In this issue of CRM, Wu et al. retrospectively reviewed their single center echo lab experience with the incidence and treatment of severe primary mitral regurgitation (DMR) [ ]. Based on chart review they conclude that in contemporary clinical practice, less than half of patients with moderate-severe and severe primary MR received surgery and many were not referred for surgical consultation.

Their review sheds light on contemporary practice for the management of DMR and validates other studies that show a large number of patients with this valve lesion do not undergo either repair surgery or catheter intervention [ ]. This observation is consistent with prior reports and suggests that undertreatment in recent experience remains problematic [ ].

Many patients do not meet criteria for surgery, or their MR may improve with medical therapy. In this report, the group categorized as “medical therapy” is not well described. Were they candidates for surgery, did they meet ACC guidelines criteria for surgery, or were they just not offered surgery? This heterogenous subset plus patients lost to followup appear to be the biggest underserved groups. Structured follow up is the essential. Potentially treating a reading of severe MR on an echo reading as a “critical lab value” that requires an action or specific dismissal would also be helpful. The multidisciplinary “heart team” is a class I indication for the evaluation of patients for TAVR and should be considered for patients with severe MR.

From a universe of almost 2000 echo exams, severe MR was noted in about 20%, and DMR in about 9% of the total. The study population consists of patients referred for echocardiography. The selection bias inherent in referral for echo might lead to overestimation of the proportion of MR patients, since suspected valve disease drives these referrals. At the same time the proportion of patients who underwent treatment for DMR may be a fair representation.

Why do so many patients with a highly treatable valve lesion not find their way to therapy? The authors note that many were not referred for surgical consultation. The findings were based upon retrospective chart review so the basis for referral or non-referral could not be ascertained. There are clear reservations for referral of elderly patients for cardiac surgery, both among patients and many physicians, despite the potential for surgical repair, and in more recent practice for a variety of percutaneous repair and replacement options. This report spanned 2011–2016 and thus included only the early time frame after MitraClip approval for high risk patients with DMR in 2013. The use of MitraClip has increased rapidly since then and it would be useful to repeat this kind of analysis in more recent practice. Experience in some other institutions has been different. Goel et al. reported that only 16% of a large DMR cohort went without surgery, which may reflect referral bias or patient selection [ ]. The broader experience in US practice is also improving. Isolated primary mitral valve operations reported in the Society of Thoracic Surgeons Adult Cardiac Surgery Database have increased by 24% between 2011 and 2016 [ ].

A large proportion of DMR valves are replaced rather than repaired in US practice. This may contribute to the hesitancy some patients and physicians have about mitral valve surgery. In programs with high mitral surgery volumes repair rates exceed 90%, but in lower volume centers valve replacement, rather than repair, may be the end result of surgery in 20–50% of patients [ ]. Many factors contribute the less than ideal repair rates in DMR surgery. We also continue to train new operators to perform these complex procedures, despite the low volumes of mitral surgery performed by most operators in the United States [ ]. While it is important to expand the number of well-trained surgeons, as clearly there is a deficit in the numbers being offered therapy, it is also important that there is a focus in practice allowing surgeons to develop their practices and ideally improve on outcomes. Another step in the right direction may be public reporting, allowing patients to seek out high volume repair doctors knowing they will receive the correct operation for their pathology.

How can we better reach this large untreated patient group? The authors note the importance of better recognition of MR diagnosis and the guidelines for intervention. The unmet need for physician and patient education remain challenging. The volume of on-line material is overwhelming for patients and the deluge of guidelines is similarly difficult for practitioners, not only in cardiology but especially in primary care. Guidelines are slowly becoming more dynamic, with more and more accessibility using on-line tools. The importance of implementing guidelines for valve disease is growing as the population ages. Putting the algorithms for evaluation of valve disease at the fingertips of the practice community using an online or app guideline approach may ultimately improve the proportion of treated patients.

The growing availability of percutaneous mitral repair and replacement devices may also help to provide therapy alternatives to patients for whom surgery poses high risks for mortality and a protracted recovery. Just as in surgery, a poorly performed transcatheter procedure is likely to lead to a poor outcome. Therefore, there needs to be the same scrutiny applied to all procedures used in treating MR, and a multidisciplinary approach where both cardiology and cardiac surgery see complex patients together may be the best way for the patient to benefit from a shared decision toward treatment. As the population ages the number of elderly patients with symptomatic primary MR, often due to chordal rupture associated with fibroelastic deficiency, is growing. The rapid increase in use of MitraClip in this population is an indicator that having a less invasive alternative to surgery will help to decrease the number of patients who are not referred for treatment [ ].