Intraoperative echocardiographic assessment of mitral valve translocation.

OBJECTIVES: The aim of this study was to present a rigorous method to analyse the intraoperative echocardiographic images from the novel mitral translocation procedure, which assesses the changes in mitral structure and function and compares this data to a control group of patients who have no mitral regurgitation (MR). METHODS: Transoesophageal echocardiography was post-processed using dedicated 3D software. Ten patients with normal mitral valves (MV) undergoing non-mitral cardiac surgery served as controls. Mitral coaptation area, mid-leaflet coaptation length and mitral annular circumference were measured in 3D. RESULTS: Twenty-three consecutive patients with severe secondary MR underwent MV translocation. All patients had none/trace MR post-translocation. The mean coaptation surface area increased from 63 to 427 mm2 (P < 0.001) and coaptation length increased from 1.0 to 10.5 mm (P < 0.001). The control group coaptation surface area (136 mm2) and length (2.5 mm) were greater than pre-translocation (P = 0.019; P < 0.001) and less than post-translocation (P < 0.001; P < 0.001). 3D mitral annular circumference in the translocation group decreased 15% (130-110 mm) (P < 0.001). Post-translocation, the mean gradient was 2(2-3) mmHg with the diastolic mitral orifice area of 3.4 ± 0.3 cm2 by planimetry and 3.5 ± 0.3 cm2 by pressure half-time. The coaptation to septum distance remained unchanged (P = 0.305) without systolic anterior leaflet motion. CONCLUSIONS: This echocardiographic analysis method demonstrates that MV translocation abolishes secondary MR, increases coaptation area and length and produces acceptable diastolic function. This method of analysis should allow precise structural and quantitative assessment of the durability of the repair in future long-term follow-up.

Translocation of the Mitral Valve in an Acute Large Animal Model.

Current repair options for functional mitral regurgitation (FMR) are not durable and do not adequately address underlying pathophysiology including leaflet tethering and insufficient coaptation. The feasibility of mitral valve translocation as a repair strategy for FMR was examined in normal swine. Seven pigs (median 62 kg, IQR 55-65 kg) with normal cardiac function were implanted with a 1-cm frustum-shaped pericardial patch inserted between the native mitral annulus and intact mitral leaflets. Operative survival was 100% with no post-procedure mitral stenosis, systolic anterior motion, or central mitral regurgitation observed on echocardiography. Post-translocation mean gradient was 3.5 mmHg (IQR 1.5-4 mmHg); trace or mild suture line leaks on the atrial suture line were noted in 5/7 pigs. Median leaflet coaptation increased from 2.4 (IQR 2.1-4.3 mm) to 12.4 mm (IQR 10.8-13.4 mm) after translocation (P = 0.016). Translocation dramatically increases leaflet coaptation without impairing diastolic function in animals with normal left ventricular function and is a promising technique for repair of FMR. Implantation of a 1.0-cm circumferential pericardial patch (mitral valve translocation) increases leaflet coaptation in a normal animal model.

Echocardiographic guidance for HARPOON beating-heart mitral valve repair.

The HARPOON mitral valve (MV) repair system has been shown to safely and effectively treat a degenerative MV prolapse with transventricular implantation of artificial cords on a beating heart. The low profile system is introduced and precisely steered under 3D TEE guidance towards the previously selected target on a prolapsing MV segment. It allows puncture and deployment of a knot on the leaflet. The procedure is repeated until desired number of knots are implanted and the cords are optimally tensioned to restore coaptation. The cords are then tied down on the epicardium over a felt pledget. State of the art echocardiographic imaging is a crucial part of the procedure. It starts from patients screening, pre-procedural analysis and planning, access selection, navigation, deployment, optimal cordal tensioning, and final MV assessment and is continued during the follow-up assessment. This article illustrates the specific echocardiographic aspects of the HARPOON procedure including 2D and advanced 3D TEE techniques. The echocardiographic protocol was developed based on initial experience in 60 procedures. Detailed training of the echocardiographer and surgical team, is mandatory to achieve excellent results of this procedure, being now introduced in the clinical practice.

