Pulmonary Veno-occlusive Disease

Pulmonary veno-occlusive disease (PVOD) is a rare and highly lethal disorder of the pulmonary vasculature. In contrast to the insights into pathophysiology and management that have characterized the diagnosis and treatment of idiopathic pulmonary arterial hypertension (IPAH; formerly known as primary pulmonary hypertension) over the past decade, the pathophysiologic mechanisms underlying PVOD are incompletely understood, the clinical diagnosis is notoriously difficult, and therapy is largely unsatisfactory. Historically, what is now called PVOD has been variably termed “isolated pulmonary venous sclerosis,” “obstructive disease of the pulmonary veins,” or “the venous form of primary pulmonary hypertension.” Over the past decade, “pulmonary obstructive venopathy” has been proposed as a more accurate alternative description, but this phrase has not been adopted into wide clinical use. It is important to note that PVOD is completely distinct from stenosis of one or more of the four main pulmonary veins. Stenosis of these large pulmonary veins is primarily a result of congenital malformation, but may also develop as a complication following cardiothoracic surgery. In addition, large-vessel pulmonary venous stenosis has been increasingly reported as a complication following radio-frequency ablation for atrial fibrillation or other dysrhythmias.