Mitral Valve Re-repair After Late Rupture of Expanded Polytetrafluoroethylene Neochords

Mitral valve chordae replacement using expanded polytetrafluoroethylene (ePTFE) GORE-TEX sutures (W.L. Gore & Associates Inc., Newark, DE) has enabled durable repair strategies that “respect rather than resect” the native leaflet tissue1,2. This nonabsorbable monofilament suture material is flexible, pliable, and resistant to degeneration1. As such, there are few isolated cases of ruptured ePTFE neochords. We describe a case of late rupture of CV-5 ePTFE neochords with successful re-repair. Mitral valve chordae replacement using expanded polytetrafluoroethylene (ePTFE) GORE-TEX sutures (W.L. Gore & Associates Inc., Newark, DE) has enabled durable repair strategies that “respect rather than resect” the native leaflet tissue1,2. This nonabsorbable monofilament suture material is flexible, pliable, and resistant to degeneration1. As such, there are few isolated cases of ruptured ePTFE neochords. We describe a case of late rupture of CV-5 ePTFE neochords with successful re-repair. A 60-year-old man was admitted to our hospital with heart failure following 2-weeks of progressive dyspnea. Eight years ago, he had undergone mitral valve repair for prolapsed P2 segment using CV-5 ePTFE GORE-TEX neochords and a 30mm Physio II (Edwards Lifesciences, Irvine, CA) annuloplasty ring and since, had been clinically well. Eight months prior to admission, a routine follow-up transthoracic echocardiogram showed normal biventricular function with moderate mitral regurgitation (MR). On admission, echocardiography showed normal biventricular function with severe anteriorly directed mitral regurgitation due to recurrent prolapse of the posterior leaflet (Figure 1A). Given his acute change in symptoms and imaging findings, he was consented for a redo-mitral valve operation. With a redo median sternotomy approach, the heart was arrested and the mitral valve was exposed through a left atrial incision. Valve analysis found the previously implanted annuloplasty ring to be completely endothelialized. The 4 GORE-TEX neochords that had been inserted on to the free margin of the lateral and medial aspect of P2 had ruptured mid-way between the leaflet and papillary muscles (Figure 2). Neochord insertions at the leaflet and the papillary muscles were intact, and removed prior to re-repair. The previous annuloplasty ring was left in-situ and working through the ring, the valve was re-repaired using 6 CV-4 ePTFE neochords, sutured from the free edge of P2 to the medial and lateral papillary muscle heads. Residual clefts between P1 and P2, and P2 and P3 were sutured closed. Post-cardiopulmonary bypass transesophageal echocardiography revealed trivial to mild residual mitral regurgitation (Figure 1B). The patient’s post-operative course was uncomplicated. With atrial fibrillation delaying his discharge, the patient went home from hospital on post-operative day 8. Follow up echocardiography 1.5 years after reoperation showed normal biventricular function with trivial MR. Chordal replacement with ePTFE sutures was first reported by David et al. and has since garnered reproducible results1David T.E. David C.M. Lafreniere-Roula M. Manlhiot C. Long-term outcomes of chordal replacement with expanded polytetrafluoroethylene sutures to repair mitral leaflet prolapse.J Thorac Cardiovas Surg. 2020; 160: 385-394Abstract Full Text Full Text PDF Scopus (44) Google Scholar. Rupture of ePTFE neochords is a rare event, with reports suggesting it can occur from 2 months to 14 years, post-operatively2Castillo J.G. Anyanwu A.C. El-Eshmawi A. Gordon R.E. Adams D.H. Early rupture of an expanded polytetrafluoroethylene neochord after complex mitral valve repair: an electron microscopic analysis.J Thorac Cardiovasc Surg. 2013; 145: 329-331Abstract Full Text Full Text PDF Scopus (15) Google Scholar, 3Butany J. Collins M.J. David T.E. Ruptured synthetic expanded polytetrafluoroethylene chordae tendinae.Cardiovasc Pathol. 2004; 13: 182-184Crossref PubMed Scopus (41) Google Scholar, 4Fukunaga S. Tomoeda H. Ueda T. Mori R. Aoyagi S. Kato S. Recurrent mitral regurgitation due to calcified synthetic chordae.Ann Thorac Surg. 2010; 89: 955-957Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar. Most previously reported cases have required subsequent valve replacement. In cases of early rupture, within months of the operation, the neochords appeared structurally normal. Neochord failure has been attributed to excessive intracardiac forces on the sutures or excessive friction following a loop-in-loop technique2Castillo J.G. Anyanwu A.C. El-Eshmawi A. Gordon R.E. Adams D.H. Early rupture of an expanded polytetrafluoroethylene neochord after complex mitral valve repair: an electron microscopic analysis.J Thorac Cardiovasc Surg. 2013; 145: 329-331Abstract Full Text Full Text PDF Scopus (15) Google Scholar. Late rupture is believed to be associated with suture calcification, causing weakness and loss of integrity3Butany J. Collins M.J. David T.E. Ruptured synthetic expanded polytetrafluoroethylene chordae tendinae.Cardiovasc Pathol. 2004; 13: 182-184Crossref PubMed Scopus (41) Google Scholar,4Fukunaga S. Tomoeda H. Ueda T. Mori R. Aoyagi S. Kato S. Recurrent mitral regurgitation due to calcified synthetic chordae.Ann Thorac Surg. 2010; 89: 955-957Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar. We report a similar case of late ePTFE neochord rupture suspected to be due to suture calcification and weakening, based on gross inspection of the explanted neochords. Histopathology was not obtained, however, previous reports that included histopathological analyses showed that late ruptured ePTFE sutures had focal dystrophic calcification of the fibrous tissue covering the sutures with markers of inflammation4Fukunaga S. Tomoeda H. Ueda T. Mori R. Aoyagi S. Kato S. Recurrent mitral regurgitation due to calcified synthetic chordae.Ann Thorac Surg. 2010; 89: 955-957Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar. Other reports mention near complete replacement of the synthetic material with calcium deposits3Butany J. Collins M.J. David T.E. Ruptured synthetic expanded polytetrafluoroethylene chordae tendinae.Cardiovasc Pathol. 