Some people who are thin may actually feel the aneurysm, which feels like a pulsating mass. But others cause no symptoms. In those cases, the aneurysm might be discovered by accident while doctors are analyzing a patient's gall bladder or performing an ultrasound study for some other reason. Aneurysms also tend to run in families, so doctors increasingly are screening the siblings and offspring of patients who have abdominal aneurysms. Once doctors find an aneurysm, however, it's not always clear which ones merit surgery.
Repair requires a large abdominal incision and recuperation from surgery can take weeks.
Many patients with aneurysms are older and most could safely live the rest of their lives without need for repair. But Vorp said autopsies had shown that smaller aneurysms can burst and many large aneurysms may be safe. So Vorp and M.L. Raghavan, a doctoral student, use information from CT scans to construct 3-D images of the aneurysm so they can analyze its shape. They combine this information with the patient's blood pressure to calculate the amount of stress and the areas of greatest stress on the aneurysm. Asymmetrical aneurysms and those that have a twisted shape seem to be most vulnerable to bursting, Vorp said.