08-10-2010, 10:06 PM
In patients with pulmonary hypertension, single lung transplant creates a relative ventilation-perfusion imbalance between the native lung and the allograft. Because airway resistance and compliance of the native lung and the allograft are similar, ventilation is evenly divided between the two lungs. However, the preponderance of perfusion (usually greater than 80%) is directed to the allograft because of the high vascular resistance in the native lung.