6 - Thoracic, thoracoabdominal and suprarenal aortic aneurysms

Summary

Key points

• Aneurysm disease affects the thoracic aorta much less commonly than the infrarenal aorta

• Most patients are asymptomatic but may have chest, back or abdominal pain

• Diagnosis is on computed tomography (CT) angiogram and the Crawford classification is used to describe the extent of the aneurysm

• Intervention is recommended if the aneurysm is >6 cm (or 5 cm in the presence of a connective tissue disorder or a family history of rupture)

• Open surgery remains the standard treatment for complex suprarenal, thoracic and thoracoabdominal aneurysms

• Specific complications incude risks of paraplegia and renal and visceral ischaemia

• Endovascular repair is suitable for descending thoracic aneurysms

Epidemiology

The incidence of aneurysmal disease affecting the suprarenal aorta and the thoracic aorta is difficult to estimate since it is a condition that is usually asymptomatic and rupture, which is often rapidly fatal, is commonly misattributed to other causes such as myocardial infarction or pulmonary embolism. The incidence is approximately 6 per 100,000 people per year. Males are affected about twice as commonly as females but interestingly the gender difference is less than for infrarenal aortic aneurysms, where the ratio is up to 7:1.

Natural history data are scarce, typically involving retrospective observation of patients not fit for open repair. In a series of 1600 cases the rupture risk for a 6 cm aneurysm of the thoracic aorta was 3.6% per year and for the composite endpoint of rupture/dissection/death the annual risk was 14.1%.