Ex Vivo Biomechanical Analysis of Pulmonary Autograft Inclusion Techniques in the Ross Procedure

The Ross procedure inclusion technique seeks to limit autograft dilation by enclosing it within a synthetic graft, yet its impact on neoaortic valve function is incompletely characterized. We sought to assess whether different inclusion techniques alter neoaortic leaflet or sinus function.

Eight porcine pulmonic roots were harvested with aortic controls for assessment in a 3D-printed left-heart simulator in the following conditions: unsupported autograft, external annular ring and sinotubular straight graft, Valsalva graft inclusion technique, and straight graft inclusion technique. Hemodynamic, kinematic, and echocardiographic outcomes were measured in systemic and pulmonic conditions.

Valves within a straight graft had higher transvalvular gradients (7.01±0.96 mmHg) compared to the annular/STJ (1.33±0.96 mmHg), unsupported (3.42±0.96 mmHg) and control groups (AC: 3.72±0.96, PC: 1.47±0.96 mmHg, p<0.01). All conditions had similar leaflet velocities, but the Valsalva condition had higher relative opening forces (1.81±0.21) compared to the annular/STJ (0.93±0.21), unsupported (0.98±0.21) and control (AC: 1.00±0.21, PC: 0.97±0.21) conditions (p<0.01). Leaflet forces normalized with Valsalva sinus modification (2mm slit). Root strain was higher in pulmonic controls (18.21±2.35%, p<0.01) while maximum sinus diameter was reduced in the straight graft and pulmonic control conditions relative to supported and unsupported techniques (p<0.01). In a sensitivity analysis of only systemic conditions, more restrictive inclusion techniques had significantly reduced root strain relative to the annular/STJ support condition (p<0.01).

We demonstrate that autografts implanted within common inclusion techniques achieve leaflet and sinus performance comparable to native, unsupported autografts, while likely mitigating the risks of future autograft dilatation and neoaortic insufficiency.