The hydrodynamic function and leaflet dynamics of aortic and pulmonary roots and valves: an in vitro study

Abstract

Fresh homograft aortic and pulmonary roots were tested in a pulsatile flow simulator to assess their hydrodynamic function and leaflet opening characteristics. Simultaneous flow and pressure measurements were obtained for a range of cardiac outputs. The effective orifice area and regurgitant volumes were calculated. The mean pressure difference across the pulmonary roots was obtained under both left and right side pressures. A video recording of valve leaflet function was also obtained for each valve. A comparison was made with four porcine bioprosthetic heart valves (21 and 23 mm). The mean pressure difference with respect to flow for the 21 mm Hancock II and Intact porcine bioprostheses was significantly higher than that for all aortic roots tested. The 24 mm aortic root showed significantly lower pressure drop compared to all porcine valves tested. The mean pressure difference across each pulmonary root at pulmonary pressures was significantly greater than at systemic pressures. At systemic pressures the fully open leaflets had a triangular orifice with low leaflet open bending strains at the commissures. At the lower internal pressures, with reduced dilation of the root, higher bending strains were noted. These were not as severe as seen in porcine valves.

Development and Characterization of Acellular Porcine Pulmonary Valve Scaffolds for Tissue Engineering

“…The pressure drops generated by the fresh pulmonary roots in this study complied to previous studies. 46,47 The hydrodynamic performance of the acellular roots was similar to the fresh roots. No significant difference was observed for either EOA or leaflet phase durations between the decellularized and fresh pulmonary roots, in any of the flow conditions used.…”

“…The hydrodynamic performance and leaflet kinematics of the acellular pulmonary roots were similar to the fresh valves. The hydrodynamic performance of the fresh porcine pulmonary roots was compared to the pulmonary homograft (the current gold standard) 46 and the fresh porcine pulmonary roots tested by others 47 under similar conditions. The pressure drops generated by the fresh pulmonary roots in this study complied to previous studies.…”

The Ross Procedure

“…Besides the experimental work performed by Lower, elegant biomechanical stress studies performed in Poland by Gorczynski et al 14 in 1982 confirmed that the tensile strength of the pulmonary valve was superior to that showed by the aortic valve. Weerasena et al 15 in 1992 reported the excellent hemodynamics shown by the pulmonary valve. Doubts about short‐ and long‐term structural deterioration of the autograft under systemic pressure were also responded to satisfactorily 16…”

Yorkshire Regional Tissue Bank—Circa 50 Years of Tissue Banking

“…Rigorous donor testing and validation of sterilisation techniques were early priorities (Kearney 1987;Kearney 1988;Aguirregoicoa and Kearney 1989;Kearney 1989;Kearney and Johnson 1991;Kearney et al 1993;Kearney 1997;. Although the basic philosophy for banking of tissues remained Weerasena et al 1992;Ketheesan et al 1994;Harris et al 1995;Kearney and Lomas 1997;Kearney 1999;Lomas et al 2000;Lomas et al 1999;Fisher et al 1990;Butterfield et al 1990;, developments in cryopreservation of tissues Ingham et al 1993;Ketheesan et al 1997;) and the new field of tissue engineering, as applied to skin cell culture (Rowling et al 1988;Taylor et al 1990;Rowling et al 1990;Walters et al 1995;Khammo et al 1997;Daniels et al 1997;Ingham et al 1998), and blood vessels (Haynes et al 1990, Haynes and, were explored within the continuing R&D programme.…”