Research Article: Correlation between the native lung volume change and postoperative pulmonary function after single lung transplantation for lymphangioleiomyomatosis: Evaluation of lung volume by three-dimensional computed tomography volumetry

Date Published: February 11, 2019

Publisher: Public Library of Science

Author(s): Hirotoshi Suzuki, Hisashi Oishi, Masafumi Noda, Tatsuaki Watanabe, Yasushi Matsuda, Junya Tominaga, Tetsu Sado, Akira Sakurada, Hajime Kurosawa, Kei Takase, Yoshinori Okada, Peggy S. Lai.

http://doi.org/10.1371/journal.pone.0210975

Abstract

Whereas native lung overinflation has been thought to happen in recipients of single lung transplantation for lymphangioleiomyomatosis because of its increased compliance, there is no study that has reported the details on the change of the native lung volume after single lung transplantation by three-dimensional computed tomography volumetry. The purpose of the present study was to evaluate the lung volume after single lung transplantation for lymphangioleiomyomatosis by three-dimensional computed tomography volumetry and investigate the correlation between the native lung volume change and postoperative pulmonary function.

We retrospectively reviewed the data of 17 patients who underwent single lung transplantation for lymphangioleiomyomatosis. We defined the ratio of the native lung volume to total lung volume (N/T ratio) as an indicator of overinflation of the native lung. In order to assess changes in the N/T ratio over time, we calculated the rate of change in the N/T ratio which is standardized by the N/T ratio at 1 year after single lung transplantation: rate of change in N/T ratio (%) = {(N/T ratio at a certain year)/(N/T ratio at 1 year)– 1}× 100.

We investigated the correlations between the N/T ratio and the pulmonary function test parameters at 1 year and 5 years; however, there was no significant correlation between them. On the other hand, there was a significant negative correlation between the rate of change in the N/T ratio and that in forced expiratory volume in 1 second %predicted (%FEV1) at 5 years after single lung transplantation.

The single lung transplantation recipients for lymphangioleiomyomatosis showed increased rate of change in the N/T ratio in the long-time course after lung transplantation with the decrease of %FEV1. We expect that these cases will probably cause the overinflation of the native lung in the future.

Partial Text

Lung transplantation is an established therapeutic option for patients with various types of end-stage lung disease. Internationally, the annual number of bilateral lung transplants (BLTs) is greater than that of single lung transplants (SLTs) because of the better survival with the former procedure [1]. On the other hand, the current situation in Japan is completely different from other countries. The number of SLTs performed in Japan is almost the same as the number of BLTs. Miyoshi et al. reported that, given the severe donor shortage in Japan, SLT can be the first choice of surgical procedure type with acceptable outcomes if there is no contraindication to SLT [2].

Overinflation of the native lung is one of the challenging complications after SLT for obstructive lung diseases, such as COPD. In such patients, the compliance of the native lung is much higher than that of the healthy lung, transplanted lung. As a result of the difference in the compliance between the native and transplanted lungs, overinflation can occur only in the native lung. We recognize overinflation of the native lung after SLT in COPD by the shifted mediastinum in CT and chest X-ray. LVRS [6] and BLVR [7] have been applied for this complication in SLT recipients for COPD. Some SLT recipients for LAM also show a shift of the mediastinum to the transplanted lung side. However, it still remains unclear if overinflation of the native lung really happens in such patients. Another question we have in daily practice is whether overinflation of the native lung affects the post-transplant pulmonary function of the SLT recipients for LAM.

 

Source:

http://doi.org/10.1371/journal.pone.0210975

 

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