2023 Mar 18. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–.
Pulmonary hypertension (PH) is defined as a resting mean pulmonary arterial pressure (mPAP) of more than 20 mmHg. Pulmonary hypertension is a complex, heterogeneous disease with multiple etiologies, subtypes, and various methods were used to classify the disease. WHO has categorized pulmonary hypertension into five broad clinical groups based on the underlying etiologies, similarities in pathophysiology, and treatment approach.
WHO group 1 is generally referred to as pulmonary arterial hypertension (PAH). WHO group 2 PH is caused by left heart disease. WHO group 3 is PH related to lung disease and/or hypoxia. WHO group 4 is PH due to pulmonary artery obstructions such as chronic thromboembolic pulmonary hypertension (CTEPH). WHO group 5 PH has unclear and/or multifactorial mechanisms.
Pulmonary veno-occlusive disease (PVOD) is a rare subtype of PAH characterized by progressive obstruction of small pulmonary veins leading to elevated pulmonary arterial pressure and right-sided heart failure. Although PVOD was first described in 1934, the understanding of the disease remains poor.
The clinical features are very non-specific and can resemble congestive heart failure, idiopathic pulmonary arterial hypertension (IPAH), and restrictive lung diseases such as pulmonary fibrosis. The gold standard for diagnosis is a biopsy, which is risky and not advisable in pulmonary hypertension due to a high risk of procedure-related complications such as life-threatening bleeding.
No medical therapy is supported by evidence, and the only curative option is lung transplantation. The prognosis is poor, and life expectancy is two years after symptom onset. This review aims to educate clinicians on this rare, less emphasized, and poorly understood disease.