A primer on infrarenal abdominal aortic aneurysms

Abstract

Ruptured abdominal aortic aneurysms have an alarmingly high mortality rate that often exceeds 50%, even when patients survive long enough to be transported to hospitals. Historical data have shown that ruptures are especially likely to occur with aneurysms measuring ≥6 cm in diameter, but there are so many exceptions to this that several randomized clinical trials have been done in an attempt to determine whether smaller aneurysms should be repaired electively as soon as they are discovered. More recently, further trials have been conducted in order to compare the relative benefits and disadvantages of modern endovascular aneurysm repair to those of traditional open surgery. This review summarizes current evidence from randomized trials and large population-based datasets regarding two questions that are uppermost in the mind of virtually every patient who is found to have an abdominal aortic aneurysm. Should it be fixed? What are the risks?

Keywords: abdominal aortic aneurysm; endovascular repair; open repair; rupture.

Figure 1.. Images of infrarenal abdominal aortic aneurysms.

( a) Autopsy specimen showing the relationship of an intact infrarenal aneurysm to the renal arteries. ( b) Operative photograph during transabdominal open repair with a knitted bifurcation graft. ( c) Three-dimensional computed tomogram after transfemoral endovascular repair in another patient.

Figure 2.. Eventual repair rates for abdominal aortic aneurysms in the surveillance cohorts of the UKSAT , ADAM , CAESAR , and PIVOTAL trials.

The reasons for the eventual repairs included rupture, the onset of back pain or local tenderness, rapid growth on consecutive ultrasound scans or enlargement to a size exceeding the trial protocol, and patient preference. ADAM, Aneurysm Detection and Management trial; CAESAR, Comparison of surveillance versus Aortic Endografting for Small Aneurysm Repair trial; PIVOTAL, Positive Impact of endoVascular Options for Treating Aneurysms earLy trial; UKSAT, United Kingdom Small Aneurysm Trial.

Figure 3.. Hazard ratios for endovascular aortic aneurysm repair versus open repair in a meta-analysis of pooled individual patient data from the EVAR-1, DREAM, OVER, and ACE trials .

EVAR had a survival advantage at 6 months because of a lower 30-day mortality rate, followed by a gradually higher incidence of aneurysm-related deaths or re-interventions. ACE, Anevrysme de l’aorte abdominale: Chirurgie versus Endoprothese trial; DREAM, Dutch Randomized Endovascular Aneurysm Management trial; EVAR, endovascular aneurysm repair; OVER, Open Versus Endovascular Repair trial.