[5]–[7], [13] Human data on the other hand is less clear. A retrospective case-control study using a large Canadian administrative database showed that patients with AAA treated with ACE inhibitors, but not those treated with other anti-hypertensives are less likely to present with ruptured AAA. [3] In contrast, a study by Wilmink failed to observe a beneficial effect of ACE inhibitors on aneurysm progression, [15] whereas Sweeting et al. [16] observed accelerated aneurysm growth in patients taking ACE inhibitors. This evidence concerns the gene ACE and triple-A syndrome.