Direct transatrial transcatheter SAPIEN valve implantation through right minithoracotomy in a degenerated mitral bioprosthetic valve

Transcatheter mitral valve implantation for degenerated mitral bioprostheses or failed surgical annuloplasty rings: A systematic review and meta-analysis

BACKGROUND

Transcatheter mitral valve-in-valve (TMVIV) and valve-in-ring (TMVIR) implantation for degenerated mitral bioprostheses and failed annuloplasty rings have recently emerged as treatment options for patients deemed unsuitable for repeat surgery.

METHODS

A systematic literature review was conducted to summarize the data regarding the baseline characteristics and clinical outcomes of patients undergoing TMVIV and TMVIR procedures.

RESULTS

A total of 245 patients (172 patients who underwent TMVIV surgery and 73 patients who underwent TMVIR surgery) were included in the study; 93.5% of patients experienced successful TMVIV or TMVIR implantation. The mortality rates at discharge, 30 days, and 6 months were 5.7%, 8.1%, and 23.4%, respectively. The transapical (TA) access route was used in most procedures (55.2%). The TA and transseptal (TS) access routes resulted in similar outcomes. No significant differences were observed in the short-term outcomes between the patients who developed mitral stenosis versus mitral regurgitation as the mode of failure.

CONCLUSIONS

TMVIV and TMVIR implantation for degenerated mitral bioprostheses and failed annuloplasty rings are safe and effective. Both procedures, via TA or TS access, can result in excellent short-term clinical outcomes in patients with mitral stenosis or regurgitation, but long-term follow-up data are currently lacking to determine the durability of these procedures.

Hybrid Open Minimally Invasive Transcatheter Mitral Valve Replacement

We describe a hybrid surgical interventional technique for minimally invasive implantation of a transcatheter aortic valve in the mitral position. This technique does not require circular mitral annular calcification and minimizes the risk of left ventricular outflow tract obstruction. We believe this technique represents a useful approach for surgeons and interventional cardiologists until specialized transcatheter mitral valve devices become available.

Transcatheter mitral valve implantation: a percutaneous transapical system

Objectives

Despite recent achievements, implantation of a transcatheter mitral valved stent remains challenging. In this study, we present a different approach for implantation of a percutaneous mitral valved stent.

Methods

Percutaneous transapical access is combined with, respectively, a left-transatrial, right-transatrial/transseptal or transfemoral/transseptal approach for mitral valve stent implantation and secure fixation. The apical fixation and occlusion are ensured with an Amplatzer occluder. This novel approach was tested in 22 porcine hearts in an in vitro setting under the guidance of fluoroscopy ( n  = 11) and endoscopy ( n  = 11). The in vitro setup included continuous flushing at 37 °C. We determined the feasibility, time of implantation, stent deployment and stent fixation.

Results

Percutaneous mitral valved stent implantation was successful in all cases. Good handling properties and precise positioning were achieved. Time of implantation was comparable in the fluoroscopic and endoscopic groups at 10:41 ± 3:18 and 10:09 ± 2:42 min, respectively. Apical fixation with the occluder was excellent in all 22 cases.

Conclusions

The feasibility of percutaneous mitral valved stent implantation has been demonstrated in preliminary in vitro experiments. Subsequent studies are warranted to determine the efficacy of this minimally invasive catheter-based mitral valved stent implantation.

Fully percutaneous transthoracic left atrial entry and closure as a potential access route for transcatheter mitral valve interventions

BACKGROUND

Percutaneous access for mitral interventions is currently limited to transapical and transseptal routes, both of which have shortcomings. We hypothesized that the left atrium could be accessed directly through the posterior chest wall under imaging guidance.

METHODS AND RESULTS

We tested percutaneous transthoracic left atrial access in 12 animals (10 pigs and 2 sheep) under real-time magnetic resonance imaging or x-ray fluoroscopy plus C-arm computed tomographic guidance. The pleural space was insufflated with CO2 to displace the lung, an 18F sheath was delivered to the left atrium, and the left atrial port was closed using an off-the-shelf nitinol cardiac occluder. Animals were survived for a minimum of 7 days. The left atrial was accessed, and the port was closed successfully in 12/12 animals. There was no procedural mortality and only 1 hemodynamically insignificant pericardial effusion was observed at follow-up. We also successfully performed the procedure on 3 human cadavers. A simulated trajectory to the left atrium was present in all of 10 human cardiac computed tomographic angiograms analyzed.

