The Journal of Thoracic and Cardiovascular Surgery, Vol 97, 587-592, Copyright © 1989 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Airway obstruction after autologous reimplantation of the porcine lobe
ED McGahren, WG Teague, TL Flanagan, BJ White, GW Barone, AM Johnson and IL Kron
Department of Surgery, University of Virginia School of Medicine, Charlottesville 22908.
Bronchiolitis obliterans (irreversible small airway obstruction) is a late
complication of heart-lung transplantation. Chronic immune rejection is
believed to be the major cause of this complication. Our hypothesis was
that denervation might contribute to airway obstruction. To test this
hypothesis in the absence of immune rejection, we performed a lobectomy of
the upper lobe of the left lung and autologous reimplantation of the lower
lobe of the left lung in 13 growing pigs. To serve as age-matched controls,
six other pigs had sham left thoracotomy and nine others had a lobectomy of
the upper lobe of the left lung alone. Nine to 10 weeks after operation,
the animals were anesthetized and the lungs mechanically ventilated. The
lobes were then isolated in vivo to measure differential transrespiratory
mechanics and volumes. Dynamic compliance was significantly lower in the
reimplanted lobe than it was in the contralateral right lung. This was the
case after lobectomy of the upper lobe of the left lung or sham
thoracotomy. Dynamic resistance was significantly higher in the reimplanted
lobe than it was in the contralateral right lung and in the left lung after
sham thoracotomy. Measurements of extravascular lung water, dry lobe
weight, alveolar cross-sectional area, and volumetric proportions of lung
parenchyma and alveolar spaces did not demonstrate abnormal structural
growth after reimplantation. We conclude that lobectomy of the upper lobe
of the left lung and autologous reimplantation of the left lower lobe leads
to adverse changes in flow-dependent measurements of airway patency.
Changes in bronchomotor regulation imposed by denervation may contribute to
airway obstruction after heart-lung transplantation.