Effect of anterior strut chordal transection on the force distribution on the marginal chordae of the mitral valve

• Type of Material: Article
• Authors: Muralidhar Padala, Emory University; Lazarina Gyoneva, Georgia Institute of Technology; Ajit Yoganathan, Emory University
• Language: English
• Date: 2012-09-01
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: Copyright © 2012 by The American Association for Thoracic Surgery.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jtcvs.2011.10.032
• Title of Journal or Parent Work: Journal of Thoracic and Cardiovascular Surgery
• ISSN: 0022-5223
• Volume: 144
• Issue: 3
• Start Page: 624
• End Page: +
• Grant/Funding Information: M.P. was supported by an American Heart Association Fellowship (#0815159E) during the course of this study at Georgia Institute of Technology; L.G. was supported by a Georgia Tech Presidential Undergraduate Fellowship; and A.Y. and the research work were partially supported by NHLBI grant R01-HL090661.
• Keywords: MECHANISM; TENDINEAE; TENSION; Cardiovascular System & Cardiology; Science & Technology; INSIGHTS; EFFICACY; Respiratory System; MYOCARDIAL-INFARCTION; Cardiac & Cardiovascular Systems; REGURGITATION; LEAFLET; Surgery; Life Sciences & Biomedicine; TRANSLOCATION; IN-VITRO
• Research Categories: Engineering, Biomedical; Health Sciences, Medicine and Surgery

Abstract

Objectives: Transection of the secondary chordae on the anterior leaflet of the mitral valve to relieve leaflet tethering and reduce regurgitation is an experimentally proven procedure to correct functional mitral regurgitation. In the present study, we sought to investigate whether transecting the secondary chordae would have an effect on the marginal chordal force on the same leaflet. Methods: Adult porcine mitral valves (n = 8) were studied in a pulsatile heart simulator, in which the papillary muscle positions can be precisely positioned. Miniature transducers were inserted into the anterior marginal chordae to measure the chordal forces. Each valve was studied under baseline conditions, 3 different tethering conditions (apical, apical-lateral, and apical-lateral- posterior), and after chordal cutting in the 3 tethering conditions. The temporal changes and peak and average marginal chordal forces under each condition are reported. Results: Apical tethering increased the marginal chordal force by an average of 96% but remained unchanged after chordal cutting. With apical-lateral tethering, the marginal chordal force increased by 210% from baseline and increased further to 350% of baseline after chordal cutting. After apical-lateral-posterior tethering, the marginal chordal force increased to 335% of baseline before transection and by 548% after transection. Conclusions: The increase in the marginal chordal force after secondary chordal cutting depends on the location of the papillary muscles and the extent of leaflet tethering. Although chordal cutting might not alter the valve mechanics under minimal leaflet tethering, it significantly affects the mechanics when the leaflet tethering is more pronounced, which is typically seen in patients with functional mitral regurgitation.