Mitral Valve Translocation: A Novel Operation for the Treatment of Secondary Mitral Regurgitation.

BACKGROUND: Conventional annuloplasty repair of secondary (functional) ischemic mitral regurgitation (IMR) is associated with a 60% recurrence of moderate or greater mitral regurgitation at 2 years. We developed a novel repair technique for IMR that addresses the underlying geometric alterations of the mitral valve apparatus and compared outcomes with those of conventional repair in a swine model. METHODS: Chronic IMR was induced by percutaneous embolization of the circumflex artery. Swine with severe IMR (median 9 weeks after infarction) underwent undersized rigid annuloplasty (n = 5) or translocation repair (n = 6). Translocation repair consisted of detaching the mitral valve en bloc at the annulus, creating a 1 cm wide frustum-shaped pericardial patch, and suturing the outer circumference of the patch to the annulus and inner circumference to the mitral valve. RESULTS: Operative survival was 92% (11 of 12). All animals had none/trace residual central mitral regurgitation, and mean inflow gradients were similar (1 mm Hg [interquartile range, 1 to 2] vs 2 mm Hg [interquartile range, 1 to 2]; P = .75) in the annuloplasty and translocation groups, respectively. Median coaptation length marginally improved in conventional swine (3 to 4 mm, P = .05), but dramatically improved in translocation swine (3 to 8 mm, P = .003). Posterior leaflet angle increased from 39 to 80 degrees (P = .05) in annuloplasty swine but decreased from 50 to 31 degrees (P = .03) in translocation swine. The posterior leaflet was immobile after annuloplasty but had preserved motion after translocation (excursion, 1 degree vs 24 degrees; P = .045). CONCLUSIONS: Mitral valve translocation effectively treats mitral regurgitation by relieving leaflet tethering. Compared with annuloplasty, mitral valve translocation creates a larger surface of coaptation and preserves leaflet mobility without compromising diastolic function.

Initial Clinical Experience With Mitral Valve Translocation for Secondary Mitral Regurgitation.

BACKGROUND: Functional (secondary) mitral regurgitation (FMR) results from altered geometry of the mitral valve apparatus. Repair with restrictive mitral annuloplasty is associated with high rates of recurrent mitral regurgitation (MR). We developed a novel operative repair for FMR that translocates the intact mitral valve towards the apex. METHODS: The mitral valve was detached circumferentially and translocated into the ventricle with a frustum-shaped glutaraldehyde-treated autologous pericardial patch. Clinical and echocardiographic follow-up was performed. RESULTS: Fifteen consecutive patients with FMR (mean age, 59 years; 67% female) had mitral valve translocation between 2018 and 2020. Preoperative mean ejection fraction, left ventricular end-diastolic dimension, and systolic pulmonary artery pressure were 40% ± 11%, 59 ± 8 mm, and 49 ± 21 mm Hg, respectively; 33% had atrial fibrillation. Cardiomyopathy was ischemic in 4 and nonischemic in 11. Concomitant procedures included tricuspid valve operation (n = 8), coronary artery bypass grafting (n = 4), and atrial fibrillation ablation (n = 5). Post bypass transesophageal echocardiogram demonstrated none/trace MR in all patients and mean gradient of 3 mm Hg (interquartile range, 2-4 mm Hg). Mean leaflet extent of coaptation was 14 ± 2 mm (range, 11-17 mm). There was no postoperative mortality, stroke, or renal failure. Predismissal echocardiography showed none/trace MR in 14 patients and mild MR in 1. One patient underwent successful late rerepair of a suture line leak. Twelve patients were alive at latest follow-up and MR at 1 and 6 months was mild or less in all patients with mean leaflet extent of coaptation of 14 ± 2 mm (range, 12-16 mm) at 6 months. CONCLUSIONS: Mitral valve translocation creates a large surface of coaptation and effectively corrects FMR. Further study is needed to demonstrate the long-term durability and clinical utility of this operation.

