Patient-specific computational fluid dynamics analysis of transcatheter aortic root replacement with chimney coronary grafts

Abstract

OBJECTIVES Transcatheter aortic root repair (TARR) consists of the simultaneous endovascular replacement of the aortic valve, the root and the proximal ascending aorta. The aim of the study is to set-up a computational model of TARR to explore the impact of the endovascular procedure on the coronary circulation supported by chimney grafts. METHODS Computed tomography of a patient with dilated ascending aorta was segmented to obtain a 3-dimensional representation of the proximal thoracic aorta, including aortic root and supra-aortic branches. Computed assisted design tools were used to modify the geometry to create the post-procedural TARR configuration featuring the main aortic endograft integrated with 2 chimney grafts for coronary circulation. Computational Fluid Dynamics simulations were run in both pre- and post-procedural configurations using a pulsatile inflow and lumped parameter models at the outflows to simulate peripheral aortic and coronary circulation. Differences in coronary flow and pressure along the cardiac cycle were evaluated. RESULTS After the virtual implant of the TARR device with coronary grafts, the flow became more organized and less recirculation was seen in the ascending aorta. Coronary perfusion was guaranteed with negligible flow differences between pre- and post-procedural configurations. However, despite being well perfused by chimney grafts, the procedure induces an increase of the pressure drop between the coronary ostia and the ascending aorta of 8 mmHg. CONCLUSIONS The proposed numerical simulations, in the specific case under investigation, suggest that the TARR technique maintains coronary perfusion through the chimney grafts. This study calls for experimental validation and further analyses of the impact of TARR on cardiac afterload, decrease of aortic compliance and local pressure drop induced by the coronary chimney grafts.

Hemodynamic changes for half cover Left subclavian artery ostium during thoracic endovascular aortic repair

“…The blood ow satis es the Navier-Stokes equation, in which the blood density (ρ) is 1060 kg/m3 and the blood viscosity coe cient is µ. 0.0035 kg/ms, the number of iterations is 500, the time step is 0.001 s, and the maximum number of iterations is 50 [17].…”

Effects of two different surgical methods for endovascular repair of the thoracic aorta on the hemodynamics of the left subclavian artery

“…The blood ow satis es the Navier-Stokes equation, in which the blood density (ρ) is 1060 kg/m3 and the blood viscosity coe cient is μ. 0.0035 kg/ms, the number of iterations is 500, the time step is 0.001 s, and the maximum number of iterations is 50 [27].…”

Improvement in quality of life by surgical management of the ascending aortic aneurysm

“…However, the need to search for new materials for the formation of aortic prostheses is still relevant. Dacron valve-containing conduits are most often used for ascending aorta and aortic valve replacement [5]. Various methods of preoperative preparation of the Dacron tube have also been proposed to reduce bleeding, however, these techniques made the prosthesis rigid and more rigid, which made it difficult to create anastomoses, especially with the orifices of the coronary arteries [6].…”

“…Recent references are suggested on complications and reoperations in ascending aortic aneurysm shows that a leaky anastomosis is the cause of bleeding, and then the formation of pseudoaneurysms and fistulas. Along with the improvement and widespread use of artificial prostheses for replacing the affected aorta, another original direction, the use of biological tissue was further developed [5,6]. However, experience has shown that the problem of an "ideal" prosthesis has not yet been solved and it is necessary to continue the search for new options for implanting artificial conduits to prevent complications.…”