Effect of Aortic Thrombus on Outcomes Following Repair of Juxtarenal Aneurysms Using Physician Modified Endografts.

Objective: Studies have suggested that aortic thrombus may be associated with adverse outcomes following endovascular repair of aortic aneurysms, while other reports have suggested higher rates of sac regression and a reduced risk of endoleak. However, the effect of thrombus burden on outcomes following physician modified endografts (PMEGs) remains unknown. This study aimed to assess the volume and morphology of thrombus burden and the effect on outcomes following PMEG for juxtarenal abdominal aortic aneurysm.

Methods: This was a retrospective cohort study of patients who underwent PMEG from 2009 to 2021 in a single centre, investigational device exemption trial. Thrombus burden was measured as a percentage of luminal volume using pre-operative computed tomography scans from the lowest renal artery to the level of the aortic bifurcation using centreline reconstruction software. Morphology was documented by the presence of finger like projections. Univariable and multivariable analyses evaluated the impact on peri-operative and long term outcomes.

Results: Volumetric and morphological measures of thrombus burden were assessed in 142 patients; 40.1% of the cohort were classified as having a high thrombus burden (≥ 50% luminal volume) on volumetric assessment and 22.5% had finger like projections on morphological assessment. Type II endoleak was more frequently observed in those with low thrombus burden (60.0% vs. 33.3%; p = .008) and persisted after multivariable analysis (odds ratio 2.5, 95% confidence interval 1.1 - 5.8), but there were no other statistically significant differences in peri-operative adverse events or late outcomes, including sac behaviour, freedom from re-intervention, and overall survival when stratifying thrombus burden by quantitative or qualitative measures. There were no observed differences in operative or anatomical characteristics, including landing zone characteristics and rates of inferior mesenteric artery patency.

Conclusion: While thrombus burden and morphology were not associated with adverse peri-operative events or survival, low thrombus burden was associated with an increase in type II endoleak. These findings suggest that thrombus burden should not deter treatment for patients requiring PMEG.