Comparison of Predicted Total Lung Capacity and Total Lung Capacity by Computed Tomography in Lung Transplantation Candidates

Purpose: Lung size mismatch is a major cause of poor lung function and worse survival after lung transplantation (LTx). We compared predicted total lung capacity (pTLC) and TLC measured by chest computed tomography (TLCCT) in LTx candidates. Materials and Methods: We reviewed the medical records of patients on waiting lists for LTx. According to the results of pulmonary function tests, patients were divided into an obstructive disease group and restrictive disease group. The differences between pTLC calculated using the equation of the European Respiratory Society and TLCCT were analyzed in each group. Results: Ninety two patients met the criteria. Thirty five patients were included in the obstructive disease group, and 57 patients were included in the restrictive disease group. pTLC in the obstructive disease group (5.50 +/- 1.07 L) and restrictive disease group (5.57 +/- 1.03 L) had no statistical significance (p=0.747), while TLCCT in the restrictive disease group (3.17 +/- 1.15 L) was smaller than that I the obstructive disease group (4.21 +/- 1.38 L) (p<0.0001). TLCCT/pTLC was 0.770 in the obstructive disease group and 0.571 in the restrictive disease group. Conclusion: Regardless of pulmonary disease pattern, TLCCT was smaller than pTLC, and it was more apparent in restrictive lung disease. Therefore, we should consider the difference between TLCCT and pTLC, as well as lung disease patterns of candidates, in lung size matching for LTx.