Prosthetic replacement of the aorta is a risk factor for aortic root aneurysm development.
BACKGROUND
Noncompliant prostheses are used in aortic replacement. We hypothesized that this leads to increased distension and wall stress in the aortic root because of the loss of ventriculo arterial coupling.


METHODS
Pressure relations in the aortic root caused by changes of aortic elasticity simulating prosthetic aortic replacement were tested in a computer model. We then developed an in vitro model using porcine aortas and performed in vivo validation.


RESULTS
Findings in vitro and in vivo confirmed the predicted changes of the computer model. Pressure amplitude increased significantly by 17% after prosthetic replacement (p < 0.01). Pressure-time differential (Dp/dt) and dicrotic notch pressure amplitude both increased significantly. Echocardiography demonstrated systolic aortic root distension with percentage area change increasing in vitro from 28.2%+/-9.7% to 35.9%+/-10% (p < 0.05) and in vivo from 13.3%+/-3.1% to 24.3%+/-3.1% (p < 0.0001). Aortic root wall stress increased markedly.


CONCLUSIONS
Replacement of the aorta with vascular prostheses causes important negative alterations of hemodynamics and increases in wall stress.
Simon-Kupilik
Natascha
N
Department of Cardiac and Thoracic Surgery and LBI for Cardiosurgical Research, Institute for Biomedical Engineering, University of Vienna, Austria.
Schima
Heinz
H
Huber
Leopold
L
Moidl
Reinhard
R
Wipplinger
Gerhard
G
Losert
Udo
U
Wolner
Ernst
E
Simon
Paul
P
D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D001794:Blood Pressure / Q000502:physiology; D019917:Blood Vessel Prosthesis Implantation; D003198:Computer Simulation; D004548:Elasticity; D006801:Humans; D008955:Models, Cardiovascular; D011183:Postoperative Complications / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D011474:Prosthesis Design; D013552:Swine; D014655:Vascular Resistance / Q000502:physiology