Development of a Reproducible Swine Model of Chronic Ischemic Mitral Regurgitation: Lessons Learned.

BACKGROUND: Durability of mitral valve repair for ischemic mitral regurgitation (IMR) remains poor. We established a swine model of chronic IMR, and describe the methods and lessons learned from this model. METHODS: Thirty-five swine underwent percutaneous myocardial infarction with ethanol ablation of the circumflex or obtuse marginal (OM) arteries. Swine were followed with routine echocardiography for the development of severe IMR. Once severe IMR was established, swine underwent mitral valve operations on cardiopulmonary bypass. After operation, swine were survived up to 7 weeks. Angiographic and echocardiographic features of swine who developed severe IMR (IMR swine) and those who did not (non-IMR swine) were compared. RESULTS: The median number of OM arteries was 3, with 2 OM arteries infarcted. Acute survival after the myocardial infarction was 74% (26 of 35) with 3 (9%) early, postoperative deaths. Among the 23 swine with follow-up to determine IMR status, 14 of 23 (61%) developed significant IMR. Among IMR pigs, left ventricular (LV) ejection fraction decreased from 65% pre-myocardial infarction to 45% pre-mitral valve intervention (P < .001). Among non-IMR swine, LV ejection fraction decreased nonsignificantly from baseline (60%) to latest follow-up (55%) (P = .443). LV end-diastolic dimension (P = .039), wall motion score (P = .027), global circumferential strain (P = .014), and global longitudinal strain (P = .023) were significantly worse in IMR compared with non-IMR swine. CONCLUSIONS: A reproducible percutaneous model of severe IMR in swine is feasible with a guided anesthetic and perioperative approach. This model can serve as a platform to better understand the mechanism of IMR and subsequently to test novel repair techniques.

Safety and performance of a novel transventricular beating heart mitral valve repair system: 1-year outcomes.

OBJECTIVES: The objective of this study was to evaluate the safety and performance of a novel, beating heart procedure that enables echocardiographic-guided beating heart implantation of expanded polytetrafluoroethylene (ePTFE) artificial cords on the posterior mitral leaflet of patients with degenerative mitral regurgitation. METHODS: Two prospective multicentre studies enrolled 13 (first-in-human) and 52 subjects, respectively. Patients were treated with the HARPOON beating heart mitral valve repair system. The primary (30-day) end point was successful implantation of cord(s) with mitral regurgitation reduction to ≤moderate. An independent core laboratory analysed echocardiograms. RESULTS: Of 65 patients enrolled, 62 (95%) achieved technical success, 2 patients required conversion to open surgery and 1 procedure was terminated. The primary end point was met in 59/65 (91%) patients. Among the 62 treated patients, the mean procedural time was 2.1 ± 0.5 h. Through discharge, there were no deaths, strokes or renal failure events. At 1 year, 2 of the 62 patients died (3%) and 8 (13%) others required reoperations. At 1 year, 98% of the patients with HARPOON cords were in New York Heart Association class I or II, and mitral regurgitation was none/trace in 52% (n = 27), mild in 23% (n = 12), moderate in 23% (n = 12) and severe in 2% (n = 1). Favourable cardiac remodelling outcomes at 1 year included decreased end-diastolic left ventricular volume (153 ± 41 to 119 ± 28 ml) and diameter (53 ± 5 to 47 ± 6 mm), and the mean transmitral gradient was 1.4 ± 0.7 mmHg. CONCLUSIONS: This initial clinical experience with the HARPOON beating heart mitral valve repair system demonstrates encouraging early safety and performance. CLINICAL REGISTRATION NUMBERS: NCT02432196 and NCT02768870.

A Novel Quantitative Ex Vivo Model of Functional Mitral Regurgitation.

