Quantitative lung perfusion following single lung transplantation.

Background: Following successful lung transplantation, most of the lung perfusion, as well as ventilation, is shifted towards the transplanted lung. We investigated the changes in perfusion during exercise in lung transplant recipients.

Patients And Methods: Twelve patients were included in the study. Six patients had emphysema and 6 patients had idiopathic pulmonary fibrosis (IPF). Patients underwent two upright lung perfusion scans: the first at rest and the second during a maximal cardiopulmonary exercise test. Lung perfusion was assessed in each lung and regionally.

Results: At rest, patients with emphysema had 83.3 +/- 8 % of total perfusion to the transplanted side and 16.7 +/- 8 % to the native lung, while in the IPF patients, it was 68.7 +/- 12 and 32.7 +/- 10 %, respectively ( P = 0.028). At peak exercise, perfusion shifted from the transplanted lung to the native lung ( P = 0.0095) both in emphysema and IPF patients.

Conclusions: Following successful lung transplantation, most of the perfusion is directed towards the transplanted lung. During exercise, there was a small but significant shift towards the native lung. These findings highlighted the important role of the native lung during maximal exercise.