Growth of thrombus may be a better predictor of rupture than diameter in patients with abdominal aortic aneurysms.

OBJECTIVES: to investigate the relationships between diameter, surface and thrombus area in abdominal aortic aneurysms (AAAs) <5 cm. METHODS AND MATERIAL: sixty-seven patients with AAA underwent at least 2 CT examinations. At the point of maximal diameter, surface area and thrombus area were calculated and related to rupture, or impending rupture, during follow-up. RESULTS: the mean increase in measured diameter, surface area and thrombus area were 3.4 mm, 1.9 cm(2)and 1.7 cm(2)per year respectively. Patients with AAA >4 cm and whose thrombus area increased >1.5 cm(2)/year were more likely to rupture (6/24 vs 1/23). CONCLUSIONS: a rapid increase of thrombus area may be a better predictor of AAA rupture than increase in maximal diameter.