Detection of Restored Lung by Novel Radiologic Parameter in Living Lobar Lung Transplant Donors

Abstract

Purpose Postoperative compensatory lung growth (CLG) after lung resection has been established in animal models. However, detecting CLG in clinical patients is limited. Our purpose was to determine CLG by evaluating preoperative and postoperative “estimated lung weight (ELW)” in living lobar lung transplant donors. Methods and Materials A total of 18 consecutive patients who underwent a right or left lower lobectomy as a living donor for lung transplantation from 2008 to 2010 were selected. The 18 patients were evaluated by spirometry, CT volumetry, and mean CT numbers (Hounsfield Units) both before and one year after surgery. “ELW” was calculated by multiplying lung volume (ml) and estimated mean lung density (g/ml): density = (mean CT number + 1000) / 1000. All parameters were evaluated by “%postoperative values”: actual postoperative values / predicted post operative values (%); predicted values were based on the number of resected segments. [figure 1] Results The predicted postoperative values of spirometry underestimated the actual values and the differences were significant (forced vital capacity, p<0.001, forced expiratory volume in 1 second, p<0.001 and diffusing capacity for carbon monoxide, p=0.002). The cohort had significantly larger % postoperative lung volumes (152±31.5%, p<0.001) and “ELW” (126±15.2%) than the predicted values on the surgical side. Conclusions Restored lung function, volume and quantity after major lung resection in living lobar lung transplant donors was revealed by the novel radiologic parameter. Major lung resection may trigger CLG on the surgical side that can be clinically evaluated by the “ELW.”