Transcatheter Mitral Valve Replacement: Current Evidence and Concepts

Impact of cardiac conduction disease in patients with cardiac amyloidosis: A national retrospective cohort study

BACKGROUND

There is a paucity of data regarding the impact of cardiac conduction disease (CD) on clinical outcomes in patients with cardiac amyloidosis (CA).

METHODS

The National Inpatient Sample (NIS) was queried to identify all CA admissions and those with CD using ICD-10 codes from 2016 to 2019. We explored baseline characteristics and used multivariate logistic regression to assess the association between CD and several clinical outcomes during index admission; a p-value of <0.05 was significant. Propensity score matching (PSM) was performed to validate our results.

RESULTS

A total of 12,185 patients with CA were identified. Of these, 920 (7.6 %) had CD. The median age of the sample was 72 years (IQR: 64-80). After multivariate adjustment and PSM, the presence of CD in CA was associated with higher odds of ventricular arrhythmias (VA) (aOR = 2.97, 95 % CI 1.78-4.96, p < 0.001), syncope (aOR = 3.44, 95 % CI 1.51-7.83, p = 0.003), and cardiovascular implantable electronic device (CIED) implantation (aOR = 12.86, 95 % CI 5.50-30.04, p < 0.001) but not with sudden cardiac arrest (p = 0.092), acute heart failure (p = 0.060), all-cause in-hospital mortality (p = 0.384), and non-routine discharge in patients admitted for CA (p = 0.271).

CONCLUSIONS

Although CD was not associated with all-cause in-hospital mortality, there was a significant association with VAs and syncope. Syncope is associated with worse survival in patients with CA. Further studies that prospectively follow patients are needed to determine the true effect of cardiac CD on mortality in patients with CA.

Post-procedural structural heart CT imaging: TAVR, TMVR, and other interventions

Transcatheter valve replacement has experienced substantial growth in the past decade and this technique can now be used for any of the four heart valves. Transcatheter aortic valve replacement (TAVR) has overtaken surgical aortic valve replacement. Transcatheter mitral valve replacement (TMVR) is often performed in pre-existing valves or after prior valve repair, although numerous devices are undergoing trials for replacement of native valves. Transcatheter tricuspid valve replacement (TTVR) is similarly under active development. Lastly, transcatheter pulmonic valve replacement (TPVR) is most often used for revision treatment of congenital heart disease. Given the growth of these techniques, radiologists are increasingly called upon to interpret post-procedural imaging for these patients, particularly with CT. These cases will often arise unexpectedly and require detailed knowledge of potential post-procedural appearances. We review both normal and abnormal post-procedural findings on CT. Certain complications-device migration or embolization, paravalvular leak, or leaflet thrombosis-can occur after replacement of any valve. Other complications are specific to each type of valve, including coronary artery occlusion after TAVR, coronary artery compression after TPVR, or left ventricular outflow tract obstruction after TMVR. Finally, we review access-related complications, which are of particular concern due to the requirement of large-bore catheters for these procedures.

Transcatheter mitral and tricuspid interventions-the bigger picture: valvular disease as part of heart failure

The prevalence of mitral (MR) and tricuspid regurgitation (TR), especially in heart failure (HF) populations, is high. However, the distinct role of atrioventricular valve diseases in HF, whether they are merely indicators of disease status or rather independent contributors in a vicious disease cycle, is still not fully understood. For decades, tricuspid regurgitation (TR) was considered an innocent bystander subsequent to other heart or lung pathologies, thus, not needing dedicated treatment. Recent increasing awareness towards the role of atrioventricular valve diseases has revealed that MR and TR are, in fact, independent predictors of outcome in HF, thus, warranting attention in the HF treatment algorithm. This awareness arose, especially, with the development of minimally invasive transcatheter solutions providing new treatment options, which can also be used for patients considered as having increased surgical risk. However, outcomes of such transcatheter treatments have, in part, been sub-optimal and likely influenced by the status of the concomitant HF disease. Thus, this review aims to summarize data on the current understanding regarding the role of MR and TR in HF, how HF impacts outcomes of transcatheter MR and TR interventions, and how the understanding of this relationship might help to identify patients that benefit most from these therapies, which have proven to be lifesaving in properly selected candidates.

