pulmonary veno-occlusive disease

Pulmonary veno-occlusive disease (PVOD) is considered an uncommon variant of primary pulmonary hypertension (PPH) that preferentially affects the postcapillary pulmonary vasculature. It is still controversial if this condition and pulmonary capillary haemangiomatosis (PCH) are varied expressions of the same condition or different entities.

Epidemiology

It is thought to account for ~5-10% of cases initially considered to be idiopathic PAH .

It is rare but can potentially affect all age groups with no geographic predilection. The majority of affected patients are under 50 years of age .

  • in the pediatric population, both sexes are equally affected
  • in the adult population, the ratio of male to female patients is approximately 2:1

Clinical presentation

Its presentation can be similar to other forms of pulmonary arterial hypertension such as progressive dyspnea, cough, fatigue and also hemoptysis.

Pulmonary capillary wedge pressure (PCWP) is usually normal due to patchy involvement. This is in contrast to the elevated pressures commonly obtained in patients with obstructed or stenotic larger pulmonary veins, mitral stenosis or left ventricular failure .

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Pathology

It is characterized by extensive occlusion of pulmonary veins by fibrous tissue in a patchy distribution. This may be loose and edematous or dense and sclerotic .

Associations

PVOD is still considered an idiopathic disease but innumerable associated conditions have been reported in the medical literature, which include :

A recent discovery has suggested a biallelic mutation in the EIF2AK4 gene as a cause of heritable form .

Radiographic features

In general, imaging features can be non-specific and a definitive diagnosis often requires a lung biopsy .

Plain radiograph

Usually demonstrates nonspecific features of pulmonary hypertension, such as an enlarged pulmonary trunk and main pulmonary arteries and prominent heart right chambers.

CT

Reported HRCT chest findings include :

The normal appearances of the heart left chambers in the setting of these pulmonary findings favors that the transudation of fluid into the lung interstitium is possibly PVOD related.

Angiography (DSA)

PVOD pulmonary arteriographic findings include :

  • enlarged central pulmonary arteries
  • subtle narrowing of the distal arterial branches
  • no arterial filling defects
  • heterogeneous contrast blush in the parenchymal phase
  • prolonged lung circulation time
  • normal or small left atrium

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Treatment and prognosis

Pulmonary veno-occlusive disease generally carries a poor prognosis (some report a 72% mortality at one year from diagnosis ). Lung transplantation is the treatment of choice .

It is important to note that vasodilators commonly used to treat patients with primary pulmonary hypertension, such as calcium-channel blockers , epoprostenol (PGI2) or prostacyclin  can lead to disastrous outcomes (severe pulmonary edema) in patients with pulmonary veno-occlusive disease.

History and etymology

The first description of the condition is thought to have been first dreported by J Hora (German physician)  et al. in 1934 . The term "pulmonary veno-occlusive disease" was thought to have been coined by Heath et.al in 1966 .

Differential diagnosis

Possible differential considerations include

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See also

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