Thrombus volume is similar in patients with ruptured and intact abdominal aortic aneurysms

Objective: Most abdominal aortic aneurysms (AAAs) contain intraluminal thrombus (ILT), which has been demonstrated to contain proteolytic enzymes and proinflammatory cytokines implicated in AAA progression and rupture. In animal models, anticoagulants have been shown to limit AAA progression. Whether ILT plays a role in AAA rupture is unknown. The aim of this study was to compare the volume of ILT in patients with ruptured and intact AAAs. Methods: We matched by maximum axial diameter alone, on a 1: 2 basis, 28 patients with ruptured AAAs and 56 patients with intact AAAs. Total infrarenal aortic volume and ILT volume were measured from computed tomography angiograms using a previously validated and reproducible semiautomated workstation protocol. Clinical risk factors were also recorded. The Mann-Whitney U test was used to compare ILT volumes between patients with ruptured and intact AAAs. Results: Median (interquartile range [IQR]) maximum AAA diameter (84.0 [77.5-93.9] mm vs 82.6 [77.1-93.3] mm; P = .769) and median (IQR) total AAA volume (372.8 [277.4-486.1] cm(3) vs 358.4 [289.1-563.4] cm(3); P = .977) were similar in patients with ruptured and intact AAAs. Median (IQR) AAA ILT volume was similar in patients with ruptured (152.7 [84.8-252.4] cm(3)) and intact (180.1 [89.9-254.8] cm(3); P = .414) AAAs. Conclusions: This study suggests that ILT volume is not different in ruptured and intact AAAs.