Coarctation of the aorta (CoA) is a congenital heart disease characterized by a severe stenosis of the main artery that delivers blood from the heart to the rest of the body. CoA affects 5,000 to 8,000 births annually in the United States and has a dismal outcome as 90% of patients will die by age 50 if left untreated. Although excellent treatments for CoA exist, life expectancy is substantially reduced and long-term problems including hypertension often develop. The invasive nature of surgical treatments combined with the shorter hospitalization, reduced pain and decreased cost of catheter-based therapies has led to stent implantation playing an increasing role in the treatment of CoA. Stents are permanent metal scaffolds that can be implanted during a minimally-invasive procedure to restore blood flow beyond a vascular blockage. Currently there are no FDA-approved stents specifically designed for children and recent studies have documented several fundamental concerns regarding the use of these stents in a manner other than that for which they were intended (i.e. off-label). These concerns include whether or not the stent can increase in size as the child grows and its potential to cause adverse changes in the stiffness and structural components of the aorta, residual stress imparted on the left ventricle of the heart and hemodynamic factors including blood flow, pressure and the frictional force acting on the walls of the aorta and its branches as a result of flowing blood. The objective of this investigation is to answer several of the pressing questions that have surfaced since the initial use of stents for the treatment of CoA. This objective will be accomplished by combining the results of an experimental model of CoA that introduces changes in blood flow, blood pressure and aortic structure resembling those observed clinically with computer-based representations of the blood vessel environment generated from medical imaging data. Concurrently, medical imaging data from untreated and treated human patients with CoA will also be used to create computer-based representations of the blood vessel environment and measure changes in hemodynamic factors resulting from stent implantation. The collective results from these computational models and analysis of changes in cardiac and vascular structure and function will reveal important information that can be extremely difficult or time consuming to acquire in a clinical situation, but is vital to truly understanding the impact of stents on the treatment of CoA. In this manner, we will be able to investigate concerns and elucidate any potential sources of long-term problems associated with stenting decades before they are clinically apparent.
Congenital heart disease is the most common birth defect and the leading cause of death due to birth defects. Stent implantation continues to emerge as a potential means of treating aortic coarctation, one of the most common forms of congenital heart disease. None of the stents currently used to treat aortic coarctation are FDA-approved indicating that these devices are not being used for their specified purpose and this project will therefore quantify stent-induced changes in arterial and cardiac structure and function to determine the ultimate utility of stents for the treatment of aortic coarctation.
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