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.
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.
Authors: Eric J Keller; S Chris Malaisrie; Jane Kruse; Patrick M McCarthy; James C Carr; Michael Markl; Alex J Barker; Jeremy D Collins Journal: Interact Cardiovasc Thorac Surg Date: 2016-05-30