Percutaneous valve replacement and repair

Percutaneous valve procedures: Present and future

Percutaneous mitral commissurotomy and aortic valvuloplasty have been being performed since the mid-1980s. Balloon commissurotomy has been used in thousands of cases worldwide and it provides good short- and long-term results in a wide range of patients. It has virtually replaced surgical commissurotomy in the treatment of mitral stenosis. In contrast, percutaneous aortic valvuloplasty is almost abandoned worldwide due to its lack of efficacy and the risks involved. The new techniques of percutaneous valve intervention: aortic valve replacement and mitral valve repair are at an early stage: the first in-man applications of these fledgling techniques started in 2002. Preliminary series show that they are feasible; however, they need to be further evaluated in comparison with contemporary treatment to assess accurately how efficient they are and the risks involved. Currently potential applications concern high-risk patients, however, in the future, after thorough evaluation, this may be extended to others. Thus, percutaneous interventions already play an important role in treatment of valvular heart disease, a role that seems set for future expansion.

Echocardiography-guided interventions

A major advantage of echocardiography over other advanced imaging modalities (magnetic resonance imaging, computed tomographic angiography) is that echocardiography is mobile and real time. Echocardiograms can be recorded at the bedside, in the cardiac catheterization laboratory, in the cardiovascular intensive care unit, in the emergency room-indeed, any place that can accommodate a wheeled cart. This tremendous advantage allows for the performance of imaging immediately before, during, and after various procedures involving interventions. The purpose of this report is to review the use of echocardiography to guide interventions. We provide information on the selection of patients for interventions, monitoring during the performance of interventions, and assessing the effects of interventions after their completion. In this document, we address the use of echocardiography in commonly performed procedures: transatrial septal catheterization, pericardiocentesis, myocardial biopsy, percutaneous transvenous balloon valvuloplasty, catheter closure of atrial septal defects (ASDs) and patent foramen ovale (PFO), alcohol septal ablation for hypertrophic cardiomyopathy, and cardiac electrophysiology. A concluding section addresses interventions that are presently investigational but are likely to enter the realm of practice in the very near future: complex mitral valve repairs, left atrial appendage (LAA) occlusion devices, 3-dimensional (3D) echocardiographic guidance, and percutaneous aortic valve replacement. The use of echocardiography to select and guide cardiac resynchronization therapy has recently been addressed in a separate document published by the American Society of Echocardiography and is not further discussed in this document. The use of imaging techniques to guide even well-established procedures enhances the efficiency and safety of these procedures.

Echocardiographic Guidance and Assessment of Percutaneous Repair for Mitral Regurgitation With the Evalve MitraClip: Lessons Learned From EVEREST I

OBJECTIVE

Percutaneous mitral repair is rapidly developing as an alternative to cardiac surgery in select patients. The Evalve percutaneous E2E system uses the MitraClip to replicate the surgical suture-based approach. This procedure requires real-time echocardiographic guidance in a unique and significant collaboration between echocardiographer and interventionalist. transesophageal echocardiography (TEE) is used as the primary imaging modality to guide this procedure and is essential to its success.

METHODS

In EVEREST I, the US multicenter phase I safety and feasibility trial, 47 patients with 3 or 4+ mitral regurgitation (MR) were enrolled. The trial involved a standardized echocardiographic imaging protocol with a standardized anatomic-based vocabulary, predetermined standard TEE views, preprocedural strategy meetings, and display of echocardiographic aids to optimize communication and procedural efficiency during placement of the clip.

RESULTS

TEE guidance facilitated the creation of a double-orifice mitral valve in all 47 patients enrolled (100%), and 40 patients were discharged with 1 or more clips (85%). At discharge, successful placement of a clip and <or= 2+ MR was present in 34 patients (74%). The standardized approach contributed to a reduction in the time to perform the procedure over the course of the trial at both initial and new sites.

CONCLUSIONS

TEE is essential to the guidance of percutaneous MitraClip E2E repair. A streamlined approach to echocardiographic guidance, using predetermined standardized views, a common anatomic-based vocabulary, preprocedural strategy meetings, and a display of echocardiographic aids in the catheterization laboratory shortens the procedure time and allows for efficient percutaneous repair.

Coronary sinus stent implantation improves acute ischaemic mitral valve regurgitation; an experimental safety and efficacy study

AIMS

Percutaneous implantation of a large stent was performed in the coronary sinus of pigs, to assess safety and immediate efficacy for reduction of acute ischaemic mitral regurgitation.

METHODS AND RESULTS

Acute ischaemic mitral regurgitation (MR) was produced in seven pigs, continuously monitored with echocardiography, during repeated balloon inflations in the proximal left circumflex artery. The protocol was repeated following placement of a stent in the coronary sinus. Five pigs survived the period of acute ischaemia and developed severe mitral regurgitation (>/=3+/4+). Following successful stent implantation, the MR area decreased from 2.4+/-0.4 cm2 to 1.1+/-0.6 cm2 (p=0.016) and the proximal isovelocity surface area (PISA) MR flow from 63.9+/-37.3 ml/sec to 44.0+/-35.0 ml/sec (p=0.029). Coronary sinus stent prevented the ischaemia-induced increase in septal-lateral mitral annulus dimension (p=0.041) and left ventricular dilatation. Three animals were allowed to recover and underwent histological analysis of the coronary sinus stent at 30 days, showing endothelialisation and minimal hyperplasia, without thrombus formation.

CONCLUSIONS

A percutaneously deployed stent in the coronary sinus may help to decrease the severity of acute ischaemic mitral regurgitation.

Current status of percutaneous valvular procedures

OPINION STATEMENT

During the past few decades, percutaneous valvular procedures have been used in mitral and aortic stenosis. Percutaneous mitral commissurotomy, which has virtually replaced surgical commissurotomy in the treatment of mitral stenosis, has been performed since the mid-1980s and has provided good results in thousands of patients worldwide. Percutaneous balloon aortic valvuloplasty has largely been abandoned due to its limited efficacy and the risks involved. New percutaneous procedures are currently being developed in mitral regurgitation and aortic stenosis, which represent the two most frequent valve diseases in industrialized countries. They are in the early stages of development but have opened a very exciting field of investigation. Two percutaneous mitral valve treatment techniques have been used: the edge-to-edge technique and the prosthetic ring annuloplasty. Preliminary series show that they are feasible; however, they need to be further evaluated in comparison with contemporary treatment to accurately assess their effectiveness and the risks involved. Since 2003, percutaneous aortic valve replacement has been performed in approximately 100 compassionate cases with end-stage aortic stenosis, formally declined for surgery. It results in hemodynamic and clinical improvement, with an acceptable risk in this highly selected population. The evaluation of these new percutaneous procedures requires a close collaboration between interventionalists, echocardiographers, engineers, and surgeons. It is probable that they will play an important role in the treatment of valve disease in the future.

Mitral regurgitation: overview of current surgical techniques and future developments

Mitral regurgitation is a complex disease with many different etiologies, underlying dysfunctions and histologic alterations. Surgical correction of this condition dramatically improves the life expectancy and life quality of affected patients. The structure of the mitral valve lends itself to many surgical techniques. The purpose of this review is to offer readers an overview on this subject.