Mitral regurgitation (MR) is the most prevalent valve disease in Europe and America, affecting 13% of people over the age of 75. In Spain, by 2040, around 16% of the population is expected to be over 65, indicating approximately 2 million people with significant valvular disease. Given this scenario, it is essential for practitioners addressing this pathology to be prepared to meet this challenge.
Over the past decade, TEER has revolutionized MR treatment. FDA approved TEER in 2013, recommending it for severe symptomatic primary MR in patients at high or prohibitive surgical risk (class IIa recommendation in American guidelines, IIb in European). Furthermore, based on promising results from secondary MR clinical trials, TEER now has a class IIb recommendation in European guidelines for inoperable patients with secondary MR and suitable anatomy. Despite encouraging results post-initial TEER, the increase in cases has led to a rise in reinterventions via repeat TEER or mitral valve surgery (MVS). Reintervention rates range from 8% to 21%, with a high 30-day mortality rate averaging between 9% and 10%. However, these data are primarily from case series and limited studies. With the anticipated rise in patients needing reintervention, it is critical to understand risk factors and outcomes in a more real-world representative context.
In response, the University of Michigan examined the incidence, characteristics, and outcomes of reinterventions following initial TEER using a nationally representative study (US) based on Medicare® beneficiary data. Data from 11,396 patients who underwent initial TEER between July 2013 and November 2017 were reviewed. These patients were prospectively tracked, identifying those requiring repeat TEER or MVS. Primary outcomes included 30-day mortality, 30-day readmission, 30-day composite morbidity (pneumonia, transfusion requirement, stroke, acute renal failure, or cardiac arrest), and cumulative survival. Of the 11,396 TEER patients, 548 (4.8%) required reintervention after an average interval of 4.5 months. Overall, 30-day mortality was 8.6%, readmission was 20.9%, and composite morbidity was 48.2%. By type of reintervention, 294 (53.7%) underwent repeat TEER, and 254 (46.3%) underwent MVS. Patients undergoing MVS were more likely to be younger and female but had a similar comorbidity burden compared with the repeat TEER cohort. After adjusting data, no differences in 30-day mortality (adjusted odds ratio [AOR]: 1.26) or 30-day readmission (AOR: 1.14) were found. MVS was associated with greater 30-day morbidity (AOR: 4.76) compared to repeat TEER. The need for reintervention was an independent risk factor for long-term mortality in a Cox proportional hazards model (hazard ratio: 3.26).
The authors conclude that reintervention after initial TEER is a high-risk procedure with significant mortality, underscoring the importance of ensuring initial TEER procedural success to avoid the overall morbidity of reintervention.
COMMENTARY:
Approximately 150,000 MitraClip® by Abbott® implants have been performed worldwide to date. In this pioneering national study led by Kaneko et al., 11,396 initial TEER implants were analyzed, with long-term follow-up for both cohorts—those who did not require reintervention and those who did (either via repeat TEER or mitral valve surgery). Among these patients, 548 (4.8%) required reintervention, including 254 who needed surgery. Key findings from this research include:
- The reintervention rate after the initial TEER procedure was lower than in previous studies, with most occurring within the first year.
- The 30-day mortality rate for reinterventions (either repeat TEER or surgery) in MitraClip® patients was 8.6%, confirming the high risk associated with these procedures.
- Short-term morbidity was common in nearly half of the patients, but significantly higher in those requiring surgery compared to those undergoing repeat TEER, with an almost fivefold increased risk.
The reintervention rate in this study was 4.8%, considerably lower than in relevant studies like EVEREST II (21%) and European registries (8-10%), but similar to American registries that used national readmission data (3.6%). This lower incidence of reintervention could be due to several factors: 1) Selection bias, where many patients, despite being eligible for reintervention, were not candidates due to their very high risk. This is supported by the fact that the non-reintervened group was older and had higher comorbidity than the reintervened group. 2) A lower incidence of severe residual MR after TEER due to growing experience among centers and professionals, which potentially reduced the need for reinterventions.
