Endovascular treatment of the ascending aorta - a feasibility study in a porcine model for evaluation of transcardiac access routes
Sabine Wipper, E. Sebastian Debus, Christina Lohrenz, Oliver Ahlbrecht, Christian Detter, Tilo Kölbel.
University Heart Center Hamburg Eppendorf, Hamburg, Germany.
OBJECTIVE: Endovascular treatment of the ascending aorta and the aortic arch is currently performed in selective patients. Multiple tortuous segments may lead to inability to advance or deploy endograft and may prohibit precise stentgraft placement. Aim of this study was to compare feasibility and hemodynamic effects of conventional retrograde-ransfemoral (TFA) to antegrade-transseptal access (TSA) and antegrade-transapical access (TAA) using through-and-through guidewire technique to the ascending aorta for endograft introduction in pigs.
METHODS: TFA (n=6, 52±8kgBW) was compared to TAA (n=6, 54±8kgBW) and TSA (n=6 pigs, 54±6kgBW). Custom-made endografts (polyester-tube + 2 nitinol-stents, 24x32mm) were advanced and deployed under fluoroscopy into the ascending aorta. Myocardial and cerebral perfusion were assessed by fluorescent-microspheres (FM). Transit-time flow measurement (TTFM) on the carotid artery was performed. Hemodynamic parameters were evaluated during baseline (T1), sheath forwarding (T2), endograft deployment (T3) and after retraction of the sheath (T4).
RESULTS: Endograft deployment was feasible in all animals. All coronary arteries remained patent. Cardiac-output, heart rate and central-venous-pressure were stable throughout the whole study in all animals (p=n.s.). During T2 transient hemodynamic alteration due to severe valve insufficiency occurred during TSA and TAA reflected by significantly higher ratio between pulmonary-arterial and mean-arterial pressure (p<0.05), while values remained stable during TFA. During T4 hemodynamic stability recovered within ten minutes in all animals. The innominate artery was partially occluded in 4 animals in each group (66%), reflected by reduced TTFM (p<0.05). There was no periprocedural deterioration of myocardial end cerebral perfusion assessed by FM. Endograft deployment during TAA lasted significantly shorter than in TSA and TFA.
CONCLUSIONS: TSA, TFA and TAA to the ascending aorta are feasible in a porcine model. Transient hemodynamic alteration in TSA and TAA recovered to near preoperative values. TAA caused less hemodynamic alteration. Transcardiac-access might be an alternative route for selective patients in the future.
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