Predicting the effect on pulse wave reflection of different endovascular repair techniques in abdominal aortic aneurysm using 1D patient-specific models

Abstract

Abdominal aortic aneurysm (AAA) is a pathological dilation of the abdominal aorta, generally distal to the renal arteries. In relation to this, minimally invasive endovascular aortic repair has become a common technique, and great efforts have been made to characterize surgical outcome in terms of endograft displacement, leakages, aneurysm sac enlargement or other post-operative complication. Recently, two novel devices (AFX and Nellix sealing device) were developed to surpass these complications, but there is no work accounting for the effects they may have on the pressure waveform. In this study, we address the problem of generating a patient-specific 1D model of an aortic aneurysm, and compute the impact that these devices can have on pressure, in terms of wave reflection. As a result, we found both endovascular repair devices decrease the reflected wave transient time by one order of magnitude, and that the Nellix device shows increased reflected wave amplitude at proximal abdominal aorta and at renal artery level compared to AFX (33 % and 75 % increase in amplitude ratio compared to a non-diseased aorta, respectively). Due to the importance that pressure at renal site and pulse waveform have on the overall cardiovascular physiology, the validity of these results should be carefully studied in order to develop a patient-specific tool for medical planning of interventions.