Arterio-venous aneurysm Health Dictionary

  1. Health Encyclopedia
  2. Arterio-venous Aneurysm

Arterio-venous Aneurysm: From 1 Different Sources

An abnormal communication between an artery and a vein. It is usually the result of an injury, such as a stab or a gunshot wound, which involves both a neighbouring artery and vein.
Health Source: Medical Dictionary
Author: Health Dictionary

Aneurysm

A localised swelling or dilatation of an artery (see ARTERIES) due to weakening of its wall. The most common sites are the AORTA, the arteries of the legs, the carotids and the subclavian arteries. The aorta is the largest artery in the body and an aneurysm may develop anywhere in it. A dissecting aneurysm usually occurs in the ?rst part of the aorta: it is the result of degeneration in the vessel’s muscular coat leading to a tear in the lining; blood then enters the wall and tracks along (dissects) the muscular coat. The aneurysm may rupture or compress the blood vessels originating from the aorta: the outcome is an INFARCTION in the organs supplied by the affected vessel(s). Aneurysms may also form in the arteries at the base of the brain, usually due to an inherited defect of the arterial wall.

Aneurysms generally arise in the elderly, with men affected more commonly than women. The most common cause is degenerative atheromatous disease, but other rarer causes include trauma, inherited conditions such as MARFAN’S SYNDROME, or acquired conditions such as SYPHILIS or POLYARTERITIS NODOSA. Once formed, the pressure of the circulating blood within the aneurysm causes it to increase in size. At ?rst, there may be no symptoms or signs, but as the aneurysm enlarges it becomes detectable as a swelling which pulsates with each heartbeat. It may also cause pain due to pressure on local nerves or bones. Rupture of the aneurysm may occur at any time, but is much more likely when the aneurysm is large. Rupture is usually a surgical emergency, because the bleeding is arterial and therefore considerable amounts of blood may be lost very rapidly, leading to collapse, shock and even death. Rupture of an aneurysm in the circle of Willis causes subarachnoid haemorrhage, a life-threatening event. Rupture of an aneurysm in the abdominal aorta is also life-threatening.

Treatment Treatment is usually surgical. Once an aneurysm has formed, the tendency is for it to enlarge progressively regardless of any medical therapy. The surgery is often demanding and is therefore usually undertaken only when the aneurysm is large and the risk of rupture is therefore increased. The patient’s general ?tness for surgery is also an important consideration. The surgery usually involves either bypassing or replacing the affected part of the artery using a conduit made either of vein or of a man-made ?bre which has been woven or knitted into a tube. Routine X-ray scanning of the abdominal aorta is a valuable preventive procedure, enabling ‘cold’ surgery to be performed on identi?ed aneurysms.... aneurysm

Central Venous Pressure

The pressure of blood within the right atrium of the HEART as measured by a catheter and manometer.... central venous pressure

Berry Aneurysm

An abnormal swelling that occurs at the junction of arteries supplying the brain. Berry aneurysms, which are usually due to a congenital weakness, can sometimes rupture, resulting in a subarachnoid haemorrhage.

(See also aneurysm.)... berry aneurysm

Cirsoid Aneurysm

The condition in which a group of arteries become abnormally dilated and tortuous.... cirsoid aneurysm

Venous

Pertaining to the veins, or more broadly to include both venous AND lymphatic circulation.... venous

Venous Stasis

Having congested venous blood and lymph. Usually a larger condition effecting tissue or organ function, as opposed to the more vascular implications of venosities and varicosities.... venous stasis

Venous Ulcer

See under ULCER.... venous ulcer

Anomalous Pulmonary Venous Drainage

a congenital abnormality in which the pulmonary veins enter the right atrium or vena cava instead of draining into the left atrium. The clinical features are those of an *atrial septal defect.... anomalous pulmonary venous drainage

Aortic Aneurysm

see aneurysm.... aortic aneurysm

Arteriovenous Aneurysm

a direct communication between an artery and vein, without an intervening capillary bed. It can occur as a congenital abnormality or it may be acquired following injury or surgery. It may affect the limbs, lungs, or viscera and may be single or multiple. If the connection is large, the short-circuiting of blood may produce heart failure. Large isolated arteriovenous aneurysms may be closed surgically.... arteriovenous aneurysm

Central Venous Catheter

an intravenous catheter for insertion directly into a large vein, most commonly the subclavian vein, during its passage under the clavicle, or the jugular in the neck. Such catheters can also be inserted into the femoral vein at the groin. They enable intravenous drugs and fluids to be given and intravenous pressures to be measured, which is often useful during operations or in intensive care. Central venous catheters must be inserted under strictly sterile conditions using a local anaesthetic.... central venous catheter

Cerebral Venous Sinus Thrombosis

the presence of thrombosis in the dural venous sinuses, which drain blood from the brain. Symptoms may include headache, abnormal vision, any of the symptoms of stroke (such as weakness of the face and limbs on one side of the body), and seizures. Treatment is with anticoagulants.... cerebral venous sinus thrombosis

Endovascular Aneurysm Repair

(EVAR) a recently developed technique that involves the insertion of a covered metal *stent into an *aneurysm. The stent lines the aneurysm and thereby excludes it from the circulation, preventing further expansion and rupture. The delivery system containing the stents is introduced through the common femoral artery. *Fluoroscopy provides real-time imaging to guide placement of the stents and ensure they are in the correct anatomical position.... endovascular aneurysm repair

Jugular Venous Pressure

(JVP) the pressure in the internal jugular vein, which is an indirect measurement of *central venous pressure (CVP) in the right atrium. In clinical practice the JVP is estimated by visual inspection at the bedside with the patient reclining at 45 degrees.... jugular venous pressure

Venous Thromboembolism

(VTE) the formation of a blood clot in a vein, which may become detached and lodged elsewhere. It includes deep vein thrombosis (see phlebothrombosis) and *pulmonary embolism. VTE is a leading direct cause of maternal death (see maternal mortality rate). See also thromboembolism.... venous thromboembolism

Health encyclopedia icon Health Encyclopedia

Recent Searches