Aberrant left atrial chorda in a patient with mitral regurgitation requiring surgery.

We present a rare case of an 84-year-old woman with a left atrial chorda. She was admitted with heart failure and echocardiography revealed severe mitral valve insufficiency due to chordal rupture and prolapse of the posterior leaflet. In addition, a left atrial chorda was diagnosed, attached to the anterior leaflet, restricting the valve and contributing to the insufficiency. The patient underwent surgery with the removal of the atrial chorda and insertion of two neochordae and mitral annuloplasty with a ring. Postoperative echocardiography showed a well-functioning valvuloplasty.

Muscularization of the chordae tendinea of the mitral anterior papillary muscle.

The chordae tendineae, described as fibro-collagenous structures, support the leaflets of the atrioventricular valves of the heart in various ways. The chordae tendineae are composed of collagen and elastic fibers. They connect to the ventricular side of the valve leaflets' free border and hinder the leaflets from swinging back into the atrial cavity during systole. Mitral valve chordae tendineae have been classified using a variety of classification systems. To our knowledge, we report a variant chordae tendinea that has yet to be described in the literature. The variant, present only on the mitral anterior papillary muscle, did not show the characteristic appearance of the chorda tendineae. Muscular fibers were observed extending from a larger than usual mitral anterior papillary muscle, inserting into the rough zone of the anterior leaflet. Several tendinous primary and secondary true leaflet chordae emerge from the apical portion of the anterior papillary muscle, inserting into the anterior leaflet's free edge and rough zone. Contraction of this muscular chorda during systole could disrupt the mechanics of valvular closure and result in possible regurgitation across the mitral valve. Additionally, this structure may be subject to rupture during myocardial infarction, leading to valvular dysfunction. The developmental connection between the chordae and papillary muscles could explain the anomalous muscularization of the chordae tendineae observed in this case.

Prolonged survival with mitral valve plasty for acute mitral regurgitation due to mitral valve dysplasia and chordal rupture in a young small dog: A case report.

Background: We aimed to report the second case of mitral valve plasty (MVP) for acute mitral regurgitation (MR) due to mitral valve dysplasia in a young small dog. Case Description: A 5-month-old female Jack Russell, weighing 3.5 kg, presented with dyspnea and collapse upon excitation. Acute MR with pulmonary edema due to chordal rupture was diagnosed with a suspected congenital mitral valve anomaly. Despite treatment with high-dose drugs, heart failure symptoms and enlargement worsened. An artificial chordal replacement (ACR) was inserted using polytetrafluoroethylene sutures, and annuloplasty was performed. The dog was discharged on postoperative day 7. After 7 years, the dog underwent operations for complete anterior cruciate ligament tears with no cardiac signs. After 11.5 years, the dog showed no cardiac issues and died from a non-cardiac disease. Conclusion: The MVP method with ACR employed demonstrated better durability and promoted longer survival than that of previous dog mitral valve replacements.

Artificial Chordae Implantation vs Posterior Leaflet Preservation: A Comparison of Midterm Results After Mitral Valve Replacement.

BACKGROUND: Various techniques have been proposed for the preservation of the subvalvular apparatus (SVA) in mitral valve replacement. This study aimed to compare the midterm results of posterior leaflet preservation with the results of selective preservation of the SVA involving artificial chordae implantation in terms of left ventricular performance in patients undergoing mitral valve replacement. METHODS: In total, 127 patients were included in this study. Patients were allocated to 1 of 2 groups according to the techniques used to preserve the SVA. Patients in group 1 underwent posterior leaflet preservation: The anterior leaflet was completely resected, and the posterior leaflet was preserved. In group 2, which comprised patients with severe leaflet extension and subvalvular fusion, the mitral valve was excised completely and substituted with artificial chordae. All relevant preoperative, intraoperative, and postoperative data were recorded. RESULTS: Mean (SD) ages in groups 1 and 2 were 63.1 (9.65) and 57.1 (12.3) years, respectively (P = .003). Mean (SD) follow-up time was 59.97 (23.63) months (range, 6-99 months). Left ventricular end-diastolic diameter decreased significantly after artificial chordae implantation (P < .001), while the decrease after posterior leaflet preservation was not statistically significant (P = .20). In both groups, there were statistically significant reductions (P < .001) in left ventricular end-systolic diameter and left atrium diameter in the postoperative period compared with respective preoperative levels. During follow-up, left ventricular ejection fraction was found to have increased beyond the preoperative levels in both groups, but the differences were not statistically significant (P > .05). CONCLUSION: Results of echocardiographic observations regarding the preservation of the SVA via artificial chordae implantation for mitral valve disease in this sample were satisfactory. Findings suggest that artificial chordae implantation should be considered when posterior leaflet preservation is not suitable.

