Evaluation of normal abdominal aortic diameters in the Indian population using computed tomography

Abstract

Objectives: The aim of this study was to establish normal diameters for the suprarenal and infrarenal abdominal aorta measured at T12 and L3 vertebral levels in the Indian population and to study the variation in aortic diameters with age, sex, height, weight, body mass index (BMI), and body surface area (BSA). Materials and Methods: One hundred and forty-two patients who underwent helical contrast-enhanced computed tomography (CT) scans of the abdomen for non-cardiovascular reasons were recruited.. The mean internal diameters of the suprarenal and infrarenal abdominal aorta (maximum anteroposterior and transverse diameter) were measured at T12 and L3 vertebral levels and tabulated according to various age groups for both men and women. Pearson correlation coefficient was used to evaluate the correlation between aortic diameters, height, weight, BSA, and BMI. Results: The mean diameters of the suprarenal and infrarenal abdominal aorta measured at T12 and L3 vertebral levels, in men were 19.0 ± 2.3 and 13.8 ± 1.9 mm and in women 17.1 ± 2.3 and 12.0 ± 1.6 mm, respectively. The aortic diameter progressively increased in caliber with increasing age of the patients and was smaller in women than men. A significant positive correlation was found in men between the suprarenal and infrarenal aortic diameters and weight, BSA, and BMI. In women, this correlation was significant in the infrarenal aorta but not in the suprarenal aorta. Conclusion: We obtained a set of normal values for the abdominal aorta in the Indian population. The aortic diameters correlated with age, gender, and body size of the patients as seen with previously published data in the Western population. A brief comparison of data between Indian and Western population showed that the values obtained were less than published elsewhere and hence, this should be considered while formulating intervention protocols.

Strengths and Limitations of Current Adult Nomograms for the Aorta Obtained by Noninvasive Cardiovascular Imaging

“…The lack of data of non‐Caucasian subjects is another major limitation, with only a few studies evaluating Asian subjects . There are no data available for black subjects.…”

“…Numerical limitations were the small sample size of many studies, 16,17,26,[29][30][31][32]36 scarce representation of some data (for example, aortic arch), and the lack of data for non-Caucasian population. (Table I) Criteria for the definition of the sample size in the building of nomograms require the division of the population into age strata and the calculation of a minimum number for every age group.…”

“…13,14,25 The lack of data of non-Caucasian subjects is another major limitation, with only a few studies evaluating Asian subjects. 16,18,23,29,32 There are no data available for black subjects. In addition, aortic arch data 15,31,33 and MRI based data were very limited.…”

“…25,27,28 In the remaining, the sample size was limited 33 (i.e. 300 subjects) or very limited, 24,[29][30][31][32] ranging from a minimum of 70 to a maximum of 142 subjects. There were sufficient data for ascending and descending aorta measurements, while data on the aortic arch were limited.…”

“…8,9,43 Questions have been raised whether, a single set of cutoff values for intervention is applicable to all subjects with aortic aneurysm, or specific cutoffs are needed for individual subjects. 9,43 Various adult aortic nomograms have been proposed over the years for the commonly employed imaging techniques: echocardiography, [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] CT [25][26][27][28][29][30][31][32][33][34] and MRI. [35][36][37][38][39][40][41] The aim of this study is to review the strengths and limitations of published adult nomograms for aortic dimensions at multiple levels evaluated by different imaging techniques.…”