Infrarenal abdominal aortic aneurysm repair: past, present and future or tempus rerum imperator

The first infrarenal open aneurysm repair (OAR), performed by Dubost in 1952, was a milestone of modern vascular surgery. In the aftermath, generations of vascular surgeons have treated the abdominal aortic aneurysm (AAA) by open surgery. Nevertheless, the invasiveness of the procedure, the perioperative blood loss and the advanced age and co-morbidities of the patients called for a more gentle, minimally invasive treatment option, particularly in patients with a high perioperative risk for the OAR [1]. The rest is well known: the first successful endovascular aneurysm repair of an infrarenal AAA by Juan Parodi in 1990 and the endovascular era take-off in the 2000s, which led to the establishment of the endovascular aneurysm repair (EVAR) as the gold standard alongside with the OAR. In the current European Society for Vascular Surgery guidelines, EVAR is regarded as the ‘preferred treatment modality for the infrarenal AAA in case of anatomical suitability and reasonable life expectancy’ due to favourable early postoperative EVAR outcomes with mortality Reduction in comparison to the OAR as reported by randomized control trials [2, 3]. These results stimulated the preferential use of EVAR and the increasing treatment rate of older patients with the severe risk profile, who had not been deemed candidates for elective open surgery. The study by Tseng et al. has been inspired by the temporal evolution of the AAA repair in the Taiwanese health system. The authors used the interrupted time series to evaluate the development and the outcomes of the disposable treatment modalities in elective and emergent groups, before (2000–2004) and after the establishment of the EVAR reimbursement (2010–2016) [4]. Thus, in the first period, only OAR was performed, whereas the second period was marked by the predominant endovascular treatment (2016: 98%) accompanied by the increase in the overall AAA volume and the higher age of treated patients. In the period after the EVAR reimbursement, the 30-day mortality, the 30-day readmission rate, and the hospitalization time decreased, whereas the late mortality and late re-interventions were significantly higher in the EVAR era. This study is based on the Taiwanese National Health Insurance Research Database and comprises 11 000 patients treated for AAA between 2000 and 2016. Thus, its worth lies in the evaluation of the established results (randomized control trials) in a real-world setting. Thereby, the outcomes harmonize with the key findings of the EVAR-1 trial, which also reported superior early survival benefits after EVAR in comparison to the OAR. Comparably with the current study, the late mortality and the rate of re-interventions during the follow-up peaked in the endovascular arm of the EVAR-1 study [5]. Furthermore, Tseng et al. give insights into an almost complete shift from open surgery towards EVAR in a national health system within <2 decades and report the increase of the total AAA volume. Being less invasive, EVAR offers an excellent alternative to the OAR particularly for patients at an advanced age or/and with severe comorbidities, which may be responsible for the increase in the overall number of treated patients. A less extreme, but still comparable treatment modality shift was observed in Europe [6]. Current trends, however, show stagnation or slight decline of EVAR therapy in comparison to the OAR, which may be due to several reasons: First, supported by the current evidence, the European Society for Vascular Surgery guidelines recommend the OAR as the first-line therapy for patients with a life expectancy of >10–15 years. Furthermore, the same guidelines recommend conservative treatment for patients with a limited life expectancy (<2–3 years), as for small, asymptomatic, fusiform aneurysms (≤55 mm) [2]. Second, the current National Institute for Health and Care Excellence (NICE) guidelines strengthen the role of the OAR in the elective AAA treatment and recommend EVAR as the first-line therapy only in the case of severe comorbidity-based perioperative (anaesthetic) risk or hostile abdomen [7]. Third, through the rise of EVAR, the open surgical training has been neglected, which sensitized the vascular society and led to an open debate on how to ensure the survival of open skills for the upcoming generations of vascular surgeons. The article by Tseng et al. underlines the present role of EVAR in the treatment of infrarenal AAA, which is unquestionable. Furthermore, the continuous research and development of new technical EVAR features may further improve the outcomes and, thus, solidify the status of EVAR. However, the current debate and the reappraisal of the open repair in the guidelines may contribute to a more balanced treatment modality choice and patient selection in the future. Conflict of interest: Mario Lescan is a consultant and a proctor for Terumo Aortic and Artivion.