Author + information
- Jason H. Rogers, MD∗ ( and )
- Reginald I. Low, MD
- ↵∗Reprint requests and correspondence:
Dr. Jason H. Rogers, University of California, Davis Medical Center, Division of Cardiovascular Medicine, 4860 Y Street, Suite 2820, Sacramento, California 95817.
MitraClip therapy (Abbott, Abbott Park, Illinois) is an important treatment for correcting clinically significant mitral regurgitation (MR) in patients at increased risk for surgery. This therapy can now be offered to many patients with comorbidities who are at high surgical risk and would not otherwise undergo surgery because of perceived excessive morbidity and mortality (1). The MitraClip system was CE-mark approved in March 2008, and over 8,000 patients have been treated worldwide to date, mostly in Europe, and predominantly in those at high surgical risk with functional mitral regurgitation (FMR). During this time, the MitraClip system has remained investigational in the United States until October 2013, when FDA approval was granted for patients at high surgical risk with degenerative MR.
Despite a high prevalence of FMR treatment, approximately 25% of high surgical risk patients currently being treated worldwide have degenerative MR (DMR), and this remains a very important target population (2,3). Unlike aortic stenosis, which generally has a singular pathology (calcific leaflet stenosis), the etiologies of MR are highly varied. Because MR can result from a multitude of pathologies, identifying specific subgroups of MR that would benefit from catheter-based MR correction is important.
In this issue of the Journal, Estévez-Loureiro et al. (4) report the first patient series using the MitraClip system to treat noncentral DMR. The authors describe results from 3 highly experienced centers in Europe using the MitraClip in patients with DMR who are at high risk for surgery as determined by a multidisciplinary heart team. This unique analysis consists of examining procedural and short-term outcomes for patients with central (n = 49) versus noncentral (n = 30) DMR who were predicted to benefit from MR correction. Patients were excluded for primarily anatomic reasons that would preclude MitraClip implantation, such as a flail gap >20 mm, active endocarditis, intracardiac thrombus, mitral stenosis, or other anatomy unsuitable for transseptal puncture. The paper highlights several important technical considerations for the treatment of noncentral MR. It is noted that there is a complex structure of fan-shaped subcommissural chordae, which could increase the risk of MitraClip entanglement. In this series, clip entanglement, defined as manipulation of the system >120 s to free the MitraClip, did not occur, which speaks to the experience of these operators. There are also other important technical considerations, including optimization of transseptal puncture height, and liberal use of 3-dimensional transesophageal echocardiography. The MitraClip delivery system is versatile and allows placement of the MitraClip in a wide variety of locations along the coaptation line of the mitral leaflets. For medial jets, it is often necessary to retract the guide catheter into the right atrium, whereas for lateral jets, the system must be advanced more deeply into the left atrium than for central pathologies (Fig. 1). Despite these technical nuances, the authors reported equivalent outcomes with both patient groups: specifically, those patients with noncentral versus central DMR had similar procedural success, MR reduction, New York Heart Association functional class, adverse events, heart failure admissions, and death.
The treatment of noncentral MR with the edge-to-edge technique is not a new concept, and has been reported by many in the surgical literature. Alfieri et al. (5) first described the surgical edge-to-edge repair technique as using suture to approximate the A2–P2 segments of the mitral valve, thereby converting a single regurgitant mitral orifice into a competent double-orifice valve with decreased regurgitation. The surgical management of noncentral or paracommissural prolapse can be technically challenging, and multiple repair techniques have been described, including partial leaflet resection, annular plication, and chordal transfer. In the setting of endocarditis with leaflet destruction, surgeons have used autologous pericardium, autologous tricuspid valve posterior leaflet, or partial mitral homografts (6). However, numerous surgical reports have established the simplicity and efficacy of edge-to-edge repair for noncentral MR.
Alfieri et al. (5) has described that the edge-to-edge technique can be applied successfully to noncentral MR. This paracommissural edge-to-edge repair results in a single-orifice mitral valve with a relatively smaller area (Fig. 2). In the words of Alfieri et al. (5): “commissural edge-to-edge repair with annuloplasty is probably the simplest and most reproducible method to repair commissural lesions.” Mathieu et al. (6) have reported on the use of the edge-to-edge technique in 115 patients with isolated commissural prolapse or flail. The freedom from reoperation at 5 years was 97.5%. In 108 patients with echocardiography at a mean follow-up of 2.3 ± 1.9 years (median 2.0 years, range 1 to 8.3 years), MR was absent in 60 patients (55.6%), mild in 43 (39.8%), moderate in 3 (2.8%), and severe in 2 (1.9%, both reoperated on). There were no cases of mitral stenosis (7,8).
Other reports include Gillinov et al. (9) from the Cleveland Clinic who reported using this technique in more than 100 patients, with no instances of mitral stenosis, suture dehiscence, or recurrent prolapse at the site of repair. Aubert et al. (10) reported a retrospective analysis of 128 consecutive patients who underwent surgical mitral valve repair for commissural prolapse; 65 (50.8%) were treated with edge-to-edge commissural closure. There were no cases of mitral stenosis resulting from repair, and transthoracic echocardiography at discharge showed no residual mitral insufficiency in 94 cases (73.4%) and grade 1 in 34 cases (26.6%). Excellent outcomes were reported, with 96.7% survival and 96.6% freedom from mitral valve reoperation at 5 years (10). Finally, Shimomura et al. (11) reported the use of the edge-to-edge technique in 12 patients with commissural prolapse due to degenerative disease with no significant recurrence of regurgitation at a mean follow-up interval of 49.8 months. In all surgical series, an annuloplasty ring was implanted at the time of paracommissural edge-to-edge repair.
Given the success of surgical edge-to-edge repair, the current article is a very important clinical report, and for the first time, addresses outcomes in MitraClip patients with noncentral DMR. Although the U.S. EVEREST (Endovascular Valve Edge-to-Edge Repair) trials and REALISM (Real World ExpAnded MuLtIcenter Study of the MitraClip System) continued access registry have limited therapy to patients with predominantly central (A2/P2) MR, it is well known that treatment in Europe and in the U.S. Compassionate Use Pathway has included patients with noncentral MR. Until now, we have not had any formal reports describing this technique.
It is also notable in the current report by Estévez-Loureiro et al. (4) that of 173 high-risk surgical patients treated at these centers with the MitraClip from 2009 to 2012, 70 (46%) had DMR—this is somewhat higher than expected because the general impression is that the majority of patients being treated outside the United States are patients with FMR. It is also notable that approximately one-third (38%) of patients with DMR had noncentral DMR, highlighting the significant prevalence of noncentral MR. These patient characteristics and results are very important for defining the patient groups eligible for treatment, and also highlight that of high-risk patients, a significant number have degenerative and noncentral MR, and should be considered candidates for this therapy.
In summary, the authors have provided evidence that MitraClip therapy may be expanded to include a new niche—treatment of noncentral MR. One would advise that further reports are needed, and a more systematic description of protocol/technique is necessary before widespread adoption by lower volume or less experienced MitraClip operators. Nonetheless, it appears that the procedure can be done safely in patients with noncentral MR, with clinical outcomes that are similar to the treatment of central MR.
The authors wish to thank Rebekka Berger for assistance in generating Figure 1.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Low is a consultant for Abbott Vascular. Dr. Rogers has reported that he had no relationships relevant to the contents of this paper to disclose.
- 2013 American College of Cardiology Foundation
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