Longitudinal study to changes in shape and motion of the aorta and endoprosthesis after fenestrated endovasculair aneurysm repair

Rationale: Fenestrated endovascular aortic repair (F-EVAR) uses stent grafts with customized fenestrations to treat complex aortic aneurysms in patients at risk of aneurysm rupture. The long-term durability of these stent grafts is hindered by complications requiring reintervention. Especially the perirenal fixation and sealing area is of vital importance. The customized fenestrations in the stent graft are cannulated with stents into the renal and/or mesenteric arteries, challenging the perirenal fixation. Once implanted, the aorta dynamics and the device affect each other in ways that are currently not understood. Pre and post-operative imaging of aortic aneurysm is routinely performed using computerised tomographic angiography (CTA). However, these static techniques do not consider the aorta dynamics.
Consequently, our understanding of the dynamic behaviour of the stent graft and stented target vessels is limited. ECG-gated CTA is a technique that takes the patient’s heart cycle into account, enabling studies to the motion of aorta and implanted devices.



Objective: Information on the dynamics and shape of the stent graft and stented target vessels, and how these change over time will improve our understanding about the fixation and/or sealing of the stent graft, which may help in stent graft selection and in designing stent grafts that are more durable.

Study design: Explorative observational cohort study with aortic abdominal aneurysm (AAA) patients undergoing endovascular repair with the fenestrated Anaconda™ stent graft (F-EVAR).
Study population: The study population consists of 20 patients with an AAA to be treated with F-EVAR, aged >65.



Intervention: Present practise is that all patients with a complex AAA undergo CTA of the abdominal aorta pre-operatively and post-operatively before discharge or after 6 to 8 weeks, after 3 to 6 months, after 12 months, and yearly thereafter. Patients included in this study receive an ECG-gated CTA before intervention and three ECG-gated CTs post-operatively: at discharge, after 6-8 weeks, and after 12 months. Thereafter the routine follow up scheme will be followed.

Main study parameters/endpoints: Of primary interest are the changes in the diameter of the stent ring due to hemodynamic forces and the changes in the dynamic interaction between the main body, the branches, and the renal and/or mesenteric arteries. We distinguish between changes during the heartbeat (pulsatility) and changes over a period of several months (expansion). By relating the observed motions to computational models of the stent and the biomechanics of the vessel wall, the change in vessel compliance can be estimated.



Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The ECG-gated CTA protocol results in a higher dose in comparison to a routine scan. However the additional risk on the chance of acquiring cancer as a result of this higher dose is estimated to be negligible, because the study population has a low life expectancy and only patients above 65 will be included.

Information on the dynamics and shape of the stent graft and stented target vessels, and how these change over
time will improve our understanding about the fixation and/or sealing of the stent graft, which may help in stent
graft selection and in designing stent grafts that are more durable.

-Inclusion of patients complete

-Each included patient is scanned pre-operatively and three times post-operatively until 12 months follow-up.

Present practise is that all patients with a complex AAA undergo CTA of the abdominal aorta pre-operatively and post-operatively before discharge or after 6 to 8 weeks, after 3 to 6 months, after 12 months, and yearly thereafter. Patients included in this study receive an ECG-gated CTA before intervention and three ECG-gated CTs post-operatively: at discharge, after 6-8 weeks, and after 12 months. Thereafter the routine follow up scheme will be followed.