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div>We depicted in this investigation anisotropic elasticity behaviour of decellularized allografts similar to intact untreated aorta. Additionally, we could underline the significant negative differences in mechanical properties and behavior of synthetic material, which was demonstrated by large changes in stress-strain and stiffness, in comparison with native and decellularized aortic tissue. Nevertheless, we report here for the first time that the observed hemodynamic changes after total aortic arch replacement with conventional prostheses have a profound influence on mechanoenergetics. The unaltered myocardial contractility and the significant increase of Ea led to a marked worsening of the ventriculoarterial coupling ratio in the prosthesis group. The data of the present study suggest that multiple changes of afterload, preload, and left ventricular contractility additively result in unfavorable mechanoenergetics, which is in accordance with previous works. We determined ventricular afterload in terms of TPR and Ea, as well as RIN and Z. Although TPR and RIN showed a tendency towards or significantly lower values, this alteration only characterizes the state of peripheral precapillary resistence arteries, thus it can be unequivocally attributed to the CPR-induced peripheral vasodilatation. Because flow through the cardiovascular system is pulsatile, these conventional parameters of afterload exclude the significant contribution of pulsatile blood flow to the understanding of systemic hemodynamics. Moreover, the important function of large elastic arteries must also be taken into consideration in the aortic arch replacement setting. To further Staurosporine elucidate these aspects of afterload changes, we performed a Fourier analysis for assessment of vascular impedance spectrums distal to the aortic arch. Although RIN showed decreased values after replacement, vascular impedance at harmonics between 1 and 6Hz was markedly increased in the prosthesis group, which is in line with previous studies. This indicates an increased stiffness of the central arterial system and partial loss of the aortic Windkessel function and can be attributed to the synthetic Dacron material with strongly limited elastic properties compared to the native aortic arch. Impaired Windkessel properties increase wall tension and rate of pressure rise, which may have clinical impact with respect to a sudden and sustained rise of mechanical load in the residual aorta, especially at the vulnerable proximal descending part. Moreover, impaired Windkessel function of the aorta has been proven to induce hypertrophy of the left ventricle and might lead to the development of heart failure. In contrast, replacement of the aortic arch with decellularized allografts was associated with unchanged Ees, Ea and VAC, indicating intact mechanoenergetics. Analysis of vascular impedance spectrum in the allograft group revealed completely unaltered, physiological stiffness and elastic properties of the arterial system with the implanted decellularized aortic arch allograft. There are several key findings of this study. First, to the best of our knowledge, this is the first report of the generation of decellularized aortic arch allografts containing a preserved ECM composition. Second, we describe for the first time a successful application of an in-vivo model of total aortic arch replacement with hypothermic circulatory arrest and selective antegrade cerebral perfusion. Third, total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio along with impaired ventricular efficiency after implantation of a conventional prosthesis in our animal model. Implantation of decellularized allografts preserved characteristic impedance and ventricular efficiency, thereby improved ventriculoarterial mechanoenergetics after aortic arch replacement. Fourth, the fabricated aortic arch neoscaffold matches the elastic and viscoelastic properties of untreated aortic tissue. In summary, these studies serve as proof of concept to generate bioengineered aortic arch neoscaffolds as an off-the-shelf alternative over currently available synthetic grafts. The decellularized allograft could be tailored to a range of lengths and diameters, widely available, and easily transported. Our work has the potential for an important clinical contribut