Aortic Aneurysm in Emergency: Radiological Signs of Pre-Rupture and of Rupture

Aortic aneurysms are often asymptomatic and have a subclinical course. In some cases, the first manifestation of aneurysm is extremely variable, from pain (symptomatic aneurysm), frequently prodromal to the rupture phase, to an emergency condition characterized by hemodynamic shock due to the laceration of the vessel. In this scenario, the role of imaging in the early recognition of radiological signs associated with the pre-rupture and rupture is fundamental. Aortic rupture should be suspected in all patients presenting with acute pain, in which diagnostic imaging shows an aortic aneurysm with apparent preserved aortic wall integrity. In these cases, recurrent pain or pain refractory to analgesic therapy, as well as the presence of pleural or peritoneal effusions, that increase in time, identify patients at increased risk for aortic rupture. In the radiological diagnosis, unbuffered aortic rupture may be differentiated from buffered one. The difference from frank free rupture (in which rupture of all layers of the aortic wall results in the formation of a massive hematoma/spillage) and tamponade ruptures of aortic aneurysms (with or without pseudoaneurysm formation) is that in this latter perivascular hematoma is contained by periaortic structures, such as the pleura, pericardium, or retroperitoneal space, as well as surrounding organs. Therefore, patients with contained aortic rupture are hemodynamically stable. In some cases, when the first episode of rupture is entirely contained, a chronic pulsatile extra-aortic hematoma may form. Finally, an additional possible complication of aortic aneurysm is the increased risk of formation of an aortic dissection.