Correlation Between Proteolytic Activity and Abdominal Aortic Aneurysm Wall Morphology with Intraluminal Thrombus Volume

Background: The aim of this study was to examine the influence of intraluminal thrombus (ILT) volume on the level of proteolytic activity and the content of abdominal aortic aneurysm (AAA) wall.Methods: The research was designed as a cross-sectional study at the Clinic for Vascular and Endovascular Surgery, Clinical Center of Serbia in the period from April 2017 to February 2018. During this period, a total of 155 patients with asymptomatic AAA underwent open surgical treat-ment and 50 were included in the study based on inclusion and exclusion criteria. Before sur-gery, patients included in the study were examined by MRI. During the operation, samples of ILT and AAA wall were taken for biochemical analysis.Results: A statistically significant correlation was found between the volume of the ILT and largest AAA diameter (r = 0.56; P < 0.001). The correlation of the ILT volume on the anterior wall and the con-centration of MMP-9, MMP-2 and NE/ELA in the wall did not find statistical significance. Also, no sta-tistically significant association was found between the volume of ILT and the concentration of ECM proteins (collagen type 3, elastin, proteoglycan) in the corresponding part of the wall. The association of ILT volume with MDA was also of no statistical significance. There was a positive statistical signifi-cance found in correlation of volume of ILT and catalase activity in the wall of AAA (r = 0.28, P= 0.049).Conclusions: The volume of ILT in the aneurysmal sac seemed not to affect the level of pro-teolytic activity and the content of the aneurysm wall. However, a positive correlation was found between the ILT and the catalase activity. The effect of ILT on the aneurysm wall and its role in the progression of aneurysmal disease should be examined in future studies.

Automated summary

The study found a significant correlation between ILT volume and the largest AAA diameter, but no statistical significance in relation to proteolytic activity and protein content of the vascular wall. However, a positive correlation was found between ILT and catalase activity in the AAA wall. Future studies are needed to investigate the impact of ILT on aneurysm progression.