Expansion rate of nonaneurysmatic abdominal aorta: Over 10 years of follow-up CT studies

Expansion rate of the nonaneurysmatic abdominal aorta (NAA) is completely unknown. The purpose was to evaluate the expansion rate of the NAA and the factors influencing its enlargement.114 subjects without aortic disease were entered into this retrospective study (mean age: 58.7 years). In all subjects, follow-up CT studies were obtained for more than 10 years after initial CT studies (mean: 147.0 months). The diameter of the abdominal aorta was measured at two sites (suprarenal and infrarenal abdominal aorta), and the growth rate was calculated at each site. The growth rate of NAA and the factors influencing its enlargement were evaluated.In 68 (59.6%), the suprarenal segment of NAA increased in size with a mean growth rate of 1.3 mm/10 years. In 49 subjects (43.0%), the infrarenal segment of NAA increased in size during the follow-up period with the mean growth rate of 1.0 mm/10 years.The mean growth rate was significantly higher in the suprarenal segment (p = 0.002). The suprarenal segment of NAA and presence of hyperlipidemia were significant risk factors for NAA enlargement.NAA enlargement is more likely to occur in the suprarenal segment than in the infrarenal segment. The presence of hyperlipidemia was also a significant risk factor for NAA enlargement.