Current status and clinical development of transcatheter approaches for severe mitral regurgitation

New developments in transcatheter therapy of mitral valve disease

Mitral valve regurgitation (MR) belongs to one of the most common acquired valve diseases in western countries with increasing prevalence in older age. For patients with high perioperative risk and older age prohibitive for valve surgery, the development of transcatheter mitral valve therapies offers new options. Assessment of the severity and etiology of MR and thorough imaging of the mitral valve anatomy and pathology are necessary prerequisites for appropriate decision making in the field of transcatheter mitral valve therapies. Different transcatheter repair and replacement techniques are on the market, most of them mimicking surgical techniques. With some techniques (e.g., the MitraClip device), there is good clinical experience (>80,000 devices implanted worldwide), and evidence (three randomized studies), whereas for newer procedures, safety and efficacy data are still very limited. Transcatheter mitral repair and replacement techniques have to be considered as complementary treatment options for high-risk patients indicated by the Heart Teams. The different techniques and devices will be introduced and discussed in the following paper.

Cardiac Computed Tomography - More Than Coronary Arteries? A Clinical Update

BACKGROUND

 Rapid improvement of scanner and postprocessing technology as well as the introduction of minimally invasive procedures requiring preoperative imaging have led to the broad utilization of cardiac computed tomography (CT) beyond coronary CT angiography (CTA).

METHOD

 This review article presents an overview of recent literature on cardiac CT. The goal is to summarize the current guidelines on performing cardiac CT and to list established as well as emerging techniques with a special focus on extracoronary applications.

RESULTS AND CONCLUSION

 Most recent guidelines for the appropriate use of cardiac CT include the evaluation of coronary artery disease, cardiac morphology, intra- and extracardiac structures, and functional and structural assessment of the myocardium under certain conditions. Besides coronary CTA, novel applications such as the calculation of a CT-derived fractional flow reserve (CT-FFR), assessment of myocardial function and perfusion imaging, as well as pre-interventional planning in valvular heart disease or prior pulmonary vein ablation in atrial fibrillation are becoming increasingly important. Especially these extracoronary applications are of growing interest in the field of cardiac CT and are expected to be gradually implemented in the daily clinical routine.

KEY POINTS

  · Coronary artery imaging remains the main indication for cardiac CT. · Novel computational fluid dynamics allow the calculation of a CT-derived fractional flow reserve in patients with known or suspected coronary artery disease. · Cardiac CT delivers information on left ventricular volume as well as myocardial function and perfusion. · CT is the cardinal element for pre-interventional planning in transcatheter valve implantation and pulmonary vein isolation.

CITATION FORMAT

· Taron J, Foldyna B, Eslami P et al. Cardiac Computed Tomography - More Than Coronary Arteries? A Clinical Update. Fortschr Röntgenstr 2019; 191: 817 - 826.

Chest Radiographic Appearance of Minimally Invasive Cardiac Implants and Support Devices: What the Radiologist Needs to Know

Minimally invasive implantable cardiac devices used in valve repair and replacement, cardiovascular support, and partial chamber and appendageal occlusion represent a burgeoning area of both bioengineering and clinical innovation. In addition to familiarizing the reader with the radiographic appearance of the most commonly utilized and encountered newer devices, this review will also address the relevant clinical and pathophysiological indications for usage and deployment as well as potentially encountered complications.

Future Technology

Mitral regurgitation is the most common valvular disease and significant (moderate/severe) mitral regurgitation is found in 2.3% of the population older than 65 years. New transcatheter minimally invasive technologies are being developed to address mitral valve disease in patients deemed too high a risk for conventional open-heart surgery. There are several features of the mitral valve (saddle-shaped noncalcified annulus with irregular leaflet geometry) that make a transcatheter approach to repair or replacing the valve more challenging compared with the aortic valve. Several devices are under investigation for transcatheter mitral valve replacement, and also for mitral valve repair targeting the mitral valve leaflets, chordae tendinae, and mitral annulus. The MitraClip device is the only Food and Drug Administration-approved device to treat mitral regurgitation by targeting the mitral leaflets. There are eight minimally invasive devices being studied in humans that target the mitral annulus, and at least two devices being studied in animal models. There are 5 devices in clinical trials for minimally invasive approaches targeting the chordae tendinae. More than 10 different transcatheter mitral valves are in various stages of development and clinical trials. These transcatheter mitral valves can be delivered either through a transseptal, transapical, transaortic, or left atriotomy approach. It seems likely that transcatheter treatment approaches to mitral valve disease will become more common, at least in the sick and elderly patient population.

