Key points

• An aneurysm is an abnormal focal dilatation of a vessel with a greater than 50% increase in its diameter

• Elastin degradation due to matrix metalloproteinases (mainly 2.9 and 12) in the aortic media is the most significant pathology

• Smoking, male gender, hypertension and genetics are the main risk factors

• The annual risk of rupture between 5 and 5.9 cm is 5%

• Contrast enhanced computed tomography (CT) is the gold standard for measuring size and morphology

• The UK Small Aneurysm Trial (UKSAT) helped reach a consensus about the minimal size of treatment, which is 5.5 cm

• The UK Endovascular Aneurysm Repair (EVAR) 1 (in fit patients) trial showed that the 30-day mortality for EVAR was 1.7% versus 4.7% for open repair, although by 4 years all-cause mortality was the same

• The EVAR 2 trial (in unfit patients) showed no difference in mortality between conservative management and stenting

• Fenestrated grafts allow stenting of juxtarenal aneurysms

• Stenting for ruptured aortic aneurysms has shown promising results and a UK trial is currently underway

Introduction

Abdominal aortic aneurysm (AAA) was first described around AD 100 by Roman physicians. In 1923, Rudolf Matas successfully ligated the aorta of a patient with an AAA. The intervening years have seen many advances and improvements in diagnosis and treatment, however ruptured AAAs still cause around 6000 deaths in England and Wales per annum.

Definition

An aneurysm is defined as an abnormal, focal dilatation of a vessel, with greater than a 50% increase in the diameter.