Aortic Leaflet Stress in Surgery for Genetically Determined Root Aneurysms: Biomechanical Insights

Abstract

We are grateful to Tasca and colleagues [1] for their comparative biomechanical study of valve-sparing root replacement with the sleeve or David techniques. We believe that their results and our own studies of flow and wall stress after personalized external aortic root support (PEARS) are complementary [2,3]. Our studies with sheep [4,5] show consistently that the PEARS mesh is incorporated into the aortic wall, which is stabilized and believed to be structurally as strong as a tube graft. We are particularly interested in their findings with respect to the aortic valve leaflets, which we have not studied ourselves.In the 1990s, when surgeons were achieving consistently good results with the modern Bentall, one of the unknowns in adopting valve-sparing surgery was whether the integrity of the leaflets could be relied upon. Subsequent clinical follow-up studies have shown that the leaflets generally prove durable. This new study of the biomechanics of valve-sparing root replacement adds further reassuring information that may be directly applicable to PEARS [1]. Specifically, their study indicates that preserved leaflet and sinus continuity may be a favorable feature of the sleeve compared with the David. This advantage is likely to apply to PEARS in which all the relationships are preserved, completely unchanged, and the vascular endothelium remains intact.Both simplifying the operation and reducing complications seem to be worthwhile and achievable goals. Considering our own biomechanical results [2,3] in the light of this study, we are optimistic that the PEARS mesh-aorta composite will offer the stability required to allow long-term aortic valve function.

Reply

“…Our numerical simulations showed that after the sleeve procedure, stresses in the leaflet belly, at the commissures, and at the interleaflets triangles, respectively, are 35%, 44%, and 28% lower than those associated with the David procedure [2]. Motivated by Izgi and colleagues [1], we further analyzed our data focusing on the diastolic geometry of the aortic root, as increased peak stresses may be associated with geometrical factors: leaflet curvature, because stresses in pressurized membranous structures depend on curvature; and discontinuities at the leaflet-graft transition, which may induce stress concentrations or influence leaflet configuration. Our results suggest that geometrical discontinuities at the leaflet-graft transition likely play a role.…”

“…Subsequent clinical follow-up studies have shown that the leaflets generally prove durable. This new study of the biomechanics of valve-sparing root replacement adds further reassuring information that may be directly applicable to PEARS [1]. Specifically, their study indicates that preserved leaflet and sinus continuity may be a favorable feature of the sleeve compared with the David.…”

“…We would like to thank Izgi and colleagues [1] for their comments on our research [2]. We are aware of their studies and of the excellent clinical results of the personalized external aortic root support (PEARS), which we follow with interest.…”

“…We read with great interest the research article by Navia and colleagues [1] on tricuspid regurgitation (TR) associated with ischemic mitral regurgitation (MR) in which the authors proposed a new insight into ischemic TR. They hypothesized that ischemic TR might be a direct consequence of rightsided ischemic disease.…”

“…

We are grateful to Tasca and colleagues [1] for their comparative biomechanical study of valve-sparing root replacement with the sleeve or David techniques. We believe that their results and our own studies of flow and wall stress after personalized external aortic root support (PEARS) are complementary [2,3].

…”