Optimized mitral annuloplasty ring design reduces loading in the posterior annulus

• Type of Material: Article
• Authors: Beatrice E. Ncho, Georgia Institute of Technology; Eric L. Pierce, Georgia Institute of Technology; Charles H. Bloodworth, Georgia Institute of Technology; Akito Imai, University of Pennsylvania; Keitaro Okamoto, University of Pennsylvania; Yoshiaki Saito, University of Pennsylvania; Robert C. Gorman, University of Pennsylvania; Joseph H. Gorman, University of Pennsylvania; Ajit Yoganathan, Emory University
• Language: English
• Date: 2020-05-01
• Publisher: Mosby-Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2019 by The American Association for Thoracic Surgery
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jtcvs.2019.05.048
• Title of Journal or Parent Work: Journal of Thoracic and Cardiovascular Surgery
• Volume: 159
• Issue: 5
• Start Page: 1766
• End Page: +
• Grant/Funding Information: This study was partially supported by the National Heart, Lung and Blood Institute (R01HL113216), and a grant from the National Science Foundation (DGE-1148903; ELP).
• Keywords: Leaflet; Cardiac & Cardiovascular Systems; Valve repair; Science & Technology; Mechanism; mitral regurgitation; Respiratory System; mitral repair; suture forces; Cardiovascular System & Cardiology; mitral annuloplasty; Life Sciences & Biomedicine; Surgery; ring dehiscence; Coaptation; Sut; Shape; Reoperation; Regurgitation; Dehiscence
• Research Categories: Engineering, Biomedical; Health Sciences, Medicine and Surgery; Health Sciences, Health Care Management

Abstract

Objective: The study objective was to develop a novel annuloplasty ring with regional flexibility and assess its suture force dynamics in healthy ovine subjects, as compared to fully-rigid or fully-flexible rings. Methods: Materially heterogeneous rings were created with rigid anterior and posterior, and flexible commissural segments. These rings were created to match the geometry of the Medtronic Profile 3D ring. Each ring was instrumented with ten force transducers to measure cyclic suture forces (FC) and undersized annuloplasty was performed in six healthy ovine subjects. FC were recorded and examined for cardiac cycles reaching a maximum left ventricular pressure of 100, 125, and 150mmHg. FC was compared to previously reported values from fully-rigid Profile 3D and fully-flexible prototype rings. Results: Relative to the fully-rigid, the heterogeneous ring exhibited 48% reduction in Fc at its commissural (rigid vs heterogeneous: 1.80 ± 0.94N vs 0.95 ± 0.52N, p<0.001) and 32% reduction in posterior (1.90 ± 0.92N vs 1.29 ± 0.91N, p <0.001) regions, but not in its anterior region (2.45 ± 1.21N vs 2.23 ± 1.22N, p = 0.279). Relative to the fully-flexible ring, the heterogeneous ring exhibited no significant differences in FC in any region. Conclusions: The reduced FC of the heterogeneous ring relative to the fully-rigid ring, suggest a promising approach to reduce suture loading, while preserving the annular remodeling capability of fully-rigid rings. Future studies in diseased subjects are necessary to explore repair effectiveness of this ring.