Humpath.com - Human pathology

Home > E. Pathology by systems > Respiratory system > Lungs > pulmonary venous hypertension

pulmonary venous hypertension

Friday 12 March 2010

Patients with pulmonary venous hypertension have elevated pulmonary venous pressure (as reflected in the pulmonary capillary wedge pressure), most frequently as a consequence of either mitral valve disease or left ventricular diastolic dysfunction.

Although mitral stenosis was the most common cause of this entity decades ago, left ventricular diastolic dysfunction is the most common cause of pulmonary venous hypertension seen in our referral practice.

It is presumed that the mechanism of both is similar. Specifically, a chronic elevation in the diastolic filling pressure of the left heart causes a backward transmission of the pressure to the pulmonary venous system, which triggers vasoconstriction in the pulmonary arterial bed.

Microscopy

Histologically, abnormal thickening of the veins and formation of a neointima are seen. The latter can be quite extensive.

As secondary features, medial hypertrophy and, with time, thickening of the neointima on the arterial side of the pulmonary circulation occur as well.

There is great potential for reversibility of these changes with improvement in the cause of the venous hypertension.

The variability in the response of the pulmonary arterial circulation to the elevated venous pressure indicates that genetic factors also dictate the potential reversibility of the disease.

Insulin resistance, frequently observed in association with impaired left ventricular diastolic function, is independently linked to the development of pulmonary arterial hypertension (PAH).

When pulmonary venous hypertension is not the result of left ventricular diastolic dysfunction or obstruction at the level of the mitral valve, (ie, pulmonary veno-occlusive disease), the genetic etiology may be similar to that of idiopathic pulmonary hypertension.

Pulmonary occlusive venopathy

- septal veins with nearly occluded lumens by fibrous intimal thickening, marked lymphatic dilation, and congested alveolar capillaries
- obstructive fibrous intimal thickening
- recanalization channels in septal veins
- pulmonary microvasculopathy
- focal thickening of alveolar septa by proliferated capillaries
- nodular capillary proliferation
- pulmonary venous disease

See also

- pulmonary hypertension

References

- Diagnosis and Treatment of Secondary (Non–Category 1) Pulmonary Hypertension. Stuart Rich; Marlene Rabinovitch. Circulation. 2008;118:2190-2199 Pubmed