Association between hyperhomocysteinaemia and abdominal aortic aneurysm

Background: Hyperhomocysteinaemia is associated with occlusive vascular disease. In vitro evidence has demonstrated the induction of a serine elastase by homocysteine in vascular smooth muscle. Anecdotal evidence from case reports and post‐mortem studies has suggested an association with abdominal aortic aneurysm (AAA). The aim was to determine the prevalence of hyperhomocysteinaemia in patients with AAA. Methods: Some 120 subjects (60 controls and 60 patients with AAA) were studied prospectively. Epidemiological, clinical and haematological data were collected. Patients were defined as having AAA if ultrasonographic measurement of the aorta was greater than 4·5 cm. Those with evidence of occlusive peripheral vascular disease or an ankle: brachial pressure index lower than 0·8 were excluded. Homocysteine was measured with a commercial high‐pressure liquid chromatography analyser. The reference range from age‐matched controls was 8·9–14·3 µmol l −1 . Results: The median(s.d.) value of homocysteine for patients was significantly higher than that for the control group: 13·1(7·88) versus 10·9(5·07) µmol l −1 ( P = 0·03, Mann–Whitney U test). Hyperhomocysteinaemia (homocysteine concentration greater than 14·3 µu;mol l −1 ) was present in 48 per cent of patients with AAA, compared with 24 per cent of the control population ( P < 0·01, χ 2 test). There were no significant differences between groups with regard to age, folate levels, vitamin B 12 concentration or renal function. Conclusion: These results strongly suggest an association between hyperhomocysteinaemia and AAA. If studies currently ongoing demonstrate a causal relationship between hyperhomocysteinaemia and vascular disease progression, it raises the possibility of treating small aneurysms with vitamin supplementation to slow their growth. © 2001 British Journal of Surgery Society Ltd