The blood flow channel index as novel predictor of abdominal aortic aneurysm impending rupture based on the intraluminal thrombus angio-CT study

Abstract Objective In this study the hypothesis that the thickness of the thinnest part of the thrombus, combined with bleeding into the intraluminal thrombus (ILT), is associated with a possible higher risk of abdominal aortic aneurysm (AAA) rupture was investigated, independently of aneurysm diameter, by using angio-CT. This article describes blood flow channel index based on the CT imaging findings that may help identify impending rupture prior to complete rupture. Methods Computed tomographic images of 310 hospitalized patients with infrarenal AAA, were collected over a three-year period. They were divided into two main groups: 125 with bleeding into the ILT and control group 185 without the presence of blood in the thrombus. Patients were also analyzed in subgroups with ruptured, symptomatic and asymptomatic AAAs. A blood flow channel index was formulated as: maximal/minimal thickness ratio of thrombus from the same CT scan. Results In dissected ILT group blood flow channel index was over a twofold higher than in group with intact ILT (19.0 [1.2–89.3] vs. (9.7 [1.3–38.9]; p < 0.001), respectively. Median thickness at the thinnest part of the ILT in dissected thrombus group was lower (1.3 mm [0.3–16.0]) than in group with intact ILT (1.7 mm [0.2–23.4]; p < 0.003). Conclusion An association between a high blood flow channel index and bleeding into the ILT based on angio-CT study was demonstrated, and can suggest the aneurysm propensity for rupture.