Are we ignoring the importance of ankle pressures in patients with abdominal aortic aneurysm?

Abstract

Background and purpose: the ankle/brachial pressure index (ABPI) has been shown to be a reliable marker of cardiovascular risk in population studies. We investigated whether the ABPI was a useful prognostic index for patients with abdominal aortic aneurysm. Methods: patients entered into the U.K. Small Aneurysm and Study had their ABPI measured in both legs at baseline (mean ABPI reported) and were followed up until 30 June 1998, with information about cause of death being obtained from the Office of National Statistics. This study focussed on cardiovascular and all-cause mortality. Results: a total of 1827 men and 478 women, mean age 69 years, median aneurysm diameter 4.4 cm, were followed up for a median of 5.7 years. A total of 829 deaths were reported (rate 8.1 per 100 person-years), 546 (66%) from cardiovascular causes. The all-cause mortality risk increased as the ABPI decreased, hazard ration 1.25 per 0.2 unit decrease in ABPI (95% C1 1.17 to 1.34, p<0.001). For patients in the lowest textile group (ABPI <0.87) there were 11.6 deaths per 100 person-years. This increased risk persisted after adjustment for age, sex, evidence of ischaemia on resting ECG and initial aneurysm diameter, adjusted hazard ratio 1.17 per 0.2 unit decrease in ABPI (95% CI 1.07 to 1.28, p<0.0001). Conclusion: the ankle/brachial pressure index is an important prognostic indicator for patients with abdominal aortic aneurysm. Patients with an ABPI below 0.87 (limit of lowest tertile) have the highest mortality risk and best clinical practice demands that attention is focussed on active treatment to minimise their cardiovascular risk factors.