Compliance mismatch and compressive wall stresses drive anomalous remodelling of pulmonary trunks reinforced with Dacron grafts

Ross operation 23 years after surgery: It should not be a “forgotten” option

“…In our series, we reported a significant increase in diameters at the level of the sinus of Valsalva and STJ at 15 years follow‐up in nonreinforced PA as compared to reinforced autografts 3 . In in‐vivo studies using an experimental model of Ross operation, 9‐13 we demonstrated the physical‐mechanical relation between stress‐strain, somatic growth, and histological remodeling, highlighting the possibility of inducing changes to the properties of the PA by using a semiresorbable prosthesis consisting of expanded polytetrafluoroethylene and polydioxanone as external supports 8,14 …”

“…We previously described with finite‐element analysis, the interplay among material properties of the autograft and aorta, suture regions, geometry, and dilation constraints. This interaction is crucial to determine the effects that actual stress concentrations, strain localization, and deformation gradients have on the success of the Ross operation 3,8 . In our series of Ross operation, we previously reported excellent response of PA in terms of stress and strain to circumferential and longitudinal mechanical stresses for conduit lengths restricted to 35 mm, while the valve leaflets were resistant to 1800 mm Hg of pressure loads 3 …”

Pulmonary autograft in aortic position: is everything known?

“…However, the autograft encased in a straight Dacron prosthetic graft would be dramatically impaired in its pulsatility and compliance. Moreover, we previously demonstrated as Dacron graft and other synthetic polyesters severely impair aortic compliance when used as vascular replacement and elicit a strong inflammatory reaction with significant damage to vessel wall when used a pulmonary artery reinforcement (46,62). From these standpoints, we focused in improving the biomechanical behavior of the reinforced pulmonary artery using a composite biodegradable and auxetic material.…”

“…This composite prosthesis prevented pulmonary autograft dilation while reabsorption of its PDS layer promoted a connective remodeling of the pulmonary autograft wall resulting in a neo-vessel formation, with increased elastin content and therefore potentially improved biomechanical properties. Moreover, application of a bio-resorbable reinforcement is able to modify the behavior of the curve of distensible materials, such as vessels wall, obtaining an increase of their elastic properties (41)(42)(43)46,49). Pre-clinical and clinical evaluations of the biomechanical properties of these reinforced pulmonary autografts might shed new light on the current debate about the long-term fate of the pulmonary autograft after Ross procedure, in order to improve the outcomes of the treated young patients.…”

“…Histologic analysis proved that loss and fragmentation of medial elastin fibers and increased adventitial collagen deposition occur after implantation (36)(37)(38). Since late autograft dysfunction remains a daunting issue in the Ross operation, our group and others tried to characterize the biomechanical aspects of pulmonary autograft failure (39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49) to understand in details the long-term effects and develop future frontiers in both surgical and basic researches.…”