Sept. 23, 2025
Mayo Clinic cardiac surgery researchers found that for patients with obstructive hypertrophic cardiomyopathy (HCM) and degenerative mitral regurgitation (MR), repair performed with extended transaortic myectomy is both safe and durable. The findings were published in the Journal of Thoracic and Cardiovascular Surgery.
Long-term durability data for mitral valve (MV) repair performed concurrently with septal myectomy in patients with obstructive HCM and degenerative MR has been lacking. This study evaluated the safety and long-term outcomes of this repair-based approach and compared them with results of MV repair for isolated degenerative MR in patients without obstructive HCM.
"There has been some controversy as to how to approach the MV in patients with obstructive HCM undergoing myectomy," says Jeffrey B. Geske, M.D., a cardiologist who leads hypertrophic cardiomyopathy (HCM) research efforts at Mayo Clinic in Rochester, Minnesota, and a study author. "Understanding the durability of repair in this clinical scenario is important, as MV replacement carries significant downsides such as anticoagulation for mechanical prostheses and durability for bioprostheses. This data empowers us to pursue MV repair in the correct clinical scenarios."
Replacement risks
Hypertrophic cardiomyopathy is the most common genetic cardiomyopathy. In obstructive HCM, MR is most often secondary to systolic anterior motion (SAM) of the mitral valve apparatus and typically resolves following septal myectomy alone.
"A minority of patients, approximately 3% to 4%, presents with concomitant intrinsic degenerative MR due to pathology such as leaflet prolapse, leaflet flail or chordal rupture," says Gabor Bagameri, M.D., a cardiovascular surgeon at Mayo Clinic in Rochester, Minnesota, and one of the study's authors. "In these cases, some surgical programs advocate mitral valve replacement to address both the intrinsic valve disease and left ventricular outflow tract (LVOT) obstruction, which is restriction to the blood flow as it leaves the left ventricle. However, valve replacement in this setting introduces the potential for lifelong prosthesis-related risks, including anticoagulation requirements, thromboembolic events and structural valve deterioration."
Study highlights
The median age of patients was 63.7 years, and 35.6% were female. Among 3,853 septal myectomies performed during the study period, 120 patients (3.1%) were identified with concomitant degenerative MV disease. In this subgroup, the valve was successfully repaired in 93.8% of cases.
Operative mortality was 0.8%, identical to that observed in matched patients undergoing MV repair for isolated degenerative MR, and rates of major postoperative complications were comparable.
The median LVOT gradient decreased from 64 mm Hg preoperatively to approximately 0 mm Hg following myectomy, ensuring unobstructed ventricular ejection.
More than 90% of patients reported improved general health status. The gains in the New York Heart Association (NYHA) classification functional class paralleled those seen in the isolated degenerative MR cohort.
Opting to repair
There were no statistically significant differences in 10 years between the obstructive HCM and repair group and the isolated degenerative MR group in the incidence of severe MR recurrence, need for MV reoperation or overall survival.
"The data shows that MV repair for degenerative MR in patients with obstructive HCM undergoing myectomy at a high-volume referral center has similar durability to MV repair for degenerative MR in patients without HCM," says Dr. Geske. "MV replacement may not be needed in many cases."
Next steps
Prospective multicenter registries will be essential to validate these findings across diverse surgical settings and patient populations. "Refining selection criteria for annuloplasty versus no annuloplasty in patients with obstructive HCM could further optimize outcomes," says Dr. Bagameri. "Advanced preoperative imaging, such as 3D echocardiography and cardiac CT, may help anticipate postrepair LVOT geometry and guide surgical planning."
For more information
Qamar Y, et al. Durability of mitral valve repair for degenerative mitral valve disease in patients with obstructive hypertrophic cardiomyopathy. Journal of Thoracic and Cardiovascular Surgery. In press.
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