Thrombus within an aortic aneurysm does not reduce pressure on the aneurysmal wall

Purpose: The role of thrombus within an aneurysm in relation to the risk of rupture is controversial. In literature, reports describing reduction and increase of rupture risk can be found. In the era of endovascular treatment of abdominal aortic aneurysms, a passible reduction of risk of rupture by the presence of thrombus within the aneurysmal sac can be important in rela tion to the location of an endoleak to the aneurysmal wall and in relation to the effect of the thrombosis of the endoleak, either spontaneously or by intervention. Methods: In nine patients who underwent operation for an infrarenal aortic aneurysm by open procedure at the level of the thickest thrombus lining, th e pressure within the aneurysmal thrombus (just inside the aneurysmal wall) was measured and compared with the systemic pressure. Results: Pressure within systemic circulation and aneurysmal thrombus corre lated well for the mean pressure (r = 0.90; P < .001) and for pulse pressur e (r = 0.74; P < .01) Also, there was agreement between the levels of the m ean pressure. Conduction of mean and pulse pressure to the aneurysmal wall was not related to the thickness of the thrombus at the level of the pressu re measurement (r = 0.18 and r = 0.08, respectively). Conclusion: We conclude that thrombus within the aneurysm does not reduce b oth the mean and the pulse pressure near the aneurysmal wall and thus will not reduce the risk of rupture of the aneurysm.