OBJECTIVE: Durability of mitral valve (MV) repair for functional mitral regurgitation (FMR) remains suboptimal. We sought to create a highly reproducible, quantitative ex vivo model of FMR that functions as a platform to test novel repair techniques. METHODS: Fresh swine hearts (n = 10) were pressurized with air to a left ventricular pressure of 120 mmHg. The left atrium was excised and the altered geometry of FMR was created by radially dilating the annulus and displacing the papillary muscle tips apically and radially in a calibrated fashion. This was continued in a graduated fashion until coaptation was exhausted. Imaging of the MV was performed with a 3-dimensional (3D) structured-light scanner, which records 3D structure, texture, and color. The model was validated using transesophageal echocardiography in patients with normal MVs and severe FMR. RESULTS: Compared to controls, the anteroposterior diameter in the FMR state increased 32% and the annular area increased 35% (P < 0.001). While the anterior annular circumference remained fixed, the posterior circumference increased by 20% (P = 0.026). The annulus became more planar and the tenting height increased 56% (9 to 14 mm, P < 0.001). The median coaptation depth significantly decreased (anterior leaflet: 5 vs 2 mm; posterior leaflet: 7 vs 3 mm, P < 0.001). The ex vivo normal and FMR models had similar characteristics as clinical controls and patients with severe FMR. CONCLUSIONS: This novel quantitative ex vivo model provides a simple, reproducible, and inexpensive benchtop representation of FMR that mimics the systolic valvular changes of patients with FMR.

Intensive care and anesthesia management for HARPOON beating heart mitral valve repair.

Patients with severe mitral valve regurgitation secondary to degenerative disease are known to benefit from mitral valve repair surgery. Novel techniques for achieving mitral valve repair on the beating heart have been developed and are being introduced into clinical practice. The HARPOON Beating Heart Mitral Valve Repair System (MVRS) in recent studies has demonstrated efficacy and safety for the repair of degenerative mitral valve disease on the beating heart. The device uses transoesophageal echocardiographic guidance to implant artificial expanded polytetrafluoroethylene (ePTFE) cords on prolapsed mitral valve leaflets in the beating heart. It requires general anaesthesia and there are specific intensive care and anaesthesia considerations for the safe management of these cases. This article describes the general principles of intensive care and anaesthesia management employed for the initial patients treated with the HARPOON Beating Heart MVRS, the outcomes for these patients, and the potential challenges for the future management of these cases.

Transmitral Septal Myectomy for Hypertrophic Obstructive Cardiomyopathy.

BACKGROUND: Intrinsic abnormalities of the mitral valve are common in patients with hypertrophic cardiomyopathy and may need to be addressed at operation. METHODS: Consecutive patients undergoing transmitral septal myectomy were retrospectively reviewed. The ventricular septum was exposed through a left atriotomy, and the anterior leaflet of the mitral valve was detached from its annulus. An extended myectomy was performed to the base of the papillary muscles. After myectomy, the anterior leaflet was reattached and concomitant mitral valve repair or replacement was performed. In some cases, we performed a modified anterolateral commissural closure suture, which served to reposition the lateral aspect of the anterior leaflet out of the left ventricular outflow tract ("curtain stitch"). RESULTS: Twenty patients who underwent this procedure were identified (70% women; mean age 63 years). Mitral regurgitation was moderate in 55% and severe in 40%. Preoperative peak left ventricular outflow tract gradient was 92 ± 43 mm Hg. Mitral valve repair (n = 11) or replacement (n = 9) was performed. Predischarge transthoracic echocardiography demonstrated a left ventricular outflow tract gradient of 10 ± 5 mm Hg. There was no operative mortality. Follow-up was 100% complete and averaged 22 ± 25 months. No patient required reoperation, and there was no recurrence of left ventricular outflow tract obstruction or mitral regurgitation greater than mild. CONCLUSIONS: Potential advantages of transmitral myectomy include a panoramic view of the septum and mitral subvalvular apparatus and the ability to simultaneously address mitral valve pathology. Consideration should be given to using the transmitral approach to septal myectomy as the preferred approach for the surgical treatment of hypertrophic cardiomyopathy.

