Early rupture of an expanded polytetrafluoroethylene neochord after complex mitral valve repair: An electron microscopic analysis

A review of the development of interventional devices for mitral valve repair with the implantation of artificial chords

Mitral regurgitation (MR) was the most common heart valve disease. Surgical repair with artificial chordal replacement had become one of the standard treatments for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) was currently the most commonly used artificial chordae material due to its unique physicochemical and biocompatible properties. Interventional artificial chordal implantation techniques had emerged as an alternative treatment option for physicians and patients in treating mitral regurgitation. Using either a transapical or a transcatheter approach with interventional devices, a chordal replacement could be performed transcatheter in the beating heart without cardiopulmonary bypass, and the acute effect on the resolution of mitral regurgitation could be monitored in real-time by transesophageal echo imaging during the procedure. Despite the in vitro durability of the expanded polytetrafluoroethylene material, artificial chordal rupture occasionally occurred. In this article, we reviewed the development and therapeutic results of interventional devices for chordal implantation and discuss the possible clinical factors responsible for the rupture of the artificial chordal material.

Mitral valve repair with artificial chords: Tips and tricks

Mitral valve regurgitation (MR) is a common valvular disorder occurring in up to 10% of the general population. Mitral valve reconstructive strategies may address any of the components, annulus, leaflets, and chords, involved in the valvular competence. The classical repair technique involves the resection of the prolapsing tissue. Chordal replacement was introduced already in the '60, but in the mid '80, some surgeons started to use expanded polytetrafluoroethylene (ePTFE) Gore-Tex sutures. In the last years, artificial chords have been used also using transcatheter approach such as NeoChord DS 1000 (Neochord) and Harpoon TSD-5. The first step is to achieve a good exposure of the papillary muscles that before approaching the implant of the artificial chords. Then, the chords are attached to the papillary muscle, with or without the use of supportive pledgets. The techniques to correctly implant artificial chords are many and might vary considerably from one center to another, but they can be summarized into three big families of suturing techniques: single, running or loop. Regardless of how to anchor to the mitral leaflet, the real challenge that many surgeons have taken on, giving rise to some very creative solutions, has been to establish an adequate length of the chords. It can be established based on anatomically healthy chords, but it is important to bear in mind that surgeons work on the mitral valve when the heart is arrested in diastole, so this length could fail to replicate the required length in the full, beating heart. Hence, some surgeons suggested techniques to overcome this problem. Herein, we aimed to describe the current use of artificial chords in real-world surgery, summarizing all the tips and tricks.

Artificial chordae for mitral valve repair

BACKGROUND

Mitral valve repair using expanded polytetrafluoroethylene sutures to replace mitral chordae tendineae is a well-established procedure. However, the incidence of neo-chordae failure causing recurrent mitral regurgitation is not well defined.

METHODS

We have reviewed the reported cases of complications after mitral valve repair related to the use of neo-chordae. This study was mainly carried out through PubMed, Medline, and Google Chrome websites.

RESULTS

We have identified a total of 26 patients presenting with rupture of polytetrafluoroethylene neo-chordae, mostly being described as isolated cases. Few other cases of recurrent mitral regurgitation with hemolysis were found, where reoperation was not caused by neo-chordal failure but most likely by technical errors. At pathological investigation the findings were substantially similar in all reported cases. The neo-chordae retained their length and pliability, became covered with host tissue and rupture was mainly related to suture size. Mild calcification was observed not interfering with chordal function; chordal infection did never occur.

CONCLUSIONS

The use of artificial neo-chordae provides excellent late results with durable mitral valve repair stability. Chordal rupture may occur late postoperatively leading to reoperation because of recurrent mitral regurgitation. Despite its rarity, this potential complication should not be overlooked during follow-up of patients after mitral valve repair using artificial neo-chordae.

Calcification of Goretex neochord after mitral repair - electron microscopy

A 76 year old female presented with severe mitral valve regurgitation six years after mitral valve repair with Goretex neochords (GORE-TEX®, W. L. Gore & Associates Inc, Flagstaff, Arizona, USA) and ring annuloplasty. Echo revealed ruptured neochord. During a successful mitral valve replacement, the explanted Goretex neochords were found to be stiff and calcified with a fracture. Electron microscopy was used to examine the explant and a control neochord. There was disruption of the microstructure with extensive calcium infiltration at fracture point. Although this is a rare cause of late repair failure, it warrants yearly follow up with echocardiography.

Predictors of failure of mitral valve repair using artificial chordae

BACKGROUND

We investigate predictors of failure of mitral valve repair (MVr) using expanded polytetrafluoroethylene (ePTFE) and durability of them in the long-term period in single institution.

METHODS

Four hundred twenty-one consecutive patients with primary mitral valve disease underwent MVr using artificial chordae (group A: n=304) and suture repair (group S: n=117) at our institution from January 2002 to April 2020. A comparison study was performed to examine the long-term outcomes, re-operation rate and risk factors for re-operation.