Longitudinal Outcomes Following Surgical Repair of Primary Mitral Regurgitation

Degenerative mitral valve (MV) disease is the most common cause of organic mitral regurgitation (MR) in developed countries. Surgical mitral valve repair is the gold standard treatment for primary MR. Surgical mitral valve repair is associated with excellent outcomes in terms of survival and freedom from recurrent MR. As well, innovations in surgical repair techniques, including thoracoscopically and robotically assisted approaches, further reduce morbidity. Emerging catheter-based therapies may also provide advantages in select patient groups. Although the outcomes following surgical mitral valve repair are well described in the literature, longitudinal follow-up is heterogenous. Indeed, longitudinal follow-up and long-term data are vital to better advise treatment and counsel patients.

Clinical characteristics and outcomes of patients screened for but DEemed CLInically Not suitablE for Transcatheter Mitral Valve Replacement

BACKGROUND

Transcatheter therapies are a recognized alternative intervention in patients with severe mitral regurgitation who are at high surgical risk. The purpose of this study was to characterize patients screened for transcatheter mitral valve replacement (TMVR), establish the clinical and anatomical reasons for unsuitability, and determine clinical course and early outcomes.

METHODS

International multicenter registry was conducted of consecutive patients screened for TMVR at 12 centers in Europe, the United States and Canada between April 2015 and September 2018. Patient-level retrospective data were collected for all patients screened.

RESULTS

From a total of 294 patients, 87 (30%) patients were suitable for and underwent TMVR while 207 (70%) patients were unsuitable for TMVR. There was no difference in STS predicted risk of mortality (6.3±4.3% vs 6.7±6.1%, p=0.52) for mitral valve replacement between the groups. The most common reasons for TMVR unsuitability were mitral annular size outside therapeutic range (28%) and small predicted neo-LVOT (25%). Pre-procedural multidetector computed tomographic demonstrated that patients unsuitable for TMVR had smaller predicted neo-left ventricular outflow tract (LVOT) area (318±192mm² vs 495±202mm², p=0.04). At 30-days, there was no difference in rates of rehospitalization (8% vs 8%, p=0.21), stroke (1% vs 2%, p=0.42), or mortality (4% vs 10%, p=0.10), unadjusted for procedural risk, between unsuitable for TMVR and TMVR groups, respectively.

CONCLUSIONS

Two-thirds of patient's failed screening as anatomically unsuitable for TMVR. The findings of this study have important clinical implications, highlighting an unmet clinical need and provide a target for design innovation in future iterations of TMVR devices.

[Mitral valve: When conservative, when surgical, when interventional therapy?]

The management of severe symptomatic mitral regurgitation is in contrast to the aortic-valve-intervention more challenging due to the complex mitral-valve anatomy. In primary mitral regurgitation surgical therapy is recommended, whereas there are various therapeutic options in secondary mitral regurgitation. Besides the established mitral-valve Transcatheter Edge-to-Edge-Repair (M-TEER) and the interventional annuloplasty - devices dynamic developments have recently been made in the field of Transcatheter Mitral Valve Replacement-therapy (TMVR). This article surveys the current recommendations and available therapeutic options in mitral regurgitation.

Current devices and interventions in mitral regurgitation

Mitral regurgitation (MR) is the most common valvular disease. With a rising incidence in older age, the prevalence of relevant comorbidities inevitably increases. Considering the constantly aging population with high surgical risk, transcatheter therapy of MR is gaining increasing importance. Interventional therapy of either primary or secondary MR represents an alternative to pure drug or surgical therapy. With mitral valve transcatheter edge-to-edge repair, a well-established treatment has evolved in the past two decades. In addition, direct or indirect annuloplasty and ultimately transcatheter mitral valve implantation further expand the armamentarium. The current broad spectrum of interventional therapy options allows for patient-oriented therapy individually targeting different MR pathologies. This review discusses the current landscape of transcatheter therapies for relevant MR.