For patients with symptomatic prosthetic mitral valve dysfunction, the traditional standard of care has been repeat surgical mitral valve replacement unless the patient’s clinical risk precluded surgery. For patients at prohibitive risk for surgery, little could be offered by way of mechanical or medical therapy. Transcatheter therapies have opened up a whole realm of possibilities, and it is little more than a natural extension to apply concepts and techniques proven effective in prosthetic aortic valve dysfunction to the mitral, pulmonic and tricuspid valves. Though not without specific procedural nuances, transcatheter mitral valve in valve replacement has proven effective enough that it is now considered an “on-label” procedure [ ].

In this issue of CRM, Rufian-Andujar and colleagues report a successful transseptal transcatheter mitral valve in valve replacement in the setting of severe prosthetic mitral regurgitation and cardiogenic shock. The procedure itself is nothing new. Indeed, many operators across the world have performed it, there are designated CPT codes, and any cursory Pubmed search will yield countless case reports and series along with reviews and procedural best practices. However, the majority of these reports involve cases that were performed electively on stable patients via the transapical approach. Accordingly, the nuances warranting discussion in this case are acuity and access.

As with most novel transcatheter technologies and procedures, the natural tendency is to begin in patients who are relatively stable, although they clearly are at elevated to prohibitive risk for open surgery. However, with recognition that the physiologic insult of transcatheter therapy is considerably less than that of open surgery, it stands to reason that those in cardiogenic shock (and at extremes of surgical risk) could benefit the most from a less invasive therapy. Thus, the treatment decision to proceed with transcatheter replacement is not surprising, nor is it really out on a ledge. In this reported case, surgery was contraindicated based on a Society of Thoracic Surgery (STS) predicted risk of mortality of greater than 40%. Therefore, as long as the operators felt this patient was salvageable, proceeding with transcatheter mitral VIV replacement was appropriate.

Regarding access, while it is true that the majority of mitral VIV replacements to date have been performed via transapical access, the transseptal approach offers a number of potential advantages. It is well known from the TAVR literature that transapical access is associated with increased morbidity and mortality when compared to transfemoral access [ ]. Avoiding any insult to the left ventricular apex is desirable (particularly in patients with cardiogenic shock), and the technical aspects of a transseptal approach to valve in valve mitral replacement are well understood. In fact, over the past few years, the transseptal approach has become the preferred route provided the operators possess the necessary skillsets to undertake this approach safely and effectively.

In writing an editorial for a case report, there isn’t much to critique from a methodology perspective. Inherently, the report is single center and retrospective, and there is no control or comparison to discuss. Conceptually, however, there is much to gain from this case from the perspective of shaping our collective experiences and willingness to apply technology in somewhat nuanced and occasionally emergent or salvage indications.

When considering a transcatheter mitral valve in valve replacement (transapical or transseptal), the primary technical considerations are prosthetic valve type/size and the risk of left ventricular outflow tract (LVOT) obstruction. While a smartphone application exists to guide our choice of valve in valve prostheses based on the prior (and now dysfunctional) prosthetic valve, there are times when discrepancies exist or the prior valve is unknown. For this reason, and also for predicting the risk of LVOT obstruction, preprocedural computed tomography assessment is essential. In this case, the authors opted to forego this assessment for stated reasons of time and acute renal insufficiency. While understandable in this case, it is worth noting that the favorable results seen with these types of procedures depend on optimal planning. Although successful in this case, there was a calculated risk taken here that should not be extended to standard of care.

Another issue involves extending transcatheter valve replacement to other valves and other indications. As we all know, the first TAVR in a human was performed in April of 2002 [ ]. The last 16 years has been truly transformative to the point that TAVR is almost ubiquitous and transcatheter valve-in-valve replacement is rapidly becoming the treatment of choice for prosthetic valve dysfunction in many patients. Extending to acute indications and all valves makes perfect logical sense. However, taking a step back, a fundamental balance between possible and appropriate is key. A mentor of mine often stated that when approaching cardiac surgery in the most critically ill patients, he would imagine whether the patient would truly benefit if there was magic wand that could fix the patient’s primary issue without the inherent physiologic insult of surgery. His risk vs. benefit discussions often centered around this question. In the era of transcatheter valve replacement, we essentially have that magic wand, and it needs to be wielded responsibly. Effective valve replacement does not necessarily translate into benefit, and palliative procedures without expected long term gains have little role in clinical practice.

In this case, the authors reached for and achieved true benefit. Although their patient was in cardiogenic shock with acute renal injury, she was otherwise reasonably healthy. The procedure was performed efficiently, effectively and safely, and there was full recovery. To that end, this case serves as a fine example of outstanding patent care in a transformative era.