Mechanical properties of aortas and pulmonary arteries of calves implanted with cardiac prostheses

Left ventricular assist devices (LVAD) were implanted in calves of 3-months old between the natural left ventricular apices and middle descending aortas, while total artificial hearts (TAH) were implanted to replace the natural heart ventricles. The stiffness and strength of upper and lower descending aortas obtained from the calves implanted with the LVADs for 1–2 months were significantly lower than those of non-pumped control calves, accompanied by local detachment and damage of endothelial surfaces, while the mechanical properties of the aortas from TAH-implanted calves were very similar to those of the control calves. However, the decreased stiffness and strength of the aortas in the LVAD-implanted calves were recovered to the control levels by pumping for another 1 month or by the pump removal. These characteristic changes in aortic mechanics and structures by the LVAD pumping for an intermediary duration were ascribed to the distortion of blood flow produced around the anastomosis of the pump outflow conduit to the descending aorta.