Changes in the Normal Infrarenal Aortic Length and Tortuosity in Elderly People

PURPOSE: To investigate the changes in the infrarenal aortic length and tortuosity in elderly patients. MATERIALS AND METHODS: We retrospectively reviewed the medical records and computed tomography (CT) scans of 857 patients who underwent surgery for colorectal cancer between August 2009 and July 2012. Among these patients, 48 patients who were aged ≥60 years, underwent follow-up CT at least 5 years after surgery, did not have aortic disease, and did not receive radiation therapy were enrolled. The aortic tortuosity index (ATI) was defined by dividing the distance along the central lumen line from the lowest renal artery to the aortic bifurcation (L1) by the straight-line distance from the lowest renal artery to the aortic bifurcation (L2). Aortic diameters were measured at the lowest renal artery level (D1) and 20 mm below (D2). A paired t-test and Wilcoxon signed-rank test were used to compare lengths and diameters between the initial and final CT scan. Spearman’s correlation analysis was performed to determine the correlations between time and the changes in L1 and ATI. RESULTS: The average follow-up period was 68 months. The mean changes in L1 and L2 were 0.69 mm and –0.59 mm, respectively, while the mean changes in D1 and D2 were 0.77 mm and 0.58 mm, respectively. The mean increase in ATI was 0.015. All findings were statistically significant. On Spearman’s correlation analysis, ΔL1 and ΔATI showed no correlation with follow-up duration. CONCLUSION: The infrarenal aortic length and tortuosity of elderly patients increases at a slow rate over time.