Pulmonary arterio-veinous fistula

Other Names: Pulmonary arteriovenous fistula; Pulmonar arteriovenous aneurysm

Pulmonary arteriovenous malformation (PAVM) describes an anatomic communication between a pulmonary artery and a pulmonary vein leading to a right to left extracardiac shunt that can be asymptomatic or can lead to varying manifestations such as dyspnea, hemoptysis, and neurological symptoms.

Epidemiology

Prevalence is estimated at around 1/ 2,600. There is a minor female predominance.

Cause

The exact pathogenesis is still unknown. Although generally observed in the context of HHT, PAVMs may also be idiopathic. Much rarer etiological causes include cavopulmonary surgical corrections of cyanotic congenital heart disease; gestational trophoblastic disease; and arteriovenous fistulae induced by trauma.

Symptoms

Many people have no symptoms. When symptoms occur, they can include:

• Bloody sputum
• Difficulty breathing
• Difficulty exercising
• Nosebleeds
• Shortness of breath with exertion
• Chest pain
• Blue skin (cyanosis)
• Clubbing of the fingers

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Pulmonary arteriovenous fistulas
• Telangiectasia

30%-79% of people have these symptoms

• Dyspnea(Trouble breathing)
• Hemothorax
• Hypoxemia(Low blood oxygen level)
• Ischemic stroke
• Transient ischemic attack(Mini stroke)

5%-29% of people have these symptoms

• Abnormal thrombosis(Abnormal blood clot)
• Bacterial endocarditis
• Brain abscess
• Clubbing(Clubbing of fingers and toes)
• Cough(Coughing)
• Cyanosis(Blue discoloration of the skin)
• Epistaxis(Bloody nose)
• Heart murmur(Heart murmurs)
• Hemoptysis(Coughing up blood)
• Iron deficiency anemia
• Migraine(Intermittent migraine headaches)
• Myocardial infarction(Heart attack)
• Palpitations(Missed heart beat)
• Pleural empyema
• Pulmonary arterial hypertension(Increased blood pressure in blood vessels of lungs)
• Pulmonary hemorrhage

1%-4% of people have these symptoms

• Gastrointestinal infarctions(Death of digestive organ tissue due to poor blood supply)
• Liver abscess
• Recurrent abscess formation
• Seizure

Diagnosis

The health care provider will examine you. The exam may show:

• Abnormal blood vessels (telangiectasias) on the skin or mucus membranes
• Abnormal sound, called a murmur when a stethoscope is placed over the abnormal blood vessel
• Low oxygen when measure with a pulse oximeter

Tests that may be done include:

• Arterial blood gas, with and without oxygen
• Complete blood count (CBC)
• Chest x-ray
• Chest CT scan
• Echocardiogram to check the function of the heart
• Lung function tests
• Perfusion radionuclide lung scan to measure breathing and circulation (perfusion) in all areas of the lungs
• Pulmonary arteriogram to view the lung arteries

Treatment

A small number of people who have no symptoms may not need treatment. For most people with fistulas, the treatment of choice is to block the fistula during an arteriogram (embolization). Some people may need surgery to remove the abnormal vessels and nearby lung tissue. When arteriovenous fistulas are caused by liver disease, the treatment is a liver transplant.

Prognosis

The outlook for people with HHT is not as good as for those without HHT. For people without HHT, surgery to remove the abnormal vessels usually has a good outcome, and the condition is not likely to return.

Possible Complications Complications may include:

• Bleeding in the lung
• Stroke due to blood clot that travels from the lungs to the arms, legs, or brain (paradoxical venous embolism)
• Infection in the brain or heart valve, especially in patients with HHT

Prevention

Because HHT is often genetic, prevention is not usually possible. Genetic counseling may help in some cases.

NIH genetic and rare disease info

• NIH info on Pulmonary arterio-veinous fistula

Pulmonary arterio-veinous fistula is a rare disease.

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