Incidence, Timing, Causes and Predictors of Early and Late Re-Hospitalization in Patients Who Underwent Percutaneous Mitral Valve Repair With the MitraClip System

The pattern and reasons for re-hospitalization (RH) after MitraClip implantation are not well characterized. A total of 322 consecutive MitraClip patients were included, with data stratified by RH status. Multivariate analyses were conducted to identify predictors of early (30-day) and late (30-day to 12-month) RH. Eighty-nine patients (27.6%) were readmitted to hospital during the study period and early RH occurred in 27%. The median time from MitraClip to RH was 99 days. RH was mostly related to cardiovascular causes (66.3%). Anemia and gastrointestinal bleeding were the most frequent noncardiovascular causes. Independent predictors of early RH were length of stay ≥3 days during the index procedure (odds ratio [OR] 4.13, 95% confidence interval [CI] 1.32 to 12.91), reduction of left ventricular ejection fraction ≥5% after MitraClip implantation (OR 4.88, 95% CI 1.36 to 18.91), and severe systolic pulmonary artery pressure ≥60 mm Hg at discharge (OR 3.72, 95% CI 1.23 to 11.26). Conversely, the independent predictors of late RH were device failure (OR 4.02, 95% CI 1.22 to 13.25) and systolic pulmonary artery pressure ≥60 mm Hg at discharge (OR 2.34, 95% CI 1.01 to 5.44). In patients with early RHs, survival was significantly worse at 12 months compared with patients with late RH and no-RH (69.3% vs 82.6% vs 86%, p <0.001). In conclusion, RH is not uncommon after MitraClip implantation and cardiovascular causes represent its most frequent etiology. Clinical and echocardiographic predictors of early and late RH can be identified at discharge. Early RH carries a worse prognosis than late RH.

Successful Treatment of Mitral Regurgitation after Transapical Transcatheter Aortic Valve Implantation by Percutaneous Edge-to-edge Mitral Valve Repair (MitraClip®) -The First Combination Therapy Performed in Japan

A 75-year old man with a history of inferior myocardial infarction was admitted with symptoms of progressive heart failure 3 months after undergoing transapical transcatheter aortic valve implantation (TAVI). Echocardiography revealed severe mitral regurgitation (MR) caused by posterior leaflet tethering, without traumatic injury of the mitral valve or chordae. The patient was successfully treated by percutaneous edge-to-edge mitral valve repair (MitraClip^®). This case highlights the role of MitraClip^® in high-risk patients suffering from MR, and suggests that apical contractile loss or adhesion caused by apical puncture and suturing in transapical TAVI may be one of the mechanisms of worsening MR.

The evolution of minimally invasive cardiac surgery: from minimal access to transcatheter approaches

The field of minimally invasive cardiac surgery has undergone rapid transformation over recent years. In this review, we provide a summary of the most current evidence supporting the use of minimally invasive aortic and mitral valve replacement techniques, as well as transcatheter approaches for aortic and mitral valve disease. As an adjunct, the use of robotically assisted coronary bypass surgery and hybrid coronary revascularization procedures is discussed. In order to obtain optimal patient outcomes, a collaborative, heart-team approach between cardiac surgeons and interventional cardiologists is necessary.

Transcatheter Mitral Valve Interventions: Current Therapies and Future Directions

OPINION STATEMENT

Transcatheter interventions for the treatment of aortic valve stenosis have become commonplace since the advent of transcatheter aortic valve implantation. However, transcatheter mitral valve therapies have lagged in development due to the complexity of mitral valve anatomy. Transcatheter edge-to-edge leaflet repair using the MitraClip device provides an option for the treatment of severe primary mitral valve regurgitation in high or prohibitive surgical risk patients, and multiple novel approaches are evolving to replace or repair the mitral valve. Devices for the treatment of calcific mitral stenosis, primary mitral regurgitation, and functional mitral regurgitation have been developed and are currently either being evaluated in clinical trials or are in earlier stages of preclinical development. We are optimistic that our armamentarium will soon expand to include a myriad of transcatheter interventions for mitral valve disease.

