Intraluminal thrombus burden is an independent imaging predictor of distal runoff impairment in popliteal artery aneurysms

Background : In popliteal artery aneurysms (PAAs), computed tomography angiography (CTA)-derived intraluminal thrombus burden and distal runoff vessel patency remain insufficiently characterized. We examined this relationship and the added value of thrombus burden assessment in CTA-based radiologic evaluation of PAAs. Methods : This retrospective, single-center study included PAA cases. Aneurysm size, anatomical extent, percentage-based intraluminal thrombus burden, and coexisting aneurysms were assessed. Distal runoff was evaluated using a tibial runoff score based on the number of patent tibial arteries. Associations between runoff, clinical variables, and CTA variables were analyzed. Results : Sixty-eight patients (median age: 73 years) with 101 PAA-affected limbs were included (median aneurysm diameter: 23 mm). Thrombus was present in 73% of affected limbs and was associated with larger aneurysms ( p = 0.001). Multisegmental aneurysms were significantly larger than monosegmental aneurysms ( p < 0.001). In univariable analysis, increasing thrombus burden was associated with impaired distal runoff vessel patency (odds ratio [OR] per 10% increase: 0.85; 95% CI: 0.76–0.94; p = 0.001). Thrombus burden remained independently associated with impaired runoff after adjustment for age, sex, aneurysm diameter, and concomitant abdominal aortic aneurysm (adjusted OR per 10% increase: 0.84; 95% CI: 0.76–0.94; p = 0.001), whereas maximum aneurysm diameter was not. Concomitant abdominal aortic aneurysm was independently associated with preserved runoff vessel patency (adjusted OR: 2.34; 95% CI: 1.01–5.43; p = 0.046). Conclusion : CTA-derived intraluminal thrombus burden is independently associated with impaired distal runoff vessel patency in PAAs. Assessment of thrombus burden can be readily incorporated into routine CTA interpretation without additional imaging or postprocessing.