RESULTS

One hospital death and 5 late deaths occurred in group S, and 20 late deaths occurred in group A. The re-operation rates were similar [group A; n=8 (2.6%), group S; n=6 (5%)]. The major cause of re-operation was ruptured ePTFE (CV-4: n=1, CV-5: n=6) in group A, and suture rupture in group S. Re-operation was performed after a median period of 88 months for ruptured ePTFE, and 26 months for group S. The rate of ePTFE rupture was 1.8% with CV5 and 0.2% with CV4. Risk factors for re-operation included post-operative arrhythmia, urgent operation, no annular-ring, ruptured ePTFE and suture rupture. The rates of freedom from re-operation and actuarial mitral valve survival rates at 5, 10, and 15 years were 99%, 95%, and 93% and 96%, 91%, and 89%, respectively, in group A, and 96%, 91%, and 91% and95%, 94%, and 94% in group S.

CONCLUSIONS

The long-term surgical outcomes of MVr using both techniques were feasible. Over the long-term, the ePTFE rupture rate of CV-5 was higher than that of CV-4.

Transapical mitral valve repair with neochordae implantation: FSI analysis of neochordae number and complexity of leaflet prolapse

Transapical mitral valve repair with neochordae implantation is a relatively new minimally invasive technique to treat primary mitral regurgitation. Quantifying the complex biomechanical interaction and interdependence between the left heart structures and the neochordae during this procedure is technically challenging. The aim of this parametric computational study is to investigate the immediate effects of neochordae number and complexity of leaflet prolapse on restoring physiologic left heart dynamics after optimal transapical neochordae repair procedures. Neochordae implantation using three and four sutures was modeled under three clinically relevant prolapse conditions: isolated P2, multi-scallop P2/P3, and multi-scallop P2/P1. A fluid-structure interaction (FSI) modeling framework was used to evaluate the left heart dynamics under baseline, prerepair, and postrepair states. Despite immediate restoration of leaflet coaptation and no residual mitral regurgitation in all postrepair models, the average and peak stresses in the repaired scallop(s) increased >40% and >100%, respectively, compared with the baseline state. Additionally, anterior mitral leaflet marginal chordae tension increased >30%, while posterior mitral leaflet chordae tension decreased at least 30%. No marked differences in hemodynamic performance, in native and neochordae forces, and in leaflet stress were found when implanting three or four sutures. We report, to our knowledge, the first set of time-dependent in silico FSI human neochordae tension measurements during transapical neochordae repair. This work represents a further step towards an improved understanding of the biomechanical outcomes of minimally invasive mitral valve repair procedures.

Is there a problem with respect? Risk of neochordal rupture

PURPOSE OF REVIEW

In this review, we summarize the history of mitral valve repair, discuss the broad principles of neochord preparation and implantation, and highlight comparative outcomes between mitral valve repair strategies while focusing on the risk of neochordal rupture.

RECENT FINDINGS

There have been several recent studies comparing outcomes been leaflet-resection and nonresection, neochord-based mitral valve repair. Operative mortality was very low regardless of repair strategy; however, the rate of mitral valve reoperation is lower in those that undergo a neochord-based repair with overall lower mean mitral gradients postrepair. The introduction of minimally invasive approaches to mitral valve repair has preferentially favored an increase in neochord-based repair, given the technical simplicity compared with resection-based approaches. In very rare cases, neochord rupture can occur, likely secondary to a combination of chordal calcification and mechanical stress.

SUMMARY

The method of performing mitral valve repair with neochord implantation has demonstrated superior durability over leaflet resection approaches with equivalent operative outcomes. Although the risk of neochord rupture exists, it is exceedingly rare, and should not be considered a limitation to a neochord-based mitral valve repair. Recurrent mitral regurgitation secondary to neochord rupture is incredibly rare; however, regular echocardiographic evaluation of these patients appears warranted, especially when follow-up extends over 10 years.

Late rupture of artificial neochordae associated with hemolytic anemia

A 63-year-old man, status post-mitral valve repair for severe mitral regurgitation secondary to ruptured chordae of the anterior leaflet, was admitted seven years after surgery because of a recent history of hematuria. A new apical pansystolic murmur was audible. Hemoglobin level was 5.7 g/dL. Results of other hematologic studies and a peripheral blood smear were indicative of mechanical hemolysis. Transesophageal echocardiography showed a high-velocity jet of mitral regurgitation that directly collided with the annuloplasty ring. At re-operation, one of the artificial neochordae to A2 and A3 segments was found to be disrupted. The mitral valve was replaced with a 33/31 mm On-X valve. Hemolytic anemia disappeared immediately after surgery. Although mitral valve repair with artificial neochodae has been shown to have long-term durability, it should be recognized that artificial neochordae may rupture a long time after mitral valve repair. Also, although hemolytic anemia is known as an early complication after mitral valve repair, it is worth knowing that hemolytic anemia may occur as a late complication after mitral valve repair. Continuous long-term monitoring of the patients after mitral valve repair is recommended. <Learning objectives: Artificial neochordae may at times rupture long period after mitral valve repair. Also, although hemolytic anemia is known as an early complication after mitral valve repair, it may occur as a complication due to late rupture of artificial neochordae. Continuous long-term monitoring of the patient after mitral valve repair is recommended.>.

Rupture of GORE-TEX neochordae 10 years after mitral valve repair

The current non-resectional paradigm in mitral valve (MV) repair emphasizes the use of polytetrafluoroethylene (PTFE) for artificial chordal replacement. While excellent long-term durability of repair using PTFE neochordae has been established, there have been rare reports of neochordal rupture at various times after surgery. We report a case of artificial chordal rupture 10 years after anterior mitral leaflet repair, necessitating reoperation. This complication may have been precipitated by maldistributed intracardiac tensile forces as a consequence of a malpositioned annuloplasty band.