The characteristics of screened patients with abdominal aortic aneurysm

Screening for abdominal aortic aneurysm (AAA) has not yet been established in Japan. We therefore report the characteristics of a screened population and discuss the implications of screening using ultrasound in Japan.

The subjects in our screening group were composed of 4428 participants who were 60 years of age or older. Aneurysm was detected in 16 cases, 15 males and 1 female, the detection rate being 0.4% in total and 0.9% in the males. We compare the characteristics of screened patients (n = 16) with non-screened patients operated on for abdominal aortic aneurysm (n = 166).

There were no significant differences in the mean age or in the female ratio between the screened and non-screened groups (71 vs 70 y/o, 6% vs 13%, respectively). Solitary iliac aneurysms were significantly (p < 0.05) more frequent in the screened than in the non-screened group (19% vs 3%). The size of aneurysm in the screened group was significantly (p < 0.05) smaller compared with the non-screened group. Sixty-three per cent of the screened group and only 8% of the non-screened group had an aneurysm less than 40 mm in size. Aneurysm was palpable in only 31% of those of the screened group. There were no significant differences between the groups in the frequency of arteriosclerotic risk factors such as hypertension, ischaemic heart disease, diabetes mellitus, peripheral vascular disease and smoking habits. Surgical treatment was selected in 7 out of 16 screened patients. The remaining 9 patients with small-sized abdominal aortic aneurysms have been carefully followed up.

Screening for abdominal aortic aneurysm using ultrasound is advisable especially for male participants and for the detection of iliac aneurysms. This screening procedure is useful for early detection because the screened aneurysm is generally small-sized and impalpable.