Prevalence of abdominal aortic aneurysm in Chinese patients with severe coronary artery disease.

Background: The Asian population is believed to have lower incidence of abdominal aortic aneurysm (AAA), and hence, the benefit of screening is uncertain. The size of native aorta in Asians, which shall affect the definition of AAA, has also never been reported. Our study investigated the prevalence of AAA and the infra-renal aortic diameter (AD) in Chinese patients with severe coronary artery disease.

Methods: This is a prospective observational study of infra-renal aortic size for patients who had coronary artery bypass surgery by ultrasound. The patients' demographics, important co-morbidities and maximum AD were recorded.

Results: The study included 624 consecutive Chinese patients (mean age = 63.2 years). The mean maximum infra-renal AD was 17.5 mm for men and 14.8 mm for women. The presence of AAA was defined as maximum AD greater than 30 mm. The result was also compared with an alternate definition that defines AAA as maximum AD of greater than 1.5 times of the group's mean. Eleven patients had an AD greater than 30 mm, and the prevalence of AAA was only 1.8%. With AAA defined as maximum AD of 1.5 times greater than the group's mean, 19 patients had AAA. The prevalence of AAA in this high-risk group would become 3% overall.

Conclusion: The prevalence of AAA in Chinese patients was low, and the result did not support routine screening. The smaller mean infra-renal AD in Chinese merits validation by large-scale study and consideration when deciding threshold for small AAA repair in our locality.