Abdominal aortic aneurysms: screening, epidemiology and open surgical repair Vaux Robertson Matt Bown Abstract Abdominal Aortic Aneurysm (AAA) is a dilatation of the infra-renal abdominal aorta to greater than 3 cm. Population screening is offered to men in their 65th year in the UK. Patients with small AAAs (<5.5 cm) are entered into surveillance programs and should have cardiovascular risk factors managed aggressively. An AAA with 5.5 cm diameter should be considered for surgical repair to prevent rupture. Open sur- gical repair has proven to be a durable treatment for AAA and while less often performed than endovascular aneurysm repair (EVAR) it re- mains a common approach in the surgical management of AAA. While associated with higher short-term risks than EVAR, the long-term outcomes are similar and many younger patients have a preference for open repair as routine follow-up is not required. Keywords AAA; aneurysms; aorta; open surgical repair; risk factors; screening Introduction An aneurysm is a focal, permanent dilatation of an artery or vessel to more than 50% of its normal diameter. The natural history of aneurysms is asymptomatic growth followed by rupture, which is catastrophic in many cases. For the infra-renal abdominal aorta, an absolute diameter of 3 cm is the usual threshold at which a diagnosis of abdominal aortic aneurysm (AAA) is made. AAA af- fects approximately 5% of men 1 and 0.74% of women 2 over the age of 65, and is responsible for approximately 4000 deaths per year in the United Kingdom (UK). 3 Men aged 65 are invited for AAA screening in the UK and the prevalence of AAA in this age group is just over 1.1. 4 Approximately 8700 operations are carried out each year for AAA, 5 5500 of which are planned and 3200 are emergency. Approximately 30% of the planned and 70% of the emergencies are open AAA repairs. This article will review the options and evidence for open repair of AAA. Endovascular repair is discussed on pages 00-00 of this issue. Epidemiology and risk factors for AAA Large-scale cross-sectional studies of AAA screening with ultra- sound scans have demonstrated that the prevalence of an infra- renal aortic diameter greater than 3 cm is approximately 5% in men over the age of 65 years, 6 though this may be decreasing. The prevalence of AAA in women is lower than in men but there have been no comparable large-scale studies in the female pop- ulation. Existing evidence suggests that the prevalence of AAA in women is about five times lower than in men. Other non- modifiable risk factors for AAA include increasing age (AAA is very rare before the age of 55 years) and positive family history for the disease. Having a sibling affected by AAA increases the risk by approximately sevenfold. The strongest risk factor for AAA is cigarette smoking, the impact of which by far surpasses genetic and all other modifiable risk factors. Prospective observational studies have demon- strated that current cigarette smoking can increase the risk of AAA development by as much as eightfold compared to those that have never smoked, and that duration of smoking also has a linear correlation with AAA development. 7,8 Smoking is also related to faster AAA growth. 9 Indeed, it is likely that public health measures aimed at smoking cessation may, in part, explain the reduction in AAA prevalence seen in the past 10e15 years. 10 Other risk factors for development of AAA include hyper- cholesterolaemia and other atherosclerotic diseases. Hyperten- sion is also considered to be a risk factor, although this remains unproven with randomized evidence. Interestingly, diabetes ap- pears to protect against both the development and progression of AAA. The mechanism for this unexpected observation is unclear at present but could provide clues to developing novel pharma- cological treatments for AAA. Clinical presentation Most AAAs are asymptomatic until rupture. Occasionally, large AAAs may compress surrounding structures such as the ureters, inferior vena cava or duodenum, leading to development of symptoms, but this is unusual. It is more common for AAAs to be discovered incidentally, as part of the diagnostic work-up for unrelated conditions or to be found as part of the national screening programme. Approximately 0.65%e2% of AAA are classified as inflammatory or mycotic. These can present with abdominal or back pain, weight loss, fevers and elevated in- flammatory markers. An asymptomatic AAA may be detected as a pulsatile abdominal mass through routine physical examination; however, the sensitivity of this is poor and is affected by the examiner’s experience and the patient’s body habitus. Patients with AAA may also present with ischaemic symptoms in the lower limbs secondary to acute thrombosis or embolization to the peripheral circulation, but again this is not common. Very rarely AAA can present with haemorrhagic and thrombotic complications due to disseminated intravascular coagulation. AAA rupture classically presents as a triad of abdominal pain radiating to the back, haemorrhagic shock and a palpable pul- satile abdominal mass. However, it is important to recognize that not all cases of AAA will have all of these features. It is not uncommon for patients with ruptured AAA to be diagnosed as having ureteric colic, musculoskeletal back pain or other di- agnoses commonly presenting to the emergency department. There should therefore be a high clinical suspicion of ruptured Vaux Robertson MRCS is a Specialty Trainee in Vascular Surgery at University Hospitals of Leicester, UK. Conflicts of interest: none declared. Matt Bown MD FRCS is Professor of Vascular Surgery at University of Leicester, UK. Conflicts of interest: none declared. VASCULAR SURGERY e I SURGERY --:- 1 Ó 2018 Published by Elsevier Ltd. Please cite this article in press as: Robertson V, Bown M, Abdominal aortic aneurysms: screening, epidemiology and open surgical repair, Surgery (2018), https://doi.org/10.1016/j.mpsur.2018.03.005