CONCLUSIONS

Percutaneous transthoracic left atrial access is feasible without instrumenting the left ventricular myocardium. In our experience, magnetic resonance imaging offers superb visualization of anatomic structures with the ability to monitor and address complications in real-time, although x-ray guidance seems feasible. Clinical translation seems realistic based on human cardiac computed tomographic analysis and cadaver testing. This technique could provide a direct nonsurgical access route for future transcatheter mitral implantation.

Transcatheter valve-in-valve implantation: a systematic review of literature

INTRODUCTION

Transcatheter aortic valve implantation (TAVI) has become an alternative to open surgery in those deemed high risk. The purpose of this study was to evaluate the effectiveness and outcomes of this emerging procedure. We have examined available literature to provide an overview of valve-in-valve implantation using transcatheter heart valves (THVs) in aortic, mitral, pulmonary, tricuspid positions.

METHODS

A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google Scholar, Science Direct, and Web of Science.

RESULTS

Only 61 studies met full criteria and were included the review. This included 31 studies reporting transcatheter aortic valve-in-valve implantation, mitral valve-in-valve implantation (13 studies), tricuspid valve-in-valve implantation (12 studies), and pure native aortic valve regurgitation (nine studies). One of the limitations of this review is that most of the studies included were case reports, together with some case series.

CONCLUSION

Valve-in-valve implantation can be considered as an acceptable alternative to conventional open heart surgery for elderly high-risk surgical patients with bioprosthetic degeneration. Long-term follow-up of treated patients will be necessary to establish the true role of valve-in-valve implantation for bioprosthetic degeneration. Patients should be evaluated on an individual basis until outcomes are proven in large cohort studies or randomised trials.

Redo mitral valve replacement through a right mini-thoracotomy with an unclamped aorta

Redo cardiac surgery represents a clinical challenge due to a higher rate of perioperative morbidity and mortality. Mitral valve (MV) re operations can particularly be demanding in patients with patent coronary grafts, previous aortic valve replacement, calcified aorta or complications following a previous operation (abscesses, leaks or thrombosis). In this article we describe our technique to manage complex mitral reoperations using a minimally invasive approach, moderate hypothermia and avoiding aortic cross-clamping. Minimally invasive procedures with an unclamped aorta have the potential to combine the benefits of less invasive access and continuous myocardial perfusion. The advantage of a right mini-thoracotomy is the avoidance of sternal re-entry and limited dissection of adhesions, reducing the risk of cardiac structures or patent graft injury. Moderate hypothermia and continuous blood perfusion can guarantee adequate myocardial protection particularly in the case of patent grafts, decreasing the dangers of an incomplete or imperfect aortic clamping at mild hypothermia and potential lesions due to demanding clamp placing. Complex MV reoperations can be safely and effectively performed through a smaller right thoracotomy in the fourth intercostal space with an unclamped aorta.

Minimally invasive approach for redo mitral valve surgery

Redo cardiac surgery represents a clinical challenge due to a higher rate of peri-operative morbidity and mortality. Mitral valve re-operations can be particularly demanding in patients with patent coronary artery bypass grafts, previous aortic valve replacement, calcified aorta or complications following a previous operation (abscesses, perivalvular leaks, or thrombosis). Risk of graft injuries, hemorrhage, the presence of dense adhesions and complex valve exposure can make redo valve operations challenging through a median sternotomy. In this review article we provide an overview of minimally invasive approaches for redo mitral valve surgery discussing indications, techniques, outcomes, concerns and controversies. Scientific literature about minimally invasive approach for redo mitral surgery was reviewed with a MEDLINE search strategy combining "mitral valve" with the following terms: 'minimally invasive', 'reoperation', and 'alternative approach'. The search was limited to the last ten years. A total of 168 papers were found using the reported search. From these, ten papers were identified to provide the best evidence on the subject. Mitral valve reoperations can be safely and effectively performed through a smaller right thoracotomy in the fourth intercostal space termed "mini" thoracotomy or "port access". The greatest potential benefit of a right mini-thoracotomy is the avoidance of sternal re-entry and limited dissection of adhesions, avoiding the risk of injury to cardiac structures or patent grafts. Good percentages of valve repair can be achieved. Mortality is low as well as major complications. Minimally invasive procedures with an unclamped aorta have the potential to combine the benefits of minimally invasive access and continuous myocardial perfusion. Less invasive trans-catheter techniques could be considered as the natural future evolution for management of structural heart disease and mitral reoperations. The safety and efficacy of these procedures has never been compared to open reoperations in a randomized trial, although published case series and comparisons to historical cohorts suggest that they are an effective and feasible alternative. Ongoing follow-up on current series will further define these procedures and provide valuable clinical outcome data.

