Characterizing neoaortic valve biomechanics in the ross procedure

The National Heart, Lung, and Blood Institute awarded The Leland Stanford Junior University $163,160 on February 12, 2027, under the Cardiovascular Diseases Research program (CFDA 93.837) to characterize neoaortic valve biomechanics in the Ross procedure for congenital aortic valve disease.

The research addresses durability limitations of the Ross procedure, in which a patient's healthy pulmonic valve is translocated to the aortic position. While the procedure offers a living valve replacement that can grow with a patient, the pulmonic autograft risks dilation as it adapts to systemic pressures, ultimately causing valvular failure. The project pursues a multimodal approach combining computational modeling, ex vivo simulation, and large animal in vivo studies to optimize Ross autograft durability. Aim 1 evaluates whether external autograft support—using reinforcement with a straight Dacron jacket, Valsalva-style jacket, or straight jacket with large sinus fenestrations—preserves normal valvular function. Aim 2 assesses how age at Ross implantation affects changes in in vivo autograft function and root mechanics through four-dimensional magnetic resonance imaging and echocardiographic analysis, with tissue sample analysis to uncover cellular or biomechanical differences. The award is classified as a Project Grant, with a period of performance from February 12, 2027, through February 11, 2028, and place of performance in California.

Abstract

Congenital cardiac disease affects up to 1% of the population with aortic valve disease being among the most common. Current valve replacement prosthetics are limited: mechanical valves require a lifetime of high-risk anticoagulation therapy, bioprosthetic valves have high rates of structural failure, and neither option grows with patients as they age. The ross procedure, where a patient's healthy pulmonic valve is translocated to the aortic position, offers a living valve replacement that can grow with a patient and restores a normal life expectancy. However, the ross pulmonic autograft is at risk of dilation as IT adapts to systemic pressures, ultimately causing valvular failure. For young adults that have completed most of their growth, some surgeons have turned to external support "jackets" to minimize this risk and maximize ross durability. In patients who are too small to have external synthetic support, others have questioned whether changing the age of ross autograft implantation affects long-term durability. This proposal offers a comprehensive, multimodal approach to optimize ross autograft durability. Aim 1 evaluates whether modifications in external autograft support preserve normal valvular function. Using patient- specific fluid-structure interaction models, we will assess whether reinforcement with a straight dacron jacket, valsalva-style jacket, or straight jacket with large sinus fenestrations changes valve function. These results will be validated on our custom EX vivo simulator and translated into large animal in vivo studies. Aim 2 assesses how age at the time of ross implantation affects changes in in vivo autograft function and root mechanics with robust, four-dimensional magnetic resonance imaging and echocardiographic analysis. Finally, tissue samples will be analyzed to uncover cellular or biomechanical differences. Combining state-of-the-art computational simulation, high-fidelity EX vivo modeling, and large animal in vivo validation, this proposal offers a powerful assessment of how to optimize the ross procedure. These experiments will determine the most optimal implantation technique and timing of surgery, making the ross more durable, standardized, and approachable to surgeons as they work to reduce the burden of aortic valve disease.