A 51-year-old Japanese female ex-smoker with type 2 diabetes mellitus, hypertension and hyperlipidaemia was admitted to our hospital for closer examination of claudication. Her bilateral pedal arterial pulsations were absent; right and left ankle brachial index were 0.57 and 0.58, respectively. Three-dimensional CT revealed an occluded abdominal aorta from the juxtarenal to iliac region (figs 1 and 2). Interestingly, the abdominal aorta bifurcation was at the L3 level (fig 2D), and the aortic diameter within 10 mm of the bifurcation was 10 mm (fig 2C). Thus, the patient was diagnosed as small aorta syndrome complicating aortic occlusion.

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Figure 1

Three-dimensional CT image of the abdominal aorta.

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Figure 2

(A) Bifurcation of the left right renal artery. (B) Bifurcation of the right left renal artery. (C) Aortic diameter within 10 mm of the aortic bifurcation was 10 mm. (D) High bifurcation of the abdominal aorta at the L3 level.

In Japan, there have been very few reports to date on small aorta syndrome, which is a congenital vascular anomaly characterised by a highly bifurcated abdominal aorta, usually at the L3 level, with straight course of the iliac arteries from the aortic bifurcation to the femoral bifurcation, and hypoplastic iliofemoral artery systems. This disease is characterised by a maximum aortic diameter ⩽14 mm within a distance of 10 mm from the bifurcation.1^,2 The CT findings of the present case were met by these criteria. Surgical reconstruction with aortofemoral bypasses has resolved claudication without serious complications.

Small aorta syndrome is quite rare, especially in Asia. All previously reported cases of small aorta syndrome were diagnosed using angiographic contrast images of the inside of the vascular lumen. To our knowledge, this is the first case of high aortic occlusion associated with small aorta syndrome to be reported using three-dimensional CT images depicting the outside of the occluded vessels.