Transapical beating-heart chordae implantation in mitral regurgitation: a new horizon for repairing mitral valve prolapse

Artificial papillary muscle device for off-pump transapical mitral valve repair

OBJECTIVE

New transapical minimally invasive artificial chordae implantation devices are a promising alternative to traditional open-heart repair, with the potential for decreased postoperative morbidity and reduced recovery time. However, these devices can place increased stress on the artificial chordae. We designed an artificial papillary muscle to alleviate artificial chordae stresses and thus increase repair durability.

METHODS

The artificial papillary muscle device is a narrow elastic column with an inner core that can be implanted during the minimally invasive transapical procedure via the same ventricular incision site. The device was 3-dimensionally printed in biocompatible silicone for this study. To test efficacy, porcine mitral valves (n = 6) were mounted in a heart simulator, and isolated regurgitation was induced. Each valve was repaired with a polytetrafluoroethylene suture with apical anchoring followed by artificial papillary muscle anchoring. In each case, a high-resolution Fiber Bragg Grating sensor recorded forces on the suture.

RESULTS

Hemodynamic data confirmed that both repairs-with and without the artificial papillary muscle device-were successful in eliminating mitral regurgitation. Both the peak artificial chordae force and the rate of change of force at the onset of systole were significantly lower with the device compared with apical anchoring without the device (P < .001 and P < .001, respectively).

CONCLUSIONS

Our novel artificial papillary muscle could integrate with minimally invasive repairs to shorten the artificial chordae and behave as an elastic damper, thus reducing sharp increases in force. With our device, we have the potential to improve the durability of off-pump transapical mitral valve repair procedures.

A novel cross-species model of Barlow's disease to biomechanically analyze repair techniques in an ex vivo left heart simulator

OBJECTIVE

Barlow's disease remains challenging to repair, given the complex valvular morphology and lack of quantitative data to compare techniques. Although there have been recent strides in ex vivo evaluation of cardiac mechanics, to our knowledge, there is no disease model that accurately simulates the morphology and pathophysiology of Barlow's disease. The purpose of this study was to design such a model.

METHODS

To simulate Barlow's disease, a cross-species ex vivo model was developed. Bovine mitral valves (n = 4) were sewn into a porcine annulus mount to create excess leaflet tissue and elongated chordae. A heart simulator generated physiologic conditions while hemodynamic data, high-speed videography, and chordal force measurements were collected. The regurgitant valves were repaired using nonresectional repair techniques such as neochord placement.

RESULTS

The model successfully imitated the complexities of Barlow's disease, including redundant, billowing bileaflet tissues with notable regurgitation. After repair, hemodynamic data confirmed reduction of mitral leakage volume (25.9 ± 2.9 vs 2.1 ± 1.8 mL, P < .001) and strain gauge analysis revealed lower primary chordae forces (0.51 ± 0.17 vs 0.10 ± 0.05 N, P < .001). In addition, the maximum rate of change of force was significantly lower postrepair for both primary (30.80 ± 11.38 vs 8.59 ± 4.83 N/s, P < .001) and secondary chordae (33.52 ± 10.59 vs 19.07 ± 7.00 N/s, P = .006).

CONCLUSIONS

This study provides insight into the biomechanics of Barlow's disease, including sharply fluctuating force profiles experienced by elongated chordae prerepair, as well as restoration of primary chordae forces postrepair. Our disease model facilitates further in-depth analyses to optimize the repair of Barlow's disease.

Comparison of early postoperative results between conventional and transapical mitral valve repair

Introduction

Conventional mitral valve repair (CMVR) is well-established, safe and effective treatment for degenerative mitral regurgitation (MR). Transapical off-pump implantation of artificial chordae (TA) has been introduced into practice and gained interest among surgeons. However, there are no publications comparing the results between TA and CMVR.

Aim

To compare early postoperative outcomes of CMVR with TA in patients with degenerative MR.

Material and methods

This was a retrospective cohort study. A total of 169 patients who underwent mitral valve repair between 2011 and 2018 were included in this analysis. Patients were divided into two groups: the TA group, n = 78 and CMVR group, n = 91. The groups were compared for early postoperative outcomes.

Results

Patients in the TA group were younger, 54.2 ±11.1 vs. 59.5 ±12.8 years (p = 0.005). Patients in the CMVR group had more complicated postoperative course with higher incidence of blood transfusion (42.9% vs. 7.8%, p = 0.001), atrial fibrillation (25.3% vs. 11.7%, p = 0.031), renal insufficiency (15.4% vs. 2.6%, p = 0.007) and stroke (2.1% vs. 0%). In the early postoperative period, one patient died in the TA group, and there were no deaths in the CMVR group (p = 0.277). Residual moderate to severe mitral regurgitation was present in nine (11.5%) TA patients, while none of the patients in the CMVR group had moderate or a higher degree of residual regurgitation (p = 0.001).

Conclusions

Off-pump transapical MV repair is a feasible and safe procedure with low postoperative morbidity rates. Higher rates of mitral regurgitation reoccurrence would require a careful and thorough selection of the patients suitable for the TA approach.

Early echocardiographic results of transapical off-pump mitral valve repair with the NeoChord DS1000 device in patients with severe mitral regurgitation due to posterior leaflet prolapse: first experiences in Poland

Introduction

Minimally invasive techniques of mitral valve (MV) repair have been increasingly used in recent years. Transapical implantation of artificial chordae on a beating heart under 2D/3D transesophageal echocardiographic guidance with the NeoChord DS1000 device is a new surgical treatment of degenerative mitral regurgitation (MR).

Aim

To evaluate early results of MV repair with the NeoChord DS1000 device in the first group of consecutive patients operated on in Poland.

Material and methods

Twenty-one patients with severe MR due to posterior leaflet prolapse (81% male; mean age: 60.7 ±12.7 years) underwent MV repair with the NeoChord DS1000 system. There were 12 (57.1%) patients with type A (an isolated central prolapse/flail), 8 (38.1%) patients with type B (multisegment disease/flail) and 1 (4.8%) patient with type C (posterior/paracommisural area) MV prolapse. A flail leaflet was present in 12 (57.1%) patients. The median number of neochords was 3 (2-6). We assessed by echocardiography left-sided heart morphology and evaluated MR degree before and 6 months after chords implantation.

Results

Early procedural success was achieved in 100% of patients. At the 6-month follow-up nonsignificant MR (trace and mild) was detected in 17 (81.0%) patients, while moderate MR was detected in 4 (19.0%) patients; mean values of left-sided heart dimensions and volumes, mitral E and E' velocity of lateral MV annulus significantly decreased.

Conclusions

A novel procedure with the NeoChord DS1000 device is feasible in properly selected patients, and results in a significant reduction of MR degree and left ventricle and left atrium reverse remodeling at the 6-month follow-up.

Ex Vivo Biomechanical Study of Apical Versus Papillary Neochord Anchoring for Mitral Regurgitation

BACKGROUND

Neochordoplasty is an important repair technique, but optimal anchoring position is unknown. Although typically anchored at papillary muscles, new percutaneous devices anchor the neochordae at or near the ventricular apex, which may have an effect on chordal forces and the long-term durability of the repair.

METHODS

Porcine mitral valves (n = 6) were mounted in a left heart simulator that generates physiologic pressure and flow through the valves, and chordal forces were measured with Fiber Bragg Grating strain gauge sensors. Isolated mitral regurgitation was induced by cutting P2 primary chordae, and the regurgitant valve was repaired with polytetrafluoroethylene neochord with apical anchoring, followed by papillary muscle fixation for comparison. In both situations, the neochord was anchored to a customized force-sensing post positioned to mimic the relevant in vivo placement.

RESULTS

Echocardiographic and hemodynamic data confirmed that the repairs restored physiologic hemodynamics. Forces on the chordae and neochord were lower for papillary fixation than for the apical fixation (p = 0.003). In addition, the maximum rate of change of force on the chordae and neochordae was higher for apical fixation than for papillary fixation (p = 0.028).

CONCLUSIONS

Apical neochord anchoring results in effective repair of mitral regurgitation, albeit with somewhat higher forces on the chordae and neochord suture, as well as an increased rate of loading on the neochord compared with the papillary muscle fixation. These results may guide strategies to reduce stresses on neochordae as well as aid optimal patient selection.

Harpoon Repair for Mitral Regurgitation: A Case Report

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Primary mitral regurgitation (MR) is commonly due to mitral valve (MV) prolapse.

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Off-pump minimally invasive MV repair is an alternative to conventional MV surgery.

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This case describes MV repair using the Harpoon TSD-5 device.

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The technique facilitates image-guided minimally invasive repair.

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Early data suggest the Harpoon procedure is safe and durable and reduces morbidity.

Future Technology

Mitral regurgitation is the most common valvular disease and significant (moderate/severe) mitral regurgitation is found in 2.3% of the population older than 65 years. New transcatheter minimally invasive technologies are being developed to address mitral valve disease in patients deemed too high a risk for conventional open-heart surgery. There are several features of the mitral valve (saddle-shaped noncalcified annulus with irregular leaflet geometry) that make a transcatheter approach to repair or replacing the valve more challenging compared with the aortic valve. Several devices are under investigation for transcatheter mitral valve replacement, and also for mitral valve repair targeting the mitral valve leaflets, chordae tendinae, and mitral annulus. The MitraClip device is the only Food and Drug Administration-approved device to treat mitral regurgitation by targeting the mitral leaflets. There are eight minimally invasive devices being studied in humans that target the mitral annulus, and at least two devices being studied in animal models. There are 5 devices in clinical trials for minimally invasive approaches targeting the chordae tendinae. More than 10 different transcatheter mitral valves are in various stages of development and clinical trials. These transcatheter mitral valves can be delivered either through a transseptal, transapical, transaortic, or left atriotomy approach. It seems likely that transcatheter treatment approaches to mitral valve disease will become more common, at least in the sick and elderly patient population.

Numerical simulation of transapical off-pump mitral valve repair with neochordae implantation

BACKGROUND

Transapical off-pump mitral valve (MV) repair is a novel minimally-invasive surgical technique, allowing to correct mitral regurgitation (MR) caused by chordae tendineae rupture. While numerical simulation of the MV structure has proven to be useful to evaluate the effects of the MV surgical repair techniques, no numerical simulation studies on the outcomes of transapical MV repair have been done up to now.

OBJECTIVE

The purpose of this study is to evaluate the transapical MV repair using finite element modeling and to determine the effect of the neochordal length on the function of the prolapsing MV.

METHODS

The reconstruction of the MV geometry based on the patient-specific data was performed. In order to simulate prolapse, chordae inserted into the middle segment of the posterior leaflet (P2) were ruptured. A total of four virtual transapical repairs using neochordae of different length were performed. The function of the MV before and after virtual repairs was simulated.

RESULTS

The evaluation of the effect of the neochordal length on post-repair MV function showed that the length of the implanted neochordae has a significant impact on the correction of MR caused by chordae tendineae rupture.

CONCLUSIONS

The presented results can improve the understanding of the effects of transapical MV repair.