The Influence of Preoperative Aneurysmal Thrombus Quantity and Distribution on the Development of Type II Endoleaks with Aneurysm Sac Enlargement After EVAR of AAA

Purpose

To determine the influence of preoperative aneurysmal thrombus quantity and distribution on the development of type II endoleak with aneurysm sac enlargement after endovascular aneurysm repair (EVAR).

Materials and Methods

We retrospectively analyzed the pre- and postoperatively performed CT scans of 118 patients who had follow-up imaging for at least 1 year after EVAR available. We assessed preoperative thrombus perimeter (T _Peri), diameter (T _Dia), cross-sectional area (T _CSA), and volume (T _Vol). The preoperative thrombus distribution was classified into no thrombus, semilunar-shaped (anterior, right side, left side, posterior) thrombus, and circumferential type thrombus. The number of preoperative patent aortic side branches (ASB) was identified. Endpoint was type II endoleak with aneurysm volume (A _Vol) increase of ≥5 % during follow-up.

Results

During follow-up (2 years, range 1–9 years), 17 patients with type II endoleak had significant A _Vol increase. Less preoperative T _Peri, T _Dia, T _CSA, and T _Vol were associated with A _Vol increase. A circumferential thrombus distribution significantly protected against aneurysm enlargement (p = 0.028). The variables with the strongest significance for A _Vol increase were preoperative T _Vol/A _Vol ratio (OR 0.95; p = 0.037) and number of patent ASB (OR 3.52; p < 0.001).

Conclusion

A low preoperative T _Vol/A _Vol ratio and a high number of patent ASB were associated with aneurysm sac enlargement after EVAR.