Transapical coapatation plate for functional mitral regurgitation: An in vitro study

dc.contributor.committeeChairHe, Zhaoming
dc.contributor.committeeMemberLacerda, Carla
dc.contributor.committeeMemberParameswaran, Siva
dc.contributor.committeeMemberIdesman, Alexander V.
dc.contributor.committeeMemberRen, Beibei
dc.creatorZhang, Kailiang
dc.date.accessioned2019-02-14T17:11:47Z
dc.date.available2019-02-14T17:11:47Z
dc.date.created2018-12
dc.date.issued2018-12
dc.date.submitted2018-12
dc.date.updated2019-02-14T17:11:47Z
dc.description.abstractA novel transapical coaptation plate (TCP) device was developed and anchored by sutures and apical beam support in the mitral valve to treat functional mitral regurgitation. The objective of this study was to test efficacy of the TCP in an in vitro model. Two groups of fresh porcine mitral valves were mounted in a left heart simulator to simulate functional mitral regurgitation by means of annular dilatation and asymmetrical or symmetrical papillary muscle (PM) displacement. First study, six polyurethane TCPs in thickness of 6.4(#1), 4.8(#2), 3.2(#3) mm and hardness of durometer 30 A (H) and 30 OO(S), were fabricated and labeled as H1, H2, H3 and S1, S2, S3, respectively. These TCPs were anchored by the sutures in the mitral annulus and left ventricle myocardium apex, and tested with eight valves. Steady backward flow leakage in a hydrostatic condition and regurgitant volume in a pulsatile flow were measured before and after implantation of the TCPs. Mean regurgitant volume fractions in the asymmetric PM displacement were reduced significantly from 59.1 to 37.2% for H1, 43.2% for H2, 35.9% for S1 and 34.2% for S2 (p<0.021), after implantation of the TCPs. No significant reduction in mitral regurgitation was seen for H3 and S3 (p>0.067). Mitral regurgitation was mild in the symmetric PM displacement, and was not significantly reduced after implantation of the TCPs. In conclusion, the TCP anchored by the sutures in the mitral annulus and left ventricle apex functions successfully as a plug in the mitral valve leaflet gap. The TCP with thickness equal to or greater than 4.8 mm is effective to reduce functional mitral regurgitation. The TCP hardness has no effect on difference in reduction of functional mitral regurgitation. Another ten valves were tested by eight plates with different thickness as 6-6-6, and 9-6-9 mm, two variable widths as 30 and 35mm, and two angles between plate and beam were 0º and 30º under hydrostatic and hydrodynamic conditions before and after implantation of 3D bar TCPs. Mean regurgitant volume fractions in the asymmetric PM displacement were reduced significantly from 44.2±4.8% to below 35% after insertion of the 6-6-6 (31.7±1.7%), 9-6-9 (34.3±1.8%), 6-6-6(W) (23.3±1.7%), 9-6-9(W) (20.8±2.8%), 6-6-6(A) (30.2±3.4%) 9-6-9(A) (29.2±1.5%), 6-6-6(A, W) (18.5±2.3%) and 9-6-9(A, W) (22.3±1.4%), because all p values were less than 0.017. Mitral regurgitation was still mild in the symmetric PM displacement, and the reductions were also changed significantly from 22.3±3.6% to 22.9±6.4% (6-6-6), 19.9±5.6% (9-6-9), 14.9±2.1% (6-6-6(W)), 21.2±2.2% (9-6-9(W)), 20.2±2.5% (6-6-6(A)), 20±4.1% (9-6-9(A)), 19.7±1.8% (6-6-6(A, W)), and 18.5±2.4% (9-6-9(A, W)) (All p<0.001). In conclusion, two types of TCPs were all successful as a plug in the mitral valve leaflet gap. The TCP with thickness equal to or greater than 4.8 mm is effective to reduce functional mitral regurgitation. The TCP hardness has no effect on difference in reduction of functional mitral regurgitation. And the apical forces were in a small range from 1.8 to 2.3 N. The EOA values were decreased following plate’s the cross-section area increasing.
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/2346/82729
dc.language.isoeng
dc.rights.availabilityAccess is not restricted.
dc.subjectFunctional Mitral Regurgitation
dc.subjectTransapical Coapataion Plate
dc.titleTransapical coapatation plate for functional mitral regurgitation: An in vitro study
dc.typeThesis
dc.type.materialtext
thesis.degree.departmentMechanical Engineering
thesis.degree.disciplineMechanical Engineering
thesis.degree.grantorTexas Tech University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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