Preoperative Complement-Related Markers and Major Adverse Aortic Events after Thoracic Endovascular Aortic Repair: An Exploratory Retrospective Cohort Study.

BACKGROUND

To evaluate whether preoperative circulating complement-related markers are associated with major adverse aortic events (MAAEs) after thoracic endovascular aortic repair (TEVAR) for thoracic aortic aneurysm.

METHODS

This single-center retrospective cohort included 186 adults who underwent TEVAR between January 2020 and December 2024. Preoperative C3, C4, C3a, and C5a were assessed together with clinical, inflammatory, and coagulation variables. MAAE was defined as endoleak, secondary aortic intervention, rapid aneurysm expansion, aortic-related death, or rupture. Penalized Cox regression was the primary analysis, with receiver operating characteristic and Kaplan-Meier analyses performed exploratorily.

RESULTS

During a median follow-up of 26.1 months (interquartile range, 8.4-47.4 months), 67 patients (36.0%) developed MAAE. Patients with MAAE were older and had larger aneurysms and higher C3, C4, C3a, and C5a levels. In penalized multivariable Cox analysis, age, aneurysm diameter, C3, C3a, and D-dimer remained associated with MAAE. Exploratory areas under the curve (AUCs) were 0.761 for C3, 0.852 for C4, 0.724 for C3a, and 0.716 for C5a. A cross-validated complement-only model showed high discrimination (AUC, 0.894; Harrell C-index, 0.816), but suboptimal calibration (Hosmer-Lemeshow P = 0.041).

CONCLUSION

Preoperative complement-related markers, particularly C3 and C3a, were associated with MAAE after TEVAR. C4 showed strong exploratory discrimination and merits validation in time-to-event and external cohorts. These findings support complement activation as a potential prognostic signal.