Lower Mortality With M-TEER vs Surgery, but Devil Is in the Details

A real-world analysis of patients with severe mitral regurgitation (MR) treated in France highlights the benefit of mitral transcatheter edge-to-edge repair (M-TEER) in clinical practice, with the data suggesting the procedure was associated with a lower risk of cardiovascular mortality when compared with mitral valve surgery.

The study, which spans a 10-year period beginning in 2012 and includes patients with primary and secondary MR and those undergoing mitral valve repair and replacement, shows that the benefits of TEER were seen in older patients and those with a higher baseline risk for surgery.

Pierre Deharo, MD, PhD (Centre Hospitalier Universitaire Timone, Marseille, France), who led the study published online recently in the European Heart Journal, said their intention was to provide a snapshot of clinical practice in France as opposed to a head-to-head comparison of TEER versus surgery for severe MR.

“We're not challenging mitral surgery,” he told TCTMD. “We know that mitral surgery is a very good procedure at tackling mitral disease in young patients and is likely to have a very, very long durability for those patients. We are just evaluating daily practice of what we're doing in France. How do we treat patients with severe MR and are we still treating very, very sick patients? What we see is that MitraClip [Abbott] is not that bad and is doing a good job for patients, mostly in patients who are over 75 years old or those with a EuroSCORE [II] greater than 4.”

Cardiac surgeon Tsuyoshi Kaneko, MD (Washington University School of Medicine in St. Louis, MO), who wasn’t involved in the study, said the new analysis appears controversial at first blush, but that it largely confirms what is known about TEER and surgery for severe MR.

Kaneko believes study investigators rightly created a comparison between TEER and mitral valve surgery in a group of patients at high risk for surgery, relying on propensity-matching to adjust for baseline risk and comorbidities.

“When you look at it, the [baseline] EuroSCORE [II] is relatively similar, but these are high-risk patients that were drawn from within that surgical group,” he said. “I don’t think you can deny that. The reason I say this study confirms what we know is that we know TEER is a very good option for these high-risk cases. It’s less invasive and the results we get are excellent nowadays, as shown in some of the other studies.”

Nonetheless, Kaneko believes it’s unfair to broadly conclude that TEER is associated with lower cardiovascular mortality than mitral surgery over long-term follow-up. “We should be careful about expanding this interpretation to everything,” he said. “The generalized comment that TEER has better survival than surgery is not a good one. There’s too much of a mixed group in this comparison and I think that’s what a lot of surgeons are concerned about.”

Older, Sicker Patients Benefit

TEER was approved in Europe for patients with primary MR in 2008—and in the US in 2013—and since then indications for use have expanded to include secondary MR largely on the basis of the positive COAPT trial.

In clinical guidelines, surgery has a class 1 indication for patients with primary MR, but both the US and European experts say that TEER can be considered if patients are ineligible or at high risk for surgery. With secondary MR, TEER is backed by a class IIa recommendation in the US for those with favorable anatomy and persistent symptoms despite optimal medical therapy, while TEER is recommended in the European guidelines for those not responding to medical therapy and who are too high risk for surgery (class IIa recommendation).

To get a sense of clinical practice in France, Deharo and colleagues conducted a longitudinal cohort study of 57,030 patients hospitalized with severe MR who underwent TEER or surgery between 2012 and 2022. All patients were part of the French Programme de Médicalisation des Systèmes d’Information (PMSI) hospital discharge database, which is similar to the US Medicare system. Investigators included only those undergoing a single procedure (either TEER, mitral valve repair, or mitral valve replacement). One limitation of the database is that it does not distinguish between primary and secondary MR, with the same codes used for both conditions.  

Patients who underwent TEER were older and had higher rates of cardiovascular disease, vascular disease, chronic kidney disease, and prior history of PCI.

In a propensity-matched population of 2,160 patients in each group, the mean follow-up was 1.0 year (median 0.4 years). Overall, there was no significant difference in the risk of all-cause mortality between TEER and mitral surgery, but TEER was associated with a lower risk of cardiovascular death (HR 0.69; 95% CI 0.56-0.83). Noncardiovascular mortality was significantly higher after TEER (HR 1.56; 95% CI 1.24-1.97).

TEER also was associated with lower risks of pacemaker implantation and stroke but higher risks of pulmonary edema and cardiac arrest. There were no differences in risks of atrial fibrillation, endocarditis, major bleeding, or MI between the two treatments.

In the subgroup analysis, there was a significant interaction between the EuroSCORE II and age with clinical outcomes. In those 75 years and older, but not in younger patients, TEER was associated with a significant reduction in all-cause and cardiovascular mortality. Similarly, the risk of all-cause and cardiovascular death was reduced after TEER in patients with EuroSCORE II ≥ 4, which reflects intermediate and higher surgical risk, but not in those with a lower score.

Using clinical criteria to help distinguish primary and secondary MR—primary MR patients were classified as such if they did not have a prior history of ischemic/dilated cardiomyopathy, CAD, MI, or CABG surgery—the researchers did not observe a significant interaction between the type of MR and cardiovascular mortality. There was an interaction between lower all-cause mortality after TEER compared with surgery in those with secondary MR, however. 

“It’s just very reassuring to see that in the largest cohort of patients treated with MitraClip that we have good results,” Deharo told TCTMD. With the interaction between cardiovascular mortality and TEER in the higher-risk subgroups, the data highlight the role for mitral valve surgery in younger patients and those at low risk for mitral valve surgery, he said.  

Looking Closely at Results

Taking a deep dive into the data, Kaneko pointed out that the unmatched TEER patients had a higher burden of frailty and more comorbidities than those treated surgically. In the unmatched comparison, cardiovascular mortality was 8.75% with TEER versus 3.60% with surgery. After adjustment, however, the incidence of cardiovascular mortality with TEER was 7.96% compared with 11.44% with surgery, with the jump in cardiovascular mortality in the surgical arm reflective of a higher baseline risk to match the TEER patients. The subgroup analysis confirmed the benefit of TEER in those with a higher EuroSCORE II.

“Meaning the higher the risk gets, the efficacy of TEER in terms of mortality becomes more apparent,” said Kaneko.

With respect to the benefit seen in secondary MR patients, Kaneko said that the US guidelines give a stronger recommendation for TEER over surgery, the latter only a class IIb recommendation. “And this study supports that recommendation that TEER is preferable in that [secondary MR] population,” said Kaneko, adding that physicians typically only reserve surgery for those where TEER isn’t a good option.

For primary MR, where surgery is preferred over TEER, there are more trials coming. The REPAIR MR trial is comparing TEER with MitraClip to surgical valve repair in patients with severe MR at moderate risk for surgery while PRIMARY is a similar trial that will include patients at low risk for surgery. 

Deharo said use of TEER continues to increase annually, “but what’s interesting from our data is that the number of surgeries is not decreasing.” Deharo said there is a high demand for treating severe MR, with either surgery or TEER, but registry data have consistently shown that it’s often left untreated or treated at a late stage in the disease.