Saturday, October 16, 2010

Anomalous systemic arterial supply to the lungs



Pathology:


The bronchial arteries normally arise from the descending thoracic aorta: Usually two left & one right bronchial artery.
They supply the tracheo-bronchial lymph nodes before entering the hilum of the lung on each side.


Apart from the normal bronchial arteries, anomalous arteries may arise from the descending thoracic aorta, or the abdominal aorta: single or multiple, unilateral or bilateral. These arteries shunt blood from the systemic circulation to the pulmonary circulation (left-to-right shunt).


Sequestration:


The portion of the lung supplied by the anomalous artery may be in communication with the tracheo-bronchial tree, or sequestrated (non-communicating).
The sequestrated part does not have blood supply from the pulmonary arteries.
Sequestration usually occurs in the lower lung lobes.


Clinical picture:

  • Small shunts: asymptomatic.
  • Large shunts: CHF.
  • With sequestration: recurrent infection of the sequestrated portion of the lung.

Thus; CHF, cardiomegaly, and recurrent chest infection, with no apparent cause should raise the possibility of anomalous lung arteries with sequestration.


Chesty x-ray:

  • Cardiomegaly.
  • Pulmonary congestion.
  • Lower lobe opacity of a sequestrated part.


Electrocardiography:


LVH occurs in presence of significant shunt.


Cardiac catheterization:

  • The presence of manifestations of left-to-right shunt with normal oxygen saturation in the right side of the heart indicates an extra cardiac shunt.
  • Aortography is diagnostic.
  • In cases of sequestration: pulmonary angiography shows no branches to the sequestrated part.
  • Pulmonary vascular obstructive (PVOD) and pulmonary hypertension (PHT) may develop in patients with large left-to-right shunts.


Medical management:


Treatment of CHF & chest infections.


Surgical management:


Indications:
  • Symptomatic cases.
  • Complicated cases.


Procedures:
  • The anomalous artery is occluded by:
    • catheter embolization.
    • or surgical ligation.
  • The sequestrated part of the lung is excised.
Surgery usually results in dramatic improvement.

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