Pulmonary Arteriovenous Malformations

Having suffered progressive shortness of breath for 2 years, a 35-year-old man was eventually hospitalized. The patient's dyspnea had worsened over the past year, but he had neither chest pain nor palpitations. His primary care physician first noticed finger clubbing 8 months ago.

On admission, the patient was weak, cachectic, and in moderate respiratory distress. His vital signs were within normal limits. Notable findings on physical examination were significant bilateral clubbing of the fingers and bilateral crackles on lung auscultation; laboratory studies indicated polycythemia: hemoglobin, 17.8 g/dL and hematocrit, 65%.

An ECG showed regular sinus rhythm with no indication of infarct or ventricular hypertrophy. The patient's oxygen tension was 43.9 mm Hg while he breathed room air; oxygen saturation was 82.5%. A chest film revealed increased pulmonary interstitial markings bilaterally. Arteriovenous malformations (AVMs) were suggested by a chest CT scan and confirmed by a pulmonary angiogram, both seen here. The patient underwent transcatheter embolization therapy, and his dyspnea diminished significantly.

Pulmonary AVMs, which are often multiple and appear in the lower lobes of both lungs, consist of direct connections between a pulmonary artery branch and a vein via a thin-walled aneurysm. It is estimated that 60% of persons with pulmonary AVMs have hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome. These patients manifest AVMs in the skin, nasopharynx, gastrointestinal tract, lungs, and brain.

Pulmonary AVMs result in direct right-to-left shunts and (particularly when they are multiple) may produce dyspnea, fatigue, cyanosis, or polycythemia. Because of the shunting, affected persons are prone to brain abscess and stroke. A high-resolution CT chest scan or pulmonary angiography can help establish the diagnosis.

Management is either surgical (lobectomy or wedge resection) or by embolization therapy. In recent years, transcatheter embolization with detachable balloons or stainless steel coils has been used more frequently to close malformations such as the ones described here. Drs Arunabh and John C. Rodrigues of Mineola, NY, caution physicians to remember that pulmonary AVMs may occur in clusters within families (as part of HHT) and that the frequency increases with age and during pregnancy.