Pulmonary arteriovenous malformations (PAVM) are abnormal communications between pulmonary veins and arteries . Alternative names include pulmonary arteriovenous fistulae, pulmonary arteriovenous aneurysms, cavernous angiomas of the lung, and pulmonary telangiectases . PAVM are uncommon, but they are an important consideration in the differential diagnosis of common pulmonary problems, including hypoxemia, pulmonary nodules, and hemoptysis.
Indications for diagnostic testing, the available diagnostic tests, and an approach to the diagnostic evaluation of suspected PAVM are reviewed here. The epidemiology, etiology, pathology, clinical features, and treatment of PAVM are discussed separately. (See "Pulmonary arteriovenous malformations: Epidemiology, etiology, pathology, and clinical features".)
PAVM should be suspected and a diagnostic evaluation initiated in individuals with one or more of the following characteristics:
- One or more pulmonary nodules on a chest x-ray are suspicious for PAVM. The features of a pulmonary nodule that make it suspicious for a PAVM are described separately. (See "Pulmonary arteriovenous malformations: Epidemiology, etiology, pathology, and clinical features", section on 'Imaging findings'.)
- Stigmata of right-to-left shunting, such as dyspnea, hypoxemia, polycythemia, clubbing, cyanosis, cerebral embolism, or a brain abscess.
- Hemoptysis or hemothorax.
- Mucocutaneous telangiectases or other features suggestive of hereditary hemorrhagic telangiectasia (HHT) (table 1).
Individuals with a personal or family history of HHT should also be screened for possible PAVM, since there is a high incidence of unsuspected PAVM in this population [3-6]. This is particularly important if at least one member of the family with HHT has already been diagnosed with PAVM, as the incidence of PAVM is approximately 35 percent among relatives [7,8]. It is also recommended that all women with HHT undergo screening before becoming pregnant, since PAVM are associated with a high incidence of hemoptysis or hemothorax during the last half of pregnancy . Issues regarding screening patients with HHT for PAVMS are discussed separately. (See "Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)".)