2004; 13: 182-184Crossref PubMed Scopus (41) Google Scholar. Overall, these changes are suspected to cause significant weakening of the suture leading to rupture. While suture weakening has been reported, ePTFE neochords are by design, highly resistant to degeneration. It is chemically inert with a net electrostatic negative charge that repels blood elements and bacteria. These factors allow for the material to retain flexibility and strength. However, suture calibre does impart different propensity to rupture. An analysis of the suture rupture forces for ePTFE CV-3 to CV-6 demonstrated less force required for rupture with less suture calibre5Marin-Cuartas M. Imbrie-Moore A.M. Zhu Y. Park M.H. Wilkerson R. Leipzig M. Borger M.A. Woo Y.J. Biomechanical engineering analysis of commonly utilized mitral neochordae.JTCVS Open. 2021; 8: 263-275Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar. The mean rupture force for a single CV-5 ePTFE neochord was 39.9 Newton, or 4.1kg, in comparison to CV-4 suture with a mean rupture force of 49.0 Newton, or 5kg5. While these forces exceed predicted intracardiac forces, there is clinical data to support that CV-5 suture is significantly weaker than CV-4 suture. A retrospective cohort study of redo mitral valve repair cases found the rupture rate of CV-5 neochords to the posterior leaflet to be 2.3%, compared to the rupture rate of CV-4 neochords at 0%6Mutsuga M. Narita Y. Tokuda Y. Uchida W. Ito H. Terazawa S. Nakaguro M. Usui A. Predictors of failure of mitral valve repair using artificial chordae.Ann Thorac Surg. 2022; 113: 1136-1143Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar. Therefore, smaller suture calibre along with structural weakening of the neochords, may have contributed to this case of neochord rupture. An additional factor that may have contributed to neochord weakening in this case, was a previous motor vehicle accident within approximately 1 year of his presentation. While traumatic valvular injuries are rare following blunt chest trauma, cases of acute mitral valve regurgitation due to chordal rupture have been reported7Tea I. Rothstein P. Agarwal T. Ramchandani M. Chebrolu L. Shot through the heart: acute severe mitral regurgitation from chordal rupture following a motor vehicle accident.JACC. 2020; 75: 3326Crossref Google Scholar. The mechanism of injury is suspected to be through an acute rise in intracardiac pressure during isovolumetric contraction. Previous reports have suggested that patients myxomatous degeneration of the mitral valve may be more predisposed to traumatic chordal rupture7Tea I. Rothstein P. Agarwal T. Ramchandani M. Chebrolu L. Shot through the heart: acute severe mitral regurgitation from chordal rupture following a motor vehicle accident.JACC. 2020; 75: 3326Crossref Google Scholar. As such, it is plausible that this event may have contributed to further neochord weakening, increasing the risk of rupture in our reported case. To our knowledge, this is among the first reported cases of successful re-repair following neochord rupture6Mutsuga M. Narita Y. Tokuda Y. Uchida W. Ito H. Terazawa S. Nakaguro M. Usui A. Predictors of failure of mitral valve repair using artificial chordae.Ann Thorac Surg. 2022; 113: 1136-1143Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar. As the patient’s mitral valve apparatus was maintained except for the ruptured chords, reinsertion of neochords was feasible. CV-4 ePTFE GORE-TEX sutures were used for re-repair, as they have greater tensile strength compared to CV-5 ePTFE sutures5Marin-Cuartas M. Imbrie-Moore A.M. Zhu Y. Park M.H. Wilkerson R. Leipzig M. Borger M.A. Woo Y.J. Biomechanical engineering analysis of commonly utilized mitral neochordae.JTCVS Open. 2021; 8: 263-275Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar. In cases of progressed mitral valve sclerosis, stenosis, or other leaflet pathology, re-repair may not be a practical strategy. While rare, ePFTE neochord rupture has significant consequences. This case, among others reported, should serve as a reminder that all surgical techniques have intrinsic failure rates, highlighting the need for continual study and innovation. Additionally, this case emphasizes the necessity to continue long-term follow up with echocardiographic surveillance of post-operative patients to detect possible late complications.Novel Teaching Points•Neochord rupture may be attributed to previous chest trauma and degenerative factors•Tensile strength consideration should be a factor for determining suture calibre for neochord insertion during mitral valve repair to reduce risk of rupture•Most reports of ruptured neochords involve subsequent mitral valve replacement, but re-repair strategies should be given a greater focus •Neochord rupture may be attributed to previous chest trauma and degenerative factors•Tensile strength consideration should be a factor for determining suture calibre for neochord insertion during mitral valve repair to reduce risk of rupture•Most reports of ruptured neochords involve subsequent mitral valve replacement, but re-repair strategies should be given a greater focus None.

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