Abdominal aortic diameter and its determinants among healthy adults in Port Harcourt, Nigeria.

Background: The abdominal aorta is the largest artery in the human body. Sonographic assessment of the abdominal aortic diameter is presently the preferred screening method for an aortic aneurysm. However, there are no customized nomograms for our population and the recommended cutoffs for screening may be inappropriate. The effect of factors such as age, gender, and body mass index (BMI) on the abdominal aortic dissection (AAD) among blacks has also not been extensively investigated. Objective: To develop a nomogram of AAD at various levels in Nigerian adults using high-resolution B mode ultrasonography and to evaluate the effect of factors such as gender, age, and BMI on AAD. Methodology: This study involved a sonographic evaluation of the abdominal aortic diameter of 400 normal Nigerian adults aged 18 years and above over a period of 17 months. The scan was done using a 3.5-5 MHz curvilinear transducer on the Mindray ultrasound machine (model: DC-8, SN-QE3B001806). The AAD (mean +/- SD) was correlated with age, gender, BMI, and body surface area (BSA). Data were analyzed using SPSS version 20 for windows and P values <0.05 were considered significant. Results: The mean AADs decreased from 1.58 +/- 0.24 cm in the upper aorta (D1) to 1.40 +/- 0.20 cm at the level of the renal arteries (D2) and 1.29 +/- 0.23 cm at the bifurcation (D3). Mean AAD was significantly higher at all levels of the abdominal aorta (D1, D2, and D3) in males than in females (P < 0.00) and correlated positively with age (P = 0.00) and height (P = 0.00) at D2 and D3 levels. Conclusion: Absolute AADs were relatively smaller in adult Nigerians and this should be considered when setting up screening programs for abdominal aortic aneurysm in our population. Further studies are needed to determine factors affecting AAD.