Beating-Heart Mitral Valve Repair Using a Novel ePTFE Cordal Implantation Device: A Prospective Trial.

BACKGROUND: Conventional mitral valve (MV) operations allow direct anatomic assessment and repair on an arrested heart, but require cardiopulmonary bypass, aortic cross-clamping, sternotomy or thoracotomy, and cardioplegic cardiac arrest, and are associated with significant perioperative disability, and risks of morbidity and mortality. OBJECTIVES: This study evaluated safety and performance of a transesophageal echocardiographic-guided device designed to implant artificial expanded polytetrafluoroethylene (ePTFE) cords on mitral leaflets in the beating heart. METHODS: In a prospective multicenter study, 30 consecutive patients with severe degenerative mitral regurgitation (MR) were treated with a mitral valve repair system (MVRS) via small left thoracotomy. The primary (30-day) endpoint was successful implantation of cords with MR reduction to moderate or less. RESULTS: The primary endpoint was met in 27 of 30 patients (90%). Three patients required conversion to open mitral surgery. There were no deaths, strokes, or permanent pacemaker implantations. At 1 month, MR was mild or less in 89% (24 of 27) and was moderate in 11% (3 of 27). At 6 months, MR was mild or less in 85 % (22 of 26), moderate in 8% (2 of 26), and severe in 8% (2 of 26). Favorable cardiac remodeling at 6 months included decreases in end-diastolic (161 ± 36 ml to 122 ± 30 ml; p < 0.001) and left atrial volumes (106 ± 36 ml to 69 ± 24 ml; p < 0.001). The anterior-posterior mitral annular dimension decreased from 34.7 ± 5.8 mm to 28.2 ± 5.1 mm; p < 0.001 as did the mitral annular area (10.0 ± 2.7 cm2 vs. 6.9 ± 2.0 cm2; p < 0.0001). CONCLUSIONS: MVRS ePTFE cordal implantation can reduce the invasiveness and morbidity of conventional MV surgery. The device's safety profile is promising and prospective trials comparing the outcomes of the MVRS to conventional MV repair surgery are warranted. (CE Mark Study for the Harpoon Medical Device [TRACER]; NCT02768870).

Transapical Beating-Heart Mitral Valve Repair With an Expanded Polytetrafluoroethylene Cordal Implantation Device: Initial Clinical Experience.

BACKGROUND: Degenerative mitral valve (MV) disease is a common cause of severe mitral regurgitation (MR) and accounts for the majority of MV operations. Conventional MV surgery requires cardiopulmonary bypass, aortic cross-clamping, cardioplegia, and a thoracotomy or sternotomy and, therefore, is associated with significant disability, risks, and unpredictable rates of MV repair. Transesophageal echocardiography-guided beating-heart MV repair with expanded polytetrafluoroethylene cordal insertion has the potential to significantly reduce surgical morbidity. We report the first-in-human clinical experience with a novel preformed expanded polytetrafluoroethylene knot implantation device (Harpoon TSD-5) designed to treat degenerative MR. METHODS: Through a small left thoracotomy, the device was inserted into the heart and guided by transesophageal echocardiography to the ventricular surface of the prolapsed leaflet. Multiple expanded polytetrafluoroethylene cords were anchored in the leaflet and then adjusted to the correct length to restore MV leaflet coaptation and secured at the epicardium. RESULTS: Eleven patients with posterior leaflet prolapse and severe MR, with mean±SD age of 65±13 years and mean ejection fraction of 69±7%, were treated with 100% procedural success. Immediate postprocedural mean MR grade was trace. At 1 month, the mean MR grade was mild with significant decreases in end-diastolic volume (139 to 107 mL; P=0.03) and left atrial volume (118 to 85 mL; P=0.04). CONCLUSIONS: A novel device used for beating-heart image-guided MV repair demonstrates a significant reduction in MR with favorable left ventricular and left atrial reverse remodeling. This approach has the potential to decrease invasiveness and surgical morbidity. Further follow-up is necessary to assess long-term efficacy. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT02432196.