Remodeling of the mitral valve using radiofrequency energy: review of a new treatment modality for mitral regurgitation

Mitral regurgitation (MR) is a common valvular pathology with significant morbidity and mortality implications. Mechanical treatment of this condition is more effective than medical treatment and surgical correction has traditionally been the mechanical method of choice. Following major advances and wide acceptance of percutaneous interventions for coronary artery diseases, the field of valvular heart disease became an attractive target for transcatheter treatment modalities. Significant steps have been achieved in the field of percutaneous treatment of mitral stenosis as well as aortic stenosis, and lately, mitral regurgitation has been the focus of interest for many investigators looking for transcatheter solutions. Percutaneous edge-to-edge techniques and annuloplasty are innovative but have many disadvantages including the inability to reintervene and leaving a foreign body behind, respectively. Since the mitral and tricuspid annuli have dense collagen, a treatment modality targeting that collagen is logical. Observing the thermal effect on collagen, which causes conformational changes and shrinkage, radiofrequency energy was tested to evaluate its effect on the collagen-rich structure that is the mitral valve annulus. The potential of shrinking the mitral annulus by applying direct thermal source could be a promising modality for the treatment of mitral regurgitation with potential open and percutaneous applications. This paper presents an overview of the recent advances in transcatheter treatment of mitral regurgitation focusing on a new treatment modality that aims at reducing the mitral valve annulus diameter through the direct application of thermal energy using a radiofrequency energy probe.     

New techniques for percutaneous repair of the mitral valve

A variety of innovative techniques and devices are being developed for the percutaneous management of mitral insufficiency. More than 30 devices are in stages of development from early stage to human pivotal trials. Two devices for the management of degenerative myxomatous disease of the mitral valve replicate the Alfieri edge-to-edge surgical repair. One of those devices, the Evalve Mitraclip, is in a pivotal trial at the current time. The other devices address functional mitral regurgitation by a variety of techniques for performing mitral valve annuloplasty. The majority of devices take advantage of the proximity of the coronary sinus to the posterior mitral annulus to deliver devices that remodel the mitral annulus. Two devices perform septal lateral cinching decreasing the anterior posterior diameter of the mitral annulus and correcting leaflet malcoaptation. Numerous issues are discussed including regulatory hurdles and the integration of percutaneous techniques into clinical practice in a safe and efficacious manner.     

Percutaneous mitral valve repair: a feasibility study in an ovine model of acute ischemic mitral regurgitation.

Annuloplasty is the cornerstone of surgical mitral valve repair. A percutaneous transvenous catheter-based approach for mitral valve repair was tested by placing a novel annuloplasty device in the coronary sinus of sheep with acute ischemic mitral regurgitation. Mitral regurgitation was reduced from 3-4+ to 0-1+ in all animals (P < 0.03). The annuloplasty functioned by reducing septal-lateral mitral annular diameter (30 +/- 2.1 mm preinsertion vs. 24 +/- 1.7 mm postinsertion; P < 0.03). These preliminary experiments demonstrate that percutaneous mitral annuloplasty is feasible. Further study is necessary to demonstrate long-term safety and efficacy of this novel approach.     

Percutanenous therapies for mitral regurgitation

Percutaneous therapies for the treatment of mitral regurgitation have emerged rapidly over the past several years. Most of the percutaneous approaches are modifications of existing surgical approaches to mitral annuloplasty or leaflet repair. Most of the percutaneous devices are based on surgical approaches. Catheter-based leaflet repair with the MitraClip is accomplished using an implantable clip to mimic the surgical edge-to-edge technique. Percutaneous annuloplasty can be achieved indirectly via the coronary sinus, or directly from retrograde left ventricular access. Several of these percutaneous approaches have been successfully used in trials or are in the early stages of use in practice.     

Percutaneous repair of anterior mitral leaflet perforation

A 59-year-old male underwent coronary artery bypass grafting and mitral ring annuloplasty 4 years ago. The procedure was complicated by sternal wound infection. Recently, he presented with multiple admissions for decompensated heart failure with volume overload and pulmonary edema. He was found to have severe mitral regurgitation (MR) and transesophageal echocardiography (TEE) demonstrated severe MR through an anterior mitral leaflet perforation. Due to high surgical risk, he was referred for transcatheter repair of his mitral valve. This case illustrates the first reported use of an Amplatzer atrial septal occluder device for percutaneous mitral leaflet repair using three-dimensional TEE guidance after prior surgical mitral ring annuloplasty repair.     

