Late Breaking Abstract - Prognostic impact of decreased erector spinae muscle radiographic density after lung transplantation

Introduction: A radiographic density of erector spinae muscles (ESMs) is often decreased after lung transplantation (LTx) (Oshima Y, et al. ERJ Open Res. 2020). However, a prognostic impact of this change is not elucidated. Objective: To verify whether the decrease in the radiographic density of ESMs after LTx can be associated with a poor prognosis. Methods: Routine follow-up chest computed tomography scan data just before and 12 weeks after LTx were retrospectively retrieved for adult patients who underwent primary LTx at Kyoto University Hospital. The radiographic density of ESMs was quantitatively evaluated as the mean attenuation of the ESMs (ESMct), and an impact of the decreased ESMct during 12 weeks after LTx on overall survival (OS) was examined by Cox proportional hazard analyses. Results: A total of 165 recipients (105 deceased-donor, 59 living-donor, 1 deceased- and living-donor-mixed LTx) were included in this study. Median duration of postoperative observation was 3.2 years, and 37 recipients (22%) had died in this period. Postoperative decreased ESMct was significantly associated with poor OS (per 5 HU decrease; HR, 1.49; 95% CI, 1.16-1.92, p=0.002) by multivariate model adjusted for age, sex, preoperative steroid use, episodes of acute rejection, and preoperative ESMct. Furthermore, the similar results were obtained when the subjects were limited to the deceased donor LTx. Conclusion: Postoperative decreased ESMct was closely associated with a poor prognosis after LTx. These results suggests that to maintain the postoperative muscle radiographic density, which reflects muscle quality, may be important for the better prognosis after LTx.