Obstructive hypertrophic cardiomyopathy (oHCM) is a disease characterized by septal hypertrophy causing dynamic left ventricular outflow tract (LVOT) obstruction. In these patients, mitral regurgitation (MR) is related to systolic anterior motion (SAM) of the mitral valve (MV), which may improve after septal myectomy.

This study examines the surgical management of patients with oHCM and degenerative MR. In this setting, surgery is particularly challenging because MR may result both from SAM associated with LVOT obstruction and from intrinsic degenerative structural disease of the MV itself.

The aim of the study was to assess the feasibility and durability of MV repair combined with septal myectomy, highlighting the need to address both LVOT obstruction and valvular disease during the same operation while avoiding the complications associated with valve replacement.

This was a retrospective study performed at a specialized referral center, the Mayo Clinic. Outcomes were analyzed in patients with oHCM who underwent septal myectomy together with MV repair for degenerative disease. These patients were compared with a cohort of patients with isolated degenerative MR who underwent MV repair. The purpose was to determine whether MV repair associated with oHCM provides outcomes comparable to those achieved in patients with isolated degenerative MV disease and to provide evidence that may help guide the most appropriate surgical strategy in this group of patients.

For comparison, a control group was defined that included patients without oHCM who underwent MV repair for isolated degenerative MR. Two comparable groups of 120 patients each were obtained. Clinical, demographic, echocardiographic, and operative characteristics were analyzed, together with comorbidities, anatomic and functional cardiac features, valve repair techniques, and perioperative complications. Events of interest included survival, recurrence of significant MR, and the need for MV reoperation.

Clinical and echocardiographic follow-up was obtained from electronic records and echocardiographic studies performed during postoperative follow-up, with an approximate median follow-up of 7 years.

Median age was 64 years, and 36% were women. Patients with oHCM more frequently required leaflet plication or an Alfieri repair, whereas patients with isolated degenerative MR were more likely to undergo geometric leaflet resection and placement of artificial neochordae. Mitral annuloplasty was performed less often in patients with oHCM (60% vs 99%; p< .001). Operative mortality was low and similar in both groups, with 1 death in each cohort (.8%). Major postoperative complications occurred at comparable rates, although patients with oHCM required transfusion of blood products more frequently. During follow-up, long-term survival was similar between groups, with rates close to 80% in both cohorts. Recurrence of severe MR was also comparable, with 10-year incidences of 10.2% in the oHCM group and 6.5% in the isolated degenerative MR group. The need for MV reoperation was low in both groups, with 10-year rates of 5.5% in patients with oHCM and 2.7% in those with isolated degenerative MV disease, without statistically significant differences.

Accordingly, the authors conclude that MV repair performed concomitantly with septal myectomy in patients with oHCM and degenerative MV disease is a safe and durable strategy. Outcomes in terms of survival, recurrence of MR, and need for reoperation were comparable to those observed in patients undergoing MV repair for isolated degenerative disease. These findings suggest that when structural MV disease is present in patients with oHCM, valve repair should be attempted whenever feasible, thereby avoiding the complications associated with prosthetic valves while maintaining favorable long-term results.

COMMENTARY:

This study provides important evidence regarding the surgical management of patients with oHCM associated with degenerative MR. This is an uncommon but clinically complex association. In many cases, MV replacement has traditionally been viewed as the simplest solution because it addresses both the valvular lesion and the LVOT obstruction. However, this study evaluates an alternative strategy based on septal myectomy combined with MV repair, preserving the native valve and avoiding prosthesis-related complications.

This was a single-center retrospective observational study from the Mayo Clinic that included patients with oHCM undergoing septal myectomy who also had degenerative MR due to leaflet prolapse and underwent MV repair during the same operation.

One of the most relevant aspects of the study is that it compares the results of this strategy with those achieved in patients undergoing MV repair for isolated degenerative disease. After appropriate adjustment, this design allows a more balanced comparison between populations. In addition, the study includes prolonged follow-up, which strengthens the consistency of the findings and supports their clinical relevance.

In some cases, MV replacement has been used to solve both problems at once. Current guidelines, however, recommend valve repair whenever technically feasible because of its better long-term outcomes and lower incidence of complications related to prosthetic valves.

One of the key messages of the study is that MV repair in patients with oHCM and concomitant degenerative disease can achieve results comparable to those of MV repair in patients with isolated degenerative disease. This reinforces the concept that, whenever technically possible, repair should remain the preferred strategy over replacement, even in a more demanding anatomic setting such as oHCM.

Several limitations should be considered. First, this was a retrospective study from a single highly specialized center, which may limit the generalizability of the results to hospitals with lower surgical volume or less experience in oHCM surgery. There was also some limitation in the availability of long-term echocardiographic data, which may have influenced the assessment of MR recurrence.

Despite these limitations, the study is valuable because it provides one of the largest series evaluating the durability of MV repair in patients with oHCM. At the same time, it raises new questions that could be explored in future research. For example, it would be useful to determine which specific MV repair techniques provide the best outcomes, or whether these results can be reproduced in centers with lower surgical volume. Likewise, prospective multicenter studies could help confirm these findings and define more precisely the indications for repair versus replacement in patients with oHCM.

To answer the question posed in the title, MV repair should be considered whenever feasible in patients with concomitant oHCM, even in anatomically complex situations. Its results appear comparable to those of MV repair for isolated degenerative MR in terms of safety, durability, and survival. That said, the surgical expertise of both the operating team and the treating center remains a critical factor.

REFERENCE:

Qamar Y, Schaff HV, Geske JB, Dearani JA, Bagameri G, Todd A, Ommen SR. Durability of mitral valve repair for degenerative mitral valve disease in patients with obstructive hypertrophic cardiomyopathy. J Thorac Cardiovasc Surg. 2025;170(6):1621-1630. doi:10.1016/j.jtcvs.2025.03.032.