Transcatheter therapies for severe tricuspid regurgitation. Quo vadis?

Macrophage-extracellular matrix interactions: Perspectives for tissue engineered heart valve remodeling

In situ heart valve tissue engineering approaches have been proposed as promising strategies to overcome the limitations of current heart valve replacements. Tissue engineered heart valves (TEHVs) generated from in vitro grown tissue engineered matrices (TEMs) aim at mimicking the microenvironmental cues from the extracellular matrix (ECM) to favor integration and remodeling of the implant. A key role of the ECM is to provide mechanical support to and attract host cells into the construct. Additionally, each ECM component plays a critical role in regulating cell adhesion, growth, migration, and differentiation potential. Importantly, the immune response to the implanted TEHV is also modulated biophysically via macrophage-ECM protein interactions. Therefore, the aim of this review is to summarize what is currently known about the interactions and signaling networks occurring between ECM proteins and macrophages, and how these interactions may impact the long-term in situ remodeling outcomes of TEMs. First, we provide an overview of in situ tissue engineering approaches and their clinical relevance, followed by a discussion on the fundamentals of the remodeling cascades. We then focus on the role of circulation-derived and resident tissue macrophages, with particular emphasis on the ramifications that ECM proteins and peptides may have in regulating the host immune response. Finally, the relevance of these findings for heart valve tissue engineering applications is discussed.

Examining the forgotten valve: outcomes of tricuspid valve surgery, a 15-year experience

BACKGROUND

We have entered an era of renewed interest in novel approaches to surgical intervention and minimally invasive and transcatheter technique. With an aging population, isolated tricuspid valve regurgitation incidence is rising; however, referral for surgical intervention remains low.

AIMS

We undertook this retrospective review to assess outcomes and challenges associated with tricuspid valve intervention.

METHODS

A comprehensive retrospective review of all patients undergoing tricuspid valve intervention in our institution between 2004 and 2018 was carried out.

RESULTS

A total of 259 patients who underwent a tricuspid intervention between 2004 and 2018 were identified. Of those, 229 underwent a repair and 30 underwent a replacement. Median survival for repair was 3124 days, and replacement was 2294 days. In-patient mortality was 12% for those undergoing repair and 7% for the replacement patients. Of those undergoing redo tricuspid valve intervention, eight patients (61.5%) were alive at most recent follow-up. Eight patients required intraoperative pacemakers, 2 required postoperative pacemakers. Of those who had intraoperative epicardial pacing systems placed, 5 of the 8 remained pacing dependent on most recent follow up.

CONCLUSION

Beyond technical challenges, decision making regarding pacemaker requirement requires further exploration. Redo tricuspid valve surgery carries a significant mortality risk and consideration should be given to earlier intervention in this context.