Key result
Atrial appendage-derived neo-valves match native burst pressures at ~104 mm Hg despite lower tissue elasticity.
Why the study?
Whether atrial tissue's tensile strength correlates with pressures it can withstand to function as a neo-semilunar valve had not been studied.
Does right atrial appendage tissue have sufficient mechanical strength to function as a neo-semilunar valve in an ex vivo porcine model?
Does right atrial appendage tissue have sufficient mechanical strength to function as a neo-semilunar valve in an ex vivo porcine model?
Right atrial appendage tissue exhibits greater distensibility than native semilunar cusps but can withstand physiological hydrostatic pressures, supporting its potential use in pediatric valve reconstruction.
Mechanical mismatch with native cusps warrants caution for reconstruction; leaves open suitability as neo-valve material.
Background: Pediatric pulmonic and aortic valve insufficiency has recently been treated with novel procedures that use autologous right atrial appendage tissue. Whether atrial tissue's tensile strength correlates with pressures it can withstand to function as a neo-semilunar valve has not been studied. We therefore studied these properties using an ex vivo porcine heart model. Methods: Aortic cusps, pulmonic cusps, and right and left atrial appendage tissues were excised from 10 porcine hearts. Native leaflets and atrial appendage samples underwent circumferential and radial stretching by a uniaxial tensile machine. Right atrial appendage tissue from 14 additional porcine hearts was used to reconstruct neo-pulmonic and neo-aortic valves that were hydrostatically pressurized until failure. Results: The modulus of elasticity was significantly greater in aortic (3.11 ± 0.53 MPa circumferential; 1.31 ± 0.29 MPa radial) and pulmonic (2.99 ± 0.46 MPa circumferential; 1.12 ± 0.24 MPa radial) cusps than in right (0.36 ± 0.06 MPa circumferential; 0.30 ± 0.04 MPa radial) and left (0.41 ± 0.07 MPa circumferential; 0.36 ± 0.06 MPa radial) atrial appendage tissues. The average hydrostatic pressure at valve failure was similar between neo-pulmonic (104.9 ± 4.9 mm Hg) and neo-aortic (102.7 ± 2.4 mm Hg) valves. Conclusions: Atrial appendage tissue's greater distensibility may allow greater leaflet coaptation and accommodate expansion over time, enhancing growth potential. However, the greater pliability may predispose to valve prolapse if too much tissue is used or in the setting of elevated diastolic pressures. Longitudinal studies are warranted to further explore the potential of atrial tissue for valve reconstructions.
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Behrmann et al. (2025) studied Pediatric pulmonic and aortic valve insufficiency (n=24). Right atrial appendage tissue vs. Native aortic and pulmonic cusps was evaluated on Modulus of elasticity and hydrostatic pressure at valve failure. Atrial appendage tissues had a significantly lower modulus of elasticity than native aortic and pulmonic cusps, while reconstructed neo-valves failed at similar hydrostatic pressures (~103-105 mm Hg).
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