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Hypertrophic obstructive cardiomyopathy: the Mayo Clinic experience
Kunal D Kotkar1, Sameh M Said1, Joseph A Dearani1
1Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA.
Insights
Septal myectomy effectively treats obstructive hypertrophic cardiomyopathy (HCM) by relieving left ventricular outflow tract obstruction. This procedure offers excellent results with low mortality, significantly improving symptoms and exercise capacity in patients.
Area of Science:
- Cardiology
- Cardiac Surgery
- Genetics
Background:
- Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease causing left ventricular hypertrophy.
- Symptoms range from asymptomatic to sudden cardiac death, with medical therapy as first-line treatment.
- Septal myectomy is the preferred surgical option for medically refractory or intolerant symptomatic patients.
Purpose of the Study:
- To evaluate the efficacy and safety of septal myectomy for obstructive hypertrophic cardiomyopathy.
- To assess long-term outcomes and complications of the procedure.
Main Methods:
- Retrospective analysis of over 3,000 patients undergoing septal myectomy for HCM at Mayo Clinic (1993-2016).
- Evaluation of transaortic and transapical approaches for basal, midventricular, and apical HCM variants.
- Assessment of symptom relief, functional class improvement, and reduction in left ventricular outflow tract gradients.
Main Results:
- Hospital mortality for isolated septal myectomy is <1%, comparable to elective mitral valve repair.
- Over 90% of severely symptomatic patients experience significant improvement in functional class.
- Complications like heart block are uncommon (2%); left bundle branch block is frequent post-surgery.
- Transapical approach in 115 patients with midventricular/apical HCM showed gradient relief without major complications.
Conclusions:
- Septal myectomy is an effective and definitive treatment for relieving left ventricular outflow tract obstruction and symptoms in obstructive HCM.
- In experienced centers, early mortality is <1%, with excellent and improving outcomes.
Background:
Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease characterized by left ventricular hypertrophy in the absence of other etiologies. Clinical presentation may vary from asymptomatic to sudden cardiac death. Medical treatment is the first-line therapy for symptomatic patients. Extended left ventricular septal myectomy is the procedure of choice if medical treatment is unsuccessful or intolerable.
Mayo Clinic Experience:
More than 3,000 patients have had septal myectomy for HCM at the Mayo Clinic (MN, USA) from 1993 to 2016. Risk of hospital death after isolated septal myectomy for obstructive HCM is <1% and is similar to the risk of operation for elective mitral valve repair. Complications, such as complete heart block requiring permanent pacemaker, are uncommon (2%), although partial or complete left bundle branch block is a frequent finding on the postoperative ECG. Relief of left ventricular outflow tract (LVOT) obstruction with septal myectomy dramatically improves symptoms and exercise capacity in symptomatic patients with obstructive HCM. More than 90% of severely symptomatic patients have improvement by at least two functional classes, and reduction of outflow gradients by myectomy decreases or eliminates symptoms of dyspnea, angina and/or syncope. Basal obstruction with systolic anterior motion (SAM) is treated by transaortic myectomy. The transapical approach was applied in 115 patients with obstructive midventricular and apical variants of HCM between 1993 and 2012. All patients with midventricular obstruction had gradient relief and none developed an apical aneurysm or ventricular septal defect. Recurrent obstruction after satisfactory myectomy was rare.
Conclusions:
Septal myectomy effectively and definitively relieves LVOT obstruction and cardiac symptoms in patients with obstructive HCM. In experienced centers, early mortality for isolated septal myectomy is less than 1%, and overall results are excellent and continue to improve in the current era.
