Mediastinal perigraft seroma after thoracic aortic surgery

OBJECTIVES: We investigated pertinent factors associated with mediastinal perigraft seroma (PGS) after thoracic aortic surgery. In addition, we provided a clinical review of this entity, as reports reviewing abundant mediastinal PGS cases are rare. METHODS: Eighty-two patients who underwent either ascending aortic replacement or aortic arch replacement between 2016 and 2022 in our institution were enrolled in the present study. Postoperative computed tomography scans were performed to detect fluid capsules with a diameter ≥3.0 cm and radiodensity ≤25 Hounsfield units. Patients who did and who did not develop PGS formation were compared. Variables with a statistically significant difference between these groups were included in a multiple logistic regression analysis along with other factors associated with PGS in the literature. RESULTS: The incidence rate of PGS was 14.6% (12/82). The average radiodensity of the mass was 16.6 ± 6.3 Hounsfield units. The average onset of PGS was 8.5 months post-surgery. Multivariate logistic regression analysis revealed that ejection fraction [odds ratio (OR): 1.25, 95% confidence interval (CI): 1.03–1.50, P = 0.021], aortic dissection (versus degenerative aortic aneurysm) (OR: 6.61, 95% CI: 1.35–32.4, P = 0.02) and warfarin use (OR: 6.67, 95% CI: 1.19–37.1, P = 0.03) significantly contributed to mediastinal PGS after thoracic aortic surgery. CONCLUSIONS: High ejection fraction, warfarin use and aortic dissection (versus degenerative aortic aneurysm) contributed significantly to mediastinal PGS formation after thoracic aortic surgery. Careful serial postoperative imaging studies and fluid analysis can be used to guide treatment plans. CLINICAL TRIAL REGISTRATION: UMIN-CTR (University hospital Medical Information Network-Clinical Trial Registry) Registration number: UMIN000050764.