Our Anaesthetic Experiences in Patients Undergoing Percutaneous Mitraclip Implantation

OBJECTIVE

Percutaneous mitraclip implantation system, is a new technique developed for patients with high surgical risks. It is generally performed in a catheterisation laboratory with the guidance of fluoroscopy and transesophageal echocardiography. In this study, we aimed to share our experiences on anaesthetic in patients undergoing mitraclip implantation under general anaesthesia.

METHODS

Eighty four patients with severe, symptomatic mitral insufficiency, who had undergone MitraClip implantation under general anaesthesia between July 2012 and March 2015 (54 male, 30 female; mean age: 68.5±10.2 years) were retrospectively investigated in terms of anaesthetic management.

RESULTS

Of the 84 patients undergoing percutaneous mitraclip implantation under general anaesthesia, 84.5% had sodium thiopental and 75% had midazolam for anaesthesia induction. For the maintenance of anaesthesia, 57% of the patients were reported to have sevoflurane, whereas the rest had desflurane. The mean duration of the procedure and anaesthesia was 140.9±48.2 mins and 165.7±50.6 min, respectively. Seventy seven patients were transported to the intensive care unit and intubated after the procedure. The median extubation time was 3 h. Length of stay in the intensive care unit was 2 days, whereas it was 4 days for hospital stay. One patient died during the procedure and six patients died after the procedure.

CONCLUSION

Percutaneous mitraclip implantation procedure is quite difficult for anaesthesiologists because of the procedure itself and the population on which the procedure is performed. The primary aim of anaesthesia management is to provide haemodynamic stability. The preoperative preparation and anaesthesia methods should be the same as for patients undergoing cardiac surgery. It is reported that as the experience regarding this subject increases, success of the procedure increases, with better protected haemodynamic stability, less inotropic and vasopressor requirement and shorter length of hospital stay.

Left Atrial Remodeling in Segmental vs. Global Mitral Valve Prolapse - Three-Dimensional Echocardiography

BACKGROUND

Segmental and global mitral valve prolapse (MVP) comprise 2 representative phenotypes in this syndrome. While mitral regurgitation (MR) severity is a major factor causing left atrial (LA) remodeling in MVP, prominent mitral valve (MV) annulus dilatation in global MVP may specifically cause inferiorly predominant LA remodeling. We compared MV annulus and LA geometry in patients with segmental and global MVP.Methods and Results:LA volume as well as inferior, middle, and superior LA cross-sectional areas (CSA) were measured on 3-D echocardiography in 20 controls, in 40 patients with segmental MVP, and in 18 with global MVP. On multivariate analysis, MR severity was primarily associated with LA dilatation in segmental MVP (P<0.001), while MV annular dilatation was primarily associated with LA dilatation in global MVP (P<0.001). Although there was no regional predominance in LA dilatation in segmental MVP, inferior predominance of LA dilatation was significant in global MVP (increase in inferior, middle, and superior LA-CSA relative to mean of the controls: +220±70% vs. +171±55% vs. +137±37%, P<0.001).

CONCLUSIONS

LA remodeling in segmental and global MVP is considerably different regarding its association with MR volume or MV annular dilatation and its regional predominance. While MR volume may mainly contribute to LA remodeling in segmental MVP, MV annular dilatation seems to have an important role in LA remodeling in global MVP. (Circ J 2016; 80: 2533-2540).

Biocompatibility and Systemic Safety of a Novel Implantable Annuloplasty Ring for the Treatment of Mitral Regurgitation in a Minipig Model

Prosthetic annuloplasty rings are a common treatment modality for mitral regurgitation, and recently, percutaneous implantation techniques have gained popularity due to their favorable safety profile. Although in common use, biocompatibility of annuloplasty rings has been reported only sparsely in the literature, and none of these reports used the percutaneous technique of implantation. We report on the biocompatibility and the systemic safety of a novel transcatheter mitral valve annuloplasty ring (AMEND™) in 6 minipigs. This device is composed of a nitinol tube surrounded by a braided polyethylene terephthalate fabric tube. The device produced no adverse inflammatory response, showing gradual integration between the metal ring and the fabric by normal host fibrocellular response, leading to complete neoendocardium coverage. There was no evidence for adverse reactions, rejection, or intolerance in the valvular structure. In 2 animals, hemopericardium resulted from the implantation procedure, leading to right-sided cardiac insufficiency with pulmonary edema and liver congestion. The findings reported herein can serve as a case study for the expected healing pathology reactions after implantation of transcatheter mitral valve annuloplasty rings.