Percutaneous approaches to mitral valve regurgitation

Mitral regurgitation is a common problem associated with significant morbidity and mortality. Mitral valve surgery has been the treatment of choice for symptomatic patients with severe mitral regurgitation or asymptomatic patients with high-risk clinical features. However, a significant number of patients remain untreated related mainly due to a projected high surgical risk. Therefore, alternative percutaneous treatments including indirect annuloplasty, which takes advantage of the coronary sinus, and direct annuloplasty have recently been explored. Most recently, promising results of the first randomized trial comparing conventional mitral valve surgery to percutaneous therapy with a clip creating a double orifice much like the surgical Alfieri approach have been presented. Finally, percutaneous mitral valve replacement in an animal model has been pursued. This review serves to familiarize the reader with some anatomical concepts and devices for percutaneous mitral repair.     

经导管二尖瓣修复治疗二尖瓣反流所致心力衰竭的进展与展望

二尖瓣关闭不全主要是由于瓣膜的异常所导致的原发性或退化性的二尖瓣反流（mitral valve regurgitation,MR）,也可由继发性心肌病变引起功能性、继发性MR。药物治疗可以缓解相应症状,但却无法阻止病程进展。目前,尽管有明确的指南建议对伴有左心功能不全症状和体征的中至重度（NYHA分级超过Ⅲ级）MR患者进行手术,但由于种种客观与主观的原因大多数严重MR患者仍没有接受手术。随着经导管二尖瓣介入手术修复治疗的蓬勃发展,目前的经导管二尖瓣修复治疗的理念主要来源于外科修复技术,分别以缘对缘、人工腱索修复、人工瓣环成形等方式为代表,有不同种类的器械进入临床,取得了良好的效果。经导管介入治疗MR为二尖瓣手术高危患者提供了新的选择。本文将综述手术治疗MR所致心力衰竭的新进展。     

Percutaneous leaflet repair and annuloplasty for mitral regurgitation

Percutaneous therapy for the treatment of mitral regurgitation has emerged rapidly over the past few years. Most of the percutaneous approaches are modifications of existing surgical approaches to mitral annuloplasty or leaflet repair. Catheter-based devices mimic these surgical approaches with less procedural morbidity and mortality as a consequence of their less invasive nature. Percutaneous annuloplasty can be achieved indirectly via the coronary sinus or directly from retrograde left ventricular access. Catheter-based leaflet repair is accomplished using an implantable clip to mimic the surgical edge-to-edge technique. Several of these percutaneous approaches have been successfully used in patients to demonstrate proof of concept, while others have already stopped further development. There is increasing experience in both trials and practice to begin to define the clinical utility of percutanenous leaflet repair, and annuloplasty approaches are undergoing significant development.     

Three‐Dimensional Echocardiography‐Based Prediction of Posterior Leaflet Resection

Clinical long‐term outcomes have shown that partial leaflet resection followed by ring annuloplasty is a reliable and reproducible surgical repair technique for treatment of mitral valve (MV) leaflet prolapse. We report a 61‐year‐old male for three‐dimensional transesophageal echocardiography (3DTEE)‐based virtual posterior leaflet resection and ring annuloplasty. Severe mitral regurgitation was found and computational evaluation demonstrated substantial leaflet malcoaptation and high stress concentration. Following virtual resection and ring annuloplasty, posterior leaflet prolapse markedly decreased, sufficient leaflet coaptation was restored, and high stress concentration disappeared. Virtual MV repair strategies using 3DTEE have the potential to help optimize MV repair.     

Paravalvular leak closure of acute mitral valve ring dehiscence during mitral valve‐in‐ring procedure

The replacement of surgically corrected mitral valves, also known as percutaneous transcatheter repair, is a relatively young field. Even though these procedures are usually successful, they can present significant intraoperative or postoperative challenges. To our knowledge, we present the first case of acute focal dehiscence of mitral ring repair during the mitral valve‐in‐ring procedure.     