Gross morphology and morphometry of native and decellularized heart valves of caprine: A comparative study.

The gross morphological examination of native caprine heart valves revealed distinctive structural characteristics of the caprine's cardiac anatomy. Four primary orifices were identified, each protected by thin, valve-like structures. Atrioventricular orifices featured tricuspid and bicuspid valves, while the aorta and pulmonary arteries were guarded by semilunar valves. Within the atrioventricular apparatus, distinct features were observed including the tricuspid valve's three leaflets and the bicuspid valve's anterior and posterior leaflets. Ultrasonography provided insights into valve thickness and chordae tendineae lengths. Morphometric studies compared leaflets/cusps within individual native valves, showcasing significant variations in dimensions. Comparative analysis between native and decellularized valves highlighted the effects of decellularization on leaflet thickness and chordae tendineae lengths. Decellularized valves exhibited reduced dimensions compared to native valves, indicating successful removal of cellular components. While some dimensions remained unchanged post-decellularization, significant reductions were observed in leaflet thicknesses and chordae tendineae lengths. Notably, semilunar valve cusps displayed varying responses to decellularization, with significant reductions in cusp lengths observed in the aortic valve, while the pulmonary valve exhibited more subtle changes. These findings underscore the importance of understanding structural alterations in heart valves post-decellularization, providing valuable insights for tissue engineering applications and regenerative medicine.

Large Animal Translational Validation of 3 Mitral Valve Repair Operations for Mitral Regurgitation Using a Mitral Valve Prolapse Model: A Comprehensive In Vivo Biomechanical Engineering Analysis.

BACKGROUND: Various mitral repair techniques have been described. Though these repair techniques can be highly effective when performed correctly in suitable patients, limited quantitative biomechanical data are available. Validation and thorough biomechanical evaluation of these repair techniques from translational large animal in vivo studies in a standardized, translatable fashion are lacking. We sought to evaluate and validate biomechanical differences among different mitral repair techniques and further optimize repair operations using a large animal mitral valve prolapse model. METHODS: Male Dorset sheep (n=20) had P2 chordae severed to create the mitral valve prolapse model. Fiber Bragg grating force sensors were implanted to measure chordal forces. Ten sheep underwent 3 randomized, paired mitral valve repair operations: neochord repair, nonresectional leaflet remodeling, and triangular resection. The other 10 sheep underwent neochord repair with 2, 4, and 6 neochordae. Data were collected at baseline, mitral valve prolapse, and after each repair. RESULTS: All mitral repair techniques successfully eliminated regurgitation. Compared with mitral valve prolapse (0.54±0.18 N), repair using neochord (0.37±0.20 N; P=0.02) and remodeling techniques (0.30±0.15 N; P=0.001) reduced secondary chordae peak force. Neochord repair further decreased primary chordae peak force (0.21±0.14 N) to baseline levels (0.20±0.17 N; P=0.83), and was associated with lower primary chordae peak force compared with the remodeling (0.34±0.18 N; P=0.02) and triangular resectional techniques (0.36±0.27 N; P=0.03). Specifically, repair using 2 neochordae resulted in higher peak primary chordal forces (0.28±0.21 N) compared with those using 4 (0.22±0.16 N; P=0.02) or 6 neochordae (0.19±0.16 N; P=0.002). No difference in peak primary chordal forces was observed between 4 and 6 neochordae (P=0.05). Peak forces on the neochordae were the lowest using 6 neochordae (0.09±0.11 N) compared with those of 4 neochordae (0.15±0.14 N; P=0.01) and 2 neochordae (0.29±0.18 N; P=0.001). CONCLUSIONS: Significant biomechanical differences were observed underlying different mitral repair techniques in a translational large animal model. Neochord repair was associated with the lowest primary chordae peak force compared to the remodeling and triangular resectional techniques. Additionally, neochord repair using at least 4 neochordae was associated with lower chordal forces on the primary chordae and the neochordae. This study provided key insights about mitral valve repair optimization and may further improve repair durability.

A tissue-silicone integrated simulator for right ventricular pulsatile circulation with severe functional tricuspid regurgitation.