The need for reintervention in MitraClip patients was an independent risk factor for mortality. Most reinterventions occurred within the first year, with approximately 25% performed under urgent conditions. These findings are consistent with the EVEREST II study results. Short-term outcomes for reintervention via surgery and TEER showed minimal differences, with 30-day mortality rates of 8.6% and 30-day readmission rates of 21%, reflecting the high risk associated with these procedures. These figures align with previous studies, though they are better than those reported in smaller studies. Composite morbidity was 66% for surgery and 32% for TEER, as expected given the patient profile, which was predominantly elderly and frail. High mortality in surgery is likely due to patient comorbidity, age, and frailty rather than technical difficulties associated with reintervention in MitraClip patients. This contrasts with the situation in patients requiring reintervention after prior TAVI, where many undergo surgery on the aortic root, presenting a different set of technical challenges that increase mortality, as discussed in previous commentaries on this blog.
In contrast, long-term mortality in this study was better among patients who underwent surgery compared to those who received a new MitraClip. This could be explained by the selection of younger patients with a more favorable risk profile for surgery, naturally leading to better survival rates. Additionally, it is essential to remember that mitral valve replacement surgery practically eliminates residual MR, unlike repeat TEER, thus improving surgical survival rates.
Therefore, for high-risk surgical patients with a failed MitraClip®, surgery does not appear to be the best option for most. A repeat TEER, while not guaranteed to resolve the issue, represents a realistic alternative when no other options are available. Other options currently under study include transcatheter mitral valve replacement, even with a previously implanted MitraClip® (e.g., devices like AltaValve®). Another option is the use of the ELASTA-Clip, which involves electrocautery laceration of the clip to allow implantation of a percutaneous prosthesis. It is important to note that the patients in this study were treated between 2013 and 2017 with devices that were not up to date. Currently, newer devices like the 3rd generation MitraClip® (NTR/XTR) and the latest G4 release system (Abbott®) have significantly improved outcomes compared to earlier versions.
FDA approval for TEER in cases of degenerative MR is limited to high-risk surgical situations, including frailty and contraindications for surgery. In this patient group, whether for a first TEER or reintervention, the essential goal is to prevent strokes and improve quality of life, even if it entails a high risk of residual MR. However, it is important to remember that in degenerative MR, repair is the standard treatment (class I), rather than replacement. Repair offers benefits like better short- and long-term survival, reduced complication risks, and no long-term anticoagulation requirement. Although technically challenging, its success depends on the surgeon’s experience, and its use has increased, reaching up to 80% in some countries.
In this study, only 4% of mitral reinterventions were repairs, which is consistent with previous findings indicating that over a quarter of patients needing reinterventions have damage to the mitral leaflets, severely complicating the possibility of a successful repair. Additionally, in such cases, it is understandable that surgeons opt for mitral valve replacement, considered a safer and more effective option. Therefore, if this reintervention on MitraClip® patients were to be performed on low-risk patients, even if it entailed a reduced risk of mortality, a successful mitral repair would be unlikely. This would mean missing a valuable opportunity for a nearly guaranteed repair in a first intervention. One of the key messages I would like to convey is that it is essential not to succumb to industry pressure or patient preferences for a less invasive technique, given that TEER has neither been investigated nor authorized for use in low-risk patients with primary MR. Mitral repair outcomes are highly effective and challenging to match.
Data from this study, derived from the Medicare® database with a 5% reintervention rate, may be outdated and possibly not reflective of the current situation. As TEER is increasingly performed on younger, lower-risk patients, an imminent increase in surgical reintervention in this group is likely. Therefore, studies like this one provide invaluable information for understanding and effectively addressing a pathology that is set to become common in clinical practice.
REFERENCE:
Kaneko T, Newell PC, Nisivaco S, Yoo SGK, Hirji SA, et al. Incidence, characteristics, and outcomes of reintervention after mitral transcatheter edge-to-edge repair. J Thorac Cardiovasc Surg. 2024 Jan;167(1):143-154.e6. doi: 10.1016/j.jtcvs.2022.02.060.
