Pulmonary veno-occlusive disease: an 80-year-old mystery.

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension which occurs in 0.1-0.2 people per million. Its etiology is still poorly understood but is related to several risk factors. The histopathology of PVOD is characterized by intimal fibrosis narrowing or the occlusion of small pulmonary veins or venules. A definitive diagnosis requires a surgical biopsy, which is a risky procedure. Thus, the diagnosis must be based on high clinical suspicion and the results of various diagnostic tests, mainly high-resolution computed tomography, pulmonary function tests, bronchoalveolar lavage, and right heart catheterization. The definitive treatment is limited to lung transplantation. Several pulmonary arterial hypertension-specific agents may cause pulmonary edema in PVOD. However, the cautious use of such medications in selected patients, and surgical or mechanical supports, may successfully bridge patients to transplantation. Given the scant knowledge regarding this entity, future studies with a focus on elucidating the etiology and establishing the optimal treatment are required, as is further development in diagnosis.