Transcatheter mitral valve intervention

Mitral regurgitation is a common valvular heart disorder increasing with age. Many patients are ineligible for mitral valve surgery due to their age and other comorbidities. Left untreated, patients develop severe disease with a poor prognosis. The development of lower risk percutaneous mitral valve interventions has helped meet the needs of this previously untreated patient group. This review explores the recent and more established developments that have expanded the armamentarium for transcatheter mitral valve intervention.Key words: annuloplasty, chordal implantation, mitral regurgitation, percutaneous edge-to-edge repair, transcatheter mitral valve intervention     

Percutaneous approaches to mitral regurgitation

Percutaneous therapy for mitral repair has emerged over the past several years as an investigational option for treating mitral regurgitation (MR). A variety of novel methods to treat MR using a percutaneous route have been developed. Most of these approaches are modifications of surgical techniques, some established and some obscure. The basic surgical approaches to mitral repair are annuloplasty and leaflet repair. Catheter-based devices mimic or approximate these surgical approaches. MR as a disease process is heterogeneous, and different therapeutic approaches are needed for different etiologies of MR and morphologies of the mitral apparatus. Primary leaflet diseases are mitral prolapse and fibroelastic deficiency. Secondary, or functional, MR exists when the leaflets are normal. Functional ischemic MR and functional MR related to heart failure occur in different populations and historically have had different responses to surgical therapy. Leaflet repair using a percutaneous clip has been accomplished for patients with mitral valve prolapse and also some patients with functional MR. Indirect annuloplasty via the coronary sinus has shown promising early human trial results in patients with functional MR. Direct annuloplasty and left ventricular chamber remodeling technologies are in the earliest stages of human application. This group of approaches is being studied as an alternative to surgery for selected patients. The MitraClip (Evalve, Menlo Park, CA) for leaflet repair has been approved for use in Europe and is being applied predominantly to high-risk surgical patients with either functional or degenerative, organic MR. One of the coronary sinus devices has received approval in Europe as well. This complex clinical landscape has made device development, trial design, and patient selection complicated. Steady progress in the field is being made. Many patients with functional MR who are currently treated medically will be the subject of upcoming trials. Catheter methods for mitral repair promise to serve some patients currently considered high risk for surgery, and some patients may have catheter therapy as an alternative to surgery.     

Pigtail catheter “propping” for MitraClip percutaneous transcatheter mitral valve repair

In recent years percutaneous therapy has emerged as a feasible and effective option for the treatment of mitral regurgitation, particularly in cases where the risks of conventional cardiac surgery are prohibitively high. To date the most widely used percutaneous approach is beating heart, edge‐to‐edge repair with the MitraClip device (Abbott Vascular‐Structural Heart, Menlo Park, CA). The technique requires simultaneous grasping and approximation of both mitral valve leaflets prior to securing and releasing the clip. However, this may be technically challenging or indeed impossible in patients with failure of coaptation, particularly when there is a large coaptation gap. We present an approach for overcoming this relatively common obstacle based on “propping” the anterior mitral valve leaflet toward its posterior counterpart with a diagnostic pigtail catheter to reduce the coaptation gap and to allow grasping of both leaflets without difficulty. © 2016 Wiley Periodicals, Inc.     

Conduction disturbances related to percutaneous balloon mitral valvuloplasty

During the performance of 280 consecutive percutaneous balloon mitral valvuloplasty operations, two cases of conduction disturbances were reported (0.7%). These rare complications are transient and due to the mechanical pressure of the balloon on the conduction system.     

二尖瓣人工瓣环成形术18例

目的回顾性分析１８例二尖瓣人工瓣环成形术的疗效。方法风湿性病变３例,退行性变１１例,先天性病变４例。重度关闭不全１６例,中度关闭不全２例。根据二尖瓣病理改变对瓣叶和瓣下结构做针对性瓣膜成形术后,均植入人工瓣环。１０例在经食道超声心动图监测下行成形术。结果成形中术后二尖瓣无返流６例,轻度返流９例,中度返流１例。２例改行二尖瓣置换术。随访７个月至６年７个月,平均３．６年,心功能均有显改善。结论对于     

Is ischemic mitral regurgitation an indication for surgical repair or replacement?

