein.
Arteriovenous Hemangioma Definition: A benign vascular lesion characterized by the presence of a complex network of communicating arterial and venous vascular structures.
Shunts, Arteriovenous Definition: Shunts designed to create a graft fistula, a passage between an artery and a vein (typically in an arm), that provides access for hemodialysis procedures. These shunts typically consist of a synthetic (e.g., polytetrafluoroethylene, Dacron) tube with a thin wall and appropriate size (6 mm [0.25 inch] in diameter is the most common) and configuration to facilitate puncturing. A hollow tunneler is used to implant the shunt under the skin; a straight shunt is placed between the radial artery and the antecubital vein, and a loop shunt is placed between the brachial artery and the antecubital vein. Arteriovenous shunts are used for hemodialysis procedures when it is not possible or convenient to create a direct fistula between an artery and a vein. Percutaneous shunts (e.g., Quinton-Scribner, Thomas) intended for arm and/or leg use are no longer frequently used for hemodialysis.
Arteriovenous Shunt, Surgical Definition: Surgical shunt allowing direct passage of blood from an artery to a vein. (From Dorland, 28th ed)
arteriovenous shunt surgery Definition: surgical implantation of a shunt, allowing direct passage of blood from an artery to a vein.
Arteriovenous Shunt Procedure Definition: Surgical creation of a connection between an artery and a vein, often done for the purpose of hemodialysis.
Needles, Hemodialysis, Arteriovenous Fistula Definition: Hemodialysis needles designed for withdrawal and reinfusion of blood from an arteriovenous (AV) fistula during dialysis procedures. These needles typically consist of a thin-walled, small-length (e.g., 25 to 32 mm [1 to 1.25 inch]) stainless steel cannula (typically 14 to 17 gauge) for introduction into the AV fistula and fixed or rotational wings that help with the insertion and add protection to inadvertent pull-out; they usually also include a tube (e.g., 15 to 30 cm length) to be connected to the blood line of a dialysis machine.