Radiologic evaluation for volume and weight of remnant lung in living lung donors

Living-lung donors lose pulmonary function of a right or left lower lobe in exchange for a noble donation; however, Chen and colleagues reported postoperative pulmonary function of the donors was significantly better than the estimated values. The purpose of this study was to investigate if the improvement of postoperative pulmonary function is associated with hypertrophic phenomena of remnant lung.

A total of 35 patients who underwent a right or left lower lobectomy for living-donor lobar lung transplantation in Kyoto University Hospital from 2008 to 2011 were evaluated by means of spirometry (forced vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide), and computed tomography scans both before and 1 year after the surgery. Postoperative predictions of pulmonary function and radiologic parameters were made based on the number of resected segments. The average radiologic density of the lung was determined as follows: (mean computed tomography number + 1000)/1000, and weight of the lung was calculated as follows: lung volume (mL) × average radiologic lung density (g/mL). The radiologic analysis was performed on both the surgical and contralateral sides.

Postoperative forced vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide were significantly higher than estimated values by 17.3% ± 10.2% (P < .0001), 14.7% ± 10.2% (P < .0001), and 10.9% ± 16. % (P < .002), respectively. Postoperative lung volume and weight of the surgical side were significantly higher than estimated values by 54.4% ± 30.4% (P < .0001) and 28.1% ± 15.7% (P < .0001), respectively. On the contralateral side, the postoperative lung volume was significantly higher than the estimated value by 12.6% ± 15.3% (P < .0001), but postoperative weight was comparable with the estimated value (-2.3% ± 8.8%; P = .07).

Hypertrophic change of the ipsilateral remnant lung may be recognized in living lung donors.