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Unilateral pulmonary hypertension as a result of chronic high flow to one lung
A G Durmowicz1, J A St Cyr, D R Clarke
1Department of Pediatric Pulmonary/Critical Care University of Colorado Health Sciences Center, Denver 80262.
Insights
A migrated pulmonary artery band caused severe lung blood flow issues in a child with congenital heart disease. Surgical repair improved blood flow but led to temporary lung edema and hypoxemia.
Area of Science:
- Pediatric Cardiology
- Thoracic Surgery
- Pulmonary Hypertension
Background:
- Complex congenital heart disease (CHD) in a 27-month-old male, including left ventricular outflow tract obstruction and ventricular septal defect.
- Previous neonatal repair involving a pulmonary trunk-to-aorta graft and pulmonary artery banding.
Observation:
- A slipped pulmonary artery band migrated, obstructing the right pulmonary artery and causing severe pulmonary hypertension (94/53 mm Hg).
- Chronic high blood flow to the left lung led to its hypoperfusion due to increased vascular resistance.
- Surgical repair and band removal resulted in increased blood flow to the right lung, causing unilateral pulmonary edema and severe hypoxemia.
Findings:
- Pre-operative studies showed severe pulmonary hypertension and differential lung perfusion.
- Post-operative perfusion studies revealed a shift of >90% blood flow to the right lung.
- Persistent minimal blood flow to the left lung was noted 9 months post-surgery.
Implications:
- Highlights the impact of mechanical forces and hypoxia on pulmonary vascular remodeling in CHD.
- Underscores the complex interplay between surgical interventions and pulmonary hemodynamics.
- Informs management strategies for pulmonary complications following CHD repairs.
Abstract:
The patient presented is a 27-month-old male with complex congenital heart disease consisting of severe left ventricular outflow tract obstruction and ventricular septal defect who had undergone a pulmonary trunk-to-aorta graft and a pulmonary artery banding procedure as a neonate. Sometime after this repair, but at least 15 months prior to presentation to this institution for placement of an aortic homograft, the pulmonary trunk band apparently slipped and migrated over the right pulmonary artery, severely limiting blood flow to the right lung and increasing flow to the left. Severe pulmonary hypertension developed, with a main pulmonary artery pressure of 94/53 mm Hg. We present clinical and radiographic evidence that the resulting chronic high blood flow and pressure in the left lung ultimately resulted in hypoperfusion of that lung, presumably secondary to chronic vascular changes with greatly increased vascular resistance. Upon surgical repair and removal of the constrictive band from the previously banded right PA, blood flow was increased to the low resistance right lung causing right-sided unilateral pulmonary edema, ventilation/perfusion mismatching, and severe hypoxemia. Perfusion studies documented that less than 10% of blood was directed to the left lung, with greater than 90% to the right. Perfusion studies 9 months postoperatively continued to demonstrate minimal blood flow to the left lung. Discussion focuses on the effects of mechanical forces and the interaction with hypoxia in causing pulmonary vascular remodeling.