Mitral valve posterior leaflet and subvalvular reconstruction using a 2-ply small intestinal submucosal extracellular matrix sheet as patch material was possible in an acute porcine model. The reconstructed mitral valve was fully functional without signs of mitral valve stenosis, valve regurgitation, stenosis or systolic anterior motion. The ballooning appearance of the patch material might, however, constitute an altered leaflet stress distribution in this area.
Objective
Residual regurgitation is common after congenital surgery for right ventricular outflow tract malformation. It is accepted as there is no competent valve solution in a growing child. We investigated a new surgical technique of trileaflet semilunar valve reconstruction possessing the potential of remaining sufficient and allow for some growth with the child. In this proof-of-concept study, our aim was to evaluate if it is achievable as a functional pulmonary valve reconstruction in vitro.
Methods
Explanted pulmonary trunks from porcine hearts were evaluated in a pulsatile flow-loop model. First, the native pulmonary trunk was investigated, after which the native leaflets were explanted. Then, trileaflet semilunar valve reconstruction was performed and investigated. All valves were initially investigated at a flow output of 4 L/min and subsequently at 7 L/min. The characterization was based on hydrodynamic pressure and echocardiographic measurements.
Results
Eight pulmonary trunks were evaluated. All valves are competent on colour Doppler. There is no difference in mean pulmonary systolic artery pressure gradient at 4 L/min (P = 0.32) and at 7 L/min (P = 0.20). Coaptation length is increased in the neo-valve at 4 L/min (P < 0.001, P < 0.001, P = 0.008) and at 7 L/min (P < 0.001, P = 0.006, P = 0.006). A windmill shape is observed in all neo-valves.
Conclusions
Trileaflet semilunar valve reconstruction is sufficient and not-stenotic. It resulted in an increased coaptation length and a windmill shape, which is speculated to decrease with growth of the patient, yet remain sufficient as a transitional procedure until a long-term solution is feasible. Further in vivo investigations are warranted.
OBJECTIVES
Aortic valve repair procedures for the treatment of isolated aortic valve insufficiency may be improved by stabilizing the functional aortic annulus using a double annuloplasty ring at the aortic annulus and sinotubular junction (STJ). The objective of this study was to compare the geometrical changes and aortic root stress distribution when using a single subvalvular ring and a double sub- and supravalvular ring in vivo.
METHODS
Both the single- and double-ring procedures were performed successively in nine 80-kg pigs. Measurements were performed intraoperatively using sonomicrometry crystals in the aortic root to evaluate geometrical changes and annular and STJ force transducers measuring the segmental radial stress distribution.
RESULTS
The total force in the STJ was significantly reduced after the double-ring procedure from 1.7 ± 0.6 to 0.04 ± 1.1 N (P = 0.001). The double-ring procedure significantly reduced the STJ area from 234.8 ± 37.6 to 147.5 ± 31.8 mm2 (P = 0.001) and expansibility from 17 ± 6% to 8 ± 3% (P = 0.001). With the single-ring procedure, the STJ shape was circular but became more oval with the double-ring procedure. The double-ring procedure did not affect stress distribution or geometry in the aortic annulus.
CONCLUSIONS
The double-ring procedure stabilized the whole aortic root by reducing radial stress distribution in the STJ more efficiently than the single-ring procedure. Both area and expansibility were reduced with the double-ring procedure. These results confirm the importance of addressing the entire functional aortic annulus for optimal aortic valve repair procedures.
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