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Hypertrophic Cardiomyopathy: Preadolescence, Mitral Valve Disease, and Midventricular Obstruction
Elaine M Griffeth1, Elizabeth H Stephens1, Joseph A Dearani1
1Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota.
Insights
Septal myectomy effectively treats obstructive hypertrophic cardiomyopathy (HCM) with low complication rates. This procedure improves survival and resolves obstruction, especially when the myectomy extends to the papillary muscles.
Area of Science:
- Cardiovascular Surgery
- Cardiology
- Genetics
Background:
- Obstructive hypertrophic cardiomyopathy (HCM) requires intervention for persistent symptoms or severe gradients.
- Septal myectomy is a key surgical option for managing obstructive HCM.
Purpose of the Study:
- To summarize operative techniques and outcomes for septal myectomy in various HCM patient categories.
- To highlight the importance of apical extent in myectomy for complete obstruction resolution.
Main Methods:
- Review of institutional experience with septal myectomy.
- Analysis of operative techniques including transaortic and transapical approaches.
- Evaluation of outcomes data for obstructive and atypical HCM patients.
Main Results:
- Septal myectomy at high-volume centers demonstrates low operative mortality (1%) and complication rates.
- Improved survival observed in myectomy patients compared to medically managed or nonobstructive HCM.
- Adequate apical myectomy extent is crucial for resolving obstruction and preventing recurrence.
Conclusions:
- Septal myectomy is a safe and effective treatment for obstructive HCM, offering improved survival.
- Transapical approach may be necessary for specific cases like preadolescents or midventricular obstruction.
- Mitral valve repair is indicated only for intrinsic valvular disease, not SAM-mediated MR.
Abstract:
Septal myectomy is indicated in patients with obstructive hypertrophic cardiomyopathy (HCM) who have persistent symptoms despite medical therapy, intolerance of medication side effects, or severe resting or provocable gradients. Septal myectomy at high volume centers is safe, with low operative mortality (1%) and low rates of complications such as complete heart block or ventricular septal defect (3% and 0.5%, respectively). Additionally, improved survival following myectomy has been observed when compared to patients with obstructive HCM managed medically or those with nonobstructive HCM. As a longstanding, quaternary referral center for septal myectomy, our institution has built significant experience and expertise in the surgical and medical management of HCM, including atypical HCM, defined as preadolescent patients, those with mitral valve disease, and those with isolated midventricular obstruction. The most important factor of septal myectomy in achieving complete resolution of obstruction and avoiding recurrence is the apical extent of the myectomy trough, which must extend to the septum opposite the papillary muscles. If this cannot be fully achieved via a transaortic exposure, especially in preadolescents and patients with midventricular obstruction, then a transapical approach may be needed. Mitral valve repair is rarely necessary as SAM-mediated MR resolves with adequate myectomy alone, but mitral repair is performed in cases of intrinsic valvular disease. In this manuscript we provide a summary of current operative techniques and outcomes data from our institution on the management of these various categories of HCM.
