For the pediatric and adolescent patients diagnosed with aortic valve disease, a major challenge is determining the optimal surgical treatment. Bioprosthetic tissue valves degenerate over several years, while mechanical valves necessitate anticoagulation. Both of these also pose additional dilemma for the growing patient, and require repeated surgery to implant a larger valve. The Ross procedure is the only procedure that transplants a living valve to the aortic valve position, using the patient’s own pulmonary root and valve termed the ‘pulmonary autograft.’ With excellent hemodynamics, no need for anticoagulation, and a valve that can grow with the patient, the Ross procedure seems to offer an ideal solution for these patients.

However, the Achille’s heel of the Ross procedure is autograft dilatation, plaguing up to 25% of cases, which can lead to aortic valve insufficiency and aneurysm formation. The implications of taking pulmonary arterial tissue, which in its native setting experiences blood pressure in the range of 25/8mmHg, to the aortic position where it experiences pressures of 120/80mmHg imparts drastic changes on the pulmonary autograft’s wall stress. Given the native differences in the material properties and histology of the pulmonary artery versus aorta, coupled with pressure differences, a remodeling process is triggered. By characterizing pulmonary root material properties, and modeling dilated and non-dilated pulmonary autografts both ex-vivo and in-vivo, we will uncover how biomechanics contributes to this pathological remodeling process.