Ex Vivo Modeling of Atrioventricular Valve Mechanics in Single Ventricle Physiology

Single ventricle physiology (SVP) is used to describe any congenital heart lesion that is unable to support independent pulmonary and systemic circulations. Current treatment strategies rely on a series of palliation surgeries that culminate in the Fontan physiology, which relies on the single functioning ventricle to provide systemic circulation while passively routing venous return through the pulmonary circulation. Despite significant reductions in early mortality, the presence of atrioventricular valve (AVV) regurgitation is a key predictor of heart failure in these patients. We sought to evaluate the biomechanical changes associated with the AVV in SVP physiologies. Left and right ventricles were sutured onto patient-derived 3D-printed mounts and mounted into an ex vivo systemic heart simulator capable of reproducing Norwood, Glenn, Fontan and Late Fontan physiologies. We found that the tricuspid anterior leaflet experienced elevated maximum force, average force, and maximum yank compared to the posterior and septal leaflets. Between physiologies, maximum yank was greatest in the Norwood physiology relative to the Glenn, Fontan, and Late Fontan physiologies. These contrasting trends suggest that long- and short-term mechanics of AVV failure in single ventricle differ and that AVV interventions should account for asymmetries in force profiles between leaflets and physiologies.

Automated summary

Single ventricle physiology refers to congenital heart lesions that cannot support independent pulmonary and systemic circulations. Treatment strategies involve a series of surgeries that lead to Fontan physiology, relying on a single functioning ventricle for systemic circulation. Atrioventricular valve (AVV) regurgitation is a predictor of heart failure in these patients. Biomechanical changes of the AVV were evaluated using patient-derived 3D-printed mounts and an ex vivo heart simulator. The study found asymmetries in force profiles between leaflets and physiologies, suggesting the need for AVV interventions to account for these differences.