Ischemic mitral regurgitation (IMR) is common in patients with coronary artery disease. While it is well-known that IMR exerts a graded effect upon survival—the greater the degree of IMR, the lower the survival—the indications for surgical treatment and the choice of surgical procedure (repair versus replacement) are controversial. In patients with mild to moderate IMR, the benefit of a mitral valve procedure has not been demonstrated, and surgical practice varies. In patients with severe IMR, mitral valve surgery is the norm, but guidelines for choosing between valve repair and valve replacement do not exist. Furthermore, the survival impact of mitral valve surgery in patients with severe IMR is uncertain. When patients with severe IMR undergo mitral valve surgery, undersized annuloplasty results in durable repair in 70% to 85% of cases. Newly-developed adjunctive repair techniques may further improve results. Currently, mitral valve repair is the procedure of choice in the majority of patients having surgery for severe IMR. However, the most severely ill patients and those with certain echocardiographic characteristics (e.g. severe bileaflet tethering) should be treated with bioprosthetic mitral valve replacement rather than repair. Disclosures: Dr. Gillinov is a consultant to Edwards Lifesciences, LLC and has an equity interest in Viacor, Inc.     

Catheter-based approach to mitral regurgitation

Mitral Regurgitation (MR) is a common medical problem. MR is also a prognostic factor; patients with severe symptomatic MR have a poor prognosis with an annual mortality rate of 5% without surgical intervention. An anatomic understanding of the normal and regurgitant mitral valve is essential in order to evaluate appropriately the severity and impact of MR. We briefly discuss mitral complex anatomy, MR evaluation, and treatment options (surgical and catheter-based alternatives) according to the type of lesion found. In particular, our group has shown temporal percutaneous annuloplasty and definitive percutaneous edge-to-edge mitral valve repair to be a feasible technique. Recently a study evaluating endovascular mitral valve edge-to-edge repair was successfully initiated by our group. Acute and chronic ischemic mitral regurgitation and special situations, such as paravalvular leaks, hypertrophic obstructive cardiomyopathy, and mixed lesions are also discussed. Future directions may include the percutaneous transcatheter implantation of a bioprosthetic valve in mitral position.     

Percutaneous mitral repair with MitraClip system; safety and efficacy; initial Egyptian experience

ObjectivesTo evaluate the feasibility, efficacy, and safety of the MitraClip system in patients with severe MR.BackgroundMitral valve repair for mitral regurgitation (MR) has been performed by the use of a surgically created double orifice. Percutaneous repair based on this surgical approach has been developed by the use of a MitraClip device.MethodsFive patients with 3 to 4+ MR were selected in accordance with the American Heart Association/American College of Cardiology guidelines between March 2013 and May 2013 and underwent percutaneous mitral repair with the MitraClip system with 6 months follow up after the procedure. The primary acute safety endpoint was freedom from major adverse events (MAEs) at 30 days. The primary efficacy endpoint was acute procedural success defined as clip implant with the reduction of MR to equal or less than grade II, based on current guidelines.ResultsNo transseptal complications were reported (0%). There was no procedural mortality. No patients experienced MAE at 30 days. No cases of clip detachment or embolization were observed. Acute procedural success was achieved in all treated patients (100%). There was an improvement in the severity of MR in all patients as assessed acutely. Acute MR reduction by 3 grades was achieved in 2 patients and by 2 grades in 3 patients (reduction ⩾2 grades in 100%).ConclusionsOur initial results with the MitraClip device in a very small number of patients indicate that percutaneous edge-to-edge mitral valve repair is feasible and may be accomplished with favorable short-term safety and efficacy results.     

Antegrade percutaneous valve implantation for mitral ring dysfunction,a challenging case

The operative risk for reoperation of degenerated bioprosthetic valves or failing mitral‐valve annuloplasty is higher compared with the risks for first isolated native valve repair or replacement (Astor et al., Eur Heart J 2008;29:2382–2387). In the presence of comorbidities, these risks increase exponentially. The recent introduction of transcatheter valve implantation opened new perspectives for the treatment of patients at very high surgical risk. We report a percutaneous mitral valve (MV) implantation using a transatrial approach within a MV ring using the Edwars Sapien XT valve. © 2012 Wiley Periodicals, Inc.     

Contemporary application of cardiovascular hemodynamics: transcatheter mitral valve interventions

Since the development and refinement of echocardiography, this technique has, for some time, been the mainstay for hemodynamic assessment of the mitral valve. This article discusses the key components of the invasive hemodynamic assessment of mitral valve disease and illustrates their utility through percutaneous transluminal mitral valvuloplasty for mitral stenosis and the novel transcatheter mitral valve repair using the MitraClip for mitral regurgitation. Changes in left atrial pressure and waveform, mean gradient, and cardiac output are critical assessment parameters for both safety and efficacy. Invasive hemodynamic assessment is an essential complement to echocardiography for the optimal guidance of these procedures.