The role of arterial stiffness in the onset of Takotsubo cardiomyopathy observed with noradrenaline administration and intracranial blood injection in rabbits

Takotsubo cardiomyopathy (TCM) has been reported to occur after subarachnoid hemorrhage, and the involvement of a critical activity of catecholamines has been mentioned, but the details of its onset have not been fully clarified. Recently, proper arterial stiffness could be measured with cardio-ankle vascular index. Therefore, we aimed to clarify the role of arterial stiffness in onset of TCM using rabbits under infusion of noradrenaline and injection of blood into brain ventricle. Rabbits were divided into three groups: infusion of noradrenaline (group A), infusion of noradrenaline + injection of saline into the brain ventricle (group B), infusion of noradrenaline + injection of blood in the brain ventricle (group C). Aortic arterial stiffness beta (_Aβ) and femoral arterial stiffness beta (_Fβ) were defined according to definition of the cardio-ankle vascular index. Blood pressure (BP), _Aβ, _Fβ, and femoral vessel resistance (FVR) were measured. Left ventricular movement were monitored with echocardiography. BP increased uniformly in all three groups. _Fβ in the group A, B and C increased from 3.6 ± 3.2, 3.6 ± 3.6 and 3.9_ ± 4.2 to 15 ± 2, 17.9 ± 2.4, 34.8 ± 9.1 due to the ICP enhancements in addition to noradrenaline administration, respectively. _Fβ in groups B and C was significantly larger than that in group A. On echocardiography, a much higher akinesic area of the apex was observed in group C compared with group A and B. Cardiac movements similar to TCM were observed slightly in group B and definitely in group C. Noradrenaline administration infusion and blood injection into the brain ventricle induced TCM accompanying with enhanced femoral arterial stiffness. These results suggested that elevated arterial stiffness might be involved in the formation of TCM in addition to a critical activity of catecholamines and an increase in intracranial pressure with blood injection.