Mitral Annuloplasty Ring Suture Forces: Impact of Surgeon, Ring, and Use Conditions

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 155; no. 1; pp. 131 - 139.e3
• Main Authors: Pierce, Eric L., BS, Bloodworth, Charles H., BS, Siefert, Andrew W., PhD, Easley, Thomas F., MS, Takayama, Tetsushi, MD, Kawamura, Tomonori, MD, Gorman, Robert C., MD, Gorman, Joseph H., MD, Yoganathan, Ajit P., PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2018
• Subjects: annuloplasty; Cardiothoracic Surgery; dehiscence; force; medical device design; mitral valve; recurrent, regurgitation; suture; true-sized ring; cyclic contractile force; Profile3D TM ring; tie-down force; RT; undersized ring; Ant; Physio ring; Post; F C; LT; posterior; F TD; right trigone; anterior; IMR; 3D; T; U; ischemic mitral regurgitation; Ph; left trigone; LVP max; maximum left ventricular pressure; annuloplasty; recurrent, regurgitation; suture; medical device design; dehiscence; ANOVA; FTD; mitral valve; force; LVPmax; FC
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/j.jtcvs.2017.06.036

Abstract Objective – To quantify the effect of ring type, ring-annulus sizing, suture position, and surgeon on the forces required to tie-down and constrain a mitral annuloplasty ring to a beating heart. Methods – Physio or Profile3D annuloplasty rings were instrumented with suture force transducers and implanted in ovine subjects (N=23). Tie-down forces and cyclic contractile forces were recorded and analyzed at ten suture positions and at three levels of increasing peak left ventricular pressure. Results – Across all conditions, tie-down force was 2.7±1.4N; cyclic contractile force was 2.0±1.2N. Tie-down force was not meaningfully affected by any factor except surgeon. Significant differences in overall and individual tie-down forces were observed between the two primary implanting surgeons. No other factors were observed to significantly affect tie-down force. Contractile suture forces were significantly reduced by ring-annulus true-sizing. This was driven almost exclusively by Physio cases, and by reduction along the anterior aspect, where dehiscence is less common clinically. Contractile suture forces did not differ significantly between ring types. However, when undersizing, Profile3DTM forces were significantly more uniform around the annular circumference. A suture’s tie-down force did not correlate to its eventual contractile force. Conclusions – Mitral annuloplasty suture loading is influenced by ring type, ring-annulus sizing, suture position, and surgeon, suggesting reports of dehiscence may not be merely a series of isolated errors. When compared to forces known to cause suture dehiscence, these in vivo suture loading data aid in establishing potential targets for reducing the occurrence of ring dehiscence.