Preoperative D-dimer and Intraluminal Thrombus Ratio Appear to Interact in Predicting Aneurysm Expansion After...

To determine whether preoperative D-dimer and intraluminal thrombus ratio interact to predict aneurysm expansion in patients with persistent type 2 endoleak after endovascular aneurysm repair, informing candidate selection for prophylactic embolization.

This retrospective single-center study analyzed 138 patients with persistent type 2 endoleak confirmed at 12-month follow-up after elective infrarenal endovascular aneurysm repair (2007-2020). The primary outcome was aneurysm expansion ≥ 10 mm within 5 years, assessed by Cox models with a D-dimer × intraluminal thrombus ratio interaction term and generalized estimating equations for continuous diameter change. Patients were stratified by median D-dimer (4.1 μg/mL) and median intraluminal thrombus ratio (41.5%).

During median follow-up of 4.7 years, 27 patients (19.6%) developed the primary outcome. High D-dimer predicted expansion overall (hazard ratio 3.37; 95% confidence interval 1.39-8.21; P = 0.007). Within the high intraluminal thrombus ratio stratum, high D-dimer conferred markedly elevated risk (hazard ratio 13.06; 95% confidence interval 1.69-101.24; P = 0.014; Firth's regression: hazard ratio 8.29; P = 0.015); D-dimer was not predictive in the low intraluminal thrombus ratio stratum (P = 0.46). The three-way generalized estimating equations interaction was significant (P = 0.015); annual diameter change diverged markedly (+ 2.18 vs. + 0.04 mm/year), with a 12.6-mm difference at 60 months (P = 0.003).

Preoperative D-dimer and intraluminal thrombus ratio interact to predict midterm aneurysm expansion. In patients with high thrombus burden, D-dimer identifies a high-risk subgroup and a low-risk subgroup amenable to standard surveillance.

Level 3b, Retrospective cohort study.