Reply to Wouter K. Comment on “Lee et al. Influence of Aortoiliac Geometry on Non-Occlusive Thrombotic Risk Following Endovascular Repair of Abdominal Aortic Aneurysms. Diagnostics 2025, 15, 2134”

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We would like to thank Dr. Wouter Kok for the thoughtful critique on our recently published article entitled: Influence of Aorto-Iliac Geometry on Non-Occlusive Thrombotic Risk Following EVAR.

We totally agree with you that the conclusion in our original article should emphasize on the fact that the relative value of vessel diameter or a difference in size between left and right iliac artery in each patient had higher importance in terms of thrombosis risk prediction. Our primary analyses compared thrombotic vs. non-thrombotic limbs and demonstrated associations between larger post-EVAR limb diameter, lower graft-limb and aorto-iliac angles, and greater iliac tortuosity with iliac thrombus. We also performed paired analyses within the 18 patients who developed unilateral thrombus, which again showed significant side-to-side differences in diameter, angles, and tortuosity [1]. In detail, the 18 thrombosed iliac arteries were larger than their contralateral arteries by 3.339 mm (p = 0.012) (Table 3 [1]). Another paired comparison in 36 patients with no thrombosis complication following EVAR showed no significant difference between both iliac artery (p = 0.12). Considering the above results, the relative size between two iliac artery post-EVAR maximal diameter was related to higher risk of thrombus formation. The grouping of all non-thrombus iliac artery without selectively compare with the contralateral side might create bias and inconsistency in our study. While post-EVAR limb diameter can be affected by multiple factors, including pre-intervention vessel size, device selection and oversizing and post-implant remodeling. Absolute post-EVAR diameter can be misleading on its own. A recent multicenter analysis linked oversizing (~19%) and iliac tortuosity to higher risk of iliac limb occlusion [2]. Other studies recommended against excessive (>~20%) oversizing, balancing it against the competing endoleak/migration risks [3,4]. Taken together, these data align with the fact that relative size (side-to-side), rather than absolute size alone, influence thrombosis risk.

Comparing to other studies in the same topic, our results were relatively different from those of Draper et al. [5]. We believe that a thorough comparison between pre- and post-EVAR geometry values would enlighten this controversial finding. For future analytic directions, we would like to thanks commenter for suggesting comparison between pre- and post-intervention vessel dimension. However, one of our study design limitation is that lack of pre-intervention data. We will consider this brilliant idea for our future research, a prospective, paired design reporting pre- vs. post-EVAR diameters, oversizing percentages, and geometric asymmetry indices across both thrombotic and non-thrombotic patients.

In summary, we appreciate the emphasis on paired comparison values. Our data already show that geometry (angles/tortuosity) and diameter are associated with thrombosis; we agree that relative size and oversizing likely modulate that risk and merit explicit reporting alongside absolute diameters.