Advances in percutaneous treatment of mitral regurgitation

Percutaneous techniques for the treatment of mitral regurgitation have aroused much interest in recent years. Percutaneous mitral annuloplasty can be performed indirectly by using devices implanted in the coronary sinus or directly by using a retrograde approach. However, as yet, the results of these techniques are scarce and some devices have a high complications rate. The most frequent percutaneous mitral valve repair technique consists of mitral leaflet plication by implanting 1 or more percutaneous clips (MitraClip) in an imitation of the Alfieri surgical technique. Clinical experience with this device is broader than that with any other. The MitraClip device is associated with improved mitral regurgitation in a high percentage of carefully-selected patients. However, the single randomized study performed to date (EVEREST) showed its efficacy to be less than that of surgical repair and we await the results of new randomized studies that should clarify which patient-type can benefit most from this technique. Other left ventricular remodeling devices, tendinous cord implantation, and leaflet ablation are currently undergoing preclinical development or first-in-human experimentation. Finally, the development of biological prostheses for percutaneous mitral valve replacement is at an early stage. Many promising experiments at the preclinical phase and initial experiments in humans will very probably multiply in the near future. However, the true role of this technique in treating mitral valve disease will have to be evaluated in appropriately designed randomized controlled studies.

Valve-in-valve implantations: is this the new standard for degenerated bioprostheses? Review of the literature

Transcatheter aortic valve implantation has established itself as an alternative treatment for patients with valvular disease. In the current context of increasing bioprosthetic valve implants and an ageing population with growing comorbidities, a less invasive approach to the treatment of bioprosthetic dysfunction would be an appealing alternative to the standard of care. Transcatheter valve-in-valve implantation could be an alternative for patients who are deemed to be a high surgical risk. The valve-in-valve procedure is a minimally invasive percutaneous procedure where a valve can be implanted directly within a failing bioprosthetic valve. This technique can be applied to dysfunctional aortic bioprosthetic valves and can also be used in the pulmonary and atrioventricular valve bioprosthesis. We review the current literature to assess whether this technique may be the new standard for degenerated bioposthesis.

Transcatheter mitral valve-in-valve implantation: current experience and review of literature

PURPOSE OF REVIEW

Transcatheter mitral valve-in-valve (MVIV) implantation is an emerging technique for reoperative mitral valve replacement in high-risk patients. Clear guidelines on the use of transcatheter MVIV implantation are yet to be determined. In this review, we report our own experience as well as the recent available literature on this procedure.

RECENT FINDINGS

Since 2010, four case series of three or more patients have been reported with a total number of 23 patients. We also include unpublished data of 13 additional patients, who recently had MVIV implantation at our institution. Mean age was 78.45 ± 9.2 years with a median follow-up ranging from 70 to 357 days. Mean The Society of Thoracic Surgeons (STS) score was 14.1   ± 7.1%. All patients were in New York Heart Association (NYHA) class III or IV. Thirty days mortality was 7.5% (n = 3) and late mortality was 10% (n = 4). All patients had improvement in postoperative NYHA class to I/II following MVIV implantation. The mitral regurgitation grade was reduced from 3+ or 4+ preoperatively to a grade of 0 or 1 postoperatively. There was no structural valve deterioration reported in the follow-up period in any of the studies.

SUMMARY

The available literature supports the use of transcatheter MVIV implantation in selected high-risk patients with favorable results. Although there are no available long-term data on the procedure, the early and mid-term outcomes are excellent with no evidence of structural valve deterioration in the available follow-up period.