Evidence on Explants

Project Lead: Cristina Lopez Espada (Join the Project on Twitter)

EVAR is a treatment option widely accepted for AAA. For the last 20 years, it has been established as a safe and effective alternative to Open Repair [1]. One of the most specific complications related to this technique is the appearance of endoleaks, i.e. the existence of blood between the wall of the stent and the wall of the aorta that continues to pressurize the aneurysmal sac increasing the probability of rupture. Endoleaks have been classified into four groups and require extensive monitoring of patients to detect and correct before they could lead to rupture of the aneurysm [2].

In certain circumstances, e.g. due to the impossibility of sorting out these endoleaks and other factors such as stent migration, infection or thrombosis of a branch, the stentgraft must be explanted and replaced by a conventional bypass through a transperitoneal or retroperitoneal approach.

Open surgical conversion of EVAR (OSC) is often regarded as a last resort, reserved to treat complications refractory to endovascular re-intervention. The overall incidence of late open surgical conversion has been reported to be between 2% and 9% [3].

Systematic review and meta-analysis of elective and urgent late open conversation after failed endovascular aneurysm repair

by Goudeketting SR et al.

This report analyses 27 retrospective studies. 791 patients were included: 617 operated on an elective basis and 174 on an urgent basis. 30-day mortality rates for urgent conversions are 10 times higher than those performed electively (28,1% vs. 2,8%), with type I endoleaks being the main cause. Thus, the explant must be carried out before the rupture of the aneurysm occurs, if we want to avoid such a high mortality [4].

Alternatives to Randomised COntrolled Trials for the Poor, the Impatient, and When Evaluating Emerging Technologies

by Mani K et al.

Many of the scientific questions that arise in our daily clinical practice can be answered through different scientific methods: case-control studies, cohort studies and randomized clinical trials (RCT), among others. However, there are complications after medical interventions that due to their low frequency and great complexity require long series of cases and long-term surveillance to assess them. The design of RCT are usually not sufficiently powered for study of such rare events [5].

We have learned over the years that the creation of international research networks can study and analyze this type of low frequency pathologies. The late open conversion of EVARs is the typical example of a long-term complication that should be studied in this field of research and where the union of cases and experience accumulated in different countries might help to answer the questions that raise from these cases.

The international research networks improve vascular care by addressing variations in the use of technology, techniques and evaluation of device performance.

Therefore, within the VASCUNET collaboration, it has been possible to design a research project named VASCUNExplant Project that, using the research resources provided by this international network, could respond to the unknowns surrounding the OSC.
The VASCUNExplant Project is a collaborative and voluntary study with the aim to assess the frequency and outcome of EVAR explantations performed for EVAR failure, based on a large-scale international multicentre collaboration in a modern cohort. It aims to characterise the causes of endograft explantation and identify predictors for unfavourable outcomes for explantation procedures.

Downloads

Protocol (Google Drive Link)

Presentation (Google Drive Link)