Author + information
- Steven F. Bolling, MD∗ ()
- ↵∗Address for correspondence:
Dr. Steven F. Bolling, Department of Cardiac Surgery, University of Michigan Health System, 1500 East Medical Center Drive, SPC 5864, Ann Arbor, Michigan 48109.
In this issue of the Journal, Sorajja et al. (1) report outcomes of transcatheter mitral valve repair (TMVR) in the United States from The Society of Thoracic Surgeons (STS) and the American College of Cardiology (ACC) joint transcatheter valve therapy (TVT) registry. These investigators examine the commercial experience with the MitraClip (Abbott Vascular, Santa Clara, California) TMVR system for mitral regurgitation (MR), which was first approved for commercial use in 2013. The overall U.S. MitraClip commercial treated registry population includes almost 3,000 patients treated at 145 hospitals in an approximately a 2-year period (2014 to 2015).
In the present report, 1,800 patients had patient-specific outcomes (e.g., death, rehospitalization) from the Centers for Medicare and Medicaid Services linked to their procedure. This outcome-linked cohort had an STS predicted surgical risk of mortality rate of approximately 6% for mitral valve repair and 9% for mitral valve replacement. The median age was 82 years. The procedural success rate was very high, and mortality and morbidity associated with the procedure itself were low. Among the patients treated with the MitraClip who had reliable Centers for Medicare and Medicaid Services linkage data, the mortality rate at 30 days was 5.2% for the repair system, a rate is similar to the range of the STS-predicted mortality rate for surgical mitral repair. The results are similar to those of the EVEREST I (Endovascular Valve Edge-to-Edge REpair Study) (2). Furthermore, the 1-year mortality rate for the patients who underwent the procedure was 26%, and the 1-year rehospitalization rate for heart failure was 20%. Sorajja et al. (1) believed that these findings demonstrated that the commercial use of the TMVR system showed short-term effectiveness and safety. These investigators and, indeed, the STS/ACC TVT registry, should be congratulated for systematically following patients in this new area of percutaneous mitral technology. It is only through this type of careful analysis that new mitral technologies can be evaluated and correctly used in the appropriate patients.
Findings and variables that were associated with the worst clinical outcomes following the procedure were age, worse congestive heart failure at procedure, residual MR, lung disease, dialysis, and the presence of tricuspid regurgitation (TR). Although these findings are interesting, they are no different from the factors associated with a worse outcome after mitral valve surgery. This affirms that patient-related factors are perhaps more important than the method by which MR is approached, either surgically or percutaneously.
Three patient-related factors should be highlighted: Sorajja et al. (1) note that there is a very significant inverse relationship between the degree of residual MR after TMVR and survival. In fact, approximately 50% of patients who had grade 3 or 4 residual MR died within 1 year after the procedure. Surgeons have noted this fact for years, and the goal of MR therapy should be no residual MR, regardless of approach.
Second, the presence of and the severity of TR left untreated at the time of MitraClip therapy was a harbinger of a very poor outcome. This finding of TR adversely affecting outcome also mirrors the experience of mitral valve surgery when TR is left untreated.
Finally, the survival rate of patients with functional MR is far worse than that of patients with degenerative MR. This has become more and more apparent with both surgical and percutaneous approaches to patients with MR. Furthermore, this was the genesis for separate ACC and American Heart Association indications and treatment recommendations for these very different types of mitral valve disease. No analysis of outcomes should include both “types” of mitral valve disease. We hope to evaluate this effect of intervention in patients with functional MR from the results of the now enrolled COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial.
Clearly, the procedure itself is generally quite technically successful and safe. This may be the most important “finding” of this report. The introduction of transcatheter devices, of which MitraClip is the first example, transseptally into the left atrium and the ability to navigate and steer to the mitral leaflets and annulus will be of paramount importance to the future evolution of catheter-based treatment of MR. In fact, the safety and low biological impact of this left atrial catheter approach may allow practitioners to treat patients with MR much earlier in their disease course. Perhaps therapeutic MR intervention will be possible even long before congestive heart failure, atrial fibrillation, TR, pulmonary hypertension, and other complications of MR occur, which may obscure any benefit of obviating the MR.
Finally, it is interesting to observe that the gold standard therapy for aortic stenosis remains aortic valve replacement. Whether it was originally by surgery or now perhaps by transcatheter aortic valve replacement, the singular therapy of aortic valve replacement remains the gold standard regardless of the approach.
Conversely, the gold standard for mitral valve disease therapy has always involved 3 components, not just 1. The first is a leaflet repair therapy, such as the MitraClip, the second is some type of annular repair with a ring, and the third, which is applied only when mitral repair is judged not to be a viable option, is mitral valve replacement. These 3 components of mitral valve disease therapy (leaflet, annular ring, and replacement) will certainly remain the gold standard when surgical mitral valve disease therapy inevitably gives way to transcatheter mitral valve disease therapies.
As demonstrated in this report, the consequences of leaving MR after a “repair” do not change because of the method of approach. Indeed, the physiology of MR, and therefore the gold standard of MR therapy, will also not change because of the method of approach. In the future, we will have all 3 of these gold standard mitral tools in our transcatheter toolbox. MitraClip will probably remain a crucial tool, but perhaps more importantly we will look at the device experience as having been a gateway to the future of catheter-based mitral valve disease therapy.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the author and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr Bolling is a consultant to Abbott.
- 2017 American College of Cardiology Foundation
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