Psoas Cross-Sectional Measurements Using Manual CT Segmentation before and after Endovascular Aortic Repair (EVAR)

Sarcopenia has been associated with an increased incidence of adverse outcomes, including higher mortality, after endovascular aortic repair (EVAR). We aim to use computed tomography (CT) to quantify changes in total psoas muscles area (PMA) and psoas muscle density (PMD) after EVAR, and to evaluate the reproducibility of both measurements. PMA and PMD were assessed via manual segmentation of the psoas muscle on pre- and post-operative CT scans belonging to consecutive patients who underwent EVAR. Wilcoxon test was used to compare PMA and PMD before and after EVAR, and inter- and intra-reader agreements of both methods were evaluated through Bland-Altman analysis. A total of 50 patients, 42 of them males (84%), were included in the study. PMA changes from 1243 mm(2) (1006-1445 mm(2)) to 1102 mm(2) (IQR 937-1331 mm(2)), after EVAR (p < 0.001). PMD did not vary between pre-EVAR (33 HU, IQR 26.5-38.7 HU) and post-EVAR (32 HU, IQR 26-37 HU, p = 0.630). At inter-reader Bland-Altman analysis, PMA showed a bias of 64.0 mm(2) and a coefficient of repeatability (CoR) of 359.2 mm(2), whereas PMD showed a bias of -2.43 HU and a CoR of 6.19 HU. At intra-reader Bland-Altman analysis, PMA showed a bias of -81.1 mm(2) and a CoR of 394.6 mm(2), whereas PMD showed a bias of 1.41 HU and a CoR of 6.36 HU. In conclusion, PMA decreases after EVAR. A good intra and inter-reader reproducibility was observed for both PMA and PMD. We thus propose to use PMA during the follow-up of patients who underwent EVAR to monitor muscle depletion after surgery.