Treatment of Mitral Regurgitation: COAPT VS MITRA-FR Trials

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Treatment of Mitral Regurgitation: COAPT VS MITRA-FR Trials

A recent letter in the Journal of the American College of Cardiology (Tan, Pereira Nunes, 74 (14)) underscores the diagnostic challenges associated with functional mitral regurgitation and the importance of an integrated approach to interpretation of the COAPT and MITRA-FR trials when determining the course of treatment for patients with functional mitral valve regurgitation. 

Having an understanding of the results of these trials, to include their potential impact on existing guidelines is key to the successful integration of trial results into clinical practice.

CurrentMD™ Cardiology offers succinct and timely analysis of the strengths, shortcomings, and controversies around these data to inform your practice.

If you are a CurrentMD customer you can view the full lecture or if you are new to CurrentMD, take a look at the full transcript below.

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Full Transcript

Lesson: Treatment of Functional Mitral Regurgitation: COAPT vs MITRA FR Trials

Author: John Vavalle, MD

The Learning Objective:

In this next module, we're going to talk about the treatment of functional mitral valve regurgitation in the context of the COAPT and MITRA-FR trials. Specifically, we're going to talk about the differences in the results of these two trials.

By the end of this activity, you should be able to understand and summarize the results of the COAPT and MITRA-FR trials in the treatment of functional mitral valve regurgitation.

Preassessment Questions

Question number 1

Patients in COAPT were more likely to have severe mitral valve regurgitation and less dilated ventricles than in MITRA-FR.

Is that true or false?

Question number 2

All of the following reasons are found to explain the differences in the results between the COAPT and MITRA-FR trials except:

A) there was less residual mitral valve regurgitation in COAPT patients treatment with MitraClip as compared to MITRA-FR
B) there may have been better medical therapy optimization prior to enrollment in the COAPT trial thus identifying patients truly refractory to medical therapy in the COAPT trial
C) patients in the MITRA-FR trial may have been too sick to be helped by MitraClip
D) patients in the MITRA-FR trial had less severe MR at baseline and worse ventricular function
E) operators in the COAPT trial were less experienced and placed less clips per patient.

There's a lot of debate about the discrepancy in the results between COAPT and MITRA-FR. We have two well-done, randomized control trials in similar populations comparing MitraClip to medical therapy alone. In COAPT, there is an overwhelmingly positive result for the role of MitraClip in helping to reduce heart failure hospitalizations and mortality in these patients with severe functional mitral valve regurgitation. However, in the MITRA-FR trial, it was largely a neutral study. It showed that there was really no significant benefit to MitraClip over medical therapy alone. So, why such different results?

COAPT Vs. MITRA-FR: Possible Explanations

One possible explanation is that medical therapy may have differed between the two trials. There was aggressive up-titration of medications in the COAPT trial prior to randomization. Patients were excluded from the COAPT trial if their symptoms improved or if their MR severity improved with this up-titration of medications. As a result, this may have led to COAPT enrolling more patients who were truly refractory to medical therapy. There may have also been differences in the severity of mitral regurgitation at baseline. There appeared to be more MR and more severe MR in the COAPT trial based on the effective regurgitant orifice areas. At the same time, the left ventricular end-diastolic volume was smaller in COAPT. And so this resulted in a patient population with worse mitral valve regurgitation but less dilated ventricles as compared to MITRA-FR, and this may be the potential recipe for success given that MitraClip can only address the mitral valve regurgitation.

There are some other potential explanations. There appear to be better MR reduction with MitraClip in the COAPT trial than in the MITRA-FR trial. On average, there were more clips placed per patient in the COAPT trial. At one year, there seemed to be less residual mitral regurgitation in the COAPT trial than in the MITRA-FR trial and this may have been a result of the COAPT operators being higher volume mitral valve operators in general as compared to the MITRA-FR operators, also supporting the notion that higher volume translates into better outcomes. In addition, patients enrolled in MITRA-FR may have been too sick for really any intervention to help. This assertion really needs further investigation but the very large LV volumes do suggest that the ventricles in the MITRA-FR patients were "sicker" with more advanced disease and thus may have not had much benefit from therapy such as MitraClip.

Review Assessment Questions

Question number 1

Patients in the COAPT trial were more likely to have severe mitral valve regurgitation and less dilated ventricles than in MITRA-FR. True or false?

The correct answer is true. Patients in the COAPT trial were more likely to have severe mitral valve regurgitation at baseline and less dilated ventricles than in MITRA-FR. We think this may be the recipe for success for MitraClip. Patients who have worse mitral valve regurgitation but better ventricular function are those who are most likely to be helped by MitraClip, and this makes sense because MitraClip can really only help the mitral valve regurgitation, not the ventricular function. Patients with really dilated ventricles, bad left ventricular function, and not as severe mitral valve regurgitation are probably those who are less likely to be helped with MitraClip.

Question number 2

All of the following reasons are found to explain the differences in the results between the COAPT and MITRA-FR trials except:

A) there was less residual mitral valve regurgitation in COAPT patients treatment with MitraClip as compared to MITRA-FR
B) there may have been better medical therapy optimization prior to enrollment in the COAPT trial thus identifying patients truly refractory to medical therapy in the COAPT trial
C) patients in the MITRA-FR trial may have been too sick to be helped by MitraClip
D) patients in the MITRA-FR trial had less severe MR at baseline and worse ventricular function
E) operators in the COAPT trial were less experienced and placed less clips per patient.

The correct answer is E: All of the following were true except E, which stated operators in the COAPT trial were less experienced and placed less clips for patients. In the COAPT trial, patients were more likely to be optimized with medical therapy prior to enrollment. It's potentially better for identifying patients refractory to medical therapy. In addition, patients in COAPT had more severe MR baseline, less dilation of left ventricular, better and more reduction with the clips, more clips placed, and operators are generally more experienced. In addition, some patients enrolled in MITRA-FR may have had ventricles that were so dilated that they were probably too sick for any treatment to really help them. And we think it's this combination of reasons that partially explain the differences and the results between COAPT and MITRA-FR.

So, following this module, you should now be able to understand and summarize the results of the COAPT and MITRA-FR trials in treatment of functional mitral valve regurgitation.

Thank you for joining!