What Are Arteriovenous Malformations?

Arteriovenous malformation

Arteriovenous malformations, cardiovascular diseases, mainly manifested as abnormal mucosa or submucosal small blood vessels, severe valvular heart disease, chronic renal failure, gastrointestinal radiotherapy, chronic liver disease, collagen vascular disease. After the diagnosis is clear, it can be treated by surgery.

Arteriovenous malformation basic information

Although there are several different syndromes of arteriovenous malformations, they all have mucosal or submucosal small blood vessel abnormalities, ranging from 1mm to> 30mm in diameter.

Gastrointestinal arteriovenous malformations are unknown. In many patients, the following conditions are common, including severe valvular heart disease, chronic renal failure, gastrointestinal radiotherapy, chronic liver disease, collagen vascular disease, and hereditary bleeding capillaries Dilatation [Rendu-Osler-Weber (ROW) syndrome.

Arteriovenous malformations symptoms, signs and diagnosis

Once arteriovenous malformations occur gastrointestinal bleeding, repeated gastrointestinal bleeding, chronic anemia or severe acute gastrointestinal bleeding will often occur during the patient's disease course. Common sites of arteriovenous malformations are stomach, duodenum, proximal Small intestine or right half colon. The bleeding site of radiation telangiectasia depends on the location of the previously irradiated area.

Arteriovenous malformations of the upper digestive tract

ROW ROW syndrome with telangiectasia of the stomach, duodenum or proximal small intestine;

Upper gastrointestinal hemangioma without other ROW syndrome;

Watermelon stomach is a vascular lesion of the gastric antrum. These upper gastrointestinal lesions are often manifested as vomiting or melena.

Arteriovenous malformation

abnormal blood vessel development, often affecting the right hemicolon;

Radiation capillary telangiectasia, often located in the rectal sigmoid region, because radiotherapy is often used for the treatment of pelvic malignancies

(3) Colonic ROW telangiectasia is a rare cause of bleeding.

The most common diagnosis of arteriovenous malformation bleeding is upper gastrointestinal endoscopy, colonoscopy, enteroscopy, intraoperative endoscopy or visceral imaging (depending on the site of bleeding). Usually selective angiography or simple laparotomy can not find Arteriovenous malformations, whether obvious under endoscopy often depends on the microcirculation of the digestive tract mucosa, which is often affected by factors such as hypovolemia, anesthesia, and decreased cardiac output. Marked red blood cell scans are less sensitive, diagnostic value Lower.

Vascular dysplasia is an acquired submucosal arteriovenous malformation seen in elderly patients, which can cause lower gastrointestinal bleeding. Typical vascular dysplasia is usually 0.5 to 1.0 cm, bright red, flat or slightly convex, and covered with surface There is a thin layer of epithelium. Most patients have 2 to 3 lesions, and 70% to 90% of the lesions are located in the right hemicolon.

Patients are often older than 60 years of age and present with bloody stools or purplish stools, often with long-term repeated painless gastrointestinal bleeding, and no special abnormalities are seen by various tests (including laparotomy). Bleeding can be acute or massive Bleeding without hypotension. Although endoscopic or mesenteric imaging may have false positives, it is the best diagnostic method.

Arteriovenous malformation treatment

Exact treatment of the primary disease or precipitating factors (such as heart valvuloplasty, kidney transplantation) can cure upper gastrointestinal hemangioma or bleeding from colonic dysplasia. Pylorectomy can treat watermelon stomach, and endoscopic coagulation therapy (using Thermal probe, laser or bipolar coagulation) is only for palliative treatment, because high-risk patients can produce new arteriovenous malformations within 2 months. Combination therapy of estrogen and progesterone may be effective for some patients. Iron deficiency Anemia patients often need iron supplementation. Fecal occult blood tests, hematocrit, and determination of serum iron can monitor the recurrence and early rebleeding of gastrointestinal arteriovenous malformations. In most patients, long-term iron supplementation and regular endoscopic coagulation are used. Treatment of new arteriovenous malformations often controls gastrointestinal bleeding and anemia.

Treatment of bleeding abnormalities that have already occurred requires treatment because it can cause chronic recurrent bleeding. For severe active bleeding, after the patient is stable, vasopressin via arterial or intravenous injection may achieve rapid control, but the effect is uncertain, and then Endoscopic coagulation therapy or surgery can be used for exact treatment. The difficulty of treatment is to eliminate other potential causes of gastrointestinal bleeding and find all arteriovenous malformations. If the lesions are small or small, endoscopic thermal biopsy forceps are preferred Or laser coagulation therapy. The commonly used surgical treatment is right colectomy, because abnormal blood vessel development affects the right colon. In surgical treatment, about 15% to 25% of rebleeding can occur.