Arteriovenous malformations overview
| https://https://www.youtube.com/watch?v=IcJo9HHbhBs%7C350}} |
|
Arteriovenous malformations Microchapters |
|
Differentiating Arteriovenous malformations from other Diseases |
|---|
|
Diagnosis |
|
Treatment |
|
Case Studies |
|
Arteriovenous malformations overview On the Web |
|
American Roentgen Ray Society Images of Arteriovenous malformations overview |
|
Directions to Hospitals Treating Arteriovenous malformations |
|
Risk calculators and risk factors for Arteriovenous malformations overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kalsang Dolma, M.B.B.S.[2]
Overview
Arteriovenous malformation is a congenital disorder of the connections between veins and arteries in the vascular system. The genetic transmission patterns of AVM (if any) are unknown, and AVM is not generally thought to be an inherited disorder--unless in the context of a specific hereditary syndrome.
Historical Perspective
Emmanuel, Luschka and Virchow first described arteriovenous malformations in the mid-1800s. Olivecrona performed the first surgical excision of an intracranial AVM in 1932.
Pathophysiology
Arteries and veins are part of the human cardiovascular system. Normally, the arteries in the vascular system carry oxygen-rich blood at a relatively high pressure. Structurally, arteries divide and sub-divide repeatedly, eventually forming a sponge-like capillary bed. Blood moves through the capillaries, giving up oxygen and taking up waste products from the surrounding cells. Capillaries successively join together, one upon the other, to form the veins that carry blood away at a relatively low pressure. The heart acts to pump blood from the low pressure veins to the high pressure arteries.
Epidemiology and Demographics
An estimated 300,000 people in the US have AVMs, of which 12% (approximately 36,000) will exhibit symptoms that differ greatly in severity.
Diagnosis
Symptoms
Symptoms of AVM vary according to the location of the malformation. Roughly (88% -needs citation) AVM are asymptomatic; often the malformation is discovered as part of an autopsy or during treatment of an unrelated disorder (called in medicine an incidental finding), rarely its expansion or a micro-bleed from it, could cause epilepsy, deficit or elicit pain.
Treatment
Medical Therapy
Treatment for brain AVMs can be symptomatic, and patients should be followed by a neurologist for any seizures, headaches or focal deficits. AVM-specific treatment may also involve endovascular embolization, neurosurgery or radiation therapy. Embolization, that is, cutting off the blood supply to the AVM with coils or particles or glue introduced by a radiographically guided catheter, can be used in addition to either, but is rarely successful in isolation except for in smaller AVMs. The neurological risk of any such intervention is roughly 10%.
Surgery
The Spetzler-Martin grading system developed at the Barrow Neurological Institute is utilized by neurosurgeons to determine operative versus nonoperative management of AVMs.
Future or Investigational Therapies
Despite many years of research, the central question of whether to treat AVMs has not been answered. All treatments, whether involving surgery, radiation, or drugs, have risks and side-effects. Therefore, it might be better in some cases to avoid treatment altogether and simply accept a small risk of coming to harm from the AVM itself. This question is currently being addressed in clinical trials.[1].