Infra-renal abdominal aortic aneurysm dilation ratio (AADR): A different measurement technique for intervention

Introduction

To test the null hypothesis that the proposed abdominal aortic aneurysm (AAA) dilation ratio (AADR) obtained by dividing the widest diameter of the infra-renal AAA by the immediate native (normal) infra-renal aorta in millimetres, fails to provide accurate information about the risk of rupture in the female population, small or various sizes of infra-renal AAAs.

Methods

A retrospective study of 112 patients that underwent an infra-renal AAA repair on elective, urgent and or immediate basis with prior computed tomography angiogram (CTA) or computed tomography (CT).

Results

The mean AADR was 2.3 for asymptomatic group (n=73) and 3.3 for symptomatic group (n=28) (p<0.0001). The mean AADR was 2.88 for the tender AAA group (n=14) and 3.78 for the ruptured group (n=14) (p<0.0042).

Conclusion

Study suggests a lower threshold for female population that do not meet the interventional size. AADR≤2.8 could be a reasonable criteria for intervention irrespective of the aneurysm size. AADR can assist in doubtful or borderline scenarios, especially during the management of symptomatic patients as higher AADR>2.8 warrants an immediate operation. Finally, the AADR can be important in less privileged centres where ultrasonography (USS) and not repeated CT scan is permissible.