Abdominal Aortic aneurysms remain among the top 10 causes of death for men in North America, and the mortality rate for ruptured aortic aneurysms has barely changed in decades, hovering around 50% even for those lucky enough to reach emergency surgery.

Many of these deaths could be avoided, a fact confirmed by the UK Multicentre Aneurysm Screening Study (MASS), which followed nearly 68,000 men aged 65-74 for 7 years. Deaths from AAAs were 53% lower in the screened group than in the control group.

While emergency AAA surgery remains perilous and harrowing, our elective surgery techniques are becoming safer and less invasive, so each year the argument for screening and early intervention gets stronger. Ultrasound is quick, cheap and effective, the main downside being the high rate of “incidentalomas” due to the large body volume being screened.

At least 5% of Canadian men aged over 65 have an abdominal aneurysm greater than 3 cm. There’s less data on women but we know they are less frequent. I would continue to screen both sexes indiscriminately until more data is available. If the aneurysm is between 4 and 5 cm, both sexes should be followed clinically with repeat US every 6 months.

Women should be referred to a vascular surgeon for possible intervention if the aneurysm is over 5 cm, and men if it’s over 5.5 cm. Many experts favour referral at over 5 cm for men, too. But an aneurysm of approximately 5 cm in diameter would be of more concern to me in a shorter woman, especially one possessing several cardiac co-morbidities, than in a larger male whose candidacy for surgery would be questionable. Data from patient follow-up in Kingston, ON, suggests women are at four times the risk of rupture (3.9% vs 1% annually) in the 5-5.9 cm range. Above 6 cm, annual risk was 14.1% for men and 22.3% for women.¹

High risk

Screening is especially helpful in high-risk groups. One such group is patients with connective tissue abnormalities such as Marfan’s or Ehlers-Danlos syndrome. Many of these aneurysms will involve the ascending arch of the aorta. It’s estimated that 18% of infra-renal aneurysms are familiar and screening individuals 10 years before the prior generation’s onset of the disease should be considered.

Atherosclerosis and hypertension are also causative factors. In fact, patients with coronary artery disease have a four-fold increased risk of AAA. Peripheral vascular disease is increasingly seen as a comparable risk factor. Smoking hugely increases aneurysm risk, with nearly 95% of AAAs occurring in current or former smokers. Consider screening these patients — there’s an excellent chance you’ll prevent a disaster and save a life.