Hypoxic pulmonary vasoconstriction persists in the human transplanted lung.

1. The preservation of hypoxic pulmonary vasoconstriction (HPV) in the denervated lung was studied in five human heart–lung transplant recipients. 2. AH five patients showed significant increases in mean pulmonary artery pressure and pulmonary vascular resistance during hypoxic exposure, returning toward normoxic values during recovery. Aside from P ao 2 and P ao 2 , other factors known to influence pulmonary vascular resistance did not change significantly during the hypoxic period. 3. There was no relation between the length of the post-transplantation period and the intensity of HPV, suggesting that reinnervation of the pulmonary vascular bed did not account for persistent HPV and that HPV persists in the human transplanted lung despite the loss of autonomic neural innervation.