July 3, 2026Journal of the American College of Cardiology205 citations
View Full PaperMitral Regurgitation in Patients With Hypertrophic Obstructive Cardiomyopathy
Key Result
Among HOCM patients requiring concomitant mitral valve surgery, mitral valve repair was associated with superior 10-year survival compared with replacement (80.0% vs. 55.2%; p=0.002).
Key Points
- To explore indications and strategies for mitral regurgitation in patients undergoing septal myectomy for hypertrophic obstructive cardiomyopathy.
- Retrospective review of 2,107 septal myectomy operations between 1993 and 2014 at Mayo Clinic.
- Excluded patients with prior mitral valve surgery or apical hypertrophic cardiomyopathy.
- Evaluated pre-operative and post-operative mitral regurgitation grades.
- 57.5% of operations had pre-operative mitral regurgitation grade ≥3.
- Post-operative echocardiography showed reduction of MR grade ≥3 from 54.3% to 1.7% (p=0.001).
- Among 174 patients with concomitant surgery, MV repair led to 10-year survival rates of 80.0%, versus 55.2% for replacement (p=0.002).
Study Design
Type
Cohort (n=1,993)
Multicenter
No
PICO
P
Population
1,993 adults with hypertrophic obstructive cardiomyopathy undergoing septal myectomy, evaluated for mitral regurgitation resolution and long-term survival.
E
Exposure / Comparator
Mitral valve repair vs Mitral valve replacement
O
Primary Outcome
10-year survival, p=0.002
Main Result
Absolute Event Rate: 80% vs 55.2%
p-value: p=0.002
Abstract
BACKGROUND: Incidence and outcome of mitral valve (MV) surgery are unknown in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing extended transaortic septal myectomy. OBJECTIVES: This study sought to define indications and suitable operative strategy for mitral regurgitation (MR) in patients with HOCM. METHODS: A total of 2,107 septal myectomy operations performed in adults from January 1993 to May 2014 at Mayo Clinic in Rochester, Minnesota, were retrospectively reviewed. Patients with prior MV operation and apical hypertrophic cardiomyopathy were excluded. Overall, 2,004 operations were performed in 1,993 patients. RESULTS: Pre-operative MR was grade ≥3 (of 4) in 1,152 operations (57.5%). Systolic anterior motion of mitral leaflets caused the MR in most patients. However, intrinsic MV disease was identified pre-operatively in 99 patients, all of whom had MV surgery (with septal myectomy). In 1,905 operations, no intrinsic MV disease was identified pre-operatively; in 1,830 (96.1%), septal myectomy was performed without a direct MV procedure. For 75 patients, intrinsic MV disease discovered intraoperatively led to concomitant MV repair (86.7%) or replacement (13.3%). After isolated septal myectomy, the percentage of patients with MR grade ≥3 decreased from 54.3% to 1.7% (p = 0.001) on early post-operative echocardiography. Among 174 patients with concomitant MV surgery, late survival was superior with MV repair (n = 133 76.4%) versus replacement (10-year survival: 80.0% vs. 55.2%; p = 0.002). CONCLUSIONS: In most patients with HOCM, MR related to systolic anterior motion of the MV is relieved through adequate myectomy. Concomitant MV surgery is rarely necessary unless intrinsic MV disease is present. When MV procedures are required, repair is preferred because of improved survival compared with replacement.