Endovascular aneurysm repair in the elderly: First do no harm

Evolving from the first stent graft aneurysm repair performed in Argentina by Parodi ¹ to modern-day fenestrated and branched bespoke endeavours, endovascular repair has become the first-choice elective intervention in patients with supra-threshold aortic aneurysms. Endovascular intervention is frequently quoted to be “safer” than traditional open repair and boasts reduced peri-operative 30-day mortality, as determined by the endovascular aneurysm repair (EVAR)-1 trial. ² Subsequently, EVAR investigators related no long-term advantage of endovascular repair over open repair, and a considerable increase in cost for patients that were deemed fit for open repair. ³ The EVAR-2 trial reported outcomes of endovascular intervention versus conservative management in patients unsuitable for open repair, and determined considerable 30-day mortality without an improvement in overall patient survival. ⁴ Additional trials have confirmed that the endovascular advantage in peri-operative mortality is short lived.

Improved long-term survival may seem superfluous in the elderly, but the price of intervention warrants consideration: the financial considerations of the healthcare provider and the quality of life of the patient. It is now evident that endovascular treatment is not a cost-effective alternative to open repair, ⁵ and through ongoing surveillance and need for re-intervention, has a detrimental impact on quality of life. Additionally, there is considerable room for improvement in the medical management of aneurysm patients: triple therapy with antihypertensives, antithrombotics and statins considerably reduces mortality, but in the UK up to 30% of patients are not receiving these medications. ⁶

Aneurysm repair is indicated when the risk of rupture from an untreated aneurysm exceeds the operative mortality of intervention. The UK Small Aneurysm Trial determined the threshold as 5.5 cm based on a 5% risk of 30-day mortality from open aneurysm repair. ⁷ However, the UK Small Aneurysm Trial excluded patients over 80 years of age. Furthermore, it did not take into account the reduced peri-operative mortality of endovascular repair in the intervention group, and neither did it consider what would now be considered an integral component of best medical therapy: statins. In essence, the threshold for intervention in elderly patients has not been established.

Studies focusing on outcomes of endovascular aneurysm repair in octogenarians confirm higher peri-operative mortality of endovascular intervention as compared with younger patients. A systematic review by Henebiens et al. ⁸ in 2008 estimated 30-day mortality of endovascular aneurysm repair at 4.6% (95% CI 3.4%–6.0%) compared with 7.5% for open surgery. However, they were unable to determine long-term survival following endovascular intervention. More recently, analysis of endovascular repair outcomes from the Vascular Quality Initiative Database determined 30-day mortality of endovascular repair to be 3.8% for octogenarians compared with 1.6% for non-octogenarians, and one-year mortality for octogenarians undergoing EVAR was 8.9%. ⁹

Given the absence of a longevity benefit, and the demonstrably higher (but “acceptable”) peri-operative mortality of endovascular aneurysm repair in the elderly, case-by-case judgement needs to be exercised, and personalised-risk scores may be helpful in guiding the physician. Data combined from two Australian audits determined that one-year survival following endovascular aneurysm repair was best predicted by American Society of Anesthesiologists Physical Status Classification (ASA), creatinine, aneurysm diameter, respiratory function and iliac artery calcification. ¹⁰ Interestingly, age did not factor into the final predictive model, which can therefore be applied in the elderly without the bias of their years.

Both the high financial cost of EVAR and concerns regarding quality of life of the patient are related to the need for surveillance and re-intervention – frequently as a result of endoleaks, occurring in 20% of patients undergoing endovascular aneurysm repair. Karthikesalingam et al. ¹¹ have developed and validated a tool to stratify patients as high or low risk of endoleak based upon CT morphological data. Physiological parameters do not contribute to the risk score, again providing a personalised score potentially utilisable in elderly patients without disadvantaging them based upon age.

With an ageing population, higher utilisation of endovascular repair for older patients ¹² and increasing constraints on healthcare provision, there is a distinct need for better risk stratification and risk modification of elderly patients with large aneurysms. Wherever possible, a personalised approach should be adopted, and decisions to intervene should be influenced by validated risk scoring tools. Although the operative risk of open surgery may be unacceptable, endovascular alternatives do not prolong life, but do contribute to a lesser quality of remaining life.