Annulus tension in the tricuspid valve: The effects of annulus dilation and papilliary muscle movement
| dc.contributor.committeeChair | He, Zhaoming | |
| dc.contributor.committeeMember | Idesman, Alexander V. | |
| dc.creator | Smith, Dylan | |
| dc.date.accessioned | 2016-11-14T23:34:19Z | |
| dc.date.available | 2012-10-24T16:02:46Z | |
| dc.date.available | 2016-11-14T23:34:19Z | |
| dc.date.issued | 2012-08 | |
| dc.description.abstract | Tricuspid valve (TV) annular dilatation compromises TV coaptation and may lead to regurgitation. Annular mechanics involves interaction between the TV leaflets and right ventricle myocardium and plays a role in annular dilatation. Annulus tension (AT) is a leaflet force on the annulus and contributes to understanding of annular dilatation. The objective for this study was to determine the effect of PM position and annulus dilation on AT. Force transducers were attached to the porcine TV annulus using a TV closure test rig. The test rig allowed us to apply 40 mmHg of pressure on the TV and adjust the size of the annulus to the normal and dilatated size, which were 9.0 cm2 and 50% increase in area. Papillary muscles were secured and adjusted to simulate papillary muscle displacement, which are 5 mm apical displacement, 5mm lateral displacement, and 5 mm both apical and lateral displacement of the anterior papillary muscle. AT was measured in a normal and 3 pathological papillary muscle positions for a normal and a dilatated annuli. Eight TVs were tested. AT peaked at the commissures for both normal and dilatated annuli. The average AT in the normal TV was approximately 8.9 N/m with the highest AT along the posterior segment of the annulus. The average AT for the dilatated annulus was 16.3 N/m which was almost a 90% increase. The greatest average increase was found along the septal and anterior commissures and the smallest increase along the posterior commissure. As compared with average AT in the normal annulus, the average AT increased by 18.0%, 7.9%, and 30.3% for a 5mm apical, 5mm lateral, and both 5mm apical and lateral PM displacements, respectively. The similar AT distribution was found for both annuli. The apical anterior papillary muscle displacement increased AT evenly throughout the entire annulus. The lateral anterior papillary muscle displacement lowered AT in the anterior commissure and increased AT in other segments. Both apical and lateral anterior papillary muscle displacement caused no change of AT in the anterior commissure for the normal annulus, lowered AT in the anterior commissure for the dilated annulus, and increased AT in all other segments. In the normal annulus, the average AT is significantly increased(p<.05) for the apical and both apical and lateral anterior papillary muscle displacement, with no significant change for lateral anterior papillary muscle displacement. In the dilated annulus, the average AT is significantly increased only for the both apical and lateral anterior papillary muscle displacement, and not changed for the other two anterior PM conditions. TV AT is smaller in the TV than that in the mitral valve, which indicates the TV interacts with right ventricle wall in a weak manner. The increase in AT due to annulus dilatation and papillary muscle displacement helps to counteract TV annular dilatation. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/2346/46716 | |
| dc.language.iso | eng | |
| dc.rights.availability | Unrestricted. | |
| dc.subject | Annulus tension | |
| dc.subject | Tricuspid valve | |
| dc.subject | Annulus dilation | |
| dc.title | Annulus tension in the tricuspid valve: The effects of annulus dilation and papilliary muscle movement | |
| dc.type | Thesis |