Morphovolumetric analysis of aneurysm sac and correlation with maximum diameter for post-EVAR surveillance

Endovascular Aortic Repair (EVAR) is the current treatment of choice for suitable patients undergoing abdominal aortic aneurysm surgery, and post-EVAR follow-up has become an increasingly important topic. This study aims to identify factors influencing the remodeling of aneurysms post-EVAR and assess a more effective follow-up protocol using post-EVAR morphovolumetric analysis.

Between 2019 and 2023, 131 patients who underwent elective Endovascular Aortic Repair (EVAR) at our hospital and patients who had preoperative Computed Tomographic Angiography (CTA) were included in the study. Maximum aneurysm sac diameter, volume, thrombus volume, and infrarenal aortic neck angulation were measured. A post-EVAR volume reduction of 10% or more in the aneurysmal sac was considered a "positive remodeling" based on volumetric analysis. The reliability of post-EVAR surveillance and its correlation with the maximum diameter (Dmax) was evaluated.

Preoperative aneurysm volume larger than 233.5 cm³ (p = 0.001) and thrombus volume greater than 204 cm³ (p = 0.002) were associated with secondary interventions. Morphological changes after EVAR included neck dilatation (p < 0.001) and decreased neck angulation (p < 0.001). An alpha angle >47.5° was associated with Type 1a endoleak (p = 0.046). In the follow-up, positive remodeling was observed in 44 out of 131 patients (33.6%). The identification of more than four lumbar arteries preoperatively (p = 0.003), the use of Double Antiplatelet Therapy (DAPT) postoperatively (p = 0.017), and the presence of any type of endoleak were factors associated with negative remodeling.

Post-EVAR morphological changes include reduced infrarenal aortic lengthening and neck dilatation. Lifelong surveillance is imperative after EVAR. The most effective method of organizing these surveillance protocols may involve a combination of Dmax and volume analysis, allowing for the most economical and reliable monitoring. Dmax is currently the fastest and most reliable data in post-EVAR surveillance. However, following our current study, we observed that relying solely on Dmax can be deceptive and should be correlated with volume analysis data.