Pathophysiological Changes Of Overstretching Aortic Valve And Annulus With Balloon In The Rabbit Model

Objective：In this study, we attempted to establish a rabbit model of overstretchingaortic valve and annulus with balloon, which simulated the process of expanding Aorticvalve and annulus with balloon in PBAV and TAVR. The aim of this study was toexplore the acute complications and the pathological and physiological changes after therabbit aortic valve and annulus were overexpanded.Methods：Thirty New Zealand male rabbits which were healthy, clean and mature werechosed. Then they were randomly devided into three groups of A, B and C. Arepresented the control group, B represented the group with the balloon but withoutexpansion in the aortic valve, C represented the group that the aortic valve wasexpanded by the balloon. Blood samples and experimental data were collected at thetime of T1, T2and T3in A and B group. Blood samples and experimental data werecollected at the time of T0, T1, T2and T3in C group.Blood and heart samples werecollected after the experiment.Results：1.IL-6and cTnI were not significantly changed at T2and T3with T1among A, B and Cgroups.2. CRP and BNP were not significantly changed at T2and T3with T1in A group. CRPand BNP were significantly changed at T2and T3with T1in B and C group.3. SBP and DBP have no significant change in T1in A, B and C group. SBP and DBPhave significant change in T2in A, B and C group except SBP between A and B group. SBP and DBP have significant change in T3in A, B and C group.4. There were no significant changes in ECG in A and B group. There were1case ofST-segment elevation and2cases of ventricular fibrillation in C group.5. The size and color of hearts showed no obvious differences among A, B and C groups.Visible injuries of aortic valve, aortic annulus, aortic wall and myocardium were notobserved.6. Injuries of aortic valve, aortic annulus, aortic wall and myocardium were notobserved in A group. Mild injury of myocardium but no damages of aortic valve, aorticannulus and aortic wall were observed in B group. Severe injury of myocardium wasobserved in C group, but aortic valve and aortic wall were not obviously damaged.Injuries of aortic annulus were not observed in C group.Conclusion:1. cTnI and IL-6were not significantly changed after the aortic valve and annulus ofrabbit were overstretched.2. BNP and CRP were significantly increased after the aortic valve and annulus of rabbitwere overstretched.3. Overstretching the aortic valve and annulus contributed to cardiac dysfunction,manifested as inflammation, heart failure, cardiac conduction system injury, myocardialischemia, and damage of aortic valve, aortic wall and myocardial.4. cTnI and IL-6were not significantly changed after prolonged placement of the aorticvalve with balloon. BNP and CRP were significantly increased after prolongedplacement of the aortic valve with balloon. The injury and increase of BNP and CRPcaused by prolonged placement of the aortic valve with balloon was slighter than thatresulted from overscratching the aortic valve.