There is a great demand for development of a functional tricuspid regurgitation (FTR) model for accelerating development and preclinical study of tricuspid interventional repair devices. This study aimed to develop a severe FTR model by creating a tissue-silicone integrated right ventricular pulsatile circulatory simulator. The simulator incorporates the porcine tricuspid annulus, valve leaflets, chordae tendineae, papillary muscles, and right ventricular wall as one continuous piece of tissue, thereby preserving essential anatomical relationships of the tricuspid valve (TV) complex. We dilated the TV annulus with collagenolytic enzymes under applying stepwise dilation, and successfully achieved a severe FTR model with a regurgitant volume of 45 ± 9 mL/beat and a flow jet area of 15.8 ± 2.3 cm2 (n = 6). Compared to a normal model, the severe FTR model exhibited a larger annular circumference (133.1 ± 8.2 mm vs. 115.7 ± 5.5 mm; p = 0.009) and lower coaptation height (6.6 ± 1.0 mm vs. 17.7 ± 1.3 mm; p = 0.003). Following the De-Vega annular augmentation procedure to the severe FTR model, a significant reduction in regurgitant volume and flow jet area were observed. This severe FTR model may open new avenues for the development and evaluation of transcatheter TV devices.

[Supra-annular Mitral Valve Replacement Using a Composite Valve for an Infant with Acute Rupture of Chordae Tendineae].

Acute rupture of the chordae tendineae of the mitral valve could lead to severe mitral regurgitation and circulatory collapse in infants. Mitral valve replacement may be often challenging because of the valve-annulus size mismatch in small infants when mitral valve repair cannot be accomplished. We present an infant with acute massive rupture of the chordae tendineae of the mitral valve who successfully underwent supra-annular mitral valve replacement using the short composite valve of an expanded polytetrafluoroethylene( ePTFE) graft and a mechanical valve. His mechanical valve has been functioning without complications such as thrombosis and pulmonary venous obstruction for 20 months after surgery. This technique could be helpful even infants with acute rupture of the chordae tendineae of the mitral valve whose left atrium may not be dilated.

Severe tricuspid regurgitation with chordae tendinae rupture in CABG surgery.

A 58-year-old male patient was admitted with chest pain and was diagnosed with coronary heart disease. He was scheduled for coronary artery bypass grafting (CABG) under cardiopulmonary bypass (CPB). Intraoperative real-time transesophageal echocardiography (TEE) showed that the tricuspid valves were well-aligned and subtle regurgitation. Real-time TEE after separation from CPB showed severe tricuspid regurgitation and prolapsed chordae tendineae. The tricuspid chordae tendineae rupture due to a right atrial venous return cannula. The use of negative pressure to improve venous drainage during CPB may result in the tricuspid valve being adsorbed to the cannula, increasing the likelihood of injury to the tricuspid valve.

Feasibility Study of a Novel Transapical Chordal Implantation System in a Porcine Model.

Transapical beating-heart mitral repair with chordal implantation system has been considered as an alternative treatment for degenerative mitral regurgitation. This study aimed to assess the feasibility and safety of the E-Chord system (Med-Zenith Medical, Beijing, China) for transapical beating-heart mitral valve repair in a porcine model. Artificial chordae were transapically implanted on the mitral valves of 12 anesthetized pigs under epicardial echocardiographic guidance and secured outside the left ventricular apex. The study endpoints included procedural success, device durability, and tissue response to the device. The procedural success rate was 100% (12/12). All animals were implanted with E-Chord in the anterior and posterior leaflets, respectively, and survived uneventfully until euthanized as planned. During the 180-day follow-up, no animal had significant mitral valve dysfunction. The gross observation showed no evidence of anchor detachment and chordal rupture, and there was no obvious damage or changes to mitral leaflets. Microscopic evaluation revealed that the endothelialization of anchor and chordae was completed 90 days after implantation and there was no evidence of chordal rupture, thrombosis, or infection during the 180-day follow-up. The E-Chord system was found to be feasible and safe for heart-beating mitral chordal implantation in a porcine model. The findings of this study suggest that the E-Chord system may be a potential alternative for the treatment of degenerative mitral regurgitation in humans.

Biomechanical engineering analysis of neochordae length's impact on chordal forces in mitral repair.

OBJECTIVES: Artificial neochordae implantation is commonly used for mitral valve (MV) repair. However, neochordae length estimation can be difficult to perform. The objective was to assess the impact of neochordae length changes on MV haemodynamics and neochordal forces. METHODS: Porcine MVs (n = 6) were implanted in an ex vivo left heart simulator. MV prolapse (MVP) was generated by excising at least 2 native primary chordae supporting the P2 segments from each papillary muscle. Two neochordae anchored on each papillary muscle were placed with 1 tied to the native chord length (exact length) and the other tied with variable lengths from 2× to 0.5× of the native length (variable length). Haemodynamics, neochordal forces and echocardiography data were collected. RESULTS: Neochord implantation repair successfully eliminated mitral regurgitation with repaired regurgitant fractions of approximately 4% regardless of neochord length (P < 0.01). Leaflet coaptation height also significantly improved to a minimum height of 1.3 cm compared with that of MVP (0.9 ± 0.4 cm, P < 0.05). Peak and average forces on exact length neochordae increased as variable length neochordae lengths increased. Peak and average forces on the variable length neochordae increased with shortened lengths. Overall, chordal forces appeared to vary more drastically in variable length neochordae compared with exact length neochordae. CONCLUSIONS: MV regurgitation was eliminated with neochordal repair, regardless of the neochord length. However, chordal forces varied significantly with different neochord lengths, with a preferentially greater impact on the variable length neochord. Further validation studies may be performed before translating to clinical practices.

Evaluation of a Novel Automated Suturing Technology for Mitral Chordal Implantation: 1-Year Results.

PURPOSE: A new automated expanded polytetrafluoroethylene (ePTFE) suture placement device and a new customized titanium fastener deployment device were clinically evaluated in open and less-invasive mitral valve repair (MVr). DESCRIPTION: Twelve patients were monitored for 1 year after undergoing MVr using the study devices. The study end points included surgical outcomes, operative times, valve repair durability, adverse events, and mortality. EVALUATION: Three patients received 1 ePTFE chord using the study technology, and 9 patients received 2 chords. Mitral regurgitation at 30 days was absent in 8 patients, trace in 2, and mild in 2. At the 1-year follow-up, mitral regurgitation was absent in 7 patients, trace in 2, mild in 2, and moderate in 1. There were no replacement chord failures, reoperations, or death. CONCLUSIONS: The initial outcomes of new automated ePTFE suture placement and titanium fastener deployment devices encourage further clinical evaluations.

Gene expression of Postn and FGF7 in canine chordae tendineae and their effects on flexor tenocyte biology.

Chordae tendineae, referred to as heart tendinous cords, act as tendons connecting the papillary muscles to the valves in the heart. Their role is analogous to tendons in the musculoskeletal system. Despite being exposed to millions of cyclic tensile stretches over a human's lifetime, chordae tendineae rarely suffer from overuse injuries. On the other hand, musculoskeletal tendinopathy is very common and remains challenging in clinical treatment. The objective of this study was to investigate the mechanism behind the remarkable durability and resistance to overuse injuries of chordae tendineae, as well as to explore their effects on flexor tenocyte biology. The messenger RNA expression profiles of chordae tendineae were analyzed using RNA sequencing and verified by quantitative reverse transcription polymerase chain reaction  and immunohistochemistry. Interestingly, we found that periostin (Postn) and fibroblast growth factor 7 (FGF7) were expressed at significantly higher levels in chordae tendineae, compared to flexor tendons. We further treated flexor tenocytes in vitro with periostin and FGF7 to examine their effects on the proliferation, migration, apoptosis, and tendon-related gene expression of flexor tenocytes. The results displayed enhanced cell proliferation ability at an early stage and an antiapoptotic effect on tenocytes, while treated with periostin and/or FGF7 proteins. Furthermore, there was a trend of promoted tenocyte migration capability. These findings indicated that Postn and FGF7 may represent novel cytokines to target flexor tendon healing. Clinical significance: The preliminary discovery leads to a novel idea for treating tendinopathy in the musculoskeletal system using specific molecules identified from chordae tendineae.

Combination of an extremely rare and a common congenital valvular anomalies: Accessory mitral valve chordae from left atrium and bicuspid aortic valve.

Accessory chordae tendineae is an extremely rare anomaly. In this case report, we described a 61-year-old female patient newly diagnosed with the combination of an accessory mitral valve chordae extending from left atrium which is an extremely rare congenital anomaly and a bicuspid aortic valve. In our patient, three-dimensional echocardiography showed incremental value over two-dimensional echocardiography in the assessment of the exact localization and the extend of accessory chordea.

Feasibility of concomitant exclusion of left atrial appendage during novel transapical off-pump beating heart mitral valve repair.

The AtriClip device enables the safe and reproducible epicardial clipping of the left atrial appendage. Transapical off-pump beating heart mitral valve repair using NeoChord DS100 Artificial Chordae Delivery System has matured and become more standardized. We aim to evaluate the feasibility of combining NeoChord repair and left atrial appendage exclusion in a single procedure through the same minithoracotomy in patients with mitral valve prolapse and atrial fibrillation. From 2018 to 2019, seven patients with severe mitral regurgitation and atrial fibrillation underwent transesophageal echocardiography-guided transapical off-pump mitral valve repair with the novel NeoChord DS 1000 system and concomitant left atrial appendage exclusion using the AtriClip Pro II device. Both procedures were performed via left mini-thoracotomy. The AtriClip device was applied after the NeoChord repair was done. All seven patients had less than moderate mitral regurgitation after the NeoChord repair and successful left atrial appendage occlusion. There were no device or procedure-related complications. Clinical follow-up revealed significant symptomatic improvement, and no cardiovascular complications were reported. Transesophageal echocardiography at 6-12 months post-procedure showed stable left atrial appendage occlusion with no residual flow between the left atrium and the left atrial appendage and a stump of less than 5 mm. Beating heart epicardial clipping of the left atrial appendage using AtriClip concomitant with transapical mitral valve repair using Neochord DS 1000 system is a feasible and safe treatment option in mitral valve prolapse and atrial fibrillation in patients with limited indications. However, its safety needs to be confirmed in a larger series of patients.

Neochordal Goldilocks: Analyzing the biomechanics of neochord length on papillary muscle forces suggests higher tolerance to shorter neochordae.

OBJECTIVE: Estimating neochord lengths during mitral valve repair is challenging, because approximation must be performed largely based on intuition and surgical experience. Little data exist on quantifying the effects of neochord length misestimation. We aimed to evaluate the impact of neochord length on papillary muscle forces and mitral valve hemodynamics, which is especially pertinent because increased forces have been linked to aberrant mitral valve biomechanics. METHODS: Porcine mitral valves (n = 8) were mounted in an ex vivo heart simulator, and papillary muscles were fixed to high-resolution strain gauges while hemodynamic data were recorded. We used an adjustable system to modulate neochord lengths. Optimal length was qualitatively verified by a single experienced operator, and neochordae were randomly lengthened or shortened in 1-mm increments up to ±5 mm from the optimal length. RESULTS: Optimal length neochordae resulted in the lowest peak composite papillary muscle forces (6.94 ± 0.29 N), significantly different from all lengths greater than ±1 mm. Both longer and shorter neochordae increased forces linearly according to difference from optimal length. Both peak papillary muscle forces and mitral regurgitation scaled more aggressively for longer versus shorter neochordae by factors of 1.6 and 6.9, respectively. CONCLUSIONS: Leveraging precision ex vivo heart simulation, we found that millimeter-level neochord length differences can result in significant differences in papillary muscle forces and mitral regurgitation, thereby altering valvular biomechanics. Differences in lengthened versus shortened neochordae scaling of forces and mitral regurgitation may indicate different levels of biomechanical tolerance toward longer and shorter neochordae. Our findings highlight the need for more thorough biomechanical understanding of neochordal mitral valve repair.

Anatomical Mitral Valve Repair: Mathematical Prediction of Artificial Chordae Length in Para-Commissural Regions.

To develop a mathematical formula for calculating the length of ruptured mitral valve chordae (with a view to surgically replacing them with artificial chordae) when rupture occurs at scallop A1, A3, P1, or P3. We studied human cadaver hearts collected by the Faculty of Medicine at Amiens Picardy University Hospital. The donors' mean age standard deviation age at death was 79 ± 10. After weighing and dissection, we counted the number of para-commissural chordae per scallop and measured their length with a digital calliper. A total of 31 human cadaver hearts (14 from females and 17 from males) were analyzed. The mean lengths of scallops A1, A2, A3, P1, P2, and P3 were 17.45, 19.42, 17.58, 13.32, 14.52, and 13.26 mm, respectively. A linear regression gave the following mathematical equations: A1 = 0.96 × A2- - 1.3 (R: 0.99; P < 0.001); A3 = 0.9 × A2 + 0.17 (R: 0.95; P < 0.01); P1 = 0.87 × P2 +0.74 (R: 0.89; P < 0.001), and P3 = 0.91 × P2 - 0.01 (R: 0.87; P < 0.0001). When the patient's anatomy prevents manual measurements of the chordae during mitral valve repair surgery, the mathematical formulae derived here can be used to predict the length of the chordae on A1, A3, P1, and P3 from the length of the chordae on A2 and P2. The mitral chordae can therefore be replaced